--- /dev/null
+=head1 NAME
+
+lwptut -- An LWP Tutorial
+
+=head1 DESCRIPTION
+
+LWP (short for "Library for WWW in Perl") is a very popular group of
+Perl modules for accessing data on the Web. Like most Perl
+module-distributions, each of LWP's component modules comes with
+documentation that is a complete reference to its interface. However,
+there are so many modules in LWP that it's hard to know where to start
+looking for information on how to do even the simplest most common
+things.
+
+Really introducing you to using LWP would require a whole book -- a book
+that just happens to exist, called I<Perl & LWP>. But this article
+should give you a taste of how you can go about some common tasks with
+LWP.
+
+
+=head2 Getting documents with LWP::Simple
+
+If you just want to get what's at a particular URL, the simplest way
+to do it is LWP::Simple's functions.
+
+In a Perl program, you can call its C<get($url)> function. It will try
+getting that URL's content. If it works, then it'll return the
+content; but if there's some error, it'll return undef.
+
+ my $url = 'http://freshair.npr.org/dayFA.cfm?todayDate=current';
+ # Just an example: the URL for the most recent /Fresh Air/ show
+
+ use LWP::Simple;
+ my $content = get $url;
+ die "Couldn't get $url" unless defined $content;
+
+ # Then go do things with $content, like this:
+
+ if($content =~ m/jazz/i) {
+ print "They're talking about jazz today on Fresh Air!\n";
+ }
+ else {
+ print "Fresh Air is apparently jazzless today.\n";
+ }
+
+The handiest variant on C<get> is C<getprint>, which is useful in Perl
+one-liners. If it can get the page whose URL you provide, it sends it
+to STDOUT; otherwise it complains to STDERR.
+
+ % perl -MLWP::Simple -e "getprint 'http://cpan.org/RECENT'"
+
+That is the URL of a plaintext file that lists new files in CPAN in
+the past two weeks. You can easily make it part of a tidy little
+shell command, like this one that mails you the list of new
+C<Acme::> modules:
+
+ % perl -MLWP::Simple -e "getprint 'http://cpan.org/RECENT'" \
+ | grep "/by-module/Acme" | mail -s "New Acme modules! Joy!" $USER
+
+There are other useful functions in LWP::Simple, including one function
+for running a HEAD request on a URL (useful for checking links, or
+getting the last-revised time of a URL), and two functions for
+saving/mirroring a URL to a local file. See L<the LWP::Simple
+documentation|LWP::Simple> for the full details, or chapter 2 of I<Perl
+& LWP> for more examples.
+
+
+
+=for comment
+ ##########################################################################
+
+
+
+=head2 The Basics of the LWP Class Model
+
+LWP::Simple's functions are handy for simple cases, but its functions
+don't support cookies or authorization, don't support setting header
+lines in the HTTP request, generally don't support reading header lines
+in the HTTP response (notably the full HTTP error message, in case of an
+error). To get at all those features, you'll have to use the full LWP
+class model.
+
+While LWP consists of dozens of classes, the main two that you have to
+understand are L<LWP::UserAgent> and L<HTTP::Response>. LWP::UserAgent
+is a class for "virtual browsers" which you use for performing requests,
+and L<HTTP::Response> is a class for the responses (or error messages)
+that you get back from those requests.
+
+The basic idiom is C<< $response = $browser->get($url) >>, or more fully
+illustrated:
+
+ # Early in your program:
+
+ use LWP 5.64; # Loads all important LWP classes, and makes
+ # sure your version is reasonably recent.
+
+ my $browser = LWP::UserAgent->new;
+
+ ...
+
+ # Then later, whenever you need to make a get request:
+ my $url = 'http://freshair.npr.org/dayFA.cfm?todayDate=current';
+
+ my $response = $browser->get( $url );
+ die "Can't get $url -- ", $response->status_line
+ unless $response->is_success;
+
+ die "Hey, I was expecting HTML, not ", $response->content_type
+ unless $response->content_type eq 'text/html';
+ # or whatever content-type you're equipped to deal with
+
+ # Otherwise, process the content somehow:
+
+ if($response->decoded_content =~ m/jazz/i) {
+ print "They're talking about jazz today on Fresh Air!\n";
+ }
+ else {
+ print "Fresh Air is apparently jazzless today.\n";
+ }
+
+There are two objects involved: C<$browser>, which holds an object of
+class LWP::UserAgent, and then the C<$response> object, which is of
+class HTTP::Response. You really need only one browser object per
+program; but every time you make a request, you get back a new
+HTTP::Response object, which will have some interesting attributes:
+
+=over
+
+=item *
+
+A status code indicating
+success or failure
+(which you can test with C<< $response->is_success >>).
