Simple Comments: A Basic Perl-Based Comment System for Static Web Pages

On this page is a collection of information pertaining to WebRef's Simple Comments Perl script that allows you to implement a basic comment posting system on the static pages of your Web site. Here you'll find the latest Simple Comments zipped distribution file, a link to the latest changelog (included in the distribution), basic features and requirements of the system, links to the individual release notes, and whatever else I can think of. To get started with Simple Comments, I recommend that you read this page in its entirety. While not mandatory, the release notes for the versions also provide some potentially helpful bits of information--especially from a developer's perspective--and may be beneficial both from an implementation and an educational perspective, i.e., even if you aren't interested in using the Simple Comments script, you may be interested in reading some of the developmental issues I've encountered while developing it; points that are elaborated upon in the release notes.

Features

The key features and capabilities of the most recent version of Simple Comments include:

Requirements

To set up and use this system, you'll need Perl 5.6 or later installed on your server, the Apache Web Server with executable includes enabled (the ability to execute a Perl script when called in the HTML file as an include, see the setup instructions) access rights to create a directory outside the Web server's document root on your server, and access to place scripts into your cgi-bin. Basic Perl savvy and comfort in tossing files around on your Web server (as well as setting their access rights) will also be needed.

Though optional (beginning with .910), access to a password protected area (via Apache access controls) within your cgi-bin is also recommended; preferably reachable via an SSL server.

All but the HTML::Template module are typically installed with your Perl distribution; HTML::Template (and any others that may be missing) you can pick up from CPAN. XML::Simple is sometimes missing; if so, you may need to install both XML::Simple and XML::Parser (which XML::Simple relies on).

The following modules are recommended for use with OpenIDs (i.e., if openid_enabled is set to 1), and may in fact be required for use with some OpenID providers:

To use CAPTCHAs in your comment submission form, you need to decide whether you prefer to use the captchas.net system (see http://captchas.net) or the recaptcha system from Carnegie Mellon University (see http://recaptcha.net). If you select the captchas.net system, then you must first register with and receive a user-id and shared secret from http://captchas.net. If you select the recpatcha system, then register on the http://recaptcha.net site. Registration for both systems is free as of this writing; though both request that you warn them if your usage will be somewhat high (50k+ hits a day for captchas.net, or 100k+ hits a day for recaptcha.net). Once you've registered, you can then enable CAPTCHAS by including the appropriate _captcha and/or recaptcha_ parameter settings in the config.xml file.

To enable administrator notifications (the notify_admin_on_submit and notify_admin_on_visitor_confirm options) the Web user account (the account used by the Web server to perform system operations) must have access to sendmail. Additionally, sendmail access is required to enable the visitor registration system, since non-OpenID visitors are required to confirm their E-mail addresses as part of the registration process.

The comments script will work in both a standard and mod_perl enabled Web server.

Test Page

Want to submit a test comment? On most pages of our site (including this one) we'll only publish comments that actually pertain to the article, so you can't enter stuff like test comment or hello world. On our Test Page, however, we'll let you get away with those types of comments.

The test page also shows you what the comment display templates look like "out-of-the-box," i.e., the comments are displayed on the test page with the same templates in the Simple Comments distribution file (for the comments that appear on other pages of our site, we've modified the templates to match the WebRef look and feel). You can access the test page by clicking on the following link:

Downloads

You can download the latest version of Simple Comments by clicking this link: comments.zip. The download is provided as a zipped file; use your favorite extractor to unzip it.

Setting Up Simple Comments

Refer to the Readme.txt, included in the Zip distribution, for setup instructions.

Release Notes

These articles contain notes pertaining to each individual release of Simple Comments. Developers who are learning Perl may find these release notes of interest. The first release article (v.902) includes much of the information on this page, and also discusses the basic architecture of the scripts. Later release articles focus on new features, documentation of fixed bugs, and/or technical points of interest within the new release itself.

