4 <title>FastCGI Developer's Kit</title>
7 <body bgcolor="#FFFFFF" text="#000000" link="#cc0000" alink="#000011" vlink="#555555">
8 <a href="/fastcgi/words">
10 <p align="center"><img border="0" src="/kit/images/fcgi-hd.gif" alt="[[FastCGI]]"></a> <br
14 <h3 align="center">FastCGI Developer's Kit</h3>
15 <!--Copyright (c) 1996 Open Market, Inc. -->
16 <!--See the file "LICENSE.TERMS" for information on usage and redistribution-->
17 <!--of this file, and for a DISCLAIMER OF ALL WARRANTIES. -->
19 <p align="center">Mark R. Brown<br>
23 <p align="center">Document Version: 1.08<br>
27 <h5 align="center">Copyright © 1996 Open Market, Inc. 245 First Street, Cambridge, MA
29 Tel: 617-621-9500 Fax: 617-621-1703 URL: <a href="http://www.openmarket.com/">http://www.openmarket.com/</a><br>
30 $Id: fcgi-devel-kit.htm,v 1.2 1999/02/06 06:15:11 roberts Exp $ <br>
36 <li><a HREF="#S1">1. Introduction</a> </li>
37 <li><a HREF="#S2">2. Getting started</a> </li>
38 <li><a HREF="#S3">3. Writing applications</a> <ul type="square">
39 <li><a HREF="#S3.1">3.1 Using the <tt>fcgi_stdio</tt> library</a> </li>
40 <li><a HREF="#S3.2">3.2 Using the <tt>fcgiapp</tt> library</a> </li>
41 <li><a HREF="#S3.3">3.3 Using Perl and Tcl</a> </li>
42 <li><a HREF="#S3.4">3.4 Using Java</a> </li>
45 <li><a HREF="#S4">4. Running applications</a> <ul type="square">
46 <li><a HREF="#S4.1">4.1 Using a Web server that supports FastCGI</a> </li>
47 <li><a HREF="#S4.2">4.2 Using <tt>cgi-fcgi</tt> with any Web server</a> </li>
50 <li><a HREF="#S5">5. Known problems</a> </li>
51 <li><a HREF="#S6">6. Getting support</a> </li>
56 <h3><a NAME="S1">1. Introduction</a></h3>
58 <p>FastCGI is an open extension to CGI that provides high performance for all Internet
59 applications without the penalties of Web server APIs.</p>
61 <p>FastCGI is designed to be layered on top of existing Web server APIs. For instance, the
62 <tt>mod_fastcgi</tt> Apache module adds FastCGI support to the Apache server. FastCGI can
63 also be used, with reduced functionality and reduced performance, on any Web server that
66 <p>This FastCGI Developer's Kit is designed to make developing FastCGI applications easy.
67 The kit currently supports FastCGI applications written in C/C++, Perl, Tcl, and Java.</p>
72 <li>Describes how to configure and build the kit for your development platform. </li>
73 <li>Tells how to write applications using the libraries in the kit. </li>
74 <li>Tells how to run applications using Web servers that support FastCGI or using any Web
75 server and <tt>cgi-fcgi</tt>. </li>
78 <p>The kit includes a <a href="fastcgi-whitepaper/fastcgi.htm">technical white paper</a>, <tt>doc/fastcgi-whitepaper/fastcgi.htm</tt>.
