SAP IdM - accessing a REST API / WebService via JavaScript

[Former Member]

Using the incredibly useful post by Jannis Rondorf as a starting point, I wanted to write this blog post to show how IdM could access a REST API / WebService (HTTP & HTTPS) only using JAVA & JavaScript (without any custom JAVA classes or VDS); the following script should be pretty self-explanatory for the most part, but comments should hopefully make things a little clearer; please feel free to comment if you have any further doubts / questions and I will do my best to answer them:

// Main function:pushDataToAPI



function pushDataToAPI(Par) {

    importClass(Packages.java.net.HttpURLConnection);

    importClass(Packages.java.net.URL);

    importClass(Packages.java.io.DataOutputStream);

    importClass(Packages.java.io.ByteArrayOutputStream);



    var targetAPI = Par.get("TARGET_SYSTEM");

    var APIintent = "";



    var systemA_URL = "http://systemAHostNAME:1234/api/user"; 



    var systemD_CreateURL = "http://systemDHostName:1234/system_API/systemapi.svc/rest/createUser";

    var systemD_UpdateURL = "http://systemDHostName:1234/system_API/systemapi.svc/rest/updateUser";

    var systemD_Username = "systemDAPIUser";

    var systemD_Password = "systemD@APIUser1234";

    var systemD_Encoding = uToBase64(systemD_Username + ":" + systemD_Password); //encode the system D user credentials into Base64

    var systemA_Username = "systemARestAPIUser";

    var systemA_Password = "systemA@RestAPIUser1234";

    var systemA_Encoding = uToBase64(systemA_Username + ":" + systemA_Password); //encode the system A user credentials into Base64



    var logFileText = "";



    var urlString = "";





    //determine target URL based on passed in TARGET_SYSTEM parameter

    //with System D, there are two separate URLs for User CREATION and User UPDATING

    if (targetAPI == "systemA")

        urlString = systemA_URL;

    else if (targetAPI == "systemD") {

        APIintent = Par.get("API_intent");

        if (APIintent == "Create") {

            uWarning("In System D section now, going to hit CREATE API: ");

            urlString = systemD_CreateURL;

        } else if (APIintent == "Update") {

            uWarning("In System D section now, going to hit UPDATE API: ");

            urlString = systemD_UpdateURL;

        }

    }



    uWarning("FOR THIS API system: " + targetAPI);

    uWarning("determined URL: ");

    uWarning(urlString);





    //get the necessary attributes from the entry being processed currently



    var currentEntry = uGetEntryID();

    var allAttrs = uIS_GetEntry(currentEntry);

    var entFName = allAttrs.get("MX_FIRSTNAME");

    var entLName = allAttrs.get("MX_LASTNAME");

    var entUsername = allAttrs.get("MSKEYVALUE");

    var entServiceType = allAttrs.get("MX_FS_PERSONNEL_AREA");

    var entPayrollNo = allAttrs.get("MX_FS_PERSONNEL_NUMBER");

    var entEmail = allAttrs.get("MX_MAIL_PRIMARY");

    var entPhone = allAttrs.get("MX_PHONE_PRIMARY");

    var entMobile = allAttrs.get("MX_MOBILE_PRIMARY");

    var entDepartment = allAttrs.get("MX_DEPARTMENT");

    var entPrivCode = allAttrs.get("MX_FS_JOB_ID");

    var entEmpStatus = allAttrs.get("MX_FS_EMPLOYMENT_STATUS_ID");

    var entAdocode = allAttrs.get("MX_FS_ORGANIZATIONAL_UNIT_ID");

    var entOrgID = allAttrs.get("MX_DEPARTMENT");

    var entAccountingCode = allAttrs.get("MX_ACCOUNTING_NUMBER");





    //set up the message data based on the specific system; system A in this case accepts XML data via its API, while system D accepts JSON data.

    var systemA_ObjData = '<UserDataFeed xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="SystemA.API.Integration">\n<FirstName>' + entFName + '</FirstName>\n<LastName>' + entLName + '</LastName>\n<EmploymentTypeID>' + entServiceType + '</EmploymentTypeID>\n<StaffNumber>' + entPayrollNo + '</StaffNumber>\n<Adocode>' + entAdocode + '</Adocode>\n<UnitID>' + entOrgID + '</UnitID>\n<Workemail>' + entEmail + '</Workemail>\n<MilitaryTelephone>' + entPhone + '</MilitaryTelephone>\n<MobileTelephone>' + entMobile + '</MobileTelephone>\n<Username>' + entEmail + '</Username>\n<UserStatusID>' + entEmpStatus + '</UserStatusID>\n<UserType>' + entPrivCode + '</UserType>\n<Position>' + entDepartment + '</Position>\n<Employer>IDMEmployer</Employer>\n<BudgetCode>' + entAccountingCode + '</BudgetCode>\n</UserDataFeed>';



    var systemD_ObjData = '{"emailAddress" : "' + entEmail + '","firstName" : "' + entFName + '","lastName" : "' + entLName + '","customerIdentifier" : "' + entAdocode + '","roleIdentifier" : "' + entPrivCode + '"}';





    var objWithVars = '';