+
+=item *
+
+An HTTP status
+line that is hopefully informative if there's failure (which you can
+see with C<< $response->status_line >>,
+returning something like "404 Not Found").
+
+=item *
+
+A MIME content-type like "text/html", "image/gif",
+"application/xml", etc., which you can see with
+C<< $response->content_type >>
+
+=item *
+
+The actual content of the response, in C<< $response->decoded_content >>.
+If the response is HTML, that's where the HTML source will be; if
+it's a GIF, then C<< $response->decoded_content >> will be the binary
+GIF data.
+
+=item *
+
+And dozens of other convenient and more specific methods that are
+documented in the docs for L<HTML::Response>, and its superclasses
+L<HTML::Message> and L<HTML::Headers>.
+
+=back
+
+
+
+=for comment
+ ##########################################################################
+
+
+
+=head2 Adding Other HTTP Request Headers
+
+The most commonly used syntax for requests is C<< $response =
+$browser->get($url) >>, but in truth, you can add extra HTTP header
+lines to the request by adding a list of key-value pairs after the URL,
+like so:
+
+ $response = $browser->get( $url, $key1, $value1, $key2, $value2, ... );
+
+For example, here's how to send some more Netscape-like headers, in case
+you're dealing with a site that would otherwise reject your request:
+
+
+ my @ns_headers = (
+ 'User-Agent' => 'Mozilla/4.76 [en] (Win98; U)',
+ 'Accept' => 'image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*',
+ 'Accept-Charset' => 'iso-8859-1,*,utf-8',
+ 'Accept-Language' => 'en-US',
+ );
+
+ ...
+
+ $response = $browser->get($url, @ns_headers);
+
+If you weren't reusing that array, you could just go ahead and do this:
+
+ $response = $browser->get($url,
+ 'User-Agent' => 'Mozilla/4.76 [en] (Win98; U)',
+ 'Accept' => 'image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*',
+ 'Accept-Charset' => 'iso-8859-1,*,utf-8',
+ 'Accept-Language' => 'en-US',
+ );
+
+If you were only ever changing the 'User-Agent' line, you could just change
+the C<$browser> object's default line from "libwww-perl/5.65" (or the like)
+to whatever you like, using the LWP::UserAgent C<agent> method:
+
+ $browser->agent('Mozilla/4.76 [en] (Win98; U)');
+
+
+
+=for comment
+ ##########################################################################
+
+
+
+=head2 Enabling Cookies
+
+A default LWP::UserAgent object acts like a browser with its cookies
+support turned off. There are various ways of turning it on, by setting
+its C<cookie_jar> attribute. A "cookie jar" is an object representing
+a little database of all
+the HTTP cookies that a browser can know about. It can correspond to a
+file on disk (the way Netscape uses its F<cookies.txt> file), or it can
+be just an in-memory object that starts out empty, and whose collection of
+cookies will disappear once the program is finished running.
+
+To give a browser an in-memory empty cookie jar, you set its C<cookie_jar>
+attribute like so:
+
+ $browser->cookie_jar({});
+
+To give it a copy that will be read from a file on disk, and will be saved
+to it when the program is finished running, set the C<cookie_jar> attribute
+like this:
+
+ use HTTP::Cookies;
+ $browser->cookie_jar( HTTP::Cookies->new(
+ 'file' => '/some/where/cookies.lwp',
+ # where to read/write cookies
+ 'autosave' => 1,
+ # save it to disk when done
+ ));
+
+That file will be an LWP-specific format. If you want to be access the
+cookies in your Netscape cookies file, you can use the
+HTTP::Cookies::Netscape class:
+
+ use HTTP::Cookies;
+ # yes, loads HTTP::Cookies::Netscape too
+
+ $browser->cookie_jar( HTTP::Cookies::Netscape->new(
+ 'file' => 'c:/Program Files/Netscape/Users/DIR-NAME-HERE/cookies.txt',
+ # where to read cookies
+ ));
+
+You could add an C<< 'autosave' => 1 >> line as further above, but at
+time of writing, it's uncertain whether Netscape might discard some of
+the cookies you could be writing back to disk.
