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CGI::Simple(3pm) User Contributed Perl Documentation CGI::Simple(3pm)
NAME
CGI::Simple - A Simple totally OO CGI interface that is CGI.pm compliant
VERSION
This document describes CGI::Simple version 1.280.
SYNOPSIS
use CGI::Simple;
$CGI::Simple::POST_MAX = 1024; # max upload via post default 100kB
$CGI::Simple::DISABLE_UPLOADS = 0; # enable uploads
$q = CGI::Simple->new;
$q = CGI::Simple->new( { 'foo'=>'1', 'bar'=>[2,3,4] } );
$q = CGI::Simple->new( 'foo=1&bar=2&bar=3&bar=4' );
$q = CGI::Simple->new( \*FILEHANDLE );
$q->save( \*FILEHANDLE ); # save current object to a file as used by new
@params = $q->param; # return all param names as a list
$value = $q->param('foo'); # return the first value supplied for 'foo'
@values = $q->param('foo'); # return all values supplied for foo
%fields = $q->Vars; # returns untied key value pair hash
$hash_ref = $q->Vars; # or as a hash ref
%fields = $q->Vars("|"); # packs multiple values with "|" rather than "\0";
@keywords = $q->keywords; # return all keywords as a list
$q->param( 'foo', 'some', 'new', 'values' ); # set new 'foo' values
$q->param( -name=>'foo', -value=>'bar' );
$q->param( -name=>'foo', -value=>['bar','baz'] );
$q->param( 'foo', 'some', 'new', 'values' ); # append values to 'foo'
$q->append( -name=>'foo', -value=>'bar' );
$q->append( -name=>'foo', -value=>['some', 'new', 'values'] );
$q->delete('foo'); # delete param 'foo' and all its values
$q->delete_all; # delete everything
<INPUT TYPE="file" NAME="upload_file" SIZE="42">
$files = $q->upload() # number of files uploaded
@files = $q->upload(); # names of all uploaded files
$filename = $q->param('upload_file') # filename of uploaded file
$mime = $q->upload_info($filename,'mime'); # MIME type of uploaded file
$size = $q->upload_info($filename,'size'); # size of uploaded file
my $fh = $q->upload($filename); # get filehandle to read from
while ( read( $fh, $buffer, 1024 ) ) { ... }
# short and sweet upload
$ok = $q->upload( $q->param('upload_file'), '/path/to/write/file.name' );
print "Uploaded ".$q->param('upload_file')." and wrote it OK!" if $ok;
$decoded = $q->url_decode($encoded);
$encoded = $q->url_encode($unencoded);
$escaped = $q->escapeHTML('<>"&');
$unescaped = $q->unescapeHTML('<>"&');
$qs = $q->query_string; # get all data in $q as a query string OK for GET
$q->no_cache(1); # set Pragma: no-cache + expires
print $q->header(); # print a simple header
# get a complex header
$header = $q->header( -type => 'image/gif'
-nph => 1,
-status => '402 Payment required',
-expires =>'+24h',
-cookie => $cookie,
-charset => 'utf-7',
-attachment => 'foo.gif',
-Cost => '$2.00'
);
# a p3p header (OK for redirect use as well)
$header = $q->header( -p3p => 'policyref="http://somesite.com/P3P/PolicyReferences.xml' );
@cookies = $q->cookie(); # get names of all available cookies
$value = $q->cookie('foo') # get first value of cookie 'foo'
@value = $q->cookie('foo') # get all values of cookie 'foo'
# get a cookie formatted for header() method
$cookie = $q->cookie( -name => 'Password',
-values => ['superuser','god','my dog woofie'],
-expires => '+3d',
-domain => '.nowhere.com',
-path => '/cgi-bin/database',
-secure => 1
);
print $q->header( -cookie=>$cookie ); # set cookie
print $q->redirect('http://go.away.now'); # print a redirect header
dienice( $q->cgi_error ) if $q->cgi_error;
DESCRIPTION
CGI::Simple provides a relatively lightweight drop in replacement for CGI.pm. It shares
an identical OO interface to CGI.pm for parameter parsing, file upload, cookie handling
and header generation. This module is entirely object oriented, however a complete
functional interface is available by using the CGI::Simple::Standard module.
Essentially everything in CGI.pm that relates to the CGI (not HTML) side of things is
available. There are even a few new methods and additions to old ones! If you are
interested in what has gone on under the hood see the Compatibility with CGI.pm section at
the end.
In practical testing this module loads and runs about twice as fast as CGI.pm depending on
the precise task.
CALLING CGI::Simple ROUTINES USING THE OBJECT INTERFACE
Here is a very brief rundown on how you use the interface. Full details follow.
First you need to initialize an object
Before you can call a CGI::Simple method you must create a CGI::Simple object. You do
that by using the module and then calling the new() constructor:
use CGI::Simple;
my $q = CGI::Simple->new;
It is traditional to call your object $q for query or perhaps $cgi.
Next you call methods on that object
Once you have your object you can call methods on it using the -> arrow syntax For example
to get the names of all the parameters passed to your script you would just write:
@names = $q->param();
Many methods are sensitive to the context in which you call them. In the example above the
param() method returns a list of all the parameter names when called without any
arguments.
When you call param('arg') with a single argument it assumes you want to get the value(s)
associated with that argument (parameter). If you ask for an array it gives you an array
of all the values associated with it's argument:
@values = $q->param('foo'); # get all the values for 'foo'
whereas if you ask for a scalar like this:
$value = $q->param('foo'); # get only the first value for 'foo'
then it returns only the first value (if more than one value for 'foo' exists).
In case you ased for a list it will return all the values preserving the order in which
the values of the given key were passed in the request.
Most CGI::Simple routines accept several arguments, sometimes as many as 10 optional ones!
To simplify this interface, all routines use a named argument calling style that looks
like this:
print $q->header( -type=>'image/gif', -expires=>'+3d' );
Each argument name is preceded by a dash. Neither case nor order matters in the argument
list. -type, -Type, and -TYPE are all acceptable.
Several routines are commonly called with just one argument. In the case of these
routines you can provide the single argument without an argument name. header() happens
to be one of these routines. In this case, the single argument is the document type.
print $q->header('text/html');
Sometimes methods expect a scalar, sometimes a reference to an array, and sometimes a
reference to a hash. Often, you can pass any type of argument and the routine will do
whatever is most appropriate. For example, the param() method can be used to set a CGI
parameter to a single or a multi-valued value. The two cases are shown below:
$q->param(-name=>'veggie',-value=>'tomato');
$q->param(-name=>'veggie',-value=>['tomato','tomahto','potato','potahto']);
CALLING CGI::Simple ROUTINES USING THE FUNCTION INTERFACE
For convenience a functional interface is provided by the CGI::Simple::Standard module.
This hides the OO details from you and allows you to simply call methods. You may either
use AUTOLOADING of methods or import specific method sets into you namespace. Here are the
first few examples again using the function interface.
use CGI::Simple::Standard qw(-autoload);
@names = param();
@values = param('foo');
$value = param('foo');
print header(-type=>'image/gif',-expires=>'+3d');
print header('text/html');
Yes that's it. Not a $q-> in sight. You just use the module and select how/which methods
to load. You then just call the methods you want exactly as before but without the $q->
notation.
When (if) you read the following docs and are using the functional interface just pretend
the $q-> is not there.
Selecting which methods to load
When you use the functional interface Perl needs to be able to find the functions you
call. The simplest way of doing this is to use autoloading as shown above. When you use
CGI::Simple::Standard with the '-autoload' pragma it exports a single AUTOLOAD sub into
you namespace. Every time you call a non existent function AUTOLOAD is called and will
load the required function and install it in your namespace. Thus only the AUTOLOAD sub
and those functions you specifically call will be imported.
Alternatively CGI::Simple::Standard provides a range of function sets you can import or
you can just select exactly what you want. You do this using the familiar
use CGI::Simple::Standard qw( :func_set some_func);
notation. This will import the ':func_set' function set and the specific function
'some_func'.
To Autoload or not to Autoload, that is the question.
If you do not have a AUTOLOAD sub in you script it is generally best to use the
'-autoload' option. Under autoload you can use any method you want but only import and
compile those functions you actually use.
If you do not use autoload you must specify what functions to import. You can only use
functions that you have imported. For comvenience functions are grouped into related sets.
If you choose to import one or more ':func_set' you may have potential namespace
collisions so check out the docs to see what gets imported. Using the ':all' tag is pretty
slack but it is there if you want. Full details of the function sets are provided in the
CGI::Simple::Standard docs
If you just want say the param and header methods just load these two.
use CGI::Simple::Standard qw(param header);
Setting globals using the functional interface
Where you see global variables being set using the syntax:
$CGI::Simple::DEBUG = 1;
You use exactly the same syntax when using CGI::Simple::Standard.