79 You should read at least the first three sections of the technical white paper before
80 starting to write FastCGI applications. The <a href="fcgi-perf.htm">performance paper</a>
81 will help you understand how application design affects performance with FastCGI.</p>
83 <p>The <a href="fcgi-spec.html">FastCGI Specification</a>, <tt>doc/fcgi-spec.html</tt>,
84 defines the interface between a FastCGI application and a Web server that supports
85 FastCGI. The software in the kit implements the specification. You don't need to read the
86 specification in order to write applications.</p>
88 <p>Additional information is provided in the <a
89 href="http://www.fastcgi.com/words/FAQ.htm">FAQ</a> document, which contains frequently
90 asked questions about application development using FastCGI, as well as some general
93 <p>Experience with CGI programming will be extremely valuable in writing FastCGI
94 applications. If you don't have enough experience with CGI programming, you should read
95 one of the popular books on the topic or study the <a
96 href="http://hoohoo.ncsa.uiuc.edu/cgi/">NCSA CGI page</a>. For a more formal treatment of
98 href="http://ds.internic.net/internet-drafts/draft-robinson-www-interface-01.txt">Internet
99 Draft CGI 1.1 Specification</a>.</p>
101 <h3><a NAME="S2">2. Getting started</a></h3>
103 <p>The kit is a compressed tar (tar.Z) file, distributed via the <a
104 href="http://www.fastcgi.com/applibs/">www.fastcgi.com/applibs</a> Web page. Unpacking the
105 tar file creates a new directory <tt>fcgi-devel-kit</tt>.</p>
107 <p>Open the kit's index page, <tt>fcgi-devel-kit/index.html</tt>, using the "Open
108 File" command in your Web browser. The index page gives you an overview of the kit
109 structure and helps you navigate the kit. The index page also contains links that run some
110 example applications, but the applications won't work when index.html is opened using the
111 "Open File" command because they aren't aren't being accessed through a Web
114 <p>In order to use the kit in earnest you'll need a Web server that you control, a Web
115 server running with your user ID. The Web server will be starting FastCGI applications
116 that you will need to debug; this will be a lot more convenient for you if these processes
117 run with your user ID. It is best to have a Web server that supports FastCGI. <a
118 href="#S4">Section 4</a> discusses Web server issues.</p>
120 <p>If you can, keep the kit on a file system accessible from your personal workstation, do
121 your builds on your workstation, and run your Web server on your workstation. If that's
122 not possible, arrange a configuration such that the kit is accessible from the machine
123 that's going to run your Web server, and build the kit and your applications on a machine
124 that's configured exactly the same way (same processor architecture, operating system,
125 etc.) as the machine that's going to run your Web server.</p>
127 <p>To build the kit you execute this sequence of commands in the <tt>fcgi-devel-kit</tt>
135 <p>We've built and exercised the kit on these platforms (listed in alphabetical order):
138 <li>BSD/OS 1.1 (Intel Pentium), gcc </li>
139 <li>Digital UNIX V3.2 148 (Alpha), gcc/cc </li>
140 <li>Hewlett-Packard HP-UX A.09.05 C and B.10.01 A (PA-RISC), gcc/cc </li>
141 <li>IBM AIX 1 4 (RS/6000), gcc </li>
142 <li>Silicon Graphics IRIX 5.3 11091812 (MIPS), gcc </li>
143 <li>Sun Solaris 2.4 and 2.5 (SPARC), gcc/cc </li>
144 <li>Sun SunOS 4.1.4 (SPARC), gcc </li>
147 <p>Once you've built the kit, follow the directions in <a href="#S4">Section 4</a> to
148 bring up your Web server and run the example applications.</p>
150 <h3><a NAME="S3">3. Writing applications</a></h3>
152 <h4><a NAME="S3.1">3.1 Using the <tt>fcgi_stdio</tt> library</a> </h4>
154 <p>The <tt>fcgi_stdio</tt> library provides the easiest transition for C CGI programs and
155 C CGI programmers to FastCGI. Using this library your application can run using either CGI
156 or FastCGI, with the same binary for both situations.</p>
158 <p>To introduce the <tt>fcgi_stdio</tt> library we give a pair of examples: a tiny CGI
159 program and the translation of this program to FastCGI. These two example programs are
160 included in the kit.</p>
162 <p>The CGI program is <tt>examples/tiny-cgi.c</tt>:</p>
165 #include <stdio.h>
166 #include <stdlib.h>
171 printf("Content-type: text/html\r\n"
173 "<title>CGI Hello!</title>"
174 "<h1>CGI Hello!</h1>"
175 "Request number %d running on host <i>%s</i>\n",
176 ++count, getenv("SERVER_NAME"));
180 <p>The key features of this tiny CGI program are:
183 <li>The program sends data to the Web server by writing to <tt>stdout</tt>, using <tt>printf</tt>
184 in this example. The CGI program first sends a <tt>Content-type</tt> header, then a small
185 HTML document. The program includes <tt>stdio.h</tt> in order to get access to the <tt>printf</tt>
187 <li>The program obtains parameters provided by the Web server by reading environment
188 variables. The CGI program reads the <tt>SERVER_NAME</tt> variable using <tt>getenv</tt>
189 and includes the value in the HTML document. The program includes <tt>stdlib.h</tt> in
190 order to get access to the <tt>getenv</tt> function.</li>
193 <p>The <tt>count</tt> variable is degenerate in this example; the CGI program runs a
194 single request, so the request number is always one. This variable will be more
195 interesting in the FastCGI example.</p>
197 <p><a NAME="S3.1.1">The</a> corresponding FastCGI program is <tt>examples/tiny-fcgi.c</tt>:</p>
200 #include "fcgi_stdio.h"
201 #include <stdlib.h>
206 while(FCGI_Accept() >= 0)
207 printf("Content-type: text/html\r\n"
209 "<title>FastCGI Hello!</title>"
210 "<h1>FastCGI Hello!</h1>"
211 "Request number %d running on host <i>%s</i>\n",
212 ++count, getenv("SERVER_NAME"));
216 <p>The key features of this tiny FastCGI program are:
219 <li>The program is structured as a loop that begins by calling the function <tt>FCGI_Accept</tt>.
