Slashdot Mirror
Web Programming by printf()
An anonymous reader writes "Art & Logic has posted an article titled 'Why CGI is Evil'. CGI might be an obvious way to create a simple web application, but this article provides some excellent high-level reasons why CGI rarely makes long-term sense. A nice review especially for new web programmers."
instead of "why cgi is evil," maybe this article should have been named "why you should buy our product."
Gyrate Dot Org - "Where high-tech meets low-life"
I think CGI also refers only to those programs that the server calls directly passing headers in a certain format. While the script may be written in any language, they tend to be written in a language that is primarily a programming language (Perl, C, Python, etc) rather than a content-oriented language (ASP, JSP, PHP, etc).
JSP usually runs as a separate server that may be contacted by the web server, but is also capable of answering web requests by itself. ASP and PHP are run in the same process space as the web server, and thus can spare the overhead of spawning a new script interpreter for every request. All of these languages are content-oriented, meaning that the scripting code is embedded in the document, rather than having the document embedded in the code.
Hopefully I haven't confused matters even more ;)
I can't say that I don't give a fuck. I've just run out of fuck to give.
Notice how the author compares CGI unfavorably with something he calls DMF? Here it is, and it looks like one of the flagship products of this company. Imagine that.
... not that there's anything wrong with that) solution is better. When he says "CGI" he's talking about something that few people use for anything but toys. Slashdot (e.g.) uses the Perl CGI module, but runs it under mod_perl, thus obviating most of his arguments (CGI is slow, must be compiled at run-time, and has no access to the web server internals). Slashdot, again, uses a templating system, thus taking care of his second argument (programmers must copy-paste HTML into their code).
/.
He's setting up a straw man, then claiming that his own (proprietary, for-profit
Both these problems have been solved for over 5 years, yet he's trying to make it sound like his beautiful DMF is the first to even discover them. *Yawn* - another press release day on
This isn't as much "normalization" as it is "don't take so many drugs when you're designing tables."
I think CGI also refers only to those programs that the server calls directly passing headers in a certain format.
/administration/). They're compiled and placed into the classpath, and then the server executes them in the JVM when a request is made. The benefit is that the code is precompiled and the JVM is preloaded, so the execution time once loaded is almost as fast as a CGI applet would be once loaded, but the load time is less because it doesn't have to fork a separate process.
CGI refers to the method of executing external programs, passing parameters to them as environment variables, and then getting the result back from standard output. CGI tends to be external binaries, and thus PHP can be essentially CGI if you use it in its CGI binary form (needlessly complex, and even worse of a performance hit, but it works).
JSP usually runs as a separate server that may be contacted by the web server, but is also capable of answering web requests by itself.
Most of the servers I've seen tend to glob everything together, so I'd be inclined to disagree with the 'usually' here. I've usually run it as the 'tomcat' process, which is its own thing.
You neglected to mention servlets, which are a nice cross between CGI and markup languages like ASP/JSP/PHP. Servlets are small Java programs that are mapped to a directory on the website (like
That's my imput for the day. If Aridhol hasn't confused matters enough, this hopefully will.
--Dan
This is bunk! Pure FUD!
CGI is slower?? I write CGI in C++. Compiled C++ is fast. It's on par with interpreted Perl or PHP execution speed at the very least... more likely vastly faster. And this myth about process spawn time is starting to bother me. Linux can spawn processes VERY fast. Threads on Linux have traditionally been implemented as a special form of process anyhow. And even if this was a problem...the author mentions the solution, FastCGI - but seems to somehow ignore that it obliviates his whole point!
What people really like to ignore when developing on Windows is COM, Apartment Threading, and the whole process model. When you call a COM object in an ASP page or whatever, you are crossing process boundaries - all arguments are martialled through COM by VALUE. All these ASP programmers that create a COM object to use, for example, MSXML have obviously never tried creating a LARGE DOM tree. Let me tell you, it does NOT scale. Compiling all my code into a single CGI allows me to keep everything in the same process space, and vastly improves performance when things get large.
And who the hell debugs using printf? For one, I like CGI because it's easy to launch one directly from GDB! Ever tried attaching a debugger to a thread for your process inside a web server? HA! GDB lets me easily script the piping of a file to stdin of my CGI. If you are still using printf, you have more problems in learning about programming than will be solved by not using CGI.
Now, if your application is heavily template based, then yes, PHP definitely makes more sense than CGI!!! The other has a point in that you shouldn't be embedding HTML in your C code. Which brings me to my last beef...
Their product is about using pre written features rather than writing them yourself as you need to with CGI? Uh, DUH!! There are like umpteen billion CGI LIBRARIES out there!!! I happen to like GNU CGICC. It does everything, form uploading (mime and file uploads too), cookie handling, templating, etc - and it works with FastCGI too! Write it yourself??? As if! And I have no problem linking in libraries for database access, and everything else under the sun (Boost, etc) into my CGI, just like I would link them into any other program. Who the hell writes software without using any libraries?
This article is basically a bunch of FUD just to sell their product. You can safely ignore the whole thing!
However, a JSP is automatically preprocessed into a servlet before it's compiled into bytecode, so it actually is a halfway point ;)
I can't say that I don't give a fuck. I've just run out of fuck to give.
CGI is pretty much the oldest method of a web server interacting with outside code, and is kind of the only standard way. The server fork/exec's a process and has the CGI process' stdin, stdout, and stderr are pointing back to the server. The web server passes information either through environment variables (for a GET request) or additionally through the process' stdin (for POST and PUT requests).
Advantages: very clean, the process goes away after the request, so resource leaks aren't a problem. Very simple interaction, if your programming language understands stdin, stdout, and environment variables (hard to find one that doesn't) you can do CGI with it (though some are better than others obviously).
Disadvantages: fork/exec for every request. That has some overhead, sometimes more important is that the process can't use persistent state. Resources have to be acquired on every request. Anything with a great deal of overhead, say opening a database connection, has a HUGE impact on the server.
FastCGI is a pseudo-standard in that it has multiple people implementing it, but it never got approved by, say, the IETF. It's a client server kind of thing, where the first instantiation starts the server up and initializes it. Subsequent requests get sent to the CGI server and get returned. The CGI server never goes away. The cool thing is that there are no startup costs, and you can keep something like a DB pool. Never really used it, so can't comment much.
Some things just get embedded into the server, like Apache modules. You can write C code and it becomes part of the server itself.
Advantages: wicked fast. Full access to anything in the server.
Disadvantages: if your CGI has a problem, it can bring down your server. The API's can be pretty arcane. Also, it's a different API for each web server (NSAPI vs. ISAPI vs....) and even between variants (it's wildly different from Apache 1.3 and apache 2.0).
mod_perl is kind of like above, it's a perl interpreter bound into Apache. Gives a perl interface to pretty much everything apache has to offer. Not only requests, but configurations.
Advantages: perl is very flexible, can do a lot of things and use perl modules from CPAN, including templating systems and the such. You're also insulated a bit from stray pointers and such. mod_perl also precompiles all of the perl code, so you don't have the compiler overhead on every request.
Disadvantages: mod_perl can be huge sometimes, and if you have several mod_perl instances running around, you can eat memory pretty quick.
Everything else is kind of "do what you want". Tomcat itself has several protocols to talk to Apache; some are just old, some are supported on certain platforms only, yadda yadda.
That said, the article did confuse a bunch of things, CGI, C, and content management systems. He was pushing an agenda, hopoing that people couldn't see through it.
... back off printf();
I'm with you on everything else though bro'!
; -- the corruption of government starts with its secrets. a truly free people keep no secrets. --
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....