Volley - how to send DELETE request parameters?

Question

I'm trying to use Volley to send a DELETE type request to my server and add parameters to the request. So far I haven't been able to do so.

Creating a custom request and overriding the getParams() method didn't help me because this method does not get called for the DELETE type request.

How can I add parameters to a DELETE request in Volley?

Answer 1

Same problem here but I found the solution.

The problem is the implementation of the createHttpRequest method in com.android.volley.toolbox.HttpClientStack.java which will add the body only if the request method is POST, PUT or PATCH.

/**
 * Creates the appropriate subclass of HttpUriRequest for passed in request.
 */
@SuppressWarnings("deprecation")
/* protected */ static HttpUriRequest createHttpRequest(Request<?> request,
        Map<String, String> additionalHeaders) throws AuthFailureError {
    switch (request.getMethod()) {
        case Method.DEPRECATED_GET_OR_POST: {
            // This is the deprecated way that needs to be handled for backwards compatibility.
            // If the request's post body is null, then the assumption is that the request is
            // GET.  Otherwise, it is assumed that the request is a POST.
            byte[] postBody = request.getPostBody();
            if (postBody != null) {
                HttpPost postRequest = new HttpPost(request.getUrl());
                postRequest.addHeader(HEADER_CONTENT_TYPE, request.getPostBodyContentType());
                HttpEntity entity;
                entity = new ByteArrayEntity(postBody);
                postRequest.setEntity(entity);
                return postRequest;
            } else {
                return new HttpGet(request.getUrl());
            }
        }
        case Method.GET:
            return new HttpGet(request.getUrl());
        case Method.DELETE:
            return new HttpDelete(request.getUrl());
        case Method.POST: {
            HttpPost postRequest = new HttpPost(request.getUrl());
            postRequest.addHeader(HEADER_CONTENT_TYPE, request.getBodyContentType());
            setEntityIfNonEmptyBody(postRequest, request);
            return postRequest;
        }
        case Method.PUT: {
            HttpPut putRequest = new HttpPut(request.getUrl());
            putRequest.addHeader(HEADER_CONTENT_TYPE, request.getBodyContentType());
            setEntityIfNonEmptyBody(putRequest, request);
            return putRequest;
        }
        case Method.HEAD:
            return new HttpHead(request.getUrl());
        case Method.OPTIONS:
            return new HttpOptions(request.getUrl());
        case Method.TRACE:
            return new HttpTrace(request.getUrl());
        case Method.PATCH: {
            HttpPatch patchRequest = new HttpPatch(request.getUrl());
            patchRequest.addHeader(HEADER_CONTENT_TYPE, request.getBodyContentType());
            setEntityIfNonEmptyBody(patchRequest, request);
            return patchRequest;
        }
        default:
            throw new IllegalStateException("Unknown request method.");
    }
}

So you have to use your own implementation of HttpStack.java or you override HttpClientStack class.

First of all your should replace your initialization of RequestQueue from

RequestQueue requestQueue = Volley.newRequestQueue(sContext);

to

    String userAgent = "volley/0";
    try {
        String packageName = getContext().getPackageName();
        PackageInfo info = getContext().getPackageManager().getPackageInfo(packageName, 0);
        userAgent = packageName + "/" + info.versionCode;
    } catch (PackageManager.NameNotFoundException e) {}
    HttpStack httpStack = new OwnHttpClientStack(AndroidHttpClient.newInstance(userAgent));
    RequestQueue requesQueue = Volley.newRequestQueue(sContext, httpStack);

and write your own implementation of HttpClientStack where you change the case of "Method.POST:" in the method createHttpRequest(). You also have to create an Object like "OwnHttpDelete" as extention of HttpEntityEnclosingRequestBase to use the method setEntityIfNonEmptyBody().

