Resteasy multipart/data-form file upload on GAE

Question

I'm trying to use resteasy 2.0.1.GA to upload a form with a file in it into GAE application, using the method advised at How do I do a multipart/form file upload with jax-rs?

Index.html

<form action="/rest/upload" method="post" enctype="multipart/form-data">
  <input type="text" name="name" />
  <input type="file" name="file" />
  <input type="submit" />
</form>

Rest.java

@Path("")
public class Rest {
    @POST
    @Path("/rest/upload")
    @Consumes("multipart/form-data")
    public String postContent(@MultipartForm UploadForm form) {
        System.out.println(form.getData().length);
        System.out.println(form.getName());
        return "Done";
    }
}

UploadForm.java

public class UploadForm {

    private String name;
    private byte[] data;

    @FormParam("name")
    public void setPath(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    @FormParam("file")
    public void setContentData(byte[] data) {
        this.data = data;
    }

    public byte[] getData() {
        return data;
    }
}

But I'm getting the following error message (probably due to the RESTEasy Provider's implmenetation that uses temporary files to handle the input stream):

HTTP ERROR 500

Problem accessing /files/service/upload. Reason:

    java.io.FileOutputStream is a restricted class. Please see the Google  App Engine developer's guide for more details.

Caused by:

java.lang.NoClassDefFoundError: java.io.FileOutputStream is a restricted class. Please see the Google  App Engine developer's guide for more details.
    at com.google.appengine.tools.development.agent.runtime.Runtime.reject(Runtime.java:51)
    at org.apache.james.mime4j.storage.TempFileStorageProvider$TempFileStorageOutputStream.<init>(TempFileStorageProvider.java:117)
    at org.apache.james.mime4j.storage.TempFileStorageProvider.createStorageOutputStream(TempFileStorageProvider.java:107)
    at org.apache.james.mime4j.storage.ThresholdStorageProvider$ThresholdStorageOutputStream.write0(ThresholdStorageProvider.java:113)
    at org.apache.james.mime4j.storage.StorageOutputStream.write(StorageOutputStream.java:119)
    at org.apache.james.mime4j.codec.CodecUtil.copy(CodecUtil.java:43)
    at org.apache.james.mime4j.storage.AbstractStorageProvider.store(AbstractStorageProvider.java:57)
    at org.apache.james.mime4j.message.BodyFactory.textBody(BodyFactory.java:167)
    at org.apache.james.mime4j.message.MessageBuilder.body(MessageBuilder.java:148)
    at org.apache.james.mime4j.parser.MimeStreamParser.parse(MimeStreamParser.java:101)
    at org.apache.james.mime4j.message.Message.<init>(Message.java:141)
    at org.apache.james.mime4j.message.Message.<init>(Message.java:100)
    at org.jboss.resteasy.plugins.providers.multipart.MultipartInputImpl.parse(MultipartInputImpl.java:76)
    at org.jboss.resteasy.plugins.providers.multipart.MultipartFormAnnotationReader.readFrom(MultipartFormAnnotationReader.java:55)
    at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:105)
    at org.jboss.resteasy.plugins.interceptors.encoding.GZIPDecodingInterceptor.read(GZIPDecodingInterceptor.java:46)
    at org.jboss.resteasy.core.interception.MessageBodyReaderContextImpl.proceed(MessageBodyReaderContextImpl.java:108)
    at org.jboss.resteasy.core.messagebody.ReaderUtility.doRead(ReaderUtility.java:111)
    at org.jboss.resteasy.core.messagebody.ReaderUtility.doRead(ReaderUtility.java:93)
    at org.jboss.resteasy.core.MessageBodyParameterInjector.inject(MessageBodyParameterInjector.java:146)
    at org.jboss.resteasy.core.MethodInjectorImpl.injectArguments(MethodInjectorImpl.java:114)
    at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:137)
    at org.jboss.resteasy.core.ResourceMethod.invokeOnTarget(ResourceMethod.java:252)
    at org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:217)
    at org.jboss.resteasy.core.ResourceMethod.invoke(ResourceMethod.java:206)
    at org.jboss.resteasy.core.SynchronousDispatcher.getResponse(SynchronousDispatcher.java:514)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:491)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:120)
    at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:200)
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:48)
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:43)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    ...

Has anyone encountered this issue with GAE and RESTEasy? Has anyone solved it? I couldn't find any mentioning for this issue anywhere. Thanks!

Answer 1

I just ran into this problem and looked in the source code for mime4j's Message constructor. It gets the TempFileStorageProvider by calling DefaultStorageProvider.getInstance(). You can change the default to one that doesn't write to the filesystem by calling:

DefaultStorageProvider.setInstance(new MemoryStorageProvider());

That's org.apache.james.mime4j.storage.DefaultStorageProvider.

Thanks for the concise example of using @MultipartForm!