Blog - Let's "nofollow"! (+ time-sensitive patch)

Let's "nofollow"! (+ time-sensitive patch)

A great idea to attempt to get rid of comment spam once for all has been suggested by the people at Google to MovableType. It sums up to adding an automatic rel="nofollow" to links posted by visitors (comments and trackbacks). Cooperating search engines (so far Google, Yahoo! and MSN... not bad for starters) will from now on ignore those links, making useless the comment spammers' malicious tactics such as increasing their PageRank.

MovableType has already issued a plugin that does the above. (By the way, the plugin is said to be for MT 3.x and MT 2.661, but I have installed it on my MT 2.64 and can confirm that all seems to work as supposed to.)

However one thing bothers me about this, as was pointed out by many, not only links in spam comments are being ignored, but also the good links posted by legit readers.

In an attempt to compromise, I changed a bit the Perl version plugin (nofollow.pl) to make it time-sensitive. This means that it will only add rel="nofollow" to comments/trackbacks that are less than X hours old. X hours corresponds to the maximum time I may be without despamming.
This sure isn't perfect, since some rel="nofollow"'s may remain in my static archives until I rebuild someday, but in my opinion it's better than leaving the plugin as is. Needless to say, if you don't despam regularly, don't use this.

So here's my patch.

nofollow.pl

Near the top of the file, let's say before the first eval (line 12), add the variable that contains the minimum number of hours. Change the 24 to whatever you like.

my $nofollowfy_hours_limit = 24;  # Number of hours to nofollowfy
                                  # set this to the maximum time you may not despam

Then, in the nofollowfy_hdlr sub, just below the line that reads
    my $out = $fn->($ctx, $args, $cond);
add:

    my $created_on;
    if ($tag eq 'CommentBody' || $tag eq 'CommentAuthorLink') {
        # Comment, use "created_on" from comment
        $created_on = $ctx->stash('comment')->created_on;
    }
    else {
        # Pings, get "created_on" from latest ping for current set
        # (code from Context.pm sub _hdlr_pings)
        require MT::Trackback;
        require MT::TBPing;
        my($tb, $cat);
        if (my $e = $ctx->stash('entry')) {
            $tb = MT::Trackback->load({ entry_id => $e->id });
            return '' unless $tb;
        } elsif ($cat = $ctx->stash('archive_category')) {
            $tb = MT::Trackback->load({ category_id => $cat->id });
            return '' unless $tb;
        } elsif (my $cat_name = $args->{category}) {
            require MT::Category;
            $cat = MT::Category->load({ label => $cat_name,
                                        blog_id => $ctx->stash('blog_id') })
                or return $ctx->error("No such category '$cat_name'");
            $tb = MT::Trackback->load({ category_id => $cat->id });
            return '' unless $tb;
        }
        my $tokens = $ctx->stash('tokens');
        my %terms;
        $terms{tb_id} = $tb->id if $tb;
        $terms{blog_id} = $ctx->stash('blog_id');
        my %arg = ('sort' => 'created_on', direction => 'descend', limit => 1);
        my $iter = MT::TBPing->load_iter(\%terms, \%arg);
        if (my $ping = $iter->()) {
            $ctx->stash('ping' => $ping);
            $created_on = $ping->created_on;
        }
    }
    # If date found and older than $nofollowfy_hours_limit,
    # return without nofollowfying
    if ($created_on) {
        my @ts = gmtime (MT::Util::offset_time(time, $ctx->stash('blog_id'))-$nofollowfy_hours_limit*3600);
        my $ts = sprintf "%04d%02d%02d%02d%02d%02d",
            $ts[5]+1900, $ts[4]+1, @ts[3,2,1,0];
        return $out unless $ts < $created_on;
    }

That's all. Seems to be working fine for me.
Comments/suggestions/improvements are welcome.

Disclaimer: This has only been tested with my good old MT 2.64 and is provided with no guarantee, so backup your files and use at your own risk.

Posted on January 19, 2005 at 22:39 | Tweet |

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