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<html><head><title>FastCGI Programmer's Guide - Chapter 3, Developing FastCGI Applications in Perl</title></head>
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<a name="3659">
<center><h1>3 Developing FastCGI <br>Applications in Perl</h1></center>
</a><a name="917"></a>
This chapter explains how to code FastCGI applications in Perl. Before you can build FastCGI applications in Perl, you must have a FastCGI-savvy version of the Perl interpreter. Open Market develops such Perl binaries for popular platforms and makes them available with our developer's kit. <p>
<a name="5008"></a>
The FastCGI-savvy binaries are extensions of standard Perl, and are intended to replace your existing Perl installation. There is no need to maintain two versions of Perl: the version that we supply will work fine when invoked from a shell or a CGI program. There are also directions in the developer's kit for how to make your own FastCGI-savvy Perl, if you need a version for some platform that we don't supply.<p>
<a name="4369"></a>
FastCGI is ideal for applications written in Perl, because it provides a huge performance gain. When you run a Perl script, the Perl interpreter analyzes the entire script before executing any of it. With FastCGI, you can factor out this initialization cost and pay it only once, making execution of the actual script much faster in response to client calls.<p>
<a name="4183">
<h1> Getting Started</h1>
</a><a name="4234"></a>
The first line of any Perl script typically specifies the pathname of the Perl interpreter itself. You must specify the pathname of a FastCGI-savvy Perl. <p>
<a name="4235"></a>
Next, you must tell Perl to load the FastCGI extension. To do so, place the following line near the beginning of every FastCGI script: <p>
<pre><a name="4210">
use FCGI;
</a>
</pre><a name="4212"></a>
Then, you have to divide FastCGI scripts into the following two sections:<p>
<ul><a name="4242"></a>
<li>Initialization section, which is executed only once.
<a name="4243"></a>
<li>Response loop section, which gets executed every time the FastCGI script gets called.
</ul><a name="4248"></a>
A response loop typically has the following format:<p>
<pre><a name="4255">
while (FCGI::accept &gt;= 0) {
</a>
<a name="4256">
# body of response loop
</a>
<a name="4257">
}
</a>
</pre><a name="4258"></a>
The <code>accept</code> call returns 0 whenever a client requests the FastCGI script. Otherwise, the <code>accept</code> call returns -1. <p>
<a name="5002">
<h1> Example: TinyFastCGI</h1>
</a><a name="4588"></a>
Here is a simple example of a FastCGI application written in Perl:<p>
<pre><a name="4589"></a>
#!fcgi-savvy-perl

use FCGI; # Imports the library; required line

# Initialization code

$cnt = 0;

# Response loop

while (FCGI::accept &gt;= 0) {
  print "Content-type: text/html\r\n\r\n";
  print "&lt;head&gt;\n&lt;title&gt;FastCGI Demo Page (perl)&lt;/title&gt;\n&lt;/head&gt;\n";
  print  "&lt;h1&gt;FastCGI Demo Page (perl)&lt;/h1&gt;\n";
  print "This is coming from a FastCGI server.\n&lt;BR&gt;\n";
  print "Running on &lt;EM&gt;$ENV{SERVER_NAME}&lt;/EM&gt; to &lt;EM&gt;$ENV{REMOTE_HOST}&lt;/EM&gt;\n&lt;BR&gt;\n";
  	$cnt++;
  print "This is connection number $cnt\n";
}
</pre>
<p>