THE CORE METHODS
new() Creating a new query object
The first step in using CGI::Simple is to create a new query object using the new()
constructor:
$q = CGI::Simple->new;
This will parse the input (from both POST and GET methods) and store it into an object
called $q.
If you provide a file handle to the new() method, it will read parameters from the file
(or STDIN, or whatever).
Historically people were doing this way:
open FH, "test.in" or die $!;
$q = CGI::Simple->new(\*FH);
but this is the recommended way:
open $fh, '<', "test.in" or die $!;
$q = CGI::Simple->new($fh);
The file should be a series of newline delimited TAG=VALUE pairs. Conveniently, this type
of file is created by the save() method (see below). Multiple records can be saved and
restored. IO::File objects work fine.
If you are using the function-oriented interface provided by CGI::Simple::Standard and
want to initialize from a file handle, the way to do this is with restore_parameters().
This will (re)initialize the default CGI::Simple object from the indicated file handle.
restore_parameters($fh);
In fact for all intents and purposes restore_parameters() is identical to new() Note that
restore_parameters() does not exist in CGI::Simple itself so you can't use it.
You can also initialize the query object from an associative array reference:
$q = CGI::Simple->new( { 'dinosaur' => 'barney',
'song' => 'I love you',
'friends' => [qw/Jessica George Nancy/] }
);
or from a properly formatted, URL-escaped query string:
$q = CGI::Simple->new( 'dinosaur=barney&color=purple' );
or from a previously existing CGI::Simple object (this generates an identical clone
including all global variable settings, etc that are stored in the object):
$old_query = CGI::Simple->new;
$new_query = CGI::Simple->new($old_query);
To create an empty query, initialize it from an empty string or hash:
$empty_query = CGI::Simple->new("");
-or-
$empty_query = CGI::Simple->new({});
keywords() Fetching a list of keywords from a query
@keywords = $q->keywords;
If the script was invoked as the result of an <ISINDEX> search, the parsed keywords can be
obtained as an array using the keywords() method.
param() Fetching the names of all parameters passed to your script
@names = $q->param;
If the script was invoked with a parameter list (e.g.
"name1=value1&name2=value2&name3=value3"), the param() method will return the parameter
names as a list. If the script was invoked as an <ISINDEX> script and contains a string
without ampersands (e.g. "value1+value2+value3") , there will be a single parameter named
"keywords" containing the "+"-delimited keywords.
NOTE: The array of parameter names returned will be in the same order as they were
submitted by the browser. Usually this order is the same as the order in which the
parameters are defined in the form (however, this isn't part of the spec, and so isn't
guaranteed).
param() Fetching the value or values of a simple named parameter
@values = $q->param('foo');
-or-
$value = $q->param('foo');
Pass the param() method a single argument to fetch the value of the named parameter. If
the parameter is multi-valued (e.g. from multiple selections in a scrolling list), you can
ask to receive an array. Otherwise the method will return a single value.
If a value is not given in the query string, as in the queries "name1=&name2=" or
"name1&name2", it will be returned by default as an empty string. If you set the global
variable:
$CGI::Simple::NO_UNDEF_PARAMS = 1;
Then value-less parameters will be ignored, and will not exist in the query object. If you
try to access them via param you will get an undef return value.
param() Setting the values of a named parameter
$q->param('foo','an','array','of','values');
This sets the value for the named parameter 'foo' to an array of values. This is one way
to change the value of a field.
param() also recognizes a named parameter style of calling described in more detail later:
$q->param(-name=>'foo',-values=>['an','array','of','values']);
-or-
$q->param(-name=>'foo',-value=>'the value');
param() Retrieving non-application/x-www-form-urlencoded data
If POSTed or PUTed data is not of type application/x-www-form-urlencoded or
multipart/form-data, then the data will not be processed, but instead be returned as-is in
a parameter named POSTDATA or PUTDATA. To retrieve it, use code like this:
my $data = $q->param( 'POSTDATA' );
-or-
my $data = $q->param( 'PUTDATA' );
(If you don't know what the preceding means, don't worry about it. It only affects people
trying to use CGI::Simple for REST webservices)
add_param() Setting the values of a named parameter
You nay also use the new method add_param to add parameters. This is an alias to the
_add_param() internal method that actually does all the work. You can call it like this:
$q->add_param('foo', 'new');
$q->add_param('foo', [1,2,3,4,5]);
$q->add_param( 'foo', 'bar', 'overwrite' );
The first argument is the parameter, the second the value or an array ref of values and
the optional third argument sets overwrite mode. If the third argument is absent of false
the values will be appended. If true the values will overwrite any existing ones
append() Appending values to a named parameter
$q->append(-name=>'foo',-values=>['yet','more','values']);
This adds a value or list of values to the named parameter. The values are appended to
the end of the parameter if it already exists. Otherwise the parameter is created. Note
that this method only recognizes the named argument calling syntax.
import_names() Importing all parameters into a namespace.
This method was silly, non OO and has been deleted. You can get all the params as a hash
using Vars or via all the other accessors.
delete() Deleting a parameter completely
$q->delete('foo');
This completely clears a parameter. If you are using the function call interface, use
Delete() instead to avoid conflicts with Perl's built-in delete operator.
If you are using the function call interface, use Delete() instead to avoid conflicts with
Perl's built-in delete operator.
delete_all() Deleting all parameters
$q->delete_all();
This clears the CGI::Simple object completely. For CGI.pm compatibility Delete_all() is
provided however there is no reason to use this in the function call interface other than
symmetry.
For CGI.pm compatibility Delete_all() is provided as an alias for delete_all however there
is no reason to use this, even in the function call interface.
param_fetch() Direct access to the parameter list
This method is provided for CGI.pm compatibility only. It returns an array ref to the
values associated with a named param. It is deprecated.
Vars() Fetching the entire parameter list as a hash
$params = $q->Vars; # as a tied hash ref
print $params->{'address'};
@foo = split "\0", $params->{'foo'};
%params = $q->Vars; # as a plain hash
print $params{'address'};
@foo = split "\0", $params{'foo'};
%params = $q->Vars(','); # specifying a different separator than "\0"
@foo = split ',', $params{'foo'};
Many people want to fetch the entire parameter list as a hash in which the keys are the
names of the CGI parameters, and the values are the parameters' values. The Vars() method
does this.
Called in a scalar context, it returns the parameter list as a tied hash reference.
Because this hash ref is tied changing a key/value changes the underlying CGI::Simple
object.
Called in a list context, it returns the parameter list as an ordinary hash. Changing
this hash will not change the underlying CGI::Simple object
When using Vars(), the thing you must watch out for are multi-valued CGI parameters.
Because a hash cannot distinguish between scalar and list context, multi-valued parameters
will be returned as a packed string, separated by the "\0" (null) character. You must
split this packed string in order to get at the individual values. This is the convention
introduced long ago by Steve Brenner in his cgi-lib.pl module for Perl version 4.
You can change the character used to do the multiple value packing by passing it to Vars()
as an argument as shown.
url_param() Access the QUERY_STRING regardless of 'GET' or 'POST'
The url_param() method makes the QUERY_STRING data available regardless of whether the
REQUEST_METHOD was 'GET' or 'POST'. You can do anything with url_param that you can do
with param(), however the data set is completely independent.
Technically what happens if you use this method is that the QUERY_STRING data is parsed
into a new CGI::Simple object which is stored within the current object. url_param then
just calls param() on this new object.
parse_query_string() Add QUERY_STRING data to 'POST' requests
When the REQUEST_METHOD is 'POST' the default behavior is to ignore name/value pairs or
keywords in the $ENV{'QUERY_STRING'}. You can override this by calling
parse_query_string() which will add the QUERY_STRING data to the data already in our
CGI::Simple object if the REQUEST_METHOD was 'POST'
$q = CGI::Simple->new;
$q->parse_query_string; # add $ENV{'QUERY_STRING'} data to our $q object
If the REQUEST_METHOD was 'GET' then the QUERY_STRING will already be stored in our object
so parse_query_string will be ignored.
This is a new method in CGI::Simple that is not available in CGI.pm
save() Saving the state of an object to file
$q->save(\*FILEHANDLE)
This will write the current state of the form to the provided filehandle. You can read it
back in by providing a filehandle to the new() method.
