Great CPAN Modules

LWP

The LWP module collection, written by Martijn Koster and Gisle Aas,

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 provides an 

interface to the network protocol of the World Wide Web HTTP.

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 The project 

was originally based on Roy Fielding's

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 libwww perl library for Perl 4. After the 

release of Perl 5, both Martijn and Gisle built their own Perl 5 version of libwww 

perl. They decided to combine forces, and the result is the LWP module of today.

LWP modules have done for HTTP what Net::FTP did for FTP. It provides a 

simple and extensible implementation for writing HTTP clients. Given the explosive 

growth of the internet, LWP has come to hold a central place in the toolbox of 

many Perl hackers. If the data you want is on the Web, then you can use LWP to 

access it.

Another reason that LWP has been successful is that it goes to extreme lengths 

to make easy things easy while still making hard things possible. The LWP::Simple 

module that comes with LWP embodies this philosophy. For example, to fetch a 

copy of the cpan.org home page, this is all the code that's needed:

use LWP::Simple qw(get);

$contents = get( http://cpan.org );

It just doesn't get much simpler than that! But LWP doesn't end with LWP::Simple; 

for more complicated uses, it implements a fully object oriented interface with 

classes for every component of the request and response (LWP::UserAgent, 

HTTP::Request, HTTP::Response, and so on). By providing two interfaces, one 

simple enough to learn in a day and the other powerful enough to address nearly 

any need, LWP can be used by both novices and experts.

LWP's object oriented interface has provided a fruitful ground for extension 

modules. One popular example is LWP::Parallel by Marc Langheinrich, which 

extends LWP to allow users to make multiple requests simultaneously. Existing 

code that uses LWP can be modified to use LWP::Parallel very easily as most of the 

interfaces remain the same.

The LWP project has a homepage at http://www.linpro.no/lwp/. There you'll 

find links to the SourceForge hosted CVS repository and bug tracker, development 

mailing list, and a list of applications built with LWP. You'll also find links to the 

LWPng project, which Gisle Aas started to revise the implementation of LWP to 

better support HTTP/1.1.

18. With lots of help see the Acknowledgments section of the LWP documentation for a virtual 

who's who of Perl development.

19. LWP also supports HTTPS, FTP (using Net::FTP), Gopher, and NNTP, but HTTP is by far the 

most commonly used.

20. See Roy Fielding's site at http://www.ics.uci.edu/~fielding/.

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