220 The <tt>FCGI_Accept</tt> function blocks until a new request arrives for the program to
221 execute. The program includes <tt>fcgi_stdio.h</tt> in order to get access to the <tt>FCGI_Accept</tt>
223 <li>Within the loop, <tt>FCGI_Accept</tt> creates a CGI-compatible world. <tt>printf</tt>
224 and <tt>getenv</tt> operate just as in the CGI program. <tt>stdin</tt> and <tt>stderr</tt>,
225 not used by this tiny program, also operate just as in a CGI program.</li>
228 <p>The <tt>count</tt> variable increments each time through the loop, so the program
229 displays a new request number each time. You can use the reload button in your browser to
230 demonstrate this, once you've got the program built and running.</p>
232 <h4>Building the program</h4>
234 <p>If you can build <tt>examples/tiny-cgi.c</tt>, it will be straightforward for you to
235 build <tt>examples/tiny-fcgi.c</tt>. You need to:
238 <li>Add the directory containing the <tt>fcgi_stdio.h</tt> header to the compiler's include
239 search path. The kit calls this directory <tt>include</tt>.</li>
240 <li>Add the library <tt>libfcgi.a</tt> to the linker's command line so that it will be
241 searched when linking. The <tt>libfcgi.a</tt> library implements the functions defined in <tt>fcgi_stdio.h</tt>.
242 The kit calls the directory containing this library <tt>libfcgi</tt>.</li>
243 <li>Determine whether or not the linker on your platform searches the Berkeley socket
244 library by default, and if not, add linker directives to force this search.</li>
247 <p>See <tt>examples/Makefile</tt> (created by <tt>configure</tt>) for a Makefile that
248 builds both programs. Autoconf handles the platform-dependent linking issues; to see how,
249 examine <tt>configure.in</tt> and <tt>examples/Makefile.in</tt>.</p>
251 <h4>Running the program</h4>
254 <p>Section 4</a> is all about how to run FastCGI applications.</p>
256 <p>You can use CGI to run application binaries built with the <tt>fcgi_stdio</tt> library.
