SREhttp/2 and CGI-BIN

SREhttp/2 supports CGI-BIN scripts. To run CGI-BIN scripts, you'll need to:

Obtain or write a CGI-BIN script. Typically, these are OS/2 executables, or REXX programs, that understand the CGI-BIN syntax.
However, SREhttp/2 also supports PERL CGI-BIN scripts.
Copy the CGI-BIN script SREHTTP2\CGI-BIN directory.
Invoke it using a standard CGI-BIN request selector :
start with a /CGI-BIN/,
Actually, as described below, you can put subdirectory information before the /CGI-BIN.
the name of the CGI-BIN program. For example, test-cgi.cmd
Optional. extra path information. This is used by some CGI-BIN scripts
Optional. a ?, followed by a list of options. Typically, each option is seperated by a &.

For example:
href=http://foo.bar.net/cgi-bin/test-cgi.cmd/morepath/?a+message.

SREhttp/2's implementation of CGI-BIN has one major improvment: the ability to send pieces of the output as they are created. That is, one can:

wait for the CGI-BIN script to end, and then send all the output it generated
... or
send output as it is generated

The second option is especially useful when large amounts of output are being generated (it avoids some troublesome server-timeout & client-impatience problems). For details see the discussion of the ENABLE_CGI_PIECES selector specific option.

SREhttp/2's implementation of CGI-BIN also includes a few minor modifications:

A few additional environment variables are created.
SREhttp/2 comes with a few sample CGI-BIN scripts (written in REXX). The TEST-CGI.CMD file (which is copied to SREHTTP2\CGI-BIN) will display the values of the CGI-BIN variables, including the variables proprietary to the above mentioned additional variables.

Using CGI-BIN scripts in other subdirectories

By default, CGI-BIN scripts are assumed to be in the CGI-BIN directory of SREHTTP2 (say D:\SRE\SREHTTP2\CGI-BIN). Obviously, this can become inconvenient once you acquire a greater-than-small set of scripts. The obvious solution is to place the script files in subdirectories.

Unfortunately, there does not seem to be a clearly specified method of doing this. Nevertheless... SREhttp/2 offers the following method of of specifying subdirectories containing your CGI-BIN scripts:

Using the portion of the request selector before the CGI-BIN/
The notion is to include subdirectory information before the CGI-BIN/ (the "this is a CGI-BIN script" indicator). SREhttp/2 will interpret this starting portion as a subdirectory of SREHTTP2\CGI-BIN,
Alternatively, this subdirectory information before the CGI-BIN/ can point to a virtual directory that can be anywhere on your computer (or LAN). For the details, see ATTRIBS.HTM

Notes:

Notes:	Remember that the `CGI-BIN` in a selector is not used as directory information. Rather, it's a flag indicating that this is a request for CGI-BIN script Requests for CGI-BIN scripts are often followed by `extra path information` This is typically used by the script (it does not point to the script). If, for some reason, you want to change the flag used to indicate CGI-BIN scripts (say, from `CGI-BIN` to `CGI`), see the `CGIBIN_FLAG` variable in SREHTTP2.CFG If, for some reason, you want to change the default CGI-BIN directory (say, from SREHTTP2\CGI-BIN to D:\SCRIPTS\CGI), see the SREHTTP2\CGI-BIN to SREHTTP2\CGISTUFF), see the `cgi_bin_dir` parameter in SREH2INI.RXX.
Examples:	`/KIDSTORE/INVENTORY/CGI-BIN/TOYCT.CMD?toddler` This invokes the TOYCT.CMD program (with an argument of `toddler`), which is (perhaps) located in \SRE\SREHTTP2\CGI-BIN\KIDSTORE\INVENTORY\ `/EVENTS/JUNE/CGI-BIN/SHOWS.CMD?time=otters` If you've defined (in ATTRIBS.CFG): realm: Zoo1 rule: /EVENTS/* redirect: dir= !CGI F:\ZOO\ANIMALS\ then use `F:\ZOO\ANIMALS\JUNE\SHOWS.CMD` as the CGI-BIN script.

Remember that the CGI-BIN in a selector is not used as directory information. Rather, it's a flag indicating that this is a request for CGI-BIN script
Requests for CGI-BIN scripts are often followed by extra path information This is typically used by the script (it does not point to the script).
If, for some reason, you want to change the flag used to indicate CGI-BIN scripts (say, from CGI-BIN to CGI), see the CGIBIN_FLAG variable in SREHTTP2.CFG
If, for some reason, you want to change the default CGI-BIN directory (say, from SREHTTP2\CGI-BIN to D:\SCRIPTS\CGI), see the SREHTTP2\CGI-BIN to SREHTTP2\CGISTUFF), see the cgi_bin_dir parameter in SREH2INI.RXX.

Examples:

/KIDSTORE/INVENTORY/CGI-BIN/TOYCT.CMD?toddler

This invokes the TOYCT.CMD program (with an argument of toddler),
which is (perhaps) located in \SRE\SREHTTP2\CGI-BIN\KIDSTORE\INVENTORY\

/EVENTS/JUNE/CGI-BIN/SHOWS.CMD?time=otters

If you've defined (in ATTRIBS.CFG):

   realm: Zoo1
   rule: /EVENTS/* 
   redirect: dir= !CGI F:\ZOO\ANIMALS\

then use F:\ZOO\ANIMALS\JUNE\SHOWS.CMD as the CGI-BIN script.

Notes on creating CGI-BIN scripts

When writing CGI-BIN scripts, keep in mind that a number of variables are available in the OS/2 environment. If you are using REXX, you can read these using avalue=VALUE(a_cgibin_var,,'OS2ENVIRONMENT')
You can output results with SAY statments.
You can use some, but not all, of the SRE2003 and SREHTTP/2 procedures. Basically, since CGI-BIN scripts run in a seperate process, procedures that extract request-specific information will not work in CGI-BIN scripts.
The PATH_INFO CGI environment variable is not clearly defined. Some scripts expect nothing when there is no extra path information, others expect a /.
To control this default, you can use the EMPTY_PATH_OKAY selector-specific option.

with EMPTY_PATH_OKAY=0, PATH_INFO='/'

with EMPTY_PATH_OKAY=1, PATH_INFO=''.
Or, you can set the default value of EMPTY_PATH_OKAY by changing a parameter in SREH2INI.RXX.
Your first SAY statements should declare the MIME type. For example: Say "Content-type: text/html" Say
As a more flexible, and somewhat quicker, alternative to CGI-BIN -- consider the use of SREhttp/2's addons

Using PERL scripts with SREhttp/2
In order to take advantage of a broad spectrum of CGI-BIN scripts, SREhttp/2 can use "non-REXX" processors to interpert CGI-BIN scripts.
As long as you have the appropriate interepreter installed on your server, it's quite easy to do this. All that you need to do is set the INTERPRET_TYPES parameter in SREH2INI.RXX.
By default, INTERPRET_TYPES is set to associate the .PL extension to PERL scripts. These are ff particular interest,since there are good OS/2 PERL interpreters available, and since there are a slew of PERL scripts out there.
Please see PERL.TXT for the details.

Last updated on 6 July 2002