Irrelevant server method called for client proxy

[eliasbalasis]

I am using GWT extension

Following the examples, I created the org.restlet.ext.servlet.ServerServlet servlet and attached a ServerResource
I also created the respective ClientProxy and matching methods in both

I initially created a test method which I I called successfully
Then I started adding and successfully calling a couple of my application's basic methods
I continued until very soon calling a specific method on the ClientProxy ends calling an irrelevant method on the ServerRecource

experimenting with different combinationa of @get and @post matching annotations I managed just to reproduce the same problem but for another method this time

this is extremely peculiar and in my case a blocking matter, it prevents me from continuing the developmoent of my application

please assist

[thboileau]

hi,
could you provide a reproductible sample test case?

[eliasbalasis]

it seems that, under GWT at least, the problem was the use of multiple methods on same ServerRecource/ClientProxy pair
using multiple ServerRecource/ClientProxy pairs each having one and only one Get/Post/etc. method solved the problem

I have to admit that requiring a ServerRecource/ClientProxy pair for each server function I need to call is not elegant enough but it works

still, I was wondering about the actual cause behind this behavior.
I am suspecting it is all about some fundamental REST requirement or something, any ideas?

I also discovered that use of multiple arguments in server functions with more than one arguments are not directly supported
the solution was to use a single compound object containing values for all my parameters as a single parameter to my server methods
I am again suspecting this is caused by some fundamental REST requirement, any ideas?

[thboileau]

Hi,

I have to admit that requiring a ServerRecource/ClientProxy pair for each server function I need to call is not elegant enough but it works.

Well, this is clearly not a goal the framework would like to target!

I am suspecting it is all about some fundamental REST requirement or something, any ideas?

I don't think so, even if it is quite difficult for me to understand your issue without sample code.

I also discovered that use of multiple arguments in server functions with more than one arguments are not directly supported

That's right, The single argument represents the single entity of a Request.
What kind of parameters are you talking about? parameters taken form a Web form?
In this case you can use the Form class :
@put (or @post)
public void myMethod(Form form){
String value1 = form.getFirstValue("input1");
[etc.]
}

Best regards,
Thierry Boileau

[eliasbalasis]

here is some sample code
I hope it helps

ServerResource (server-side)

import org.restlet.resource.Post;
import org.restlet.resource.ServerResource;

public class AdminResourceOfGetDataRowsForDatasetTask extends ServerResource {

@Post
public PagingResultDTO getDataRowsForDatasetTask(
    ParametersOfGetDataRowsForDatasetTask parameters
)
throws
    IncompatibleTaskTypeException,
    TaskNotFoundException
{
    return RPCFunctions.getDataRowsForDatasetTask(
        parameters.getTaskId(),
        parameters.getParamValues(),
        parameters.getStartRow(),
        parameters.getPageSize(),
        parameters.getColumnSorting()
        );
}

}

ClientProxy (GWT client-side)

public interface ResourceProxyOfGetDataRowsForDatasetTask extends ClientProxy {

@Post
public void getDataRowsForDatasetTask(
    ParametersOfGetDataRowsForDatasetTask parameters,
    Result<PagingResultDTO> result
);

}

observe the use of ParametersOfGetDataRowsForDatasetTask
it contains all the parameters (more than one)
it is the only way to pass multiple parameters to a server function

initial problem was that for same pair (ServerResource/ClientProxy like above) only one method (like above) can be supported
thus I was forced to use a separate pair (ServerResource/ClientProxy like above) for each server function

[eliasbalasis]

here is some sample code
I hope it helps

ServerResource (server-side)

import org.restlet.resource.Post;
import org.restlet.resource.ServerResource;

public class AdminResourceOfGetDataRowsForDatasetTask extends ServerResource {

@Post
public PagingResultDTO getDataRowsForDatasetTask(
    ParametersOfGetDataRowsForDatasetTask parameters
)
throws
    IncompatibleTaskTypeException,
    TaskNotFoundException
{
    return RPCFunctions.getDataRowsForDatasetTask(
        parameters.getTaskId(),
        parameters.getParamValues(),
        parameters.getStartRow(),
        parameters.getPageSize(),
        parameters.getColumnSorting()
        );
}

}

ClientProxy (GWT client-side)

public interface ResourceProxyOfGetDataRowsForDatasetTask extends ClientProxy {

@Post
public void getDataRowsForDatasetTask(
    ParametersOfGetDataRowsForDatasetTask parameters,
    Result<PagingResultDTO> result
);

}

observe the use of ParametersOfGetDataRowsForDatasetTask
it contains all the parameters (more than one)
it is the only way to pass multiple parameters to a server function

initial problem was that for same pair (ServerResource/ClientProxy like above) only one method (like above) can be supported
thus I was forced to use a separate pair (ServerResource/ClientProxy like above) for each server function

[thboileau]

Hi,

I guess the provided sample test code works.
I wonder if in the failing code, the ServerResource declares several Java methods annotated with the same annotation with different parameters.
@post
public void method1(Object1 myParameters){};
@post
public void method2(Object2 myParameters){};

In this case, this won't work at all.
Another case that does not work is the declaration of Java methods with several parameters :
@post
public void method(Object1 parameter1, Object2 parameter2){};

The parameter must be unique as it corresponds literally to the request's entity : one entity => one parameter.

[thboileau]

As a side note, I wonder if your "POST" method does not correspond actually to a "GET" one. In this case, you can send the parameters, not inside the entity, but simply as query parameters.

[eliasbalasis]

I thank you for your reply,

meanwhile, I have discovered the correct way,
only one method is needed per "Resource" (with PUT) and must accept only one parameter

it seems this is the only working path

[thboileau]

After reading again your sample code, just my 2 cents regarding your ServerResource called "AdminResourceOfGetDataRowsForDatasetTask".

I guess your resource could be described as follow :
"List of data rows for a dataSet task (with pagination)".

To my mind, such resource could have this kind of URI :
/dataSetTasks/{taskId}/rows

and returns its representation using the GET HTTP verb (not POST) as follow. It takes the identifier of the "task" from the URL, and the other parameters from the query:

public class DatasetTaskDataRows extends ServerResource {

@Get
public PagingResultDTO listRows() throws IncompatibleTaskTypeException, TaskNotFoundException 
{
    String taskId = (String) getRequestAttributes().get("taskId");
    String startRow = getQuery().get("startRow");
    String pageSize = getQuery().get("pageSize");
    String columnSorting = getQuery().get("columnSorting");
    String paramValues = getQuery().get("paramValues");

    return RPCFunctions.getDataRowsForDatasetTask(taskId,
                      paramValues, startRow, pageSize, columnSorting);
}
}

One of the advantage of using GET method instead of POST, is that you can leverage the caching abilities of the HTTP client (such as browser) or proxies which can drastically help reducing the load on server side.
In addition, having a name of a method inside the name of a Resource is something strange that should be avoided, to my mind.

Best regards,
Thierry Boileau

[eliasbalasis]

you guessed correctly
indeed, it is something about data and paging

your suggestion is quite interesting, allows use of GET (no parameters in method)

I will examine your approach
thanks a lot

[jlouvel]

@eliasbalasis : can we consider this old issue closed?