User Comments

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83. thomas
08/28/2008 01:43AM

issue installing

Hi Dan,

I'm having a bit of difficulty installing your perl script. perhaps you have come across this already and know the answer.

The comments script comes up and apears to work. I can Review what I've entered. however when I use the Add, button the page goes blank. teh status indicator at the bottom of the page indicates 'done'.

Bringing up the admin page seems to come up. however there are no comments to approve.

I'd assumed I had a file permission error or something but a double check seemed to indiate all is well.

also... the instructiosn indicate the "waiting_file.xml" should have a permision of RW, however this is not one of the files copied across from the zip file. I simply "touched" the file and set it up as indcated.

Thank you
Thomas

84. Dan Ragle
Admin
08/28/2008 11:26AM

29 total posts | view profile

Hi Thomas, thanks for giving the script a try, and sorry it's giving you trouble.

Do you have access to your server's error log? There's more than likely an indication there of the source of the problem. I just downloaded the .962 distribution and did a fresh install to make sure it's kosher, and it seems fine. Note the "waiting_file.xml" is a typo; it should be "waiting_comments.xml" (it's referred to correctly elsewhere in the docs; but is incorrect in the rights section). The system doesn't actually use "waiting_file.xml" (unless you've directly specified it as such in the config file). But note that that should not be the ultimate cause of the problem; since Simple Comments will actually create that file if it's missing, anyways.

Is it just the add button that's a problem? I.E., are all the other screens working fine (for example, can you review the comment prior to adding it)? If so, then the template mechanism itself must be fine. And since you're not getting the comment actually written to the file (it's not showing on the article or in the admin screen), that narrows the problem down even further.

Are you using the templates as shipped in the distribution (i.e., have you made any mods to the .tmpl files)?

My knee-jerk guess would be a problem with the submit log. Check the submit_log setting in your config file, and make sure it points either to an existing file that the Web user has read/write access to; or to a directory that the Web user has read/write access to (so that it can create the file if necessary). As a test, you could also just turn off the submit threshold entirely by setting submit_threshold to 0 in the config file (or clearing the submit_log setting entirely).

If you're still having trouble, then the easiest way to troubleshoot is to get access to that Web server error log. Let me know if you can get to it, and what error is being displayed.

Good luck!

87. Dan Ragle
Admin
08/29/2008 11:38AM

29 total posts | view profile

Hmmmmm... both problems would seem to be access related; i.e., the script is fine as long as it only needs to read data, but as soon as it tries to write something you get errors. Once you set the submit_threshold to 0 you bypassed the first file write, but the promptly received an error with the next write (which would have been to waiting_comments.xml).

Are you sure the Web server's effective UID is what you think it is? Try dropping this script in your cgi-bin and then hitting it through your server:

#!/usr/bin/perl -T

use strict;
use warnings;
use CGI ();

my $cgi = CGI->new();
print $cgi->header();

print '<h2>Real User: ', (getpwuid($<))[0], '</h2>', "\n";
print '<h2>Real Group ID(s): ', $(, '</h2>', "\n";
my $groupnames = join(', ', map { (getgrgid($_))[0] } (split(' ', $()));
print '<h2>Real Group(s): ', $groupnames, '</h2>', "\n";

print '<h2>Effective User: ', (getpwuid($>))[0], '</h2>', "\n";
print '<h2>Effective Group ID(s): ', $), '</h2>', "\n";
$groupnames = join(', ', map { (getgrgid($_))[0] } (split(' ', $))));
print '<h2>Effective Group(s): ', $groupnames, '</h2>', "\n";

Be sure to adjust the Perl path and executable rights, of course.

One other thing to try: On one of my systems here I seemed to be unable to access files in directories unless the directories were both readable and executable by everybody. So, you may need to mark your individual directories read/executable by owner, group, and others to be able to get to their files. You can always mark the individual files within the directories more strictly as necessary. Something else to try.