257 The <tt>FCGI_Accept</tt> function tests its environment to determine how the application
258 was invoked. If it was invoked as a CGI program, the first call to FCGI_Accept is
259 essentially a no-op and the second call returns <tt>-1</tt>. In effect, the request loop
262 <p>Of course, when a FastCGI application is run using CGI it does not get the benefits of
263 FastCGI. For instance, the application exits after servicing a single request, so it
264 cannot maintain cached information.</p>
266 <h4>Implementation details</h4>
269 <p>fcgi_stdio.h</tt> works by first including <tt>stdio.h</tt>, then defining macros to
270 replace essentially all of the types and procedures defined in <tt>stdio.h</tt>. (<tt>stdio.h</tt>
271 defines a few procedures that have nothing to do with <tt>FILE *</tt>, such as <tt>sprintf</tt>
272 and <tt>sscanf</tt>; <tt>fcgi_stdio.h</tt> doesn't replace these.) For instance, <tt>FILE</tt>
273 becomes <tt>FCGI_FILE</tt> and <tt>printf</tt> becomes <tt>FCGI_printf</tt>. You'll only
274 see these new names if you read <tt>fcgi_stdio.h</tt> or examine your C source code after
277 <p>Here are some consequences of this implementation technique:
280 <li>On some platforms the implementation will break if you include <tt>stdio.h</tt> after
281 including <tt>fcgi_stdio.h</tt>, because <tt>stdio.h</tt> often defines macros for
282 functions such as <tt>getc</tt> and <tt>putc</tt>. Fortunately, on most platforms <tt>stdio.h</tt>
283 is protected against multiple includes by lines near the top of the file that look like <pre>
287 <p>The specific symbol used for multiple-include protection, <tt>_STDIO_H</tt> in this
288 example, varies from platform to platform. As long as your platform protects <tt>stdio.h</tt>
289 against multiple includes, you can forget about this issue.</p>
291 <li>If your application passes <tt>FILE *</tt> to functions implemented in libraries for
292 which you have source code, then you'll want to recompile these libraries with <tt>fcgi_stdio.h</tt>
293 included. Most C compilers provide a command-line option for including headers in a
294 program being compiled; using such a compiler feature allows you to rebuild your libraries
295 without making source changes. For instance the gcc command line <pre>
296 gcc -include /usr/local/include/fcgi_stdio.h wonderlib.c
298 <p>causes gcc to include <tt>fcgi_stdio.h</tt> before it even begins to read the module <tt>wonderlib.c</tt>.</p>
300 <li>If your application passes <tt>FILE *</tt> to functions implemented in libraries for
301 which you do not have source code, then you'll need to include the headers for these
302 libraries <i>before</i> you include <tt>fcgi_stdio.h</tt>. You can't pass the <tt>stdin</tt>,
303 <tt>stdout</tt>, or <tt>stderr</tt> streams produced by <tt>FCGI_Accept</tt> to any
304 functions implemented by these libraries. You can pass a stream on a Unix file to a
305 library function by following this pattern: <pre>
306 FILE *myStream = fopen(path, "r");
307 answer = MungeStream(FCGI_ToFile(myStream));
309 <p>Here <tt>MungeStream</tt> is a library function that you can't recompile and <tt>FCGI_ToFile</tt>
310 is a macro that converts from <tt>FCGI_FILE *</tt> to <tt>FILE *</tt>. The macro <tt>FCGI_ToFile</tt>
311 is defined in <tt>fcgi_stdio.h</tt>.</p>
315 <h4>Converting CGI programs</h4>
317 <p>The main task in converting a CGI program into a FastCGI program is separating the code
318 that needs to execute once, initializing the program, from the code that needs to run for
319 each request. In our tiny example, initializing the <tt>count</tt> variable is outside the
320 loop, while incrementing the <tt>count</tt> variable goes inside.</p>
322 <p>Retained application state may be an issue. You must ensure that any application state
323 created in processing one request has no unintended effects on later requests. FastCGI
324 offers the possibility of significant application performance improvements, through
325 caching; it is up to you to make the caches work correctly.</p>
327 <p>Storage leaks may be an issue. Many CGI programs don't worry about storage leaks
328 because the programs don't run for long enough for bloating to be a problem. When
329 converting to FastCGI, you can either use a tool such as <a href="http://www.pure.com/"><i>Purify</i></a>
330 from Pure Software to discover and fix storage leaks, or you can run a C garbage collector
331 such as <a href="http://www.geodesic.com/"><i>Great Circle</i></a> from Geodesic Systems.</p>
335 <p>Currently there are some limits to the compatibility provided by the <tt>fcgi_stdio</tt>
339 <li>The library does not provide FastCGI versions of the functions <tt>fscanf</tt> and <tt>scanf</tt>.
340 If you wish to apply <tt>fscanf</tt> or <tt>scanf</tt> to <tt>stdin</tt> of a FastCGI
341 program, the workaround is to read lines or other natural units into memory and then call <tt>sscanf</tt>.