+
+
+
+=for comment
+ ##########################################################################
+
+
+
+=head2 Posting Form Data
+
+Many HTML forms send data to their server using an HTTP POST request, which
+you can send with this syntax:
+
+ $response = $browser->post( $url,
+ [
+ formkey1 => value1,
+ formkey2 => value2,
+ ...
+ ],
+ );
+
+Or if you need to send HTTP headers:
+
+ $response = $browser->post( $url,
+ [
+ formkey1 => value1,
+ formkey2 => value2,
+ ...
+ ],
+ headerkey1 => value1,
+ headerkey2 => value2,
+ );
+
+For example, the following program makes a search request to AltaVista
+(by sending some form data via an HTTP POST request), and extracts from
+the HTML the report of the number of matches:
+
+ use strict;
+ use warnings;
+ use LWP 5.64;
+ my $browser = LWP::UserAgent->new;
+
+ my $word = 'tarragon';
+
+ my $url = 'http://www.altavista.com/sites/search/web';
+ my $response = $browser->post( $url,
+ [ 'q' => $word, # the Altavista query string
+ 'pg' => 'q', 'avkw' => 'tgz', 'kl' => 'XX',
+ ]
+ );
+ die "$url error: ", $response->status_line
+ unless $response->is_success;
+ die "Weird content type at $url -- ", $response->content_type
+ unless $response->content_type eq 'text/html';
+
+ if( $response->decoded_content =~ m{AltaVista found ([0-9,]+) results} ) {
+ # The substring will be like "AltaVista found 2,345 results"
+ print "$word: $1\n";
+ }
+ else {
+ print "Couldn't find the match-string in the response\n";
+ }
+
+
+
+=for comment
+ ##########################################################################
+
+
+
+=head2 Sending GET Form Data
+
+Some HTML forms convey their form data not by sending the data
+in an HTTP POST request, but by making a normal GET request with
+the data stuck on the end of the URL. For example, if you went to
+C<imdb.com> and ran a search on "Blade Runner", the URL you'd see
+in your browser window would be:
+
+ http://us.imdb.com/Tsearch?title=Blade%20Runner&restrict=Movies+and+TV
+
+To run the same search with LWP, you'd use this idiom, which involves
+the URI class:
+
+ use URI;
+ my $url = URI->new( 'http://us.imdb.com/Tsearch' );
+ # makes an object representing the URL
+
+ $url->query_form( # And here the form data pairs:
+ 'title' => 'Blade Runner',
+ 'restrict' => 'Movies and TV',
+ );
+
+ my $response = $browser->get($url);
+
+See chapter 5 of I<Perl & LWP> for a longer discussion of HTML forms
+and of form data, and chapters 6 through 9 for a longer discussion of
+extracting data from HTML.
+
+
+
+=head2 Absolutizing URLs
+
+The URI class that we just mentioned above provides all sorts of methods
+for accessing and modifying parts of URLs (such as asking sort of URL it
+is with C<< $url->scheme >>, and asking what host it refers to with C<<
+$url->host >>, and so on, as described in L<the docs for the URI
+class|URI>. However, the methods of most immediate interest
+are the C<query_form> method seen above, and now the C<new_abs> method
+for taking a probably-relative URL string (like "../foo.html") and getting
+back an absolute URL (like "http://www.perl.com/stuff/foo.html"), as
+shown here:
+
+ use URI;
+ $abs = URI->new_abs($maybe_relative, $base);
+
+For example, consider this program that matches URLs in the HTML
+list of new modules in CPAN:
+
+ use strict;
+ use warnings;
+ use LWP;
+ my $browser = LWP::UserAgent->new;
+
+ my $url = 'http://www.cpan.org/RECENT.html';
+ my $response = $browser->get($url);
+ die "Can't get $url -- ", $response->status_line
+ unless $response->is_success;
+
+ my $html = $response->decoded_content;
+ while( $html =~ m/<A HREF=\"(.*?)\"/g ) {
+ print "$1\n";
+ }
+
+When run, it emits output that starts out something like this:
+
+ MIRRORING.FROM
+ RECENT
+ RECENT.html
+ authors/00whois.html
+ authors/01mailrc.txt.gz
+ authors/id/A/AA/AASSAD/CHECKSUMS
+ ...
+
+However, if you actually want to have those be absolute URLs, you
+can use the URI module's C<new_abs> method, by changing the C<while>
+loop to this:
+
+ while( $html =~ m/<A HREF=\"(.*?)\"/g ) {
+ print URI->new_abs( $1, $response->base ) ,"\n";
+ }
+
+(The C<< $response->base >> method from L<HTTP::Message|HTTP::Message>
+is for returning what URL
+should be used for resolving relative URLs -- it's usually just
+the same as the URL that you requested.)