78. Dan Ragle
Admin
06/26/2008 03:51PM

29 total posts | view profile

*sigh* That's another bug.

The way it was supposed to work was that yes, the user could log in prior to confirmation (only if you have require_registration_approval set to 0); but they couldn't actually do anything as both view_profile and comment submissions were supposed to be blocked for the user. In retrospect it looks like view profile is behaving correctly (it just acts like the user doesn't exist) but comment submissions are allowed which is a definite error. I'll get that cleaned up in .960.

In the mean time, if you wanted to prevent comment submissions from unconfirmed users you could just make this mod in Comments.pm:

if (($visitor->status eq 'blocked') ||
         ($visitor->status eq 'deleted')) {
   return 'Sorry, this account has been ' . $visitor->status .
          '. Please contact our administrator for assistance.';
}
elsif ($visitor->status eq 'new') {
   return 'Sorry, this account has not yet been confirmed.';
}

If you wanted to prevent them from logging in entirely, you could make mods to check_login in comments.pl; but you'd have to make several adjustments there.

79. david
06/26/2008 09:07PM

Dan, thanks again. I would suggest, if you are working on this, to disallow logging in if not active. This is because the visitor might not realize the need to activate until much later if they don't immediately comment. They log in just to ensure they are properly registered. By then the email for activation might have been lost. Another possibility is wrongly typed but valid email addresses. Registration goes through (they can log in) but they cannot find the activation email.

Preventing these visitors from commenting is not a big deal - for some reason your program thinks they are not logged in and so the comments need my OK. I have publish on submit=0 and publish visitor comments on submit=1. This was how I caught the bug BTW. My main concern right now is that the system does not weed out wrongly typed but valid/spurious email addresses. Correcting these later is messy.

72. Dan Ragle
Admin
06/20/2008 05:33PM

29 total posts | view profile

Hi nicku,

Do I understand you correctly in that you do not want visitor registrations (per se), you just want to force all submitters to pass through your Apache-based authentication prior to allowing comment submissions?

Short of editing the code I can't think of a graceful solution. You would have to post two separate copies of the script, as you suggest, but if you only do that you would not stop the bad guys from submitting comments (from their own manually crafted forms) to the public copy of comments.pl (and they could probably find where it was easy enough; since various actions--such as RSS feeds--require it to be hit directly).

So you would probably want to additionally make some slight modifications to the public version of the comments.pl, to make sure that only logged in users could submit comments. One idea that comes to mind is to just de-list the add, review, and submit actions; i.e., change this:

my @all_actions      = qw(add display review submit clear rss);

to this:

my @all_actions      = qw(display rss);

That's untested, but it should work. Unfortunately it will also disable user registrations in the public copy of the script; but if I'm reading you right you won't need those, anyways.

The other trick is that you will need to adjust the comment submission form so that it points literally to the private copy of comments.pl; otherwise it will pull the location of the comments script from the config file (which you should have set to the public comments.pl) and therefore won't actually allow any comment submissions!

Good luck!

74. Dan Ragle
Admin
06/23/2008 09:38AM

29 total posts | view profile

Great, nicku, glad it's working for you. And thanks for the heads up on get_article_name, I hadn't considered multi-line titles. I should be able to get that fix added to the next release.

For now, I'd prefer you just link back to this site for the attribution, as opposed to posting your own version, if you don't mind. As you can tell, we haven't really settled on a license scheme for the code yet, so I don't think it would be appropriate to post a GPL version somewhere else. I have nothing against the GPL, but this code belongs to my employer, and as such I cannot make any forward-looking promises pertaining to future licensing.

Of course, if and when there is any change or concrete forward direction on licensing, I'll post it up here so that everybody will have the scoop.

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Simple Comments

A basic, Perl-based comment system for static Web pages

Contents:

Features

Requirements

Test Page

Downloads

Setting Up Simple Comments

Release Notes

home / programming / perl / simple comments