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+For [[http://rtgi.fr][$work]] I need to write scrapers. It used to be
+boring and painful. But thanks to
+[[http://search.cpan.org/~miyagawa/][miyagawa]], this is not true
+anymore. [[http://search.cpan.org/perldoc?Web::Scraper][Web::Scraper]]
+offer a nice API: you can write your rules using XPath, you can chaine
+rules, a nice and simple syntax, etc.
+
+I wanted to export my data from my last.fm account but there is no API
+for this, so I would need to scrap them. All the data are available
+[[http://www.last.fm/user/franckcuny/tracks][as a web page]] that list
+your music. So the scraper need to find how many pages, and find the
+content on each page to extract a list of your listening.
+
+For the total of pages, it's easy. Let's take a look at the HTML code
+and search for something like this:
+
+#+BEGIN_EXAMPLE
+    <a class="lastpage" href="/user/franckcuny/tracks?page=272">272</a>
+#+END_EXAMPLE
+
+the information is in a class *lastpage*.
+
+Now we need to find our data: I need the artist name, the song name and
+the date I played this song.
+
+All this data are in a *table*, and each new entry is in a *td*.
+
+#+BEGIN_EXAMPLE
+    <tr id="r9_1580_1920248170" class="odd">
+    [...]
+        <td class="subjectCell">
+        <a href="/music/Earth">Earth</a>
+        <a href="/music/Earth/_/Sonar+and+Depth+Charge">Sonar and Depth Charge</a>
+        </td>
+    [...]
+    <td class="dateCell last">
+        <abbr title="2009-05-13T15:18:25Z">13 May 3:18pm</abbr>
+    </td>
+#+END_EXAMPLE
+
+It's simple: information about a song are stored in *subjectcell*, and
+the artist and song title are each in a tag *a*. The date is in a
+*dateCell*, and we need the *title* from the *abbr* tag.
+
+The scraper we need to write is
+
+#+BEGIN_SRC perl
+    my $scrap = scraper {
+        process 'a[class="lastpage"]', 'last'    => 'TEXT';
+        process 'tr',                  'songs[]' => scraper {
+            process 'abbr',                    'date' => '@title';
+            process 'td[class="subjectCell"]', 'song' => scraper {
+                process 'a', 'info[]' => 'TEXT';
+            };
+        }
+    };
+#+END_SRC
+
+The first rule extract the total of page. The second iter on each *tr*
+and store the content in an array named *songs*. This *tr* need to be
+scraped. So we look the the *abbr* tag, and store in *date* the property
+*title*. Then we look for the song and artitst information. We look for
+the *td* with a class named *subjectCell*, a extract all links.
+
+Our final script will look like this:
+
+#+BEGIN_SRC perl
+    #!/usr/bin/perl -w
+    use strict;
+    use feature ':5.10';
+
+    use Web::Scraper;
+    use URI;
+    use IO::All -utf8;
+
+    my $username = shift;
+    my $output   = shift;
+
+    my $scrap = scraper {
+        process 'a[class="lastpage"]', 'last'    => 'TEXT';
+        process 'tr',                  'songs[]' => scraper {
+            process 'abbr',                    'date' => '@title';
+            process 'td[class="subjectCell"]', 'song' => scraper {
+                process 'a', 'info[]' => 'TEXT';
+            };
+        }
+    };
+
+    my $url = "http://www.last.fm/user/" . $username . "/tracks?page=";
+    scrap_lastfm(1);
+
+    sub scrap_lastfm {
+        my $page      = shift;
+        my $scrap_uri = $url . $page;
+        say $scrap_uri;
+        my $res      = $scrap->scrape(URI->new($scrap_uri));
+        my $lastpage = $res->{last};
+        foreach my $record (@{$res->{songs}}) {
+            my $line = join("\t", @{$record->{song}->{info}}, $record->{date});
+            $line . "\n" >> io $output;
+        }
+        $page++;
+        scrap_lastfm($page) if $page <= $lastpage;
+    }
+#+END_SRC
+
+You can use this script like this:
+
+#+BEGIN_EXAMPLE
+    % perl lastfmscraper.pl franckcuny store_data.txt
+#+END_EXAMPLE