+
+That program then emits nicely absolute URLs:
+
+ http://www.cpan.org/MIRRORING.FROM
+ http://www.cpan.org/RECENT
+ http://www.cpan.org/RECENT.html
+ http://www.cpan.org/authors/00whois.html
+ http://www.cpan.org/authors/01mailrc.txt.gz
+ http://www.cpan.org/authors/id/A/AA/AASSAD/CHECKSUMS
+ ...
+
+See chapter 4 of I<Perl & LWP> for a longer discussion of URI objects.
+
+Of course, using a regexp to match hrefs is a bit simplistic, and for
+more robust programs, you'll probably want to use an HTML-parsing module
+like L<HTML::LinkExtor> or L<HTML::TokeParser> or even maybe
+L<HTML::TreeBuilder>.
+
+
+
+
+=for comment
+ ##########################################################################
+
+=head2 Other Browser Attributes
+
+LWP::UserAgent objects have many attributes for controlling how they
+work. Here are a few notable ones:
+
+=over
+
+=item *
+
+C<< $browser->timeout(15); >>
+
+This sets this browser object to give up on requests that don't answer
+within 15 seconds.
+
+
+=item *
+
+C<< $browser->protocols_allowed( [ 'http', 'gopher'] ); >>
+
+This sets this browser object to not speak any protocols other than HTTP
+and gopher. If it tries accessing any other kind of URL (like an "ftp:"
+or "mailto:" or "news:" URL), then it won't actually try connecting, but
+instead will immediately return an error code 500, with a message like
+"Access to 'ftp' URIs has been disabled".
+
+
+=item *
+
+C<< use LWP::ConnCache; $browser->conn_cache(LWP::ConnCache->new()); >>
+
+This tells the browser object to try using the HTTP/1.1 "Keep-Alive"
+feature, which speeds up requests by reusing the same socket connection
+for multiple requests to the same server.
+
+
+=item *
+
+C<< $browser->agent( 'SomeName/1.23 (more info here maybe)' ) >>
+
+This changes how the browser object will identify itself in
+the default "User-Agent" line is its HTTP requests. By default,
+it'll send "libwww-perl/I<versionnumber>", like
+"libwww-perl/5.65". You can change that to something more descriptive
+like this:
+
+ $browser->agent( 'SomeName/3.14 (contact@robotplexus.int)' );
+
+Or if need be, you can go in disguise, like this:
+
+ $browser->agent( 'Mozilla/4.0 (compatible; MSIE 5.12; Mac_PowerPC)' );
+
+
+=item *
+
+C<< push @{ $ua->requests_redirectable }, 'POST'; >>
+
+This tells this browser to obey redirection responses to POST requests
+(like most modern interactive browsers), even though the HTTP RFC says
+that should not normally be done.
+
+
+=back
+
+
+For more options and information, see L<the full documentation for
+LWP::UserAgent|LWP::UserAgent>.
+
+
+
+=for comment
+ ##########################################################################
+
+
+
+=head2 Writing Polite Robots
+
+If you want to make sure that your LWP-based program respects F<robots.txt>
+files and doesn't make too many requests too fast, you can use the LWP::RobotUA
+class instead of the LWP::UserAgent class.
+
+LWP::RobotUA class is just like LWP::UserAgent, and you can use it like so:
+
+ use LWP::RobotUA;
+ my $browser = LWP::RobotUA->new('YourSuperBot/1.34', 'you@yoursite.com');
+ # Your bot's name and your email address
+
+ my $response = $browser->get($url);
+
+But HTTP::RobotUA adds these features:
+
+
+=over
+
+=item *
+
+If the F<robots.txt> on C<$url>'s server forbids you from accessing
+C<$url>, then the C<$browser> object (assuming it's of class LWP::RobotUA)
+won't actually request it, but instead will give you back (in C<$response>) a 403 error
+with a message "Forbidden by robots.txt". That is, if you have this line:
+
+ die "$url -- ", $response->status_line, "\nAborted"
+ unless $response->is_success;
+
+then the program would die with an error message like this:
+
+ http://whatever.site.int/pith/x.html -- 403 Forbidden by robots.txt
+ Aborted at whateverprogram.pl line 1234
+
+=item *
+
+If this C<$browser> object sees that the last time it talked to
+C<$url>'s server was too recently, then it will pause (via C<sleep>) to
+avoid making too many requests too often. How long it will pause for, is
+by default one minute -- but you can control it with the C<<
+$browser->delay( I<minutes> ) >> attribute.