The format of the saved file is:
NAME1=VALUE1
NAME1=VALUE1'
NAME2=VALUE2
NAME3=VALUE3
=
Both name and value are URL escaped. Multi-valued CGI parameters are represented as
repeated names. A session record is delimited by a single = symbol. You can write out
multiple records and read them back in with several calls to new().
open my $fh, '<', "test.in" or die $!;
$q1 = CGI::Simple->new($fh); # get the first record
$q2 = CGI::Simple->new($fh); # get the next record
Note: If you wish to use this method from the function-oriented (non-OO) interface, the
exported name for this method is save_parameters(). Also if you want to initialize from a
file handle, the way to do this is with restore_parameters(). This will (re)initialize
the default CGI::Simple object from the indicated file handle.
restore_parameters($fh);
FILE UPLOADS
File uploads are easy with CGI::Simple. You use the upload() method. Assuming you have
the following in your HTML:
<FORM
METHOD="POST"
ACTION="http://somewhere.com/cgi-bin/script.cgi"
ENCTYPE="multipart/form-data">
<INPUT TYPE="file" NAME="upload_file1" SIZE="42">
<INPUT TYPE="file" NAME="upload_file2" SIZE="42">
</FORM>
Note that the ENCTYPE is "multipart/form-data". You must specify this or the browser will
default to "application/x-www-form-urlencoded" which will result in no files being
uploaded although on the surface things will appear OK.
When the user submits this form any supplied files will be spooled onto disk and saved in
temporary files. These files will be deleted when your script.cgi exits so if you want to
keep them you will need to proceed as follows.
upload() The key file upload method
The upload() method is quite versatile. If you call upload() without any arguments it will
return a list of uploaded files in list context and the number of uploaded files in scalar
context.
$number_of_files = $q->upload;
@list_of_files = $q->upload;
Having established that you have uploaded files available you can get the browser supplied
filename using param() like this:
$filename1 = $q->param('upload_file1');
You can then get a filehandle to read from by calling upload() and supplying this filename
as an argument. Warning: do not modify the value you get from param() in any way - you
don't need to untaint it.
$fh = $q->upload( $filename1 );
Now to save the file you would just do something like:
$save_path = '/path/to/write/file.name';
open my $out, '>', $save_path or die "Oops $!\n";
binmode $out;
print $out $buffer while read( $fh, $buffer, 4096 );
close $out;
By utilizing a new feature of the upload method this process can be simplified to:
$ok = $q->upload( $q->param('upload_file1'), '/path/to/write/file.name' );
if ($ok) {
print "Uploaded and wrote file OK!";
} else {
print $q->cgi_error();
}
As you can see upload will accept an optional second argument and will write the file to
this file path. It will return 1 for success and undef if it fails. If it fails you can
get the error from cgi_error
You can also use just the fieldname as an argument to upload ie:
$fh = $q->upload( 'upload_field_name' );
or
$ok = $q->upload( 'upload_field_name', '/path/to/write/file.name' );
BUT there is a catch. If you have multiple upload fields, all called 'upload_field_name'
then you will only get the last uploaded file from these fields.
upload_info() Get the details about uploaded files
The upload_info() method is a new method. Called without arguments it returns the number
of uploaded files in scalar context and the names of those files in list context.
$number_of_upload_files = $q->upload_info();
@filenames_of_all_uploads = $q->upload_info();
You can get the MIME type of an uploaded file like this:
$mime = $q->upload_info( $filename1, 'mime' );
If you want to know how big a file is before you copy it you can get that information from
uploadInfo which will return the file size in bytes.
$file_size = $q->upload_info( $filename1, 'size' );
The size attribute is optional as this is the default value returned.
Note: The old CGI.pm uploadInfo() method has been deleted.
$POST_MAX and $DISABLE_UPLOADS
CGI.pm has a default setting that allows infinite size file uploads by default. In
contrast file uploads are disabled by default in CGI::Simple to discourage Denial of
Service attacks. You must enable them before you expect file uploads to work.
When file uploads are disabled the file name and file size details will still be available
from param() and upload_info respectively but the upload filehandle returned by upload()
will be undefined - not surprising as the underlying temp file will not exist either.
You can enable uploads using the '-upload' pragma. You do this by specifying this in you
use statement:
use CGI::Simple qw(-upload);
Alternatively you can enable uploads via the $DISABLE_UPLOADS global like this:
use CGI::Simple;
$CGI::Simple::DISABLE_UPLOADS = 0;
$q = CGI::Simple->new;
If you wish to set $DISABLE_UPLOADS you must do this *after* the use statement and
*before* the new constructor call as shown above.
The maximum acceptable data via post is capped at 102_400kB rather than infinity which is
the CGI.pm default. This should be ample for most tasks but you can set this to whatever
you want using the $POST_MAX global.
use CGI::Simple;
$CGI::Simple::DISABLE_UPLOADS = 0; # enable uploads
$CGI::Simple::POST_MAX = 1_048_576; # allow 1MB uploads
$q = CGI::Simple->new;
If you set to -1 infinite size uploads will be permitted, which is the CGI.pm default.
$CGI::Simple::POST_MAX = -1; # infinite size upload
Alternatively you can specify all the CGI.pm default values which allow file uploads of
infinite size in one easy step by specifying the '-default' pragma in your use statement.
use CGI::Simple qw( -default ..... );
binmode() and Win32
If you are using CGI::Simple be sure to call binmode() on any handle that you create to
write the uploaded file to disk. Calling binmode() will do no harm on other systems
anyway.
MISCELANEOUS METHODS
escapeHTML() Escaping HTML special characters
In HTML the < > " and & chars have special meaning and need to be escaped to < >
" and & respectively.
$escaped = $q->escapeHTML( $string );
$escaped = $q->escapeHTML( $string, 'new_lines_too' );
If the optional second argument is supplied then newlines will be escaped to.
unescapeHTML() Unescape HTML special characters
This performs the reverse of escapeHTML().
$unescaped = $q->unescapeHTML( $HTML_escaped_string );
url_decode() Decode a URL encoded string
This method will correctly decode a url encoded string.
$decoded = $q->url_decode( $encoded );
url_encode() URL encode a string
This method will correctly URL encode a string.
$encoded = $q->url_encode( $string );
parse_keywordlist() Parse a supplied keyword list
@keywords = $q->parse_keywordlist( $keyword_list );
This method returns a list of keywords, correctly URL escaped and split out of the
supplied string
put() Send output to browser
CGI.pm alias for print. $q->put('Hello World!') will print the usual
print() Send output to browser
CGI.pm alias for print. $q->print('Hello World!') will print the usual
HTTP COOKIES
CGI.pm has several methods that support cookies.
A cookie is a name=value pair much like the named parameters in a CGI query string. CGI
scripts create one or more cookies and send them to the browser in the HTTP header. The
browser maintains a list of cookies that belong to a particular Web server, and returns
them to the CGI script during subsequent interactions.
In addition to the required name=value pair, each cookie has several optional attributes:
1. an expiration time
This is a time/date string (in a special GMT format) that indicates when a cookie
expires. The cookie will be saved and returned to your script until this expiration
date is reached if the user exits the browser and restarts it. If an expiration date
isn't specified, the cookie will remain active until the user quits the browser.
2. a domain
This is a partial or complete domain name for which the cookie is valid. The browser
will return the cookie to any host that matches the partial domain name. For example,
if you specify a domain name of ".capricorn.com", then the browser will return the
cookie to Web servers running on any of the machines "www.capricorn.com",
"www2.capricorn.com", "feckless.capricorn.com", etc. Domain names must contain at
least two periods to prevent attempts to match on top level domains like ".edu". If
no domain is specified, then the browser will only return the cookie to servers on the
host the cookie originated from.
3. a path
If you provide a cookie path attribute, the browser will check it against your
script's URL before returning the cookie. For example, if you specify the path
"/cgi-bin", then the cookie will be returned to each of the scripts
"/cgi-bin/tally.pl", "/cgi-bin/order.pl", and "/cgi-bin/customer_service/complain.pl",
but not to the script "/cgi-private/site_admin.pl". By default, path is set to "/",
which causes the cookie to be sent to any CGI script on your site.
4. a "secure" flag
If the "secure" attribute is set, the cookie will only be sent to your script if the
CGI request is occurring on a secure channel, such as SSL.
cookie() A simple access method to cookies
The interface to HTTP cookies is the cookie() method:
$cookie = $q->cookie( -name => 'sessionID',
-value => 'xyzzy',
-expires => '+1h',
-path => '/cgi-bin/database',
-domain => '.capricorn.org',
-secure => 1
);
print $q->header(-cookie=>$cookie);
cookie() creates a new cookie. Its parameters include:
-name
The name of the cookie (required). This can be any string at all. Although browsers
limit their cookie names to non-whitespace alphanumeric characters, CGI.pm removes
this restriction by escaping and unescaping cookies behind the scenes.
-value
The value of the cookie. This can be any scalar value, array reference, or even
associative array reference. For example, you can store an entire associative array
into a cookie this way:
$cookie=$q->cookie( -name => 'family information',
-value => \%childrens_ages );
-path
The optional partial path for which this cookie will be valid, as described above.
-domain
The optional partial domain for which this cookie will be valid, as described above.
-expires
The optional expiration date for this cookie. The format is as described in the
section on the header() method:
"+1h" one hour from now
-secure
If set to true, this cookie will only be used within a secure SSL session.
