NAME
LWP::UserAgent::Paranoid - A modern LWPx::ParanoidAgent for safer requests
SYNOPSIS
use LWP::UserAgent::Paranoid;
my $ua = LWP::UserAgent::Paranoid->new(
request_timeout => 5 # seconds; may be fractional
);
# use $ua as a normal LWP::UserAgent...
my $response = $ua->get("http://example.com");
# allow requests to localhost and 127.0.0.1
$ua->whitelisted_hosts('localhost', '127.0.0.1');DESCRIPTION
This module is a more modern LWPx::ParanoidAgent with cleaner internals and a very similar feature set. It is a not a drop-in replacement, however, since the API differs.
The primary features provided by this module:
Overall request timeout
A configurable timeout from start to finish of a "logical" request made by calling one of LWP::UserAgent's request methods. It encompasses all followed redirects to ensure that you can't be tarpitted by a series of stalling redirects. The default is 5 seconds.
Blocked private hosts and IP address ranges
All new agents are automatically made paranoid of private hostnames and IP address ranges using LWPx::ParanoidHandler. You may access the Net::DNS::Paranoid resolver via the "resolver" method in order to customize its behaviour.
For simple whitelisting and blacklisting, you may call "whitelisted_hosts" or "blocked_hosts". These methods are proxied to the corresponding methods of Net::DNS::Paranoid. The only difference is that you may pass a list to this class' methods.
EVEN MORE PARANOIA
You may also wish to tune standard LWP::UserAgent parameters for greater paranoria depending on your requirements:
Maximum number of redirects
Although generally unnecessary given the request timeout, you can tune "max_redirects" in LWP::UserAgent down from the default of 7.
Protocols/URI schemes allowed
If you don't want to allow requests for schemes other than http and https, you may use "protocols_allowed" in LWP::UserAgent either as a method or as an option to new.
$ua->protocols_allowed(["http", "https"]);WHY NOT LWPx::ParanoidAgent?
LWPx::ParanoidAgent's implemention involves a 2009-era fork of LWP's http and https protocol handlers, and it is no longer maintained. A more maintainable approach is taken by this module and LWPx::ParanoidHandler.
METHODS
All methods from LWP::UserAgent are available via inheritence. In addition, the following methods are available:
request_timeout
Gets/sets the timeout which encapsulates each logical request, including any redirects which are followed. The default is 5 seconds. Fractional seconds are OK.
resolver
Gets the DNS resolver which is used to block private hosts. There is little need to set your own but if you do it should be an Net::DNS::Paranoid object. This attribute is read-only, so if you want to replace the resolver you need to call "new" again to create a new LWP::UserAgent::Paranoid.
Use the blocking and whitelisting methods on the resolver, or this class' "whitelisted_hosts" and "blocked_hosts", to customize the behaviour.
whitelisted_hosts / blocked_hosts
Accepts a single arrayref and proxies to the method of the same name on the "resolver". For convenience, you may pass a list which will be passed as an arrayref to the resolver's method.
CAVEATS
The overall request timeout is implemented using SIGALRM. Any $SIG{ALRM} handler from an outer scope is replaced in the scope of LWP::UserAgent::Paranoid requests.
BUGS
All bugs should be reported via rt.cpan.org or bug-LWP-UserAgent-Paranoid@rt.cpan.org.
AUTHOR
Thomas Sibley <tsibley@cpan.org>
LICENSE AND COPYRIGHT
This software is primarily Copyright (c) 2013 by Best Practical Solutions, with parts of it Copyright (c) 2014-2015 by Thomas Sibley.
This is free software, licensed under:
The GNU General Public License, Version 2, June 1991