+
+For example, this code:
+
+ $browser->delay( 7/60 );
+
+...means that this browser will pause when it needs to avoid talking to
+any given server more than once every 7 seconds.
+
+=back
+
+For more options and information, see L<the full documentation for
+LWP::RobotUA|LWP::RobotUA>.
+
+
+
+
+
+=for comment
+ ##########################################################################
+
+=head2 Using Proxies
+
+In some cases, you will want to (or will have to) use proxies for
+accessing certain sites and/or using certain protocols. This is most
+commonly the case when your LWP program is running (or could be running)
+on a machine that is behind a firewall.
+
+To make a browser object use proxies that are defined in the usual
+environment variables (C<HTTP_PROXY>, etc.), just call the C<env_proxy>
+on a user-agent object before you go making any requests on it.
+Specifically:
+
+ use LWP::UserAgent;
+ my $browser = LWP::UserAgent->new;
+
+ # And before you go making any requests:
+ $browser->env_proxy;
+
+For more information on proxy parameters, see L<the LWP::UserAgent
+documentation|LWP::UserAgent>, specifically the C<proxy>, C<env_proxy>,
+and C<no_proxy> methods.
+
+
+
+=for comment
+ ##########################################################################
+
+=head2 HTTP Authentication
+
+Many web sites restrict access to documents by using "HTTP
+Authentication". This isn't just any form of "enter your password"
+restriction, but is a specific mechanism where the HTTP server sends the
+browser an HTTP code that says "That document is part of a protected
+'realm', and you can access it only if you re-request it and add some
+special authorization headers to your request".
+
+For example, the Unicode.org admins stop email-harvesting bots from
+harvesting the contents of their mailing list archives, by protecting
+them with HTTP Authentication, and then publicly stating the username
+and password (at C<http://www.unicode.org/mail-arch/>) -- namely
+username "unicode-ml" and password "unicode".
+
+For example, consider this URL, which is part of the protected
+area of the web site:
+
+ http://www.unicode.org/mail-arch/unicode-ml/y2002-m08/0067.html
+
+If you access that with a browser, you'll get a prompt
+like
+"Enter username and password for 'Unicode-MailList-Archives' at server
+'www.unicode.org'".
+
+In LWP, if you just request that URL, like this:
+
+ use LWP;
+ my $browser = LWP::UserAgent->new;
+
+ my $url =
+ 'http://www.unicode.org/mail-arch/unicode-ml/y2002-m08/0067.html';
+ my $response = $browser->get($url);
+
+ die "Error: ", $response->header('WWW-Authenticate') || 'Error accessing',
+ # ('WWW-Authenticate' is the realm-name)
+ "\n ", $response->status_line, "\n at $url\n Aborting"
+ unless $response->is_success;
+
+Then you'll get this error:
+
+ Error: Basic realm="Unicode-MailList-Archives"
+ 401 Authorization Required
+ at http://www.unicode.org/mail-arch/unicode-ml/y2002-m08/0067.html
+ Aborting at auth1.pl line 9. [or wherever]
+
+...because the C<$browser> doesn't know any the username and password
+for that realm ("Unicode-MailList-Archives") at that host
+("www.unicode.org"). The simplest way to let the browser know about this
+is to use the C<credentials> method to let it know about a username and
+password that it can try using for that realm at that host. The syntax is:
+
+ $browser->credentials(
+ 'servername:portnumber',
+ 'realm-name',
+ 'username' => 'password'
+ );
+
+In most cases, the port number is 80, the default TCP/IP port for HTTP; and
+you usually call the C<credentials> method before you make any requests.
+For example:
+
+ $browser->credentials(
+ 'reports.mybazouki.com:80',
+ 'web_server_usage_reports',
+ 'plinky' => 'banjo123'
+ );
+
+So if we add the following to the program above, right after the C<<
+$browser = LWP::UserAgent->new; >> line...
+
+ $browser->credentials( # add this to our $browser 's "key ring"
+ 'www.unicode.org:80',
+ 'Unicode-MailList-Archives',
+ 'unicode-ml' => 'unicode'
+ );
+
+...then when we run it, the request succeeds, instead of causing the
+C<die> to be called.