The cookie created by cookie() must be incorporated into the HTTP header within the string
returned by the header() method:
print $q->header(-cookie=>$my_cookie);
To create multiple cookies, give header() an array reference:
$cookie1 = $q->cookie( -name => 'riddle_name',
-value => "The Sphynx's Question"
);
$cookie2 = $q->cookie( -name => 'answers',
-value => \%answers
);
print $q->header( -cookie => [ $cookie1, $cookie2 ] );
To retrieve a cookie, request it by name by calling cookie() method without the -value
parameter:
use CGI::Simple;
$q = CGI::Simple->new;
$riddle = $q->cookie('riddle_name');
%answers = $q->cookie('answers');
Cookies created with a single scalar value, such as the "riddle_name" cookie, will be
returned in that form. Cookies with array and hash values can also be retrieved.
The cookie and CGI::Simple namespaces are separate. If you have a parameter named
'answers' and a cookie named 'answers', the values retrieved by param() and cookie() are
independent of each other. However, it's simple to turn a CGI parameter into a cookie,
and vice-versa:
# turn a CGI parameter into a cookie
$c = $q->cookie( -name=>'answers', -value=>[$q->param('answers')] );
# vice-versa
$q->param( -name=>'answers', -value=>[$q->cookie('answers')] );
raw_cookie()
Returns the HTTP_COOKIE variable. Cookies have a special format, and this method call just
returns the raw form (?cookie dough). See cookie() for ways of setting and retrieving
cooked cookies.
Called with no parameters, raw_cookie() returns the packed cookie structure. You can
separate it into individual cookies by splitting on the character sequence "; ". Called
with the name of a cookie, retrieves the unescaped form of the cookie. You can use the
regular cookie() method to get the names, or use the raw_fetch() method from the
CGI::Simmple::Cookie module.
CREATING HTTP HEADERS
Normally the first thing you will do in any CGI script is print out an HTTP header. This
tells the browser what type of document to expect, and gives other optional information,
such as the language, expiration date, and whether to cache the document. The header can
also be manipulated for special purposes, such as server push and pay per view pages.
header() Create simple or complex HTTP headers
print $q->header;
-or-
print $q->header('image/gif');
-or-
print $q->header('text/html','204 No response');
-or-
print $q->header( -type => 'image/gif',
-nph => 1,
-status => '402 Payment required',
-expires => '+3d',
-cookie => $cookie,
-charset => 'utf-7',
-attachment => 'foo.gif',
-Cost => '$2.00'
);
header() returns the Content-type: header. You can provide your own MIME type if you
choose, otherwise it defaults to text/html. An optional second parameter specifies the
status code and a human-readable message. For example, you can specify 204, "No response"
to create a script that tells the browser to do nothing at all.
The last example shows the named argument style for passing arguments to the CGI methods
using named parameters. Recognized parameters are -type, -status, -cookie, -target,
-expires, -nph, -charset and -attachment. Any other named parameters will be stripped of
their initial hyphens and turned into header fields, allowing you to specify any HTTP
header you desire.
For example, you can produce non-standard HTTP header fields by providing them as named
arguments:
print $q->header( -type => 'text/html',
-nph => 1,
-cost => 'Three smackers',
-annoyance_level => 'high',
-complaints_to => 'bit bucket'
);
This will produce the following non-standard HTTP header:
HTTP/1.0 200 OK
Cost: Three smackers
Annoyance-level: high
Complaints-to: bit bucket
Content-type: text/html
Note that underscores are translated automatically into hyphens. This feature allows you
to keep up with the rapidly changing HTTP "standards".
The -type is a key element that tell the browser how to display your document. The default
is 'text/html'. Common types are:
text/html
text/plain
image/gif
image/jpg
image/png
application/octet-stream
The -status code is the HTTP response code. The default is 200 OK. Common status codes
are:
200 OK
204 No Response
301 Moved Permanently
302 Found
303 See Other
307 Temporary Redirect
400 Bad Request
401 Unauthorized
403 Forbidden
404 Not Found
405 Not Allowed
408 Request Timed Out
500 Internal Server Error
503 Service Unavailable
504 Gateway Timed Out
The -expires parameter lets you indicate to a browser and proxy server how long to cache
pages for. When you specify an absolute or relative expiration interval with this
parameter, some browsers and proxy servers will cache the script's output until the
indicated expiration date. The following forms are all valid for the -expires field:
+30s 30 seconds from now
+10m ten minutes from now
+1h one hour from now
-1d yesterday (i.e. "ASAP!")
now immediately
+3M in three months
+10y in ten years time
Thursday, 25-Apr-1999 00:40:33 GMT at the indicated time & date
The -cookie parameter generates a header that tells the browser to provide a "magic
cookie" during all subsequent transactions with your script. Netscape cookies have a
special format that includes interesting attributes such as expiration time. Use the
cookie() method to create and retrieve session cookies.
The -target is for frames use
The -nph parameter, if set to a true value, will issue the correct headers to work with a
NPH (no-parse-header) script. This is important to use with certain servers that expect
all their scripts to be NPH.
The -charset parameter can be used to control the character set sent to the browser. If
not provided, defaults to ISO-8859-1. As a side effect, this sets the charset() method as
well.
The -attachment parameter can be used to turn the page into an attachment. Instead of
displaying the page, some browsers will prompt the user to save it to disk. The value of
the argument is the suggested name for the saved file. In order for this to work, you may
have to set the -type to 'application/octet-stream'.
no_cache() Preventing browser caching of scripts
Most browsers will not cache the output from CGI scripts. Every time the browser reloads
the page, the script is invoked anew. However some browsers do cache pages. You can
discourage this behavior using the no_cache() function.
$q->no_cache(1); # turn caching off by sending appropriate headers
$q->no_cache(1); # do not send cache related headers.
$q->no_cache(1);
print header (-type=>'image/gif', -nph=>1);
This will produce a header like the following:
HTTP/1.0 200 OK
Server: Apache - accept no substitutes
Expires: Thu, 15 Nov 2001 03:37:50 GMT
Date: Thu, 15 Nov 2001 03:37:50 GMT
Pragma: no-cache
Content-Type: image/gif
Both the Pragma: no-cache header field and an Expires header that corresponds to the
current time (ie now) will be sent.
cache() Preventing browser caching of scripts
The somewhat ill named cache() method is a legacy from CGI.pm. It operates the same as the
new no_cache() method. The difference is/was that when set it results only in the Pragma:
no-cache line being printed. Expires time data is not sent.
redirect() Generating a redirection header
print $q->redirect('http://somewhere.else/in/movie/land');
Sometimes you don't want to produce a document yourself, but simply redirect the browser
elsewhere, perhaps choosing a URL based on the time of day or the identity of the user.
The redirect() function redirects the browser to a different URL. If you use redirection
like this, you should not print out a header as well.
One hint I can offer is that relative links may not work correctly when you generate a
redirection to another document on your site. This is due to a well-intentioned
optimization that some servers use. The solution to this is to use the full URL
(including the http: part) of the document you are redirecting to.
You can also use named arguments:
print $q->redirect( -uri=>'http://somewhere.else/in/movie/land',
-nph=>1
);
The -nph parameter, if set to a true value, will issue the correct headers to work with a
NPH (no-parse-header) script. This is important to use with certain servers, such as
Microsoft ones, which expect all their scripts to be NPH.
PRAGMAS
There are a number of pragmas that you can specify in your use CGI::Simple statement.
Pragmas, which are always preceded by a hyphen, change the way that CGI::Simple functions
in various ways. You can generally achieve exactly the same results by setting the
underlying $GLOBAL_VARIABLES.
For example the '-upload' pargma will enable file uploads:
use CGI::Simple qw(-upload);
In CGI::Simple::Standard Pragmas, function sets , and individual functions can all be
imported in the same use() line. For example, the following use statement imports the
standard set of functions and enables debugging mode (pragma -debug):
use CGI::Simple::Standard qw(:standard -debug);
The current list of pragmas is as follows:
-no_undef_params
If a value is not given in the query string, as in the queries "name1=&name2=" or
"name1&name2", by default it will be returned as an empty string.
If you specify the '-no_undef_params' pragma then CGI::Simple ignores parameters with
no values and they will not appear in the query object.
-nph
This makes CGI.pm produce a header appropriate for an NPH (no parsed header) script.
You may need to do other things as well to tell the server that the script is NPH.
See the discussion of NPH scripts below.
-newstyle_urls
Separate the name=value pairs in CGI parameter query strings with semicolons rather
than ampersands. For example:
?name=fred;age=24;favorite_color=3
Semicolon-delimited query strings are always accepted, but will not be emitted by
self_url() and query_string() unless the -newstyle_urls pragma is specified.
-oldstyle_urls
Separate the name=value pairs in CGI parameter query strings with ampersands rather
than semicolons. This is the default.
?name=fred&age=24&favorite_color=3
-autoload
This is only available for CGI::Simple::Standard and uses AUTOLOAD to load functions
on demand. See the CGI::Simple::Standard docs for details.
