The Code

This Perl script, get_reviews.pl, builds a URL to the reviews page for a given ASIN, uses regular expressions to find the reviews, and breaks the review into its pieces: rating, title, date, reviewer, and the text of the review.

#!/usr/bin/perl
# get_reviews.pl
#
# A script to scrape Amazon, retrieve reviews, and write to a file
# Usage: perl get_reviews.pl <asin>
use strict;
use warnings;
use LWP::Simple;

# Take the asin from the command-line
my $asin = shift @ARGV or die "Usage: perl get_reviews.pl <asin>\n";

# Assemble the URL from the passed asin.
my $url = "http://amazon.com/o/tg/detail/-/$asin/?vi=customer-reviews";

# Set up unescape-HTML rules. Quicker than URI::Escape.
my %unescape = ('&quot;'=>'"', '&amp;'=>'&', '&nbsp;'=>' ');
my $unescape_re = join '|' => keys %unescape;

# Request the URL.
my $content = get($url);
die "Could not retrieve $url" unless $content;

#Remove everything before the reviews
$content =~ s!.*?Number of Reviews:!!ms;

# Loop through the HTML looking for matches
while ($content =~ m!<img.*?stars-(\d)-0.gif.*?>.*?<b>(.*?)</b>, (.*?)&return;
\n.*?Reviewer:\n<b>\n(.*?)</b>.*?</table>\n(.*?)<br>\n<br>!mgis) {

    my($rating,$title,$date,$reviewer,$review) = &return; 
($1||'',$2||'',$3||'',$4||'',$5||'');
    $reviewer =~ s!<.+?>!!g;   # drop all HTML tags
    $reviewer =~ s!\(.+?\)!!g;   # remove anything in parenthesis
    $reviewer =~ s!\n!!g;      # remove newlines
    $review =~ s!<.+?>!!g;     # drop all HTML tags
    $review =~ s/($unescape_re)/$unescape{$1}/migs; # unescape.

    # Print the results
    print "$title\n" . "$date\n" . "by $reviewer\n" .
          "$rating stars.\n\n" . "$review\n\n";

}