342 If you wish to apply <tt>fscanf</tt> to a stream on a Unix file, the workaround is to
343 follow the pattern: <pre>
344 FILE *myStream = fopen(path, "r");
345 count = fscanf(FCGI_ToFile(myStream), format, ...);
350 <h4>Reference documentation</h4>
352 <p>The <a href="FCGI_Accept.3"><tt>FCGI_Accept</tt> manpage</a>, <tt>doc/FCGI_Accept.3</tt>,
353 describes the function in the traditional format.</p>
355 <p>The <a href="FCGI_Finish.3"><tt>FCGI_Finish</tt></a> (<tt>doc/FCGI_Finish.3</tt>), <a
356 href="FCGI_SetExitStatus.3"><tt>FCGI_SetExitStatus</tt></a> (<tt>doc/FCGI_SetExitStatus.3</tt>),
357 and <a href="FCGI_StartFilterData.3"><tt>FCGI_StartFilterData</tt></a> (<tt>doc/FCGI_StartFilterData.3</tt>)
358 manpages document capabilities of the <tt>fcgi-stdio</tt> library that are not illustrated
361 <h4><a NAME="S3.2">3.2 Using the <tt>fcgiapp</tt> library</a></h4>
363 <p>The <tt>fcgiapp</tt> library is a second C library for FastCGI. It does not provide the
364 high degree of source code compatibility provided by <tt>fcgi_stdio</tt>; in return, it
365 does not make such heavy use of <tt>#define</tt>. <tt>fcgi_stdio</tt> is implemented as a
366 thin layer on top of <tt>fcgiapp</tt>.</p>
368 <p>Applications built using the <tt>fcgiapp</tt> library cannot run as CGI programs; that
369 feature is provided at the <tt>fcgi_stdio</tt> level.</p>
371 <p>Functions defined in <tt>fcgiapp</tt> are named using the prefix <tt>FCGX_</tt> rather
372 than <tt>FCGI_</tt>. For instance, <tt>FCGX_Accept</tt> is the <tt>fcgiapp</tt> version of
373 <tt>FCGI_Accept</tt>.</p>
375 <p>Documentation of the <tt>fcgiapp</tt> library takes the form of extensive comments in
376 the header file <tt>include/fcgiapp.h</tt>. The sample programs <tt>examples/tiny-fcgi2.c</tt>
377 and <tt>examples/echo2.c</tt> illustrate how to use <tt>fcgiapp</tt>.</p>
379 <h4><a NAME="S3.3">3.3 Using Perl and Tcl</a></h4>
381 <p>A major advantage of the FastCGI approach to high-performance Web applications is its
382 language-neutrality. CGI scripts written in popular languages such as Perl and Tcl can be
383 evolved into high-performance FastCGI applications.</p>
385 <p>We have produced FastCGI-integrated Perl and Tcl interpreters. Doing so was easy, since
386 Perl and Tcl are conventional C applications and <tt>fcgi_stdio</tt> was designed for
387 converting conventional C applications. Essentially no source code changes were required
388 in these programs; a small amount of code was added in order to make <tt>FCGI_Accept</tt>
389 and other FastCGI primitives available in these languages. And because these interpreters
390 were developed using <tt>fcgi_stdio</tt>, they run standard Perl and Tcl applications
391 (e.g. CGI scripts) as well as FastCGI applications.</p>
393 <p>See the <a href="http://www.fastcgi.com/applibs/">www.fastcgi.com/applibs</a> Web page
394 for downloadable Perl and Tcl binaries for selected platforms. Because many users of Perl
395 and Tcl run extended versions of these languages, the kit includes separate companion
396 documents describing <a href="fcgi-perl.htm">how to build FastCGI-integrated Perl</a> and <a
397 href="fcgi-tcl.htm">how to build FastCGI-integrated Tcl</a>.</p>
399 <p>Here are the Perl and Tcl versions of <tt>tiny-fcgi</tt>:</p>
405 while(FCGI::accept() >= 0) {
406 print("Content-type: text/html\r\n\r\n",
407 "<title>FastCGI Hello! (Perl)</title>\n",
408 "<h1>FastCGI Hello! (Perl)</h1>\n";
409 "Request number ", ++$count,
410 " running on host <i>";$env(SERVER_NAME)</i>");
417 while {[FCGI_Accept] >= 0 } {
419 puts -nonewline "Content-type: text/html\r\n\r\n"
420 puts "<title>FastCGI Hello! (Tcl)</title>"
421 puts "<h1>FastCGI Hello! (Tcl)</h1>"
422 puts "Request number $count running on host <i>$env(SERVER_NAME)</i>"
426 <p>Converting a Perl or Tcl CGI application to FastCGI is not fundamentally different from
427 converting a C CGI application to FastCGI. You separate the portion of the application
428 that performs one-time initialization from the portion that performs per-request