-no_debug
This turns off the command-line processing features. This is the default.
-debug1 and debug2
This turns on debugging. At debug level 1 CGI::Simple will read arguments from the
command-line. At debug level 2 CGI.pm will produce the prompt "(offline mode: enter
name=value pairs on standard input)" and wait for input on STDIN. If no number is
specified then a debug level of 2 is used.
See the section on debugging for more details.
-default
This sets the default global values for CGI.pm which will enable infinite size file
uploads, and specify the '-newstyle_urls' and '-debug1' pragmas
-no_upload
Disable uploads - the default setting
- upload
Enable uploads - the CGI.pm default
-unique_header
Only allows headers to be generated once per script invocation
-carp
Carp when cgi_error() called, default is to do nothing
-croak
Croak when cgi_error() called, default is to do nothing
USING NPH SCRIPTS
NPH, or "no-parsed-header", scripts bypass the server completely by sending the complete
HTTP header directly to the browser. This has slight performance benefits, but is of most
use for taking advantage of HTTP extensions that are not directly supported by your
server, such as server push and PICS headers.
Servers use a variety of conventions for designating CGI scripts as NPH. Many Unix
servers look at the beginning of the script's name for the prefix "nph-". The Macintosh
WebSTAR server and Microsoft's Internet Information Server, in contrast, try to decide
whether a program is an NPH script by examining the first line of script output.
CGI.pm supports NPH scripts with a special NPH mode. When in this mode, CGI.pm will
output the necessary extra header information when the header() and redirect() methods are
called. You can set NPH mode in any of the following ways:
In the use statement
Simply add the "-nph" pragma to the use:
use CGI::Simple qw(-nph)
By calling the nph() method:
Call nph() with a non-zero parameter at any point after using CGI.pm in your program.
$q->nph(1)
By using -nph parameters
in the header() and redirect() statements:
print $q->header(-nph=>1);
The Microsoft Internet Information Server requires NPH mode. CGI::Simple will
automatically detect when the script is running under IIS and put itself into this mode.
You do not need to do this manually, although it won't hurt anything if you do. However,
note that if you have applied Service Pack 6, much of the functionality of NPH scripts,
including the ability to redirect while setting a cookie, b<do not work at all> on IIS
without a special patch from Microsoft. See
http://support.microsoft.com/support/kb/articles/Q280/3/41.ASP: Non-Parsed Headers
Stripped From CGI Applications That Have nph- Prefix in Name.
SERVER PUSH
CGI.pm provides four simple functions for producing multipart documents of the type needed
to implement server push. These functions were graciously provided by Ed Jordan
<ed AT fidalgo.net> with additions from Andrew Benham <adsb AT bigfoot.com>
You are also advised to put the script into NPH mode and to set $| to 1 to avoid buffering
problems.
Browser support for server push is variable.
Here is a simple script that demonstrates server push:
#!/usr/local/bin/perl
use CGI::Simple::Standard qw/:push -nph/;
$| = 1;
print multipart_init(-boundary=>'----here we go!');
foreach (0 .. 4) {
print multipart_start(-type=>'text/plain'),
"The current time is ",scalar(localtime),"\n";
if ($_ < 4) {
print multipart_end;
}
else {
print multipart_final;
}
sleep 1;
}
This script initializes server push by calling multipart_init(). It then enters a loop in
which it begins a new multipart section by calling multipart_start(), prints the current
local time, and ends a multipart section with multipart_end(). It then sleeps a second,
and begins again. On the final iteration, it ends the multipart section with
multipart_final() rather than with multipart_end().
multipart_init() Initialize the multipart system
multipart_init(-boundary=>$boundary);
Initialize the multipart system. The -boundary argument specifies what MIME boundary
string to use to separate parts of the document. If not provided, CGI.pm chooses a
reasonable boundary for you.
multipart_start() Start a new part of the multipart document
multipart_start(-type=>$type)
Start a new part of the multipart document using the specified MIME type. If not
specified, text/html is assumed.
multipart_end() End a multipart part
multipart_end()
End a part. You must remember to call multipart_end() once for each multipart_start(),
except at the end of the last part of the multipart document when multipart_final() should
be called instead of multipart_end().
multipart_final()
multipart_final()
End all parts. You should call multipart_final() rather than multipart_end() at the end
of the last part of the multipart document.
CGI::Push
Users interested in server push applications should also have a look at the CGI::Push
module.
DEBUGGING
If you are running the script from the command line or in the perl debugger, you can pass
the script a list of keywords or parameter=value pairs on the command line or from
standard input (you don't have to worry about tricking your script into reading from
environment variables). Before you do this you will need to change the debug level from
the default level of 0 (no debug) to either 1 if you want to debug from @ARGV (the command
line) of 2 if you want to debug from STDIN. You can do this using the debug pragma like
this:
use CGI::Simple qw(-debug2); # set debug to level 2 => from STDIN
or this:
$CGI::Simple::DEBUG = 1; # set debug to level 1 => from @ARGV
At debug level 1 you can pass keywords and name=value pairs like this:
your_script.pl keyword1 keyword2 keyword3
or this:
your_script.pl keyword1+keyword2+keyword3
or this:
your_script.pl name1=value1 name2=value2
or this:
your_script.pl name1=value1&name2=value2
At debug level 2 you can feed newline-delimited name=value pairs to the script on standard
input. You will be presented with the following prompt:
(offline mode: enter name=value pairs on standard input)
You end the input with your system dependent end of file character. You should try ^Z ^X
^D and ^C if all else fails. The ^ means hold down the [Ctrl] button while you press the
other key.
When debugging, you can use quotes and backslashes to escape characters in the familiar
shell manner, letting you place spaces and other funny characters in your parameter=value
pairs:
your_script.pl "name1='I am a long value'" "name2=two\ words"
Dump() Dumping the current object details
The Dump() method produces a string consisting of all the query's object attributes
formatted nicely as a nested list. This dump includes the name/value pairs and a number
of other details. This is useful for debugging purposes:
print $q->Dump
The actual result of this is HTML escaped formatted text wrapped in <pre> tags so if you
send it straight to the browser it produces something that looks like:
$VAR1 = bless( {
'.parameters' => [
'name',
'color'
],
'.globals' => {
'FATAL' => -1,
'DEBUG' => 0,
'NO_NULL' => 1,
'POST_MAX' => 102400,
'USE_CGI_PM_DEFAULTS' => 0,
'HEADERS_ONCE' => 0,
'NPH' => 0,
'DISABLE_UPLOADS' => 1,
'NO_UNDEF_PARAMS' => 0,
'USE_PARAM_SEMICOLONS' => 0
},
'.fieldnames' => {
'color' => '1',
'name' => '1'
},
'.mod_perl' => '',
'color' => [
'red',
'green',
'blue'
],
'name' => [
'JaPh,'
]
}, 'CGI::Simple' );
You may recognize this as valid Perl syntax (which it is) and/or the output from
Data::Dumper (also true). This is the actual guts of how the information is stored in the
query object. All the internal params start with a . char
Alternatively you can dump your object and the current environment using:
print $q->Dump(\%ENV);
PrintEnv() Dumping the environment
You can get a similar browser friendly dump of the current %ENV hash using:
print $q->PrintEnv;
This will produce something like (in the browser):
$VAR1 = {
'QUERY_STRING' => 'name=JaPh%2C&color=red&color=green&color=blue',
'CONTENT_TYPE' => 'application/x-www-form-urlencoded',
'REGRESSION_TEST' => 'simple.t.pl',
'VIM' => 'C:\\WINDOWS\\Desktop\\vim',
'HTTP_REFERER' => 'xxx.sex.com',
'HTTP_USER_AGENT' => 'LWP',
'HTTP_ACCEPT' => 'text/html;q=1, image/gif;q=0.42, */*;q=0.001',
'REMOTE_HOST' => 'localhost',
'HTTP_HOST' => 'the.restaurant.at.the.end.of.the.universe',
'GATEWAY_INTERFACE' => 'bleeding edge',
'REMOTE_IDENT' => 'None of your damn business',
'SCRIPT_NAME' => '/cgi-bin/foo.cgi',
'SERVER_NAME' => 'nowhere.com',
'HTTP_COOKIE' => '',
'CONTENT_LENGTH' => '42',
'HTTPS_A' => 'A',
'HTTP_FROM' => 'spammer AT nowhere.com',
'HTTPS_B' => 'B',
'SERVER_PROTOCOL' => 'HTTP/1.0',
'PATH_TRANSLATED' => '/usr/local/somewhere/else',
'SERVER_SOFTWARE' => 'Apache - accept no substitutes',
'PATH_INFO' => '/somewhere/else',
'REMOTE_USER' => 'Just another Perl hacker,',
'REMOTE_ADDR' => '127.0.0.1',
'HTTPS' => 'ON',
'DOCUMENT_ROOT' => '/vs/www/foo',
'REQUEST_METHOD' => 'GET',
'REDIRECT_QUERY_STRING' => '',
'AUTH_TYPE' => 'PGP MD5 DES rot13',
'COOKIE' => 'foo=a%20phrase; bar=yes%2C%20a%20phrase&;I%20say;',
'SERVER_PORT' => '8080'
};
cgi_error() Retrieving CGI::Simple error messages
Errors can occur while processing user input, particularly when processing uploaded files.