    //determine data to be sent to target system

    if (targetAPI == "systemA")

        objWithVars = systemA_ObjData;

    else if (targetAPI == "systemD")

        objWithVars = systemD_ObjData;



    uWarning("determined obj data: ");

    uWarning(objWithVars);



    //convert data to be sent into ByteArray

    var bytesObj = new ByteArrayOutputStream();

    bytesObj.reset();

    for (var i = 0; i < objWithVars.length; ++i) {

        bytesObj.write(objWithVars.charCodeAt(i));

    }



    var url = new URL(urlString); //create new URL based on selected target system



    var writeConn;



    writeConn = url.openConnection(); //open an HTTP connection using the selected URL



    writeConn.setDoOutput(true); //set output flag for HTTP connection to be true

    writeConn.setDoInput(true); //set input flag for HTTP connection to be true



    var verb = "POST";



    //based on selected target system, select the HTTP VERB; in this case it is either PUT if System D has to be updated, or POST for any other scenario

    if (targetAPI == "systemD" && APIintent == "Update") {

        verb = "PUT";

        writeConn.setRequestMethod(verb);

    } else if (targetAPI == "systemA" || (targetAPI == "systemD" && APIintent == "Create")) {

        verb = "POST";

        writeConn.setRequestMethod(verb);

    }



    //set up the authorization header for based on the selected target system; this section can be skipped if using an REST / WebService endpoint, 

    //that does not require authentication

    if (targetAPI == "systemD") {

        writeConn.setRequestProperty("Authorization", "Basic " + systemD_Encoding);

    } else if (targetAPI == "systemA") {

        writeConn.setRequestProperty("Authorization", "Basic " + systemA_Encoding);

    }



    //set up the content-type header based on the selected target system

    if (targetAPI == "systemD") {

        writeConn.setRequestProperty("Content-Type", "application/json");

    } else {

        writeConn.setRequestProperty("Content-Type", "application/xml");

    }



    uWarning("set request method and content type! Going to push data to API now!");



    //initiate a connection to the selected target system and then write the composed data to that system

    //response messages are then logged once the 

	try {

	    writeConn.connect();

	    var dataOS = new DataOutputStream(writeConn.getOutputStream());

	    dataOS.write(bytesObj.toByteArray(), 0, bytesObj.size());

	    dataOS.flush();

	    dataOS.close();

	} catch (idmerr) {

	    uWarning("Encountered error while trying to push data to API: ");

	    uWarning(idmerr);

	    uWarning(idmerr.message);

	    uSkip(1);

	}



        var responseCode = writeConn.getResponseCode();

        var responseMsg = writeConn.getResponseMessage();



	uWarning("Response MSG for the " + verb + ": " + responseMsg);

	uWarning("Response CODE for the " + verb + ": " + responseCode);

	uWarning("Header FIELD 0 for the " + verb + ": " + writeConn.getHeaderField(0));





    //if a response code other than 200 or 201 is encountered, that means an error has occurred and this will then be written to an external log file

    //if logging to a file is not required this section can be removed.

    if (writeConn.getResponseCode() !== 200 && writeConn.getResponseCode() !== 201) {

        logFileText += "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\r\n";

        logFileText += "For SYSTEM " + targetAPI + "\r\n";

        logFileText += "hitting API URL: " + urlString + "\r\n";

        logFileText += "with this payload:\n " + objWithVars + "\r\n";

        logFileText += "*************************************\r\n";

        logFileText += "THIS IS THE Header FIELD 0:\n " + writeConn.getHeaderField(0) + "\r\n";

        logFileText += "THIS IS THE RESULT CODE:\n " + writeConn.getResponseCode() + "\r\n";

        logFileText += "THIS IS THE RESULT MESSAGE:\n " + writeConn.getResponseMessage() + "\r\n";

        logFileText += "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\r\n";

        uToFile("C:\\IDM_ErrorFile.txt", logFileText, true);

    }



    //finally disconnect the HTTP connection after the data has been pushed to the REST API / WebService

    writeConn.disconnect();



}

NOTE: HTTP & HTTPS connections can both be accessed using the HTTPUrlConnection JAVA Class; in the case of an HTTPS API, you will need to import the SSL certificate of the secured target API web server, into the JAVA Keystore (following the IDM documentation:Exporting and Installing the SSL Certificate - SAP Identity Management Installation and Update Guide...); if the SSL certificate is not imported you will encounter an SSL handshake error, when trying to access the secured HTTPS REST API / WebService.

Using similar logic / concepts you can retrieve data from a REST API / WebService instead of pushing data to it (as demonstrated in the above example).

I hope this helps give you a better understanding of how you can access a REST API directly from SAP IDM, simply using JAVA / JavaScript, as well as the different use cases this can be applied to.