429 processing. You put the per-request processing into a loop controlled by <tt>FCGI::accept</tt>
430 (Perl) or <tt>FCGI_Accept</tt> (Tcl). </p>
432 <h4><a NAME="S3.4">3.4 Using Java</a></h4>
434 <p>Java is not just for browser-based applets. It is already suitable for writing some Web
435 server applications, and its range of applicability will only grow as Java compilers and
436 other Java tools improve. Java's modules, garbage collection, and threads are especially
437 valuable for writing long-lived application servers.</p>
439 <p>The <tt>FCGIInterface</tt> class provides facilities for Java applications analogous to
440 what <tt>fcgi_stdio</tt> provides for C applications. Using this library your Java
441 application can run using either CGI or FastCGI.</p>
443 <p>The kit includes separate companion document on <a href="fcgi-java.htm">using FastCGI
444 with Java</a>. The source code for FastCGI classes is contained in directory <tt>java/src</tt>
445 and the compiled code in <tt>java/classes</tt>.</p>
447 <p>Here is the Java version of <tt>tiny-fcgi</tt>:</p>
450 import FCGIInterface;
453 public static void main (String args[]) {
455 while(new FCGIInterface().FCGIaccept()>= 0) {
457 System.out.println("Content-type: text/html\r\n\r\n");
459 "<title>FastCGI Hello! (Java)</title>");
460 System.out.println("<h1>FastCGI Hello! (Java)</h1>");
462 "request number " + count + " running on host <i>" +
463 System.getProperty("SERVER_NAME") + "</i>");
469 <h3><a NAME="S4">4. Running applications</a></h3>
471 <h3><a NAME="S4.1">4.1 Using a Web server that supports FastCGI</a></h3>
473 <p>For a current listing of Web servers that support FastCGI, see the <a
474 HREF="http://www.fastcgi.com/servers">www.fastcgi.com/servers</a> Web page.</p>
476 <p>All of the Web servers that support FastCGI perform management of FastCGI applications.
477 You don't need to start and stop FastCGI applications; the Web server takes care of this.
478 If an application process should crash, the Web server restarts it.</p>
480 <p>Web servers support FastCGI via new configuration directives. Since these directives
481 are server-specific, get more information from the documentation that accompanies each
484 <p>The directory <a HREF="../examples/conf"><tt>examples/conf</tt></a> contains config
485 files designed to run the example programs included in the FastCGI Developer's Kit. Each
486 config file contains specific installation instructions.</p>
488 <p>The more advanced example programs take advantage of special features of the Open
489 Market Secure WebServer, such as anonymous ticketing and support for the Authorizer role.
490 If you don't have this server, download a <a
491 HREF="http://www.openmarket.com/store/eval/swsg.htm">free evaluation copy</a> to run the
494 <h3><a NAME="S4.2">4.2 Using <tt>cgi-fcgi</tt> with any Web server</a></h3>
496 <p>The program <tt>cgi-fcgi</tt> allows you to run FastCGI applications using any Web
497 server that supports CGI.</p>
499 <p>Here is how <tt>cgi-fcgi</tt> works. <tt>cgi-fcgi</tt> is a standard CGI program that
500 uses Unix domain or TCP/IP sockets to communicate with a FastCGI application. <tt>cgi-fcgi</tt>
501 takes the path name or host/port name of a listening socket as a parameter and <tt>connect</tt>s
502 to the FastCGI application listening on that socket. <tt>cgi-fcgi</tt> then forwards the
503 CGI environment variables and <tt>stdin</tt> data to the FastCGI application, and forwards
504 the <tt>stdout</tt> and <tt>stderr</tt> data from the FastCGI application to the Web
505 server. When the FastCGI application signals the end of its response, <tt>cgi-fcgi</tt>
506 flushes its buffers and exits.</p>
508 <p>Obviously, having <tt>cgi-fcgi</tt> is not as good as having a server with integrated
512 <li>Communication is slower than with a Web server that avoids the fork/exec overhead on
513 every FastCGI request. </li>
514 <li><tt>cgi-fcgi</tt> does not perform application management, so you need to provide this
516 <li><tt>cgi-fcgi</tt> supports only the Responder role. </li>
