Retrieving Authorization or Other HTTP Headers With the Apache Server and RPG


Retrieving Authorization or Other HTTP Headers With the Apache Server and RPG

I was working on a project with a customer that was using a slimmed down version of OAuth 2.0 where in the HTTP headers containing an Authorization Token.

I know that most HTTP headers are available as environment variables (or using HTTP_<headername> as the environment variable to retrieve custom headers), but this was not.  A quick search brought me to this Stack Overflow question which explains that Apache strips out the Authentication header, but also giving a workaround.

Knowing that Apache on the IBM i isn't always the same as other versions, I decided to give it a whirl anyhow.  

Step 1:  Update my Apache Configuration File (httpd.conf)

The first thing I did was add the following line to my httpd.conf file for the web server in question:

SetEnvIf Authorization "(.*)" HTTP_AUTHORIZATION=$1

Step 2:  Restart my Apache Server Instance

The next step, to make sure that the Apache server wouldn't puke on this new configuration was to restart my Apache server instance.  I did, and what do you know, it worked (or at least it didn't crash telling me that the SetEnvIf directive was invalid)

Step 3:  Test

My next step was to test, so I wrote a simple program named HDRTEST using the eRPG SDK that looks like the following:

H DFTACTGRP(*NO) BNDDIR('ERPGSDK')                                              
 * Prototypes                                                   *               
 /COPY QCOPYSRC,P.ERPGSDK                                                       
 /COPY QCOPYSRC,P.HTTPSTD                                                       
 * Data read in from web page                                                   
D header          S           1024    Varying                                   
 * Work Variables                                                    
D headerValue     S           1024    Varying                        

  header = #getData('header');                                      
  headerValue = #getEnv('HTTP_' + %trim(header));      

  *INLR = *on;                                                                                       

The template (hdrtest.erpg) used is VERY simple and looks like this:

/%header%/ = /%value%/

Next, I used GETURI to make a request with a custom Authorization header:

PORT(443) USRHDR((Authorization 'Bearer x8x8x8x9x9x9x9x9x9x'))

To my joy the proper information was returned:

HTTP/1.1 200 OK
Date: Tue, 18 Jul 2017 15:55:51 GMT
Server: Apache
Content-Length: 42
Connection: close
Content-Type: text/html; 

AUTHORIZATION = Bearer x8x8x8x9x9x9x9x9x9x                                                         

So, again with just some simple RPG you are able to work with the rest of the world as OAuth and OAuth types of authentication become more popular.                                                  

Last edited 07/18/2017 at 11:01:16


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