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Using the GETURI API to make a RESTful or Web Service Request

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Using the GETURI API to make a RESTful or Web Service Request

GETURI has been around for along time (over 15 years!), and has been used by thousands of companies for just about any purpose.  It is similar to the cURL command used on other platforms to make requests to web services which in turn return data.

But, what some don't realize is that GETURI has an API interface as well as a command interface.

The source below is a simple example of how to use the GETURI command to retrieve the current time calling a web service.

      ****************************************************************
      /COPY GETURI/QCOPYSRC,GETURICOPY
      ****************************************************************
     D GetUriRG        pr                  extpgm('GETURIRG')    
     D   PR_In                             like(GetUri_In)                    
     D   PR_Out                            like(GetUri_Out)                   
     D   PR_Head                           like(GetUri_Head)                  
     D   PR_Data                           like(GetUri_Data)                  
     D   PR_MsgCd                          like(GetUri_MsgCd)                 
     D   PR_Msg                            like(GetUri_Msg)                   
      ****************************************************************
      /free
       EXSR $LoadParms;
       EXSR $GETURI;

       *INLR = *ON;
       //***************************************************************
       //* Call GETUI
       //***************************************************************
       BegSr $GETURI;

         GetUriRG(GetUri_In:GetUri_Out:GetUri_Head:GetUri_Data:
                  GetUri_MsgCd:GetUri_Msg);

       EndSr;
       //***************************************************************
       //* Load Parameters to call GETURIRG
       //***************************************************************
       BegSr $LoadParms;

         Clear GetUri_In;
         GI_URI = 'http://webservice.theknot.com/Time/GetTime.asmx/currentTime';
         GI_OutType = '*RETURN';
         GI_SprHead = '*YES';

       EndSr;
      /end-free

The important pieces to recognize with this are:

  1. The /COPY statement - This brings in all the variables and data structures needed to make a call to the GETURIRG API.  This /COPY book comes standard with the GETURI software.
  2. The CLEAR operation on the GetUri_In parameter - Because the variables used are in a data structure, using the CLEAR operation on the data structure will initialize each of the values to their value and we won't run into any decimal-data errors, or similar.
  3. The use of GI_OutType = '*RETURN' - What this does is return the response from the web request to the program, specifically to the GetUri_Out parameter
  4. The use of GI_SprHead = '*YES' - This tells GETURI to suppress the HTTP headers that are returned with the data.  This makes parsing the data much easier since we don't have to deal with the headers.  And, if you need to examine or use any of the header data, it will be available in the GetUri_Head variable.

If we run our program in debug, we can see the value that is returned:

                              Evaluate Expression 

 Previous debug expressions 

 > EVAL geturi_out                                                              
   GETURI_OUT =                                                                 
             ....5...10...15...20...25...30...35...40...45...50...55...60       
        1   '<?xml version="1.0" encoding="utf-8"?>  <string xmlns="http:'      
       61   '//webservice.theknot.com/Time">09/15/2014 10:48</string>    '      
      121   '                                                            '      
      181   '                                                            '      
      241   '                                                            '      
      301   '                                                            '      
      361   '                                                            '      
      421   '                                                            '      
      481   '                                                            '      
      541   '                                                            '      
      601   '                                                            '      
                                                                        More... 
 Debug . . . 

 F3=Exit   F9=Retrieve   F12=Cancel   F16=Repeat find   F19=Left   F20=Right 
 F21=Command entry       F23=Display output 

We see that the web service we're using returns XML containing the current time.

If we want to see the headers, we can simply evaluate GetUri_Head:

                              Evaluate Expression 

 Previous debug expressions 

 > EVAL geturi_head                                                             
   GETURI_HEAD =                                                                
             ....5...10...15...20...25...30...35...40...45...50...55...60       
        1   'HTTP/1.1 200 OK  Connection: keep-alive  Date: Mon, 15 Sep 2'      
       61   '014 15:48:34 GMT  Server: Microsoft-IIS/6.0  ServerID: AUSWE'      
      121   'B14  X-Powered-By: ASP.NET  Set-Cookie: temp=T20141509154834'      
      181   '524964; path=/; domain=theknot.com;expires=Fri 22-May-2020 1'      
      241   '3:00:00 GMT;  X-AspNet-Version: 2.0.50727  Cache-Control: pr'      
      301   'ivate, max-age=0  Content-Type: text/xml; charset=utf-8  Con'      
      361   'tent-Length: 116                                            '      
      421   '                                                            '      
      481   '                                                            '      
      541   '                                                            '      
      601   '                                                            '      
                                                                        More... 
 Debug . . . 

 F3=Exit   F9=Retrieve   F12=Cancel   F16=Repeat find   F19=Left   F20=Right 
 F21=Command entry       F23=Display output 

Because the information returned will be small, we can choose to return the data to our program.

The XML can then be parsed using your favorite XML parser.  

If the data returned would be quite large, it may be a better idea to return the data to a stream file instead of the program.  Then once it is retrieved you can pass the name of your stream file to your XML parser so it can do all the dirty work and get you some usable information.

 


Last edited 03/24/2015 at 14:18:38



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