519 <p>But <tt>cgi-fcgi</tt> does allow you to develop applications that retain state in
520 memory between connections, which often provides a major performance boost over normal
521 CGI. And all the applications you develop using <tt>cgi-fcgi</tt> will work with Web
522 servers that have integrated support for FastCGI.</p>
524 <p>The file <tt>examples/tiny-fcgi.cgi</tt> demonstrates a way to use <tt>cgi-fcgi</tt> to
525 run a typical application, in this case the <tt>examples/tiny-fcgi</tt> application: </p>
528 #!../cgi-fcgi/cgi-fcgi -f
529 -connect sockets/tiny-fcgi tiny-fcgi
532 <p>On most Unix platforms, executing this command-interpreter file runs <tt>cgi-fcgi</tt>
533 with arguments <tt>-f</tt> and <tt>examples/tiny-fcgi.cgi</tt>. (Beware: On some Unix
534 platforms, including HP-UX, the first line of a command-interpreter file cannot contain
535 more than 32 characters, including the newline; you may need to install the <tt>cgi-fcgi</tt>
536 application in a standard place like <tt>/usr/local/bin</tt> or create a symbolic link to
537 the <tt>cgi-fcgi</tt> application in the directory containing your application.) The <tt>cgi-fcgi</tt>
538 program reads the command-interpreter file and connects to the FastCGI application whose
539 listening socket is <tt>examples/sockets/tiny-fcgi</tt>.</p>
541 <p>Continuing the example, if <tt>cgi-fcgi</tt>'s connection attempt fails, it creates a
542 new process running the program <tt>examples/tiny-fcgi</tt> and listening on socket <tt>examples/sockets/tiny-fcgi</tt>.
543 Then <tt>cgi-fcgi</tt> retries the connection attempt, which now should succeed.</p>
545 <p>The <tt>cgi-fcgi</tt> program has two other modes of operation. In one mode it connects
546 to applications but does not start them; in the other it starts applications but does not
547 connect to them. These modes are required when using TCP/IP. The <a href="cgi-fcgi.1"><tt>cgi-fcgi</tt>
548 manpage</a>, <tt>doc/cgi-fcgi.1</tt>, tells the full story.</p>
550 <p>To run the example applications using <tt>cgi-fcgi</tt>, start your Web server and give
551 it the directory <tt>fcgi-devel-kit</tt> as the root of its URL space. If the machine
552 running your server is called <tt>bowser</tt> and your server is running on port <tt>8888</tt>,
553 you'd then open the URL <tt>http://bowser:8888/index.html</tt> to reach the kit's index
554 page. Now the links on the index page that run example applications via <tt>cgi-fcgi</tt>
555 should be active.</p>
557 <h3><a NAME="S5">5. Known problems</a></h3>
559 <p>On Digital UNIX 3.0 there's a problem with Unix domain listening sockets on NFS file
560 systems. The symptom when using cgi-fcgi is an exit status of 38 (<tt>ENOTSOCK</tt>:
561 socket operation on non-socket), but cgi-fcgi may dump core in this case when compiled
562 optimized. Work-around: Store your Unix domain listening sockets on a non NFS file system,
563 upgrade to Digital UNIX 3.2, or use TCP sockets.</p>
565 <p>On AIX there's a problem with shared listening sockets. The symptoms can include
566 application core dumps and kernel panic. Work-around: Run a single FastCGI application
567 server per listening socket.</p>
569 <h3><a NAME="S6">6. Getting support</a></h3>
571 <p>The mailing list <tt>fastcgi-developers@idle.com</tt> is used for discussions of issues
572 in developing FastCGI applications. Topics include announcement of FastCGI-capable Web
573 servers or changes to such servers, announcement of new application libraries or changes
574 to such libraries, announcement of known bugs, discussion of design trade-offs in FastCGI
575 application programming, and discussion of development plans and experiences. To join the
576 list, send a message to <a href="mailto:fastcgi-developers-request@openmarket.com">fastcgi-developers-request@idle.com</a>
577 with a message body consisting of the word "subscribe" (leaving off the quotes).</p>
579 <p>A link to a mail archive can be found on the FastCGI home page, <a
580 href="http://www.fastcgi.com">http://www.fastcgi.com</a></p>
585 © 1996, Open Market, Inc. / mbrown@openmarket.com