This blog is about Integration Gateway (IGW) in SAP Mobile Platform 3.0 (SMP).

I’d like to collect as many tips and FAQs as you may find useful.

It is an unordered collection of issues which might occur when using SAP Mobile Platform 3.0 (SMP) and Integration Gateway (IGW) and how to solve them.

Also tips and sample code should be part of this collection.

Please feel encouraged to add your own tips and sample code to the comment-section below.

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➕ Please participate !!!  

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Error

Description

When invoking a query of a REST based OData service, the following Error is logged in the SMP log:

java.lang.Exception: Error in StreetSet_REST_Query.groovy: groovy.lang.MissingPropertyException: No such property: LogMessage for class: Script1

Reason

The Groovy script contains an object that cannot be resolved. Probably the import statement is missing, or a dependency is missing

Solution:

Add the import statement, e.g.:

import com.sap.gateway.ip.core.customdev.logging.LogMessage

Error

Description

When invoking a query you get an error message in the browser response:

Internal Error

And in the SMP-log:

java.net.BindException: Cannot assign requested address: connect

Reason

Missing proxy definition in SMP Admin

Solution

Add proxy settings to your SMP server.

This is done at  https://<your_server>:8083/Admin/

Go to “Settings”-tab then “System” sub-tab


Error

Description

I had the following strange issue several times.

I installed SMP server, opened Gateway Management Cockpit and created a Destination inside corporate network.

So no proxy definition required.

In the Destination tab, I executed the “Test Connection” and it was successful.

The I created an OData service based on the REST data source.

Assigned the destination and opened the Service and Metadata documents -> fine

Then tried the entityset -> error.

Error message in response body in the browser:

For Input String’’

Error message in the log:

java.lang.NumberFormatException: For input string: “”

    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)

    at java.lang.Integer.parseInt(Integer.java:507)

    at java.lang.Integer.valueOf(Integer.java:585)

    at com.ning.http.util.ProxyUtils.createProxyServerSelector(ProxyUtils.java:157)

    at com.ning.http.client.AsyncHttpClientConfig$Builder.build(AsyncHttpClientConfig.java:1151)

    at com.sap.gateway.core.ip.camel.component.ahc.IGWAhcProducer.getClientConfig(IGWAhcProducer.jav

Reason

All settings seemed to be correct.

I searched long time for the error in the script – no chance, it didn’t even get invoked.

There didn’t seem to be a reason

Solution

At the end, I tried the following:

I entered proxy settings for SMP

Since my data source didn’t require a  proxy, I also entered my backend as non-proxy host.

Then restarted SMP server

After that, my service worked fine.



Error

Description

You’re creating a service based on REST data source

Error message in the browser:

class java.lang.Stringnull incompatible with class java.util.HashMapnull

Error message in the SMP-log:

ClassCastException.

Reason

The reason is very common for this part of the scripting.

It is about the string that is returned as “body”.

It needs to have exactly the expected structure.

If it doesn’t, this ClassCastException is thrown


Error

Description

You’re creating a service based on REST data source

When invoking the entity set, you get the usual error, which you probably don’t like so much

Reason

One possible reason is a missing property.

Remember: your OData model must have all properties that are in the REST service

The OData model may have more, but not less properties than the backend REST service

Solution

Adapt the OData model according to the backend REST service


Error

Description

You’re creating a service based on REST data source

When invoking the entity set, you get the error:

while trying to invoke the method com.sap.gateway.core.ip.component.commons.ODataResponseType.ordinal() of a null object loaded from local variable ‘responseType’

Reason

Returning Structure in message.setBody is not as expected

Solution

Fix the body string such that it meets the structure that is expected by the Integration Gateway framework

More info: http://scn.sap.com/community/developer-center/mobility-platform/blog/2015/04/08/integration-gateway-rest-data-source-overview-of-blogs



Error

Description

When implementing custom code in Javasccript, the following error is thrown in the SMP-log

Javascript error:

Caused by:

org.mozilla.javascript.EvaluatorException: missing ; before statement (/XlsServiceWithFileAccess/src/main/resources/script/OBDcodes_SCRIPT.js#32)

Reason

Don’t search for any missing   ;

It has nothing to do with that.

