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CGI
CGI has been the standard way of deploying web applications long before
ASP came along. CGI.pm is a very useful module that aids developers in
the building of these applications, and Apache::ASP has been made to
be compatible with function calls in CGI.pm. Please see cgi.htm in the
./site/eg directory for a sample ASP script written almost entirely in CGI.
As of version 0.09, use of CGI.pm for both input and output is seemless
when working under Apache::ASP. Thus if you would like to port existing
cgi scripts over to Apache::ASP, all you need to do is wrap <% %> around
the script to get going. This functionality has been implemented so that
developers may have the best of both worlds when building their
web applications.
Following are some special notes with respect to compatibility with CGI.
Use of CGI.pm in any of these ways was made possible through a great
amount of work, and is not gauranteed to be portable with other perl ASP
implementations, as other ASP implementations will likely be more limited.
Query Object Initialization
You may create a CGI.pm $query object like so:
use CGI;
my $query = new CGI;
As of Apache::ASP version 0.09, form input may be read in
by CGI.pm upon initialization. Before, Apache::ASP would
consume the form input when reading into $Request->Form(),
but now form input is cached, and may be used by CGI.pm input
routines.
CGI headers
Not only can you use the CGI.pm $query->header() method
to put out headers, but with the CgiHeaders config option
set to true, you can also print "Header: value\n", and add
similar lines to the top of your script, like:
Some-Header: Value
Some-Other: OtherValue
<html><body> Script body starts here.
Once there are no longer any cgi sytle headers, or the
there is a newline, the body of the script begins. So
if you just had an asp script like:
print join(":", %{$Request->QueryString});
You would likely end up with no output, as that line is
interpreted as a header because of the semicolon. When doing
basic debugging, as long as you start the page with <html>
you will avoid this problem.
print()ing CGI
CGI is notorious for its print() statements, and the functions in CGI.pm
usually return strings to print(). You can do this under Apache::ASP,
since print just aliases to $Response->Write(). Note that $| has no
affect.
print $query->header();
print $query->start_form();
File Upload
CGI.pm is used for implementing reading the input from file upload. You
may create the file upload form however you wish, and then the
data may be recovered from the file upload by using $Request->Form().
Data from a file upload gets written to a filehandle, that may in
turn be read from. The original file name that was uploaded is the
name of the file handle.
my $filehandle = $Request->Form('file_upload_field_name');
print $filehandle; # will get you the file name
my $data;
while(read($filehandle, $data, 1024)) {
# data from the uploaded file read into $data
};
Please see the docs on CGI.pm (try perldoc CGI) for more information
on this topic, and ./site/eg/file_upload.asp for an example of its use.
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