A client and a post web service using dropwizard

Question

I am using Dropwizard (v1.0.5) and I want to create a client to connect a post service that receives a multipart. However I obtain a "Bad Request" response.

Here the dependencies in my pom.xml

    <dependencies>
    <dependency>
        <groupId>io.dropwizard</groupId>
        <artifactId>dropwizard-core</artifactId>
        <version>${dropwizard.version}</version>
    </dependency>
    <dependency>
        <groupId>io.dropwizard</groupId>
        <artifactId>dropwizard-assets</artifactId>
        <version>${dropwizard.version}</version>
    </dependency>
    <dependency>
        <groupId>io.dropwizard</groupId>
        <artifactId>dropwizard-forms</artifactId>
        <version>${dropwizard.version}</version>
    </dependency>
    <dependency>
        <groupId>io.dropwizard</groupId>
        <artifactId>dropwizard-client</artifactId>
        <version>${dropwizard.version}</version>
    </dependency>

</dependencies>

Here my Dropwizard Application (Client2PostApplication.java):

public class Client2PostApplication extends Application<Client2PostConfiguration> {
public static void main(String[] args) throws Exception {
    new Client2PostApplication().run(args);
}

@Override
public void initialize(Bootstrap<Client2PostConfiguration> bootstrap) {
    bootstrap.addBundle(new MultiPartBundle());
}

@Override
public void run(Client2PostConfiguration configuration,
                Environment environment) throws Exception {

    environment.jersey().register(MultiPartFeature.class);

    final Client client = new JerseyClientBuilder(environment).using(configuration.getJerseyClientConfiguration()).build(getName());

    environment.jersey().register(new Client2Post(client));

    environment.jersey().register(new MyPostResource()); 

    }
}

Here my Configuration (Client2PostConfiguration.java):

public class Client2PostConfiguration extends Configuration {

    @Valid
    @NotNull
    private JerseyClientConfiguration jerseyClient = new JerseyClientConfiguration();

    @JsonProperty("jerseyClient")
    public JerseyClientConfiguration getJerseyClientConfiguration() {
        return jerseyClient;
    }
}

And now, the post web service (MyPostResource.java):

@Path("/testpost")

public class MyPostResource {

    public MyPostResource() {

    }

    @POST
    @Consumes(MediaType.MULTIPART_FORM_DATA)
    @Timed
    public String test(
        @FormDataParam("foo") String testData) throws IOException {
        return testData;
    }
}

And finally, the client (Client2Post.java):

@Produces(MediaType.TEXT_PLAIN)
@Path("/client")
public class Client2Post {

    private Client client;

    public Client2Post(Client client) {
        this.client = client;
    }

    @GET
    @Path("/test")
    public String testPost() {

    final Invocation.Builder request = client.target("http://localhost:8080/testpost").register(MultiPartFeature.class).request();

    final FormDataMultiPart entity = new FormDataMultiPart()
            .field("foo", "bar");

    final String response = request.post(Entity.entity(entity, entity.getMediaType()), String.class);

    return response;

    }
}

I want to be able to make a GET through http://localhost:8080/client/test and receive the response of http://localhost:8080/testpost that, in this case, would be "bar". However I am getting "HTTP 400 Bad Request".

What am I doing wrong?

How could I test the post service? Because I am using a firefox addon, the HttpRequester using this multipart content:

--l3iPy71otz
Content-Disposition: form-data; name="foo"
bar
--l3iPy71otz--

...and I get the same response.

Are you seeing any exceptions? Is there any message to go with the response. It's hard to say what the problem is without more information. The code looks OK — Paul Samsotha, Jun 01 '17 at 00:16
An empty line is missing after the Header `Content-Disposition`. Try `curl -F "foo=bar" localhost:8080` — Ôrel, Jun 01 '17 at 05:07
@peeskillet I don't get any exceptions, I think it doesn't even enter the function testPost because some problem with the format of the multipart, but I don't know what to do anymore! — impulso, Jun 06 '17 at 07:47
@Ôrel Executing the call from curl works just fine! I get an OK response and the content: "bar". So now, I don't understand why using the HttpRequester doesn't work (even inserting a blank line), and more importantly, why I can't make my client work... What am I missing? — impulso, Jun 06 '17 at 07:54
Good the server is working. Can you do a tcpdump to see the difference between curl and the client ? — Ôrel, Jun 06 '17 at 10:15
For your browser plugin, your payload should be like "3[\r][\n]" "bar[\r][\n]" "2b[\r][\n]"` — Ôrel, Jun 06 '17 at 14:55
https://stackoverflow.com/questions/19668426/how-to-resolve-messagebodywriter-not-found-for-media-type-multipart-form-data-er can help — Ôrel, Jun 06 '17 at 14:56
I don't have experience using tcpdump, however I run: sudo tcpdump -X -i lo And I got this output for the [call using curl](https://drive.google.com/open?id=0B4erkx-SQuKdakxVSzNOY1d4N0k), and this one for the [call using the client](https://drive.google.com/open?id=0B4erkx-SQuKdY3BtdThWOEdzZlE), I can see the size of the data sent is not the same, but I cannot figure out what to do with this information... I had already read that question linked, it helped a bit (I didn't have registered the multipart.class), but my client still doesn't work... — impulso, Jun 08 '17 at 15:09
I uploaded the code to GitHub [here](https://github.com/esparig/dwclient2post), just in case someone wants to try it. — impulso, Jun 08 '17 at 16:05

score 1 · Accepted Answer · answered Jul 22 '17 at 11:25

I found the solution to my problem in https://github.com/dropwizard/dropwizard/issues/1094. It seems that chunked encoding should be disabled for requests in the Jersey Client to work with MIME Multipart.

So my Client2PostApplication.java is now:

public class Client2PostApplication extends Application<Client2PostConfiguration> {
    public static void main(String[] args) throws Exception {
        new Client2PostApplication().run(args);
    }

    @Override
    public void initialize(Bootstrap<Client2PostConfiguration> bootstrap) {
        bootstrap.addBundle(new MultiPartBundle());
    }

    @Override
    public void run(Client2PostConfiguration configuration,
                Environment environment) throws Exception {

        environment.jersey().register(MultiPartFeature.class);
        JerseyClientConfiguration conf = configuration.getJerseyClientConfiguration();

        conf.setChunkedEncodingEnabled(false); //This line is new!!!

        final Client client = new JerseyClientBuilder(environment).using(conf).build(getName());
        environment.jersey().register(new Client2Post(client));
        environment.jersey().register(new MyPostResource());       
    }
}

And it works pertectly. The code can be retrieved in https://github.com/esparig/dwclient2post

A client and a post web service using dropwizard

1 Answers1