#! / usr / bin / env perl
use strict;
use warnings;
use CGI :: Fast;
while (my $ q = new CGI :: Fast)
{
print $ q-> header ("text / plain");
print "Hello World";
}
The difference from CGI is that there is an additional loop to accept the request. The CGI :: Fast object is the same as the CGI interface, and the script can also be used as a CGI script.
Setting up nginx + FastCGI environment
Perl uses the CGI :: Fast package to provide FastCGI services. This package provides two ways to start the FastCGI process. One is to directly use the services provided by the package to change the current process into a FastCGI process. To start.
Example of nginx configuration:
After nginx is configured, use spawn-fcgi to start the previous Hello World:
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$ spawn-fcgi -n -a 127.0.0.1 -p 8184 -f ./main.pl
Debug support
The parameter -n was used in the previous command line, so spawn-fcgi does not fork multiple processes and blocks, allowing the user to Ctrl + C to close. The product server can remove this parameter to make full use of the server's multi-core to provide higher Number of concurrency. I previously wrote a bash script that allows services to be restarted in the event of file changes to facilitate debugging of perl programs. The code is as follows:
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#! / bin / bash
#PID files and scripts that need to be started
PID_FILE = service.pid
MAIN = main.pl
#Close previously started processes
term () {
test -e $ PID_FILE || return
pid = `cat $ PID_FILE`
kill -s -0 $ pid || return
echo "Terminating $ MAIN $ pid"
rm -f $ PID_FILE
kill $ pid
wait $ pid
}
#FastCGI process is also closed when the current script exits
trap "term; exit" SIGINT SIGTERM
while true
do
#Close the previous process after the first startup or file changes
term
#Start the script in no fork mode to debug and write the PID to a file
spawn-fcgi -n -a 127.0.0.1 -p 8184 -f ./$MAIN &
pid = $!
echo $ pid> $ PID_FILE
echo "My Perl service started, pid = $ pid"
#Monitoring file changes
files = `find. -name '* .pl' -o -name '* .pm' -o -name '* .html'`
md5 = `md5sum $ files | md5sum`
#wait for file change
while [[`md5sum $ files | md5sum` =" $ md5 "]]
do
sleep 1
done
echo "File changes detected, restarting service"
done
The script has been tested under Mac OSX and Linux
Routing system
Web development is inseparable from routing implementations, to make specific responses to different requests.
Routing requests rely on two parts: HTTP Method and URI, so they are mainly needed for dispatch.
In CGI, you can obtain the request method and URI through the environment variables REQUEST_METHOD and REQUEST_URI.
Therefore, a simple routing system can actually be decomposed into a second-level map. Registering routes is actually putting processing functions corresponding to rules into this map, and dispatching requests are obtained from this map according to rules. , A simple example:
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my% routers = ();
sub not_found
{
print "Status: 404 \ n";
print "Content-Type: text / html \ n \ n";
print << EOF
<html>
<body>
<h1> 404 Not found </ h1>
Cannot find $ ENV {REQUEST_PATH}.
</ body>
</ html>
EOF
}
sub add_rule
{
my ($ method, $ path, $ callback) = @_;
my $ handlers = $ routers {$ method};
$ handlers = $ routers {$ method} = {} if not $ handlers;
$ handlers-> {$ path} = $ callback;
}
sub dispatch
{
my $ q = shift;
my $ method = $ ENV {REQUEST_METHOD};
my $ uri = $ ENV {REQUEST_URI};
$ uri = ~ s /\?.*$//;
my $ handler = ($ routers {$ method} || {})-> {$ uri} || not_found;
eval
{
& $ handler ($ q);
};
print STDERR "Failed to handle $ method $ uri: $ @ \ n" if $ @;
}
Example using this routing system:
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sub index
{
my ($ q) = @_;
print $ q-> header ('text / plain');
print "Hello World!";
}
router :: add_rule ('GET', '/', \ & index);
Template system
Perl provides a large number of template system implementations. My personal favorite is the Template Toolkit. The documentation is also very rich.
Modify the previous index to use the template example:
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use Template;
my $ tt = new Template ((INCLUDE_PATH => 'templates', INTERPOLATE => 1});
sub index
{
my ($ q) = @_;
my $ output = '';
print $ q-> header ('text / html');
$ tt-> process ('index.html', {world => 'World'}, $ output) || die $ tt-> error ();
print $ output;
}
The contents of the templates / index.html file are as follows:
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