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Re^2: Parsing ITEM Tag from RSS feed using XML::RSS::LibXML

by mr_p (Scribe)
on Jun 25, 2010 at 17:07 UTC ( #846554=note: print w/replies, xml ) Need Help??

in reply to Re: Parsing ITEM Tag from RSS feed using XML::RSS::LibXML
in thread Parsing ITEM Tag from RSS feed using XML::RSS::LibXML

Here is my code.

The TODO part is where I have to put my code. But everything I read for XML::RSS::LibXML doesn't let me pull out "item" tag.

#!/usr/bin/perl use File::Path; use Data::Dumper; use LWP::UserAgent; use XML::RSS::LibXML; use POSIX qw(strftime); use Time::HiRes qw(gettimeofday tv_interval); my $client = LWP::UserAgent->new(); my ($fh, $feed, $feed_title, $count, $node); my $rss = XML::RSS::LibXML->new; my $website_name = "usnews"; my $url = ""; $firstListing = 1; while (1) { if ( $website_name eq "" ) { next; }; print "polling: $website_name url: $url\n"; $capture = $client->get("$url", ":content_file" => "/tmp/.rss_down +load_file") || die"$!\n"; $rss->parsefile('/tmp/.rss_download_file'); print "channel: $rss->{channel}->{title}\n"; @curListOfItems = (); foreach my $item (@{ $rss->{items} }) { my $node_link = $item->{link}; if (defined $node_link) { $curItem=$node_link ."\n"; push (@curListOfItems, $curItem); } } if ($#prevListOfItems != -1 ) { # @newlyAddedLinks will be latest in curListOfItems and not in + @prevListOfItems @newlyAddedLinks=grep!${{map{$_,1}@prevListOfItems}}{$_},@curL +istOfItems; foreach my $l (@newlyAddedLinks) { my $fileName=getFileName(); $fileName="/tmp/.$website_name\_${fileName}"; my $capture = $client->get("$l", ":content_file" => "$file +Name"); # TODO: Pull out the current Item tag ( <item> .....</item +> ) } print "Getting1 $filename\n"; } elsif ( $firstListing == 1) { print "Getting2 $filename\n"; foreach my $l (@curListOfItems) { my $fileName=getFileName(); $fileName="/tmp/.$website_name\_${fileName}"; my $capture = $client->get("$l", ":content_file" => "$file +Name"); # TODO: Pull out the current Item tag ( <item> .....</item +> ) } $firstListing = 0; } @prevListOfItems = @curListOfItems; open OUT_FILE, "> /tmp/.$website_name" || die "could not open file + $!"; print OUT_FILE "@prevListOfItems"; close OUT_FILE; sleep 1; } sub getFileName { my ($seconds, $microseconds) = gettimeofday(); my $padded_usecs = sprintf ('%06d', $microseconds); my ($logType, $str1, $str2) = split ('\|',$LogElement); $todaysDate = strftime "%d", localtime; $currentDateTime = strftime "%Y:%m:%d:%H:%M:%S", localtime; ($Year,$Month,$Date,$Hour,$Minute,$Seconds) = split /:/, $currentD +ateTime; $curYear = sprintf ('%04d', $Year); $curMonth = sprintf ('%02d', $Month); $curHour = sprintf ('%02d', $Hour); $curMinute = sprintf ('%02d', $Minute); $curDate = sprintf ('%02d', $Date); $curSec = sprintf ('%02d', $Seconds); my $fname = "${curYear}${curMonth}${curMonth}${curHour}${curMinute +}${curSec}.html"; return "$fname"; }

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Re^3: Parsing ITEM Tag from RSS feed using XML::RSS::LibXML
by rowdog (Curate) on Jun 26, 2010 at 18:12 UTC

    So, you're parsing an RSS file and then, for each item, you are fetching the link. What you get back is HTML not RSS so no, I don't think you'll get far trying to process the links with XML::RSS::LibXML.

    I'm not sure what you plan to do with the HTML documents but you already have XML::LibXML loaded into RAM so you could use it to parse the HTML:

    use XML::LibXML; my $dom = XML::LibXML->load_html( location => $fileName, recover => 1, # handle marginal HTML ); print $dom->toString;

    The parser options for load_html are documented in XML::LibXML::Parser.

      I just keep polling for the same rss feed and compare the Link from last poll and when ever new Links or Item has been added I only want to parse the Item tag of the New Item.

        I think I see now. You're pushing the links for each item onto an array and then reducing to the set of new links. Once there, you want to get back to the $rss->item that the link came from.

        You still have $rss so you can find the item by searching. Maybe something like

        sub find_item() { my $link = shift; for my $item ( $rss->{items} ) { $item->{link} eq $link and return $item; } return undef; }

        On reflection, I don't really care for the way you're keeping track of seen items. All that map grep stuff can be replaced with a simple hash. Maybe you'll have more luck if you restructure things a bit. Here's my skeletal example.

        #!/usr/bin/perl use strict; use warnings; use LWP::UserAgent; use XML::RSS::LibXML; my $url = ''; my $rss_file = '/tmp/.rss_download_file'; my $website_name = "usnews"; my %seen; my $client = LWP::UserAgent->new; my $rss = XML::RSS::LibXML->new; while ( 1 ) { print "polling: $website_name url: $url\n"; $client->mirror($url, $rss_file); # be nice to the server $rss->parsefile($rss_file) or die $!; if ( !%seen ) { print "first listing\n"; } foreach my $item ( @{ $rss->{items} } ) { $seen{ $item->{link} }++ and next; # already saw this item # do stuff with the new item print $item->{title}, "\n"; print "$item->{pubDate}\n"; #$client->get() ... } sleep 15 * 60; # 15 minutes, play nice }

        As an aside, fetching the RSS file every second is a good way to convince the server that you're attacking it. 15 minutes is probably okay but you should check the Terms of Service to be sure. On that same note, I like LWP::UserAgent's mirror method because it sends the "If-Modified-Since" header so you don't fetch the file if it hasn't changed.

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