The reason is that you copied a code snippet from java

e.g.

File file = new File(fileName);

And you forgot to adapt it to

var file = new File(fileName);

Solution

Fix your erroneous code.



Error

Description

My service which contains custom code written in javascript fails and the error in the SMP log is

“An exception occurred”

Reason

The javascript code is erroneous and causes an exception

In my example:

I had created a java.util.map, there was a key (property name)  and the value was inserted programmatically.

The value turned out to be a primitive value (int) but it has to be an object (Integer)

Solution

Fix the javascript code


Error

Description

My service which contains custom code written in javascript fails and the error in the SMP log is

javax.script.ScriptException: org.mozilla.javascript.EvaluatorException: missing ) after argument list

Reason:

I forgot the + for concatenation

log.logErrors(LogMessage.TechnicalError, “===> done with test + ” hssfSheet);

Solution

Fix the code

log.logErrors(LogMessage.TechnicalError, “===> done with test + ” + hssfSheet);


Error

Description

In your browser, you go to the SMP Admin page, e.g. at https://localhost:8083/Admin/

After entering the credentials, you get that red error:

An internal server error occurred. Please contact your administrator

You nearly get crazy entering your credentials and you’re sure that they are correct.

What to do?

Reason

Don’t care

Solution

Reload the browser page by pressing F5


Error

Description

After deploying your service to SMP, you’ve changed the OData model and deployed again

During runtime, when invoking your entity set, you get an error in the SMP-log:

“failed to serve request”

Reason

SMP doesn’t know about the new changed metadata

Solution

Invoke the metadata document at <service_name>/$metadata

Then call the entity set again. Now it should work


Error

Description

You have entered the proxy settings in SMP, because you need proxy for your destination.

However, the connection still doesn’t work

Reason

Whatever

Solution

Restart the SMP server


Error

Description

You’ve changed your Eclipse project and deployed, but you don’t see the changes reflected at runtime.

Troubleshooting

– Check on OSGi console if bundle is started

– If you have started the SMP via console then check if the console is not blocked. Just hit enter in the console window

– In Eclipse, open the target folder and check if there are 2 jars. Delete them, then generate&deploy again


Error

Description

The x-csrf-token is not sent

Background

The x-csrf-token is required for modifying requests like POST, PUT, DELETE

You have to first send a GET request to a valid URL, e.g. the EntitySet URL

This GET request should be executed with the header

x-csrf-token: fetch

(Name of the header is “x-csrf-token” and the value of the header is “fetch”)

The response headers contain the header x-csrf-token and the value is the token that we need.

Now copy the value and paste it into the request header, such that you have

x-csrf-token: <value of the token from the response>

Problem

If you proceed as described above and don’t get the token, you might get crazy

Reason

The reason is that the token is always sent only once per session.

Solution

In order to force SMP to send it again, just logout from Gateway Management Cockpit or SMP Admin page and login again


Error

Description

Deployment doesn’t finish.

Reason

You have started the local SMP server via console

Somehow, you’ve clicked into the command shell

The below screenshot displays a tiny white block

This pauses the execution of SMP

Solution

Click into the command shell

Then press enter.

The white box is gone

Tip

Description

Clear metadata before restart SMP

Before restarting the SMP server, you should

– shutdown SQLAnywhere via context menu on the task bar icon 

– Delete the folder <install>\Server\work

– Delete the folder <install>\Server\configuration\org.eclipse.osgi

– Delete the folder <install>\Server\pickup\.state   (only required if you’ve deployed artifacts to the pickup)

Tip

Description

When you create a Destination in SMP server, you can execute a “Test Connection”

In case of REST service destination, this “Test Connection” might fail

Reason

The complete URL of the backend REST service has to be split and only the host is entered as Destination.

This part of the URL doesn’t respond with a success status code, therefore the “Test Connection” fails.

Solution

Create an additional dummy-destination which you don’t use for assigning it to a service.

