SAP PO Rest Integration with Salesforce (OAuth)

Our customer has  one requirement: SAP ECC sent  ads vendor data to Salesforce system with Rest.

We call know that to call Salesforce service, we need a token.

We need to send the data to Salesforce to get token:

grant_type:
client_id:
client_secret:
username:
password:

Test it with SOAPUI, we get token from response:

Then add token to the Header when call Salesforce services:

we can complete this in PO REST adapter:

But how to get the token dynamicly?
a lots of ways:

Write java mapping program?

Write a lookup function?

Design another interface and save the parameters in ECC system?

Design a complex iflow …

Can I use configuration? did a search but no anwser.

Our PO system is 7.5 with support package 7, there three options for OAuth:

Choose OAuth 2.0 Grant Tye Flow:

There are two options, we have parameter grant_type=password in SOAPUI.

Which one is for me?

After I hack into the codes of Rest Adapter and find out:

Resouce Owner Password Credentials Grant = password

Client Credentials Grant =  client_credentials

Then I have to fill all the fields:

I can tell you:

Resource Owner Client ID = client_id

Resource Owner Username = username

Resource Owner Password = password

Authorization Server Username & Password is  not used in the codes! And Salesforce  don’t give me these parameters.

Then do a test, not lucky.

Response message is :

Error while processing Authorization request! 
[EXCEPTION] 
com.sap.aii.adapter.rest.ejb.common.exception.HttpCallException: HTTP OAUTH 2.0 CLIENT CREDENTIALS GRANT call to https://test.salesforce.com:443/services/oauth2/token not successful. Error while obtaining authorization code - response code: 400 
response: 
{"error":"invalid_client","error_description":"invalid client credentials"}

There is no field for client_secret.

Ok, add ‘client_secret=……’ to Authorization Server URL,  end with ‘&’:

Look into the debug info, it works out:

I’m so happy to resolve the problem.Maybe SAP should provide more detail information about each function.We tried so many times.

Later I get this note from SAP support, https://launchpad.support.sap.com/#/notes/2405166 New Feature: Support for OAuth 2.0 Client Credentials and Resource Owner Password Credentials Grants.
It is very helpfull.