How to return HTTP error status code *and* content in Struts2

Question

I have a Controller that receives accepts http file uploads and responds with a JSON confirmation. If there is is any sort of problem with the procsessing of the upload I want to return an HTTP error status code (eg 403 for malformed requests or 500 for a general processing error), but I also want to send a JSON list of detailed error messages. I know how to return a 500 error (thanks to this post ) but I don't know how to return the 500 code and still send content.

Here's a snippit of my code (which doesn't do what I want it to):

@Action(value = "upload", results = { 
  @Result(name = SUCCESS, type = "freemarker", location = "results.ftl", params = { "contentType", "text/plain" }), 
  @Result(name = ERROR, type = "freemarker", location = "error.ftl", params = { "contentType", "text/plain" }), 
  @Result(name = ERROR, type = "httpheader", params = { "status", "500" }) 
})

public String upload() {
  //do stuff
  if(CollectionUtils.isEmpty(getActionErrors()) {
    return SUCCESS;
  } else {
     return ERROR;
  }
}

Answer 1

This is an old post, but if you are using the Struts-JSON which I suggest using you can simply return an error object with what you want and attach the status code like below:

@Result(name = ERROR, type="json", 
        params = {"root","errorResponse", "statusCode", "500"}
)   

Answer 2

Update 2/24/15 : ty-danielson's answer is the correct one. It applies to JSON responses, which is what I wanted even though I was using freemarker templates to generate them (another bad idea).

If you really want a freemarker template with error status code: My original answer is still the wrong approach because it's bad form to access the ServletResponse from inside an action method. Struts' built-in FreemarkerResult does not accept a status code parameter, but you can easily add this functionality by subclassing it (example taken from GBIF project )

/** 
 * Same as FreemarkerResult, but with added 'statusCode' parameter.  
 * (don't forget to register this result type in struts-config.xml)
 */
public class FreemarkerHttpResult extends FreemarkerResult {
  private int status;

  public int getStatusCode() {
    return status;
  }

  public void setStatusCode(int status) {
    this.status = status;
  }

  @Override
  protected void postTemplateProcess(Template template, TemplateModel data) throws IOException {
    super.postTemplateProcess(template, data);
    if (status >= 100 && status < 600) {
      HttpServletResponse response = ServletActionContext.getResponse();
      response.setStatus(status);
    }
  }
}

Then declare your action mapping like so:

@Action(value = "myAction", results = { 
    @Result(name = SUCCESS, type = "freemarker", location = "results.ftl"), 
    @Result(name = ERROR, type = "freemarkerhttp", location = "error.ftl", params = { "statusCode", "500"})            
})
public String myAction() {
   //do stuff, then return SUCCESS or ERROR
}

My Original Answer

So, I'm not sure if this is "proper" from a struts2 perspective, but here's a solution that acomplishes my goal of returning the http error code while still being able to render a freemarker template. I'll mark this as the answer until a better one comes along.

@Action(value = "upload", results = { 
@Result(name = SUCCESS, type = "freemarker", location = "results.ftl", params = { "contentType", "text/plain"}), 
@Result(name = ERROR, type = "freemarker", location = "error.ftl", params = { "contentType", "text/plain"})            
})
    public String upload() {
       try {
       //do stuff
       } Catch(SomeExceptionType ex) {
            addActionError("you did something bad");
            HttpServletResponse response = ServletActionContext.getResponse();
            response.setStatus(400);
       }


    }

Answer 3

In case someone is looking for the struts.xml version of the accepted answer, I'm going to leave it here:

    <action name="upload"
        class="...">
        <exception-mapping exception="java.lang.Exception" result="error"/>
        <result name="error" type="json">
            <param name="statusCode">418</param>
        </result>
        <result name="Success" type="json" />
    </action>

Answer 4

I don't have time to setup a test Struts2 application, but maybe have a single error result:

@Result(name = ERROR, type = "freemarker", location = "error.ftl",
    params = { "contentType", "text/plain", "status", "500" })