When these errors occur, CGI::Simple will stop processing and return an empty parameter
list. You can test for the existence and nature of errors using the cgi_error() function.
The error messages are formatted as HTTP status codes. You can either incorporate the
error text into an HTML page, or use it as the value of the HTTP status:
my $error = $q->cgi_error;
if ($error) {
print $q->header(-status=>$error);
print "<H2>$error</H2>;
exit;
}
ACCESSOR METHODS
version() Get the CGI::Simple version info
$version = $q->version();
The version() method returns the value of $VERSION
nph() Enable/disable NPH (Non Parsed Header) mode
$q->nph(1); # enable NPH mode
$q->nph(0); # disable NPH mode
The nph() method enables and disables NPH headers. See the NPH section.
all_parameters() Get the names/values of all parameters
@all_parameters = $q->all_parameters();
The all_parameters() method is an alias for param()
charset() Get/set the current character set.
$charset = $q->charset(); # get current charset
$q->charset('utf-42'); # set the charset
The charset() method gets the current charset value if no argument is supplied or sets it
if an argument is supplied.
crlf() Get the system specific line ending sequence
$crlf = $q->crlf();
The crlf() method returns the system specific line ending sequence.
globals() Get/set the value of the remaining global variables
$globals = $q->globals('FATAL'); # get the current value of $FATAL
$globals = $q->globals('FATAL', 1 ); # set croak mode on cgi_error()
The globals() method gets/sets the values of the global variables after the script has
been invoked. For globals like $POST_MAX and $DISABLE_UPLOADS this makes no difference as
they must be set prior to calling the new constructor but there might be reason the change
the value of others.
auth_type() Get the current authorization/verification method
$auth_type = $q->auth_type();
The auth_type() method returns the value of $ENV{'AUTH_TYPE'} which should contain the
authorization/verification method in use for this script, if any.
content_length() Get the content length submitted in a POST
$content_length = $q->content_length();
The content_length() method returns the value of $ENV{'AUTH_TYPE'}
content_type() Get the content_type of data submitted in a POST
$content_type = $q->content_type();
The content_type() method returns the content_type of data submitted in a POST, generally
'multipart/form-data' or 'application/x-www-form-urlencoded' as supplied in
$ENV{'CONTENT_TYPE'}
document_root() Get the document root
$document_root = $q->document_root();
The document_root() method returns the value of $ENV{'DOCUMENT_ROOT'}
gateway_interface() Get the gateway interface
$gateway_interface = $q->gateway_interface();
The gateway_interface() method returns the value of $ENV{'GATEWAY_INTERFACE'}
path_translated() Get the value of path translated
$path_translated = $q->path_translated();
The path_translated() method returns the value of $ENV{'PATH_TRANSLATED'}
referer() Spy on your users
$referer = $q->referer();
The referer() method returns the value of $ENV{'REFERER'} This will return the URL of the
page the browser was viewing prior to fetching your script. Not available for all
browsers.
remote_addr() Get the remote address
$remote_addr = $q->remote_addr();
The remote_addr() method returns the value of $ENV{'REMOTE_ADDR'} or 127.0.0.1 (localhost)
if this is not defined.
remote_host() Get a value for remote host
$remote_host = $q->remote_host();
The remote_host() method returns the value of $ENV{'REMOTE_HOST'} if it is defined. If
this is not defined it returns $ENV{'REMOTE_ADDR'} If this is not defined it returns
'localhost'
remote_ident() Get the remote identity
$remote_ident = $q->remote_ident();
The remote_ident() method returns the value of $ENV{'REMOTE_IDENT'}
remote_user() Get the remote user
$remote_user = $q->remote_user();
The remote_user() method returns the authorization/verification name used for user
verification, if this script is protected. The value comes from $ENV{'REMOTE_USER'}
request_method() Get the request method
$request_method = $q->request_method();
The request_method() method returns the method used to access your script, usually one of
'POST', 'GET' or 'HEAD' as supplied by $ENV{'REQUEST_METHOD'}
script_name() Get the script name
$script_name = $q->script_name();
The script_name() method returns the value of $ENV{'SCRIPT_NAME'} if it is defined.
Otherwise it returns Perl's script name from $0. Failing this it returns a null string ''
server_name() Get the server name
$server_name = $q->server_name();
The server_name() method returns the value of $ENV{'SERVER_NAME'} if defined or
'localhost' otherwise
server_port() Get the port the server is listening on
$server_port = $q->server_port();
The server_port() method returns the value $ENV{'SERVER_PORT'} if defined or 80 if not.
server_protocol() Get the current server protocol
$server_protocol = $q->server_protocol();
The server_protocol() method returns the value of $ENV{'SERVER_PROTOCOL'} if defined or
'HTTP/1.0' otherwise
server_software() Get the server software
$server_software = $q->server_software();
The server_software() method returns the value $ENV{'SERVER_SOFTWARE'} or 'cmdline' If the
server software is IIS it formats your hard drive, installs Linux, FTPs to www.apache.org,
installs Apache, and then restores your system from tape. Well maybe not, but it's a nice
thought.
user_name() Get a value for the user name.
$user_name = $q->user_name();
Attempt to obtain the remote user's name, using a variety of different techniques. This
only works with older browsers such as Mosaic. Newer browsers do not report the user name
for privacy reasons!
Technically the user_name() method returns the value of $ENV{'HTTP_FROM'} or failing that
$ENV{'REMOTE_IDENT'} or as a last choice $ENV{'REMOTE_USER'}
user_agent() Get the users browser type
$ua = $q->user_agent(); # return the user agent
$ok = $q->user_agent('mozilla'); # return true if user agent 'mozilla'
The user_agent() method returns the value of $ENV{'HTTP_USER_AGENT'} when called without
an argument or true or false if the $ENV{'HTTP_USER_AGENT'} matches the passed argument.
The matching is case insensitive and partial.
virtual_host() Get the virtual host
$virtual_host = $q->virtual_host();
The virtual_host() method returns the value of $ENV{'HTTP_HOST'} if defined or
$ENV{'SERVER_NAME'} as a default. Port numbers are removed.
path_info() Get any extra path info set to the script
$path_info = $q->path_info();
The path_info() method returns additional path information from the script URL. E.G.
fetching /cgi-bin/your_script/additional/stuff will result in $q->path_info() returning
"/additional/stuff".
NOTE: The Microsoft Internet Information Server is broken with respect to additional path
information. If you use the Perl DLL library, the IIS server will attempt to execute the
additional path information as a Perl script. If you use the ordinary file associations
mapping, the path information will be present in the environment, but incorrect. The best
thing to do is to avoid using additional path information in CGI scripts destined for use
with IIS.
Accept() Get the browser MIME types
$Accept = $q->Accept();
The Accept() method returns a list of MIME types that the remote browser accepts. If you
give this method a single argument corresponding to a MIME type, as in
$q->Accept('text/html'), it will return a floating point value corresponding to the
browser's preference for this type from 0.0 (don't want) to 1.0. Glob types (e.g. text/*)
in the browser's accept list are handled correctly.
accept() Alias for Accept()
$accept = $q->accept();
The accept() Method is an alias for Accept()
http() Get a range of HTTP related information
$http = $q->http();
Called with no arguments the http() method returns the list of HTTP or HTTPS environment
variables, including such things as HTTP_USER_AGENT, HTTP_ACCEPT_LANGUAGE, and
HTTP_ACCEPT_CHARSET, corresponding to the like-named HTTP header fields in the request.
Called with the name of an HTTP header field, returns its value. Capitalization and the
use of hyphens versus underscores are not significant.
For example, all three of these examples are equivalent:
$requested_language = $q->http('Accept-language');
$requested_language = $q->http('Accept_language');
$requested_language = $q->http('HTTP_ACCEPT_LANGUAGE');
https() Get a range of HTTPS related information
$https = $q->https();
The https() method is similar to the http() method except that when called without an
argument it returns the value of $ENV{'HTTPS'} which will be true if a HTTPS connection is
in use and false otherwise.
protocol() Get the current protocol
$protocol = $q->protocol();
The protocol() method returns 'https' if a HTTPS connection is in use or the
server_protocol() minus version numbers ('http') otherwise.
url() Return the script's URL in several formats
$full_url = $q->url();
$full_url = $q->url(-full=>1);
$relative_url = $q->url(-relative=>1);
$absolute_url = $q->url(-absolute=>1);
$url_with_path = $q->url(-path_info=>1);
$url_with_path_and_query = $q->url(-path_info=>1,-query=>1);
$netloc = $q->url(-base => 1);
url() returns the script's URL in a variety of formats. Called without any arguments, it
returns the full form of the URL, including host name and port number
http://your.host.com/path/to/script.cgi
You can modify this format with the following named arguments:
-absolute
If true, produce an absolute URL, e.g.