This destination uses the full URL of the REST-service and as such the “Test connection” will be successful

Tip

Description

Custom error message in response body

Background

You’re creating a service based on REST data source and in your script you want to throw an error message and you want it to be shown in the response body such that the user of the OData service can understand it.

Solution

The error message is set as body-string to the Message-instance.

However, as we know, the IGW – framework expects that the body is an xml-structure (or json-structure) that matches the OData model.

Therefore, we have to tell the IGW-FWK that there isn’t any valid response payload, but instead, an error message has to be displayed.

This is achieved by setting an error-status-code to the “camelhttpresponsecode” header.

In the following example, we’re setting status 400 which is BAD REQUEST

message.setHeader(“camelhttpresponsecode”, 400);

Note

The camelhttpresponsecode is not the HTTP status code that is responsible for the communication of the OData service that we are creating.

The camelhttpresponsecode is responsible for the communication of the IGW with the backend REST service (or other backend data source)

In general: the camelhttpresponsecode describes the integration part of the whole communication cycle


Tip

Description

You’ve set up your Eclipse environment for Groovy scripting as described here

You’re implementing methods like  def Message processResponseData(message) {

You’re still not satisfied because you don’t get code completion for the Message object?

Solution

Here’s a little trick:

def Message processResponseData(message) {

    message = (Message)message;

Tip

Description

Implement getFeed() for Custom Code data source:

You have to return a java.util.List containing entries of type java.util.Map

Example:


function getFeed(message){
    importPackage(java.util);
    var responseMap = new HashMap();
    responseMap.put("MyEntityID", "111");
    responseMap.put("Name", "MyName");
    var list = new ArrayList();
    list.add(responseMap);
    message.setBody(list);
    return message;
}









And how to get empty feed?

Solution:

You have to return a java.util.List containing nothing.

This won’t cause an error, the response will just contain a feed which is empty

Example:


function getFeed(message){
    importPackage(java.util);
    message.setBody(new ArrayList());
    return message;
}









Tip

Description

Implement getEntry() for Custom Code data source:

You have to return a java.util.Map

Example:


function getEntry(message) {
    importPackage(java.util);
    var responseMap = new HashMap();
    responseMap.put("MyEntityID", "111");
    responseMap.put("Name", "MyName");
    message.setBody(responseMap);
    return message;
}









And how to throw a “Not found” error ?

Solution

Set the body as null

Example:


function getEntry(message) {
    message.setBody(null);
    return message;
}









Note:

Setting an empty Map as body like message.setBody(new HashMap()) doesn’t give the desired result, it will cause an exception and the response will be “BAD_REQUEST”

Tip

Description

Use logger

Solution

In your custom script, the code snippet is the following:

    importPackage (com.sap.gateway.ip.core.customdev.logging);

    log.logErrors(LogMessage.TechnicalError, “Hello ;-)”);

Tip

Description

Access UriInfo

Solution

In your custom script, the code snippet is the following:

    var uriInfo = message.getHeader(“uriinfo”, org.apache.olingo.odata2.api.uri.UriInfo);

    var top = uriInfo.getTop();

    var intValue = top.intValue();

Tip

Description

Access ODataContext object, in order to access info about external call to your OData service

e.g. the headers

Solution

In your custom script, the code snippet is the following:

var value = message.getHeader(“odatacontext”, org.apache.olingo.odata2.api.processor.ODataContext).getRequestHeader(“<MyHeader>”);

 


Tip

Description

Access the configured destination

Solution

In your custom script, the code snippet is the following:

   var destinationConfiguration = message.getHeaders().get(“DestinationConfiguration”); 

   // in case of destinationConfiguration instanceof HttpDestinationConfiguration

   var destinationURL = destinationConfiguration.getDestinationUrl();

Tip

Description

Access the parameters of a function import

Solution

In your custom script, the code snippet is the following:

   importPackage(com.sap.gateway.core.ip.script);

   var paramMap = ScriptUtil.getFunctionImportParameters(message); 

   var value = paramMap.get(“<paramName>”);

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