+
+
+
+=for comment
+ ##########################################################################
+
+=head2 Accessing HTTPS URLs
+
+When you access an HTTPS URL, it'll work for you just like an HTTP URL
+would -- if your LWP installation has HTTPS support (via an appropriate
+Secure Sockets Layer library). For example:
+
+ use LWP;
+ my $url = 'https://www.paypal.com/'; # Yes, HTTPS!
+ my $browser = LWP::UserAgent->new;
+ my $response = $browser->get($url);
+ die "Error at $url\n ", $response->status_line, "\n Aborting"
+ unless $response->is_success;
+ print "Whee, it worked! I got that ",
+ $response->content_type, " document!\n";
+
+If your LWP installation doesn't have HTTPS support set up, then the
+response will be unsuccessful, and you'll get this error message:
+
+ Error at https://www.paypal.com/
+ 501 Protocol scheme 'https' is not supported
+ Aborting at paypal.pl line 7. [or whatever program and line]
+
+If your LWP installation I<does> have HTTPS support installed, then the
+response should be successful, and you should be able to consult
+C<$response> just like with any normal HTTP response.
+
+For information about installing HTTPS support for your LWP
+installation, see the helpful F<README.SSL> file that comes in the
+libwww-perl distribution.
+
+
+=for comment
+ ##########################################################################
+
+
+
+=head2 Getting Large Documents
+
+When you're requesting a large (or at least potentially large) document,
+a problem with the normal way of using the request methods (like C<<
+$response = $browser->get($url) >>) is that the response object in
+memory will have to hold the whole document -- I<in memory>. If the
+response is a thirty megabyte file, this is likely to be quite an
+imposition on this process's memory usage.
+
+A notable alternative is to have LWP save the content to a file on disk,
+instead of saving it up in memory. This is the syntax to use:
+
+ $response = $ua->get($url,
+ ':content_file' => $filespec,
+ );
+
+For example,
+
+ $response = $ua->get('http://search.cpan.org/',
+ ':content_file' => '/tmp/sco.html'
+ );
+
+When you use this C<:content_file> option, the C<$response> will have
+all the normal header lines, but C<< $response->content >> will be
+empty.
+
+Note that this ":content_file" option isn't supported under older
+versions of LWP, so you should consider adding C<use LWP 5.66;> to check
+the LWP version, if you think your program might run on systems with
+older versions.
+
+If you need to be compatible with older LWP versions, then use
+this syntax, which does the same thing:
+
+ use HTTP::Request::Common;
+ $response = $ua->request( GET($url), $filespec );
+
+
+=for comment
+ ##########################################################################
+
+
+=head1 SEE ALSO
+
+Remember, this article is just the most rudimentary introduction to
+LWP -- to learn more about LWP and LWP-related tasks, you really
+must read from the following:
+
+=over
+
+=item *
+
+L<LWP::Simple> -- simple functions for getting/heading/mirroring URLs
+
+=item *
+
+L<LWP> -- overview of the libwww-perl modules
+
+=item *
+
+L<LWP::UserAgent> -- the class for objects that represent "virtual browsers"
+
+=item *
+
+L<HTTP::Response> -- the class for objects that represent the response to
+a LWP response, as in C<< $response = $browser->get(...) >>
+
+=item *
+
+L<HTTP::Message> and L<HTTP::Headers> -- classes that provide more methods
+to HTTP::Response.
+
+=item *
+
+L<URI> -- class for objects that represent absolute or relative URLs
+
+=item *
+
+L<URI::Escape> -- functions for URL-escaping and URL-unescaping strings
+(like turning "this & that" to and from "this%20%26%20that").
+
+=item *
+
+L<HTML::Entities> -- functions for HTML-escaping and HTML-unescaping strings
+(like turning "C. & E. BrontE<euml>" to and from "C. & E. Brontë")
+
+=item *
+
+L<HTML::TokeParser> and L<HTML::TreeBuilder> -- classes for parsing HTML
+
+=item *
+
+L<HTML::LinkExtor> -- class for finding links in HTML documents
+
+=item *
+
+The book I<Perl & LWP> by Sean M. Burke. O'Reilly & Associates, 2002.
+ISBN: 0-596-00178-9. C<http://www.oreilly.com/catalog/perllwp/>
+
+=back
+
+
+=head1 COPYRIGHT
+
+Copyright 2002, Sean M. Burke. You can redistribute this document and/or
+modify it, but only under the same terms as Perl itself.
+
+=head1 AUTHOR
+
+Sean M. Burke C<sburke@cpan.org>
+
+=for comment
+ ##########################################################################
+
+=cut
+
+# End of Pod
projects / dh-make-perl / blobdiff