In this blog, I like to show an example of how you can call an External/Outgoing REST web services in a classic function.

Before we get to the example , the API used for this is called ASYRRESTCLI and the function used is EXEC_REST _WS.

So if you search our online help for ASYRRESTCLI you will see below.

Please note that this is just a simple example(there might be other ways to accomplish this). The external API call is going to a free JSON API http://fixer.io/ ( you can read more about this API by visiting their website)

The requirement presented for this example is that we like to have a button in Purchase order entry that shows the current exchange rates.

1. Open Administration, Administration, Web Services, Rest web services.
2. Click on New REST web service to create a new REST web service connection.
   
3. Enter the information like below ( for information on each field review online help)
   
   
   
   
   
4. Open Development, Script Dictionary, Windows.
5. Select OPOH windows.
6. Click on Buttons/menus Tab.
   
7. Enter a new line like below.
   
   
   
   
   
   
8. Click Save and Validate.
9. Open Setup, Purchasing, Entry transactions, Orders.
10. Select your entry transaction and click Validate.
11. Open Development, Script Dictionary, Scripts, Script editor.
12. Enter SPEPOH for the file name.
13. Enter below code.
    
    
    
    

    $ACTION
    Case ACTION
     When "EXEBOUT"    : Gosub BOUTON
    Endcase
    Return

    ##############

    $BOUTON

    If BOUT="3"  ###### this is the code of our button in Window dictionary
      # Contains the result header and body
      Local Clbfile RESHEAD(0),RESBODY(0)
      Local Integer RETVAL
      # No additional parameter nor additional header value are given here (only the values given in ORDER definition are used)
      Local Char PCOD(100)(1..10),PVAL(100)(1..10),HCOD(100)(1..10),HVAL(100)(1..10)
       RETVAL=func ASYRRESTCLI.EXEC_REST_WS("ExchangeRate","GET","/latest",PCOD,PVAL,HCOD,HVAL,"{}", 0,"",RESHEAD, RESBODY)

      If RETVAL=200 : infbox(RESBODY) : Else infbox("somwthing Went wrong") : Endif

    Endif
    Return
    
    

14. Click Save and Compile.
15. Now open Purchasing, Orders, Orders.
    
16. Select an existing Purchase order.
17. Click on your newly created button.
    
    
    
    
18. Clicking on the button will produce below.
    
    

Conclusion: You can use ASYRRESTCLI and function EXEC_REST_WS to execute an outgoing web service call.