/path/to/script.cgi
-relative
Produce a relative URL. This is useful if you want to reinvoke your script with
different parameters. For example:
script.cgi
-full
Produce the full URL, exactly as if called without any arguments. This overrides the
-relative and -absolute arguments.
-path (-path_info)
Append the additional path information to the URL. This can be combined with -full,
-absolute or -relative. -path_info is provided as a synonym.
-query (-query_string)
Append the query string to the URL. This can be combined with -full, -absolute or
-relative. -query_string is provided as a synonym.
-base
Generate just the protocol and net location, as in http://www.foo.com:8000
self_url() Get the scripts complete URL
$self_url = $q->self_url();
The self_url() method returns the value of:
$self->url( '-path_info'=>1, '-query'=>1, '-full'=>1 );
state() Alias for self_url()
$state = $q->state();
The state() method is an alias for self_url()
COMPATIBILITY WITH cgi-lib.pl 2.18
To make it easier to port existing programs that use cgi-lib.pl all the subs within
cgi-lib.pl are available in CGI::Simple. Using the functional interface of
CGI::Simple::Standard porting is as easy as:
OLD VERSION
require "cgi-lib.pl";
&ReadParse;
print "The value of the antique is $in{'antique'}.\n";
NEW VERSION
use CGI::Simple::Standard qw(:cgi-lib);
&ReadParse;
print "The value of the antique is $in{'antique'}.\n";
CGI:Simple's ReadParse() routine creates a variable named %in, which can be accessed to
obtain the query variables. Like ReadParse, you can also provide your own variable via a
glob. Infrequently used features of ReadParse(), such as the creation of @in and $in
variables, are not supported.
You can also use the OO interface of CGI::Simple and call ReadParse() and other cgi-lib.pl
functions like this:
&CGI::Simple::ReadParse; # get hash values in %in
my $q = CGI::Simple->new;
$q->ReadParse(); # same thing
CGI::Simple::ReadParse(*field); # get hash values in %field function style
my $q = CGI::Simple->new;
$q->ReadParse(*field); # same thing
Once you use ReadParse() under the functional interface , you can retrieve the query
object itself this way if needed:
$q = $in{'CGI'};
Either way it allows you to start using the more interesting features of CGI.pm without
rewriting your old scripts from scratch.
Unlike CGI.pm all the cgi-lib.pl functions from Version 2.18 are supported:
ReadParse()
SplitParam()
MethGet()
MethPost()
MyBaseUrl()
MyURL()
MyFullUrl()
PrintHeader()
HtmlTop()
HtmlBot()
PrintVariables()
PrintEnv()
CgiDie()
CgiError()
COMPATIBILITY WITH CGI.pm
I has long been suggested that the CGI and HTML parts of CGI.pm should be split into
separate modules (even the author suggests this!), CGI::Simple represents the realization
of this and contains the complete CGI side of CGI.pm. Code-wise it weighs in at a little
under 30% of the size of CGI.pm at a little under 1000 lines.
A great deal of care has been taken to ensure that the interface remains unchanged
although a few tweaks have been made. The test suite is extensive and includes all the
CGI.pm test scripts as well as a series of new test scripts. You may like to have a look
at /t/concur.t which makes 160 tests of CGI::Simple and CGI in parallel and compares the
results to ensure they are identical. This is the case as of CGI.pm 2.78.
You can't make an omelet without breaking eggs. A large number of methods and global
variables have been deleted as detailed below. Some pragmas are also gone. In the tarball
there is a script /misc/check.pl that will check if a script seems to be using any of
these now non existent methods, globals or pragmas. You call it like this:
perl check.pl <files>
If it finds any likely candidates it will print a line with the line number, problem
method/global and the complete line. For example here is some output from running the
script on CGI.pm:
...
3162: Problem:'$CGI::OS' local($CRLF) = "\015\012" if $CGI::OS eq 'VMS';
3165: Problem:'fillBuffer' $self->fillBuffer($FILLUNIT);
....
DIFFERENCES FROM CGI.pm
CGI::Simple is strict and warnings compliant.
There are 4 modules in this distribution:
CGI/Simple.pm supplies all the core code.
CGI/Simple/Cookie.pm supplies the cookie handling functions.
CGI/Simple/Util.pm supplies a variety of utility functions
CGI/Simple/Standard.pm supplies a functional interface for Simple.pm
Simple.pm is the core module that provide all the essential functionality. Cookie.pm is a
shortened rehash of the CGI.pm module of the same name which supplies the required cookie
functionality. Util.pm has been recoded to use an internal object for data storage and
supplies rarely needed non core functions and/or functions needed for the HTML side of
things. Standard.pm is a wrapper module that supplies a complete functional interface to
the OO back end supplied by CGI::Simple.
Although a serious attempt has been made to keep the interface identical, some minor
changes and tweaks have been made. They will likely be insignificant to most users but
here are the gory details.
Globals Variables
The list of global variables has been pruned by 75%. Here is the complete list of the
global variables used:
$VERSION = "0.01";
# set this to 1 to use CGI.pm default global settings
$USE_CGI_PM_DEFAULTS = 0 unless defined $USE_CGI_PM_DEFAULTS;
# see if user wants old CGI.pm defaults
do{ _use_cgi_pm_global_settings(); return } if $USE_CGI_PM_DEFAULTS;
# no file uploads by default, set to 0 to enable uploads
$DISABLE_UPLOADS = 1 unless defined $DISABLE_UPLOADS;
# use a post max of 100K, set to -1 for no limits
$POST_MAX = 102_400 unless defined $POST_MAX;
# do not include undefined params parsed from query string
$NO_UNDEF_PARAMS = 0 unless defined $NO_UNDEF_PARAMS;
# separate the name=value pairs with ; rather than &
$USE_PARAM_SEMICOLONS = 0 unless defined $USE_PARAM_SEMICOLONS;
# only print headers once
$HEADERS_ONCE = 0 unless defined $HEADERS_ONCE;
# Set this to 1 to enable NPH scripts
$NPH = 0 unless defined $NPH;
# 0 => no debug, 1 => from @ARGV, 2 => from STDIN
$DEBUG = 0 unless defined $DEBUG;
# filter out null bytes in param - value pairs
$NO_NULL = 1 unless defined $NO_NULL;
# set behavior when cgi_err() called -1 => silent, 0 => carp, 1 => croak
$FATAL = -1 unless defined $FATAL;
Four of the default values of the old CGI.pm variables have been changed. Unlike CGI.pm
which by default allows unlimited POST data and file uploads by default CGI::Simple limits
POST data size to 100kB and denies file uploads by default. $USE_PARAM_SEMICOLONS is set
to 0 by default so we use (old style) & rather than ; as the pair separator for query
strings. Debugging is disabled by default.
There are three new global variables. If $NO_NULL is true (the default) then CGI::Simple
will strip null bytes out of names, values and keywords. Null bytes can do interesting
things to C based code like Perl. Uploaded files are not touched. $FATAL controls the
behavior when cgi_error() is called. The default value of -1 makes errors silent.
$USE_CGI_PM_DEFAULTS reverts the defaults to the CGI.pm standard values ie unlimited file
uploads via POST for DNS attacks. You can also get the defaults back by using the
'-default' pragma in the use:
use CGI::Simple qw(-default);
use CGI::Simple::Standard qw(-default);
The values of the global variables are stored in the CGI::Simple object and can be
referenced and changed using the globals() method like this:
my $value = $q->globals( 'VARNAME' ); # get
$q->globals( 'VARNAME', 'some value' ); # set
As with many CGI.pm methods if you pass the optional value that will be set.
The $CGI::Simple::VARNAME = 'N' syntax is only useful prior to calling the new()
constructor. After that all reference is to the values stored in the CGI::Simple object so
you must change these using the globals() method.
$DISABLE_UPLOADS and $POST_MAX *must* be set prior to calling the constructor if you want
the changes to have any effect as they control behavior during initialization. This is the
same a CGI.pm although some people seem to miss this rather important point and set these
after calling the constructor which does nothing.