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Commit	Line	Data
6791223e	1	<html><head><title>FastCGI Programmer's Guide - Chapter 3, Developing FastCGI Applications in Perl</title></head>
0198fd3c	2	<body bgcolor=#ffffff>
	3
	4	<a href="cover.htm">[Top]</a> <a href="ch2c.htm">[Prev]</a> <a href="ch4tcl.htm">[Next]</a> <a href="ap_guida.htm">[Bottom]</a>
	5	<hr><br>
	6
	7	<a name="3659">
	8	<center><h1>3 Developing FastCGI <br>Applications in Perl</h1></center>
6791223e	9	</a><a name="917"></a>
0198fd3c	10	This chapter explains how to code FastCGI applications in Perl. Before you can build FastCGI applications in Perl, you must have a FastCGI-savvy version of the Perl interpreter. Open Market develops such Perl binaries for popular platforms and makes them available with our developer's kit. <p>
6791223e	11	<a name="5008"></a>
0198fd3c	12	The FastCGI-savvy binaries are extensions of standard Perl, and are intended to replace your existing Perl installation. There is no need to maintain two versions of Perl: the version that we supply will work fine when invoked from a shell or a CGI program. There are also directions in the developer's kit for how to make your own FastCGI-savvy Perl, if you need a version for some platform that we don't supply.<p>
6791223e	13	<a name="4369"></a>
0198fd3c	14	FastCGI is ideal for applications written in Perl, because it provides a huge performance gain. When you run a Perl script, the Perl interpreter analyzes the entire script before executing any of it. With FastCGI, you can factor out this initialization cost and pay it only once, making execution of the actual script much faster in response to client calls.<p>
6791223e	15	<a name="4183">
0198fd3c	16	<h1> Getting Started</h1>
6791223e	17	</a><a name="4234"></a>
0198fd3c	18	The first line of any Perl script typically specifies the pathname of the Perl interpreter itself. You must specify the pathname of a FastCGI-savvy Perl. <p>
6791223e	19	<a name="4235"></a>
0198fd3c	20	Next, you must tell Perl to load the FastCGI extension. To do so, place the following line near the beginning of every FastCGI script: <p>
6791223e	21	<pre><a name="4210">
0198fd3c	22	use FCGI;
0198fd3c	23	</a>
6791223e	24	</pre><a name="4212"></a>
0198fd3c	25	Then, you have to divide FastCGI scripts into the following two sections:<p>
6791223e	26	<ul><a name="4242"></a>
0198fd3c	27	<li>Initialization section, which is executed only once.
6791223e	28	<a name="4243"></a>
0198fd3c	29	<li>Response loop section, which gets executed every time the FastCGI script gets called.
6791223e	30	</ul><a name="4248"></a>
0198fd3c	31	A response loop typically has the following format:<p>
6791223e	32	<pre><a name="4255">
0198fd3c	33	while (FCGI::accept >= 0) {
	34	</a>
	35	<a name="4256">
	36	# body of response loop
	37	</a>
	38	<a name="4257">
	39	}
	40	</a>
6791223e	41	</pre><a name="4258"></a>
0198fd3c	42	The <code>accept</code> call returns 0 whenever a client requests the FastCGI script. Otherwise, the <code>accept</code> call returns -1. <p>
6791223e	43	<a name="5002">
0198fd3c	44	<h1> Example: TinyFastCGI</h1>
6791223e	45	</a><a name="4588"></a>
0198fd3c	46	Here is a simple example of a FastCGI application written in Perl:<p>
6791223e	47	<pre><a name="4589"></a>
0198fd3c	48	#!fcgi-savvy-perl
	49
	50	use FCGI; # Imports the library; required line
	51
	52	# Initialization code
	53
	54	$cnt = 0;
	55
	56	# Response loop
	57
	58	while (FCGI::accept >= 0) {
	59	print "Content-type: text/html\r\n\r\n";
	60	print "<head>\n<title>FastCGI Demo Page (perl)</title>\n</head>\n";
	61	print "<h1>FastCGI Demo Page (perl)</h1>\n";
	62	print "This is coming from a FastCGI server.\n<BR>\n";
	63	print "Running on <EM>$ENV{SERVER_NAME}</EM> to <EM>$ENV{REMOTE_HOST}</EM>\n<BR>\n";
	64	$cnt++;
	65	print "This is connection number $cnt\n";
	66	}
	67	</pre>
	68	<p>
6791223e	69
0198fd3c	70	<hr><br>
	71
	72	<a href="cover.htm">[Top]</a> <a href="ch2c.htm">[Prev]</a> <a href="ch4tcl.htm">[Next]</a> <a href="ap_guida.htm">[Bottom]</a>
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