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Reading in POST data using the eRPG SDK (ie, XML, JSON...)

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Reading in POST data using the eRPG SDK (ie, XML, JSON...)

If you are trying to read in straight POST data using the eRPG SDK then it will be a little different than reading in name/value pairs.

For example, lets assume your trading partner is sending you straight JSON data in a POST to one of your web servers.  If you're used to using the #getData() subprocedure to read the value of a specific name/value pair, this won't work because, there is no name.  Just a value.

In order to read this data you will have to use a different subprocedure availble with the eRPG SDK.  This would be the #RdStin() (or Read Standard Input) subprocedure.  This will return all of the POST data in one big variable.

Let's assume we're making a request as such using GETURI to simulate the POST request (you could also use cURL or something similar):

GETURI URI('www.yourserver.com/cgi-bin/rdstin1') 
DATA('{"name":"Brad", "age":"43", "favoriteshow":"Wheeler Dealers"}') 
METHOD(*POST)

When the request comes to our server it will look like this:

HTTP/1.1 200 OK  
Content-Length: 61  

{"name":"Brad", "age":"43", "favoriteshow":"Wheeler Dealers"}  

Notice there is no name/value pair for the data itself.  Just straight JSON.

This is where the #RdStin() subprocedure comes into play.  If I simply want to read in this data, the program example would look like the following:

H DFTACTGRP(*NO) BNDDIR('ERPGSDK')                                         
 ****************************************************************          
 * Prototypes                                                   *          
 ****************************************************************          
 /COPY QCOPYSRC,P.ERPGSDK                                                  
 /COPY QCOPYSRC,P.HTTPSTD                                                  
 ****************************************************************          
D Data            S          65535    Varying                              
 ****************************************************************          
 /free                                                                     
  #startup();                                                              
  Data = #RdStin();                                                        
  #writeTemplate('stdhtmlheader.erpg');                                    
  #loadTemplate('rdstin1.erpg');                                           
  #replaceData('/%data%/':Data);                                           
  #writeSection();                                                         
  #cleanup();                                                              
  *INLR = *on;      
 /end-free  

You'll see that most of the eRPG program is familiar, except that we are using #RdStin() to read the data in instead of #getData() to read the value of the name/value pairs that are normally used when submitting a form.

The data returned to GETURI will be as follows:

HTTP/1.1 200 OK
Date: Mon, 11 Aug 2014 22:24:59 GMT
Server: Apache
Pragma: no-cache
Expires: Saturday, February 15, 1997 10:10:10 GMT
Content-Length: 61
Connection: close
Content-Type: text/html; charset=ISO-8859-1

{"name":"Brad", "age":"43", "favoriteshow":"Wheeler Dealers"}

If you were to tell GETURI to omit the headers then the data returned would simply be:

{"name":"Brad", "age":"43", "favoriteshow":"Wheeler Dealers"}

Now, instead of just echoing the value of Data in our eRPG program we would process it and return a message to the requestor, but this is just a simple example to show the difference when reading POST data vs. a name/value pair.

If the data you will be reading is larger than 65k there is more than would need to be done, but this should work for most smaller batches of data.


Last edited 09/08/2014 at 11:36:37



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