The following globals are no longer relevant and have all been deleted:
$AUTOLOADED_ROUTINES
$AUTOLOAD_DEBUG
$BEEN_THERE
$CRLF
$DEFAULT_DTD
$EBCDIC
$FH
$FILLUNIT
$IIS
$IN
$INITIAL_FILLUNIT
$JSCRIPT
$MAC
$MAXTRIES
$MOD_PERL
$NOSTICKY
$OS
$PERLEX
$PRIVATE_TEMPFILES
$Q
$QUERY_CHARSET
$QUERY_PARAM
$SCRATCH
$SL
$SPIN_LOOP_MAX
$TIMEOUT
$TMPDIRECTORY
$XHTML
%EXPORT
%EXPORT_OK
%EXPORT_TAGS
%OVERLOAD
%QUERY_FIELDNAMES
%SUBS
@QUERY_PARAM
@TEMP
Notes: CGI::Simple uses IO::File->new_tmpfile to get tempfile filehandles. These are
private by default so $PRIVATE_TEMPFILES is no longer required nor is $TMPDIRECTORY. The
value that were stored in $OS, $CRLF, $QUERY_CHARSET and $EBCDIC are now stored in the
CGI::Simple::Util object where they find most of their use. The $MOD_PERL and $PERLEX
values are now stored in our CGI::Simple object. $IIS was only used once in path_info().
$SL the system specific / \ : path delimiter is not required as we let IO::File handle our
tempfile requirements. The rest of the globals are HTML related, export related, hand
rolled autoload related or serve obscure purposes in CGI.pm
Changes to pragmas
There are some new pragmas available. See the pragmas section for details. The following
CGI.pm pragmas are not available:
-any
-compile
-nosticky
-no_xhtml
-private_tempfiles
Filehandles
Unlike CGI.pm which tries to accept all filehandle like objects only \*FH and $fh are
accepted by CGI::Simple as file accessors for new() and save(). IO::File objects work
fine.
Hash interface
%hash = $q->Vars(); # pack values with "\0";
%hash = $q->Vars(","); # comma separate values
You may optionally pass Vars() a string that will be used to separate multiple values when
they are packed into the single hash value. If no value is supplied the default "\0" (null
byte) will be used. Null bytes are dangerous things for C based code (ie Perl).
cgi-lib.pl
All the cgi-lib.pl 2.18 routines are supported. Unlike CGI.pm all the subroutines from
cgi-lib.pl are included. They have been GOLFED down to 25 lines but they all work pretty
much the same as the originals.
CGI::Simple COMPLETE METHOD LIST
Here is a complete list of all the CGI::Simple methods.
Guts (hands off, except of course for new)
_initialize_globals
_use_cgi_pm_global_settings
_store_globals
import
_reset_globals
new
_initialize
_read_parse
_parse_params
_add_param
_parse_keywordlist
_parse_multipart
_save_tmpfile
_read_data
Core Methods
param
add_param
param_fetch
url_param
keywords
Vars
append
delete
Delete
delete_all
Delete_all
upload
upload_info
query_string
parse_query_string
parse_keywordlist
Save and Restore from File Methods
_init_from_file
save
save_parameters
Miscellaneous Methods
url_decode
url_encode
escapeHTML
unescapeHTML
put
print
Cookie Methods
cookie
raw_cookie
Header Methods
header
cache
no_cache
redirect
Server Push Methods
multipart_init
multipart_start
multipart_end
multipart_final
Debugging Methods
read_from_cmdline
Dump
as_string
cgi_error
cgi-lib.pl Compatibility Routines - all 2.18 functions available
_shift_if_ref
ReadParse
SplitParam
MethGet
MethPost
MyBaseUrl
MyURL
MyFullUrl
PrintHeader
HtmlTop
HtmlBot
PrintVariables
PrintEnv
CgiDie
CgiError
Accessor Methods
version
nph
all_parameters
charset
crlf # new, returns OS specific CRLF sequence
globals # get/set global variables
auth_type
content_length
content_type
document_root
gateway_interface
path_translated
referer
remote_addr
remote_host
remote_ident
remote_user
request_method
script_name
server_name
server_port
server_protocol
server_software
user_name
user_agent
virtual_host
path_info
Accept
accept
http
https
protocol
url
self_url
state
NEW METHODS IN CGI::Simple
There are a few new methods in CGI::Simple as listed below. The highlights are the
parse_query_string() method to add the QUERY_STRING data to your object if the method was
POST. The no_cache() method adds an expires now directive and the Pragma: no-cache
directive to the header to encourage some browsers to do the right thing. PrintEnv() from
the cgi-lib.pl routines will dump an HTML friendly list of the %ENV and makes a handy
addition to Dump() for use in debugging. The upload method now accepts a filepath as an
optional second argument as shown in the synopsis. If this is supplied the uploaded file
will be written to there automagically.
Internal Routines
_initialize_globals()
_use_cgi_pm_global_settings()
_store_globals()
_initialize()
_init_from_file()
_read_parse()
_parse_params()
_add_param()
_parse_keywordlist()
_parse_multipart()
_save_tmpfile()
_read_data()
New Public Methods
add_param() # adds a param/value(s) pair +/- overwrite
upload_info() # uploaded files MIME type and size
url_decode() # decode s url encoded string
url_encode() # url encode a string
parse_query_string() # add QUERY_STRING data to $q object if 'POST'
no_cache() # add both the Pragma: no-cache
# and Expires/Date => 'now' to header
cgi-lib.pl methods added for completeness
_shift_if_ref() # internal hack reminiscent of self_or_default :-)
MyBaseUrl()
MyURL()
MyFullUrl()
PrintVariables()
PrintEnv()
CgiDie()
CgiError()
New Accessors
crlf() # returns CRLF sequence
globals() # global vars now stored in $q object - get/set
content_length() # returns $ENV{'CONTENT_LENGTH'}
document_root() # returns $ENV{'DOCUMENT_ROOT'}
gateway_interface() # returns $ENV{'GATEWAY_INTERFACE'}
METHODS IN CGI.pm NOT IN CGI::Simple
Here is a complete list of what is not included in CGI::Simple. Basically all the HTML
related stuff plus large redundant chunks of the guts. The check.pl script in the /misc
dir will check to see if a script is using any of these.
Guts - rearranged, recoded, renamed and hacked out of existence
initialize_globals()
compile()
expand_tags()
self_or_default()
self_or_CGI()
init()
to_filehandle()
save_request()
parse_params()
add_parameter()
binmode()
_make_tag_func()
AUTOLOAD()
_compile()
_setup_symbols()
new_MultipartBuffer()
read_from_client()
import_names() # I dislike this and left it out, so shoot me.
HTML Related
autoEscape()
URL_ENCODED()
MULTIPART()
SERVER_PUSH()
start_html()
_style()
_script()
end_html()
isindex()
startform()
start_form()
end_multipart_form()
start_multipart_form()
endform()
end_form()
_textfield()
textfield()
filefield()
password_field()
textarea()
button()
submit()
reset()
defaults()
comment()
checkbox()
checkbox_group()
_tableize()
radio_group()
popup_menu()
scrolling_list()
hidden()
image_button()
nosticky()
default_dtd()
Upload Related
CGI::Simple uses anonymous tempfiles supplied by IO::File to spool uploaded files to.
private_tempfiles() # automatic in CGI::Simple
tmpFileName() # all upload files are anonymous
uploadInfo() # relied on FH access, replaced with upload_info()
Really Private Subs (marked as so)
previous_or_default()
register_parameter()
get_fields()
_set_values_and_labels()
_compile_all()
asString()
compare()
Internal Multipart Parsing Routines
read_multipart()
readHeader()
readBody()
read()
fillBuffer()
eof()
EXPORT
Nothing.
AUTHOR INFORMATION
Originally copyright 2001 Dr James Freeman <jfreeman AT tassie.au> This release by Andy
Armstrong <andy AT hexten.net>
This package is free software and is provided "as is" without express or implied warranty.
It may be used, redistributed and/or modified under the terms of the Perl Artistic License
(see http://www.perl.com/perl/misc/Artistic.html)
Address bug reports and comments to: andy AT hexten.net. When sending bug reports, please
provide the version of CGI::Simple, the version of Perl, the name and version of your Web
server, and the name and version of the operating system you are using. If the problem is
even remotely browser dependent, please provide information about the affected browsers as
well.
Address bug reports and comments to: andy AT hexten.net
CREDITS
Lincoln D. Stein (lstein AT cshl.org) and everyone else who worked on the original CGI.pm
upon which this module is heavily based
Brandon Black for some heavy duty testing and bug fixes
John D Robinson and Jeroen Latour for helping solve some interesting test failures as well
as Perlmonks: tommyw, grinder, Jaap, vek, erasei, jlongino and strider_corinth
Thanks for patches to:
Ewan Edwards, Joshua N Pritikin, Mike Barry, Michael Nachbaur, Chris Williams, Mark
Stosberg, Krasimir Berov, Yamada Masahiro
LICENCE AND COPYRIGHT
Copyright (c) 2007, Andy Armstrong "<andy AT hexten.net>". All rights reserved.
This module is free software; you can redistribute it and/or modify it under the same
terms as Perl itself. See perlartistic.
SEE ALSO
CGI, CGI::Simple::Standard, CGI::Simple::Cookie, CGI::Simple::Util, CGI::Minimal
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