How to Post a HTTP Request using 4GL SOCKETS

How to Post a HTTP Request using 4GL Sockets
How to send parameters to a WebSpeed Program using 4GL sockets
How to build a simple HTTP client using 4GL sockets
Creating ABL Client to Consume a REST Web Service

Prior to OpenEdge 11.5.1, which  provides's built in support for consuming REST webservices, sockets can be used.

•  Is there an HTTP client for OpenEdge?  

The following pseudo code attached to this article [ PostHTTPRequestUsing4GLSockets.p ]
It uses the  POST method to send the request content to a Web server URL and waits for its reply. 

1.   Connects to the Server, using a hostname and port
2.   Sends a piece of data, consisting of:

• The URL that will be dealing the request, the sample uses a webspeed URL, but could it be anything in the other side as long as it is HTTP. Sonic http listeners are good example of real needs for usage of this technique
• The data in the format: param=value&param=value&param=value. 

3.   Gets the answer in the procedure getResponse, which can be customized to read, parse and work with the results.
Only basic headers are sent, which can be extended to support headers like cookies, different content types 

Refer to the documentation and related Articles below to extend this sample procedure and make it more powerful:

DEFINE VARIABLE vcHost     AS CHARACTER    INITIAL "localhost"   NO-UNDO.
DEFINE VARIABLE vcPort     AS CHARACTER    INITIAL "8080"        NO-UNDO.
DEFINE VARIABLE vhSocket   AS HANDLE                             NO-UNDO.

CREATE SOCKET vhSocket.
vhSocket:CONNECT('-H ' + vcHost + ' -S ' + vcPort) NO-ERROR.
    
IF vhSocket:CONNECTED() = FALSE THEN
DO:
    MESSAGE "Connection failure" VIEW-AS ALERT-BOX.   
    MESSAGE ERROR-STATUS:GET-MESSAGE(1) VIEW-AS ALERT-BOX.
    RETURN.
END.
ELSE
   MESSAGE "Connect"
       VIEW-AS ALERT-BOX.

vhSocket:SET-READ-RESPONSE-PROCEDURE('getResponse').
/* supposes there is an webspeed app called yourapp.w that receives param1, param2, param3 */
RUN PostRequest (
    INPUT '/scripts/cgiip.exe/WService=wsbroker1/yourApp.w', 
 INPUT 'param1=value&param2=value&param3=value'
 ).

WAIT-FOR READ-RESPONSE OF vhSocket. 
vhSocket:DISCONNECT() NO-ERROR.
DELETE OBJECT vhSocket.
QUIT.

PROCEDURE getResponse:
 DEFINE VARIABLE vcWebResp AS CHARACTER  NO-UNDO.
 DEFINE VARIABLE lSucess  AS LOGICAL   NO-UNDO.
 DEFINE VARIABLE mResponse AS MEMPTR   NO-UNDO.
 
 IF vhSocket:CONNECTED() = FALSE THEN do:
  MESSAGE 'Not Connected' VIEW-AS ALERT-BOX.
  RETURN.
 END.
 lSucess = TRUE.
  
 DO WHILE vhSocket:GET-BYTES-AVAILABLE() > 0:
   
   SET-SIZE(mResponse) = vhSocket:GET-BYTES-AVAILABLE() + 1.
   SET-BYTE-ORDER(mResponse) = BIG-ENDIAN.
   vhSocket:READ(mResponse,1,1,vhSocket:GET-BYTES-AVAILABLE()).
   vcWebResp = vcWebResp + GET-STRING(mResponse,1).
 END.
 /*
 *PUT HERE THE CODE TO MANIPULATE THE ANSWER
 */

PROCEDURE PostRequest:
 DEFINE VARIABLE vcRequest  AS CHARACTER.
 DEFINE VARIABLE mRequest  AS MEMPTR.
 DEFINE INPUT PARAMETER postUrl AS CHAR. 
 /* URL that will send the data. It must be all the path after the server. IE:/scripts/cgiip.exe/WService=wsbroker1/myApp.htm */
 DEFINE INPUT PARAMETER postData AS CHAR.
 /* Parameters to be sent in the format paramName=value&paramName=value&paramName=value */
 vcRequest =
  'POST ' +
  postUrl +
  ' HTTP/1.0~r~n' +
  'Content-Type: application/x-www-form-urlencoded~r~n' +
  'Content-Length:' + string(LENGTH(postData)) +
  '~r~n' + '~r~n' +
  postData + '~r~n'.

 MESSAGE vcREquest  VIEW-AS ALERT-BOX.

 SET-SIZE(mRequest)   = 0.
 SET-SIZE(mRequest)   = LENGTH(vcRequest) + 1.
 SET-BYTE-ORDER(mRequest)  = BIG-ENDIAN.
 PUT-STRING(mRequest,1)  = vcRequest .

 vhSocket:WRITE(mRequest, 1, LENGTH(vcRequest)).
END PROCEDURE.

 

References to Other Documentation:

OpenEdge Development: Programming Interfaces, Sockets:
https://documentation.progress.com/output/ua/OpenEdge_latest/index.html#page/dvpin/Sockets_2.html  

Progress Articles:
 TCP port remains in use forever when the socket client has disappeared  
 ABL program with client socket programming becomes slower and slower  
 Sample 4GL Socket Programming Code for Client Side  
 Sample 4GL Socket Programming Code for Server Side   
 How to send UTF-8 data to a socket from a client with a single byte code page?   
 How to calculate Content-Length value using ABL sockets?  
 Sample Code To Send Email via Internet SMTP with 4GL Sockets