Results tagged “CGI::Simple”

A midwinter box bike ride
Recently I've been reviewing how various Perl frameworks and modules generate HTTP headers. After reviewing several approaches, it's clear that there are two major camps: those which put the response headers in a specific order and those which don't. Surely one approach or the other would seem like it would be more spec-compliant, but RFC 2616 provides [conflicting guidance on this point]( The bottom line is that spec says that *"the order in which header fields with differing field names are received is not significant"*. But then it goes on to say that it is a "good practice" (and it puts "good practice" in quotes) to order the headers a particular way. So, without strict guidance from the spec about the importance of header ordering, it would be interesting to know if header order caused a problem in practice. The [Plack::Middleware::RearrangeHeaders]( documentation suggests there is some benefit to strict header ordering: *"to work around buggy clients like very old MSIE or broken HTTP proxy servers"* You might wonder what the big deal is-- why not just stick to the "good practice" recommendation all the time? The difference can be seen in the benchmarks provided by [HTTP::Headers::Fast]( By ignoring the good-practice header order, an alternate implementation was able to speed-up header generation to be about twice as fast. Considering that a web-app needs to generate a header on every single request, making header generation smaller and faster is potentially a tangible win, while also still being spec-compliant.
baby sleeps again I've spent a lot time recently [triaging bugs for]( I've enjoyed the process, and respect as a widely used Perl module. I'm not in love all aspects of module. I don't use or recommend the HTML generation features-- I recommend using HTML template files and [HTML::FillInForm]( for filling them. Whenever I think about how I'd like to change,what I have mind is often the same choice that [CGI::Simple]( made. There was a time years ago that I focused my attention on CGI::Simple and tried it in production, only to be bit by a compatibility issue, so I reverted back to I don't remember what the specific issue, and it's likely been fixed by now. But the pragmatic point remained with me: CGI::Simple may have clean code and a good test suite, but it's not necessarily free of defects and in particularly it lacks the vastly larger user base that has to provide real world beta testing.
This weekend I spent some quality time with HTTP Cookie Specs ( [RFC 2109]( and [RFC 2695]( ), and looked closely how at the cookie parsing and handling is done in three Perl frameworks: [Titanium](, [Catalyst]( and [Mojo]( Titanium uses [CGI::Cookie]( by default, while Catalyst uses [CGI::Simple::Cookie]( and Mojo uses built-in modules including [Mojo::Cookie::Request]( I'll look at these solutions through the filters of Standards, Security, and Convenience. ## Standards: Max-Age, Set-Cookie2 and commas Max-Age is cookie attribute which gives the expiration time as a relative value. This is considered a more secure replacement for the "Expires" header, which gives the time as an absolute value, making it vulnerable to clock skew on the user's systems. and Mojo support it, but CGI::Simple does not. This is potentially an issue for Catalyst users, if they believe they have Max-Age support because the documentation refers them to CGI::Cookie, but they actually don't because they are using CGI::Simple::Cookie. Set-Cookie2 is a standard from 2000 to replace Set-Cookie, which became a standard in 1997. Mojo is the only of the three that supports it. However, Set-Cookie2 [never caught on]( Firefox 3 doesn't even support it, and neither does IE 6. Still, I like the idea of deciding for myself about supporting new standards, rather than having tools that only support older standards. Mojo wins here. The RFCs say that servers should accept a comma as well as semicolon between cookie values. and Mojo comply here, CGI::Simple does not. (I've submitted a [patch to address this](, along with a few other places I felt CGI::Simple cookie parsing lagged ## Security CGI::Simple cookies are potentially less secure because they lack "Max-Age" support. Mojo's cookie implementation appears to be vulnerable to an injection attack where untrusted data in a cookie value can write a new HTTP body. I have notified the developers of my findings there. and CGI::Simple both avoid the injection attack by URI-encoding the cookie values, (a spec-compliant solution). ## Convenience and CGI::Simple share several convenient user interface features which Mojo currently lacks. They allow you to set multiple-values for a single cookie, including setting a hashref. They also provide a convenient shorthand for giving expiration times, like "+10m" for "10 months in the future". Mojo lacks these features. If you have a Catalyst app that uses the multiple-values features, a port to Mojo could mean a painful cookie transition, since Mojo does not have a built-in understanding of the format uses to store cookie values. (This detail is not dictated by the cookie spec so both value formats are "spec compliant"). ## Conclusions Sebastian Riedel, the Mojo author, promotes Mojo as being focused on standards. From my findings here, I have to say that I agree that Mojo is a leader here, currently at the expense of a potentially serious security issue, and lacking some usability features that the others offer. CGI::Simple has a reputation but being a lighter and better enigeneered version of Certainly the overall the design and focus of CGI::Simple is an improvement. But the reality is that CGI::Simple was forked from in 2001. has received many improvements since then including improved cookie handling, like adding support for "Max-Age". However, CGI::Simple doesn't seem to make a point of tracking and merging improvements that originate in CGI::Simple is perhaps more like a lighter, tighter alternative to as it existed several years ago. The mature-but-maligned comes out fairing the best for cooking handling in my opinion. It did not have any of the potential security issues I found with the other two, and it has a range of convenient methods for cookie access. But as a final note, I encourage to you check with the specific projects for the most current information, as some of the deficiencies I found here may already be addressed.