public class OwnHttpClientStack extends com.android.volley.toolbox.HttpClientStack {
    private final static String HEADER_CONTENT_TYPE = "Content-Type";

    public OwnHttpClientStack(HttpClient client) {
        super(client);
    }

    @Override
    public HttpResponse performRequest(Request<?> request, Map<String, String> additionalHeaders)
            throws IOException, AuthFailureError {
        HttpUriRequest httpRequest = createHttpRequest(request, additionalHeaders);
        addHeaders(httpRequest, additionalHeaders);
        addHeaders(httpRequest, request.getHeaders());
        onPrepareRequest(httpRequest);
        HttpParams httpParams = httpRequest.getParams();
        int timeoutMs = request.getTimeoutMs();
        // TODO: Reevaluate this connection timeout based on more wide-scale
        // data collection and possibly different for wifi vs. 3G.
        HttpConnectionParams.setConnectionTimeout(httpParams, 5000);
        HttpConnectionParams.setSoTimeout(httpParams, timeoutMs);
        return mClient.execute(httpRequest);
    }

    private static void addHeaders(HttpUriRequest httpRequest, Map<String, String> headers) {
        for (String key : headers.keySet()) {
            httpRequest.setHeader(key, headers.get(key));
        }
    }

    static HttpUriRequest createHttpRequest(Request<?> request, Map<String, String> additionalHeaders) throws AuthFailureError {
        switch (request.getMethod()) {
            case Request.Method.DEPRECATED_GET_OR_POST: {
                byte[] postBody = request.getPostBody();
                if (postBody != null) {
                    HttpPost postRequest = new HttpPost(request.getUrl());
                    postRequest.addHeader(HEADER_CONTENT_TYPE, request.getPostBodyContentType());
                    HttpEntity entity;
                    entity = new ByteArrayEntity(postBody);
                    postRequest.setEntity(entity);
                    return postRequest;
                } else {
                    return new HttpGet(request.getUrl());
                }
            }
            case Request.Method.GET:
                return new HttpGet(request.getUrl());
            case Request.Method.DELETE:
                OwnHttpDelete deleteRequest =  new OwnHttpDelete(request.getUrl());
                deleteRequest.addHeader(HEADER_CONTENT_TYPE, request.getBodyContentType());
                setEntityIfNonEmptyBody(deleteRequest, request);
                return deleteRequest;
            case Request.Method.POST: {
                HttpPost postRequest = new HttpPost(request.getUrl());
                postRequest.addHeader(HEADER_CONTENT_TYPE, request.getBodyContentType());
                setEntityIfNonEmptyBody(postRequest, request);
                return postRequest;
            }
            case Request.Method.PUT: {
                HttpPut putRequest = new HttpPut(request.getUrl());
                putRequest.addHeader(HEADER_CONTENT_TYPE, request.getBodyContentType());
                setEntityIfNonEmptyBody(putRequest, request);
                return putRequest;
            }
            case Request.Method.HEAD:
                return new HttpHead(request.getUrl());
            case Request.Method.OPTIONS:
                return new HttpOptions(request.getUrl());
            case Request.Method.TRACE:
                return new HttpTrace(request.getUrl());
            case Request.Method.PATCH: {
                HttpPatch patchRequest = new HttpPatch(request.getUrl());
                patchRequest.addHeader(HEADER_CONTENT_TYPE, request.getBodyContentType());
                setEntityIfNonEmptyBody(patchRequest, request);
                return patchRequest;
            }
            default:
                throw new IllegalStateException("Unknown request method.");
        }
    }

    private static void setEntityIfNonEmptyBody(HttpEntityEnclosingRequestBase httpRequest,
                                                Request<?> request) throws AuthFailureError {
        byte[] body = request.getBody();
        if (body != null) {
            HttpEntity entity = new ByteArrayEntity(body);
            httpRequest.setEntity(entity);
        }
    }

    private static class OwnHttpDelete extends HttpPost {
        public static final String METHOD_NAME = "DELETE";

        public OwnHttpDelete() {
            super();
        }

        public OwnHttpDelete(URI uri) {
            super(uri);
        }

        public OwnHttpDelete(String uri) {
            super(uri);
        }

        public String getMethod() {
            return METHOD_NAME;
        }
    }
}

I hope my code will help someone. It should also be possible to add parameters to a HEAD request.

Answer 2

After some more reading and a bit of digging through Volley's code, I'd come to the conclusion that there isn't a way of attach parameters to a DELETE request in Volley - most probably as a design choice as it seems to be frowned upon generally.

I wanted to figure out how to do it because I wanted to attach an API key to every type of request I'm sending to my server.

If anyone finds himself with a similar problem, then what I ended up doing (and I'm pretty sure now that that's the way to go here) is send the API key in the headers part of the request. Specifically in Volley this means overriding the getHeaders() method and add the parameters you need there.

Here's my bit of code:

@Override
public Map<String, String> getHeaders() throws AuthFailureError {
    Map<String, String> headers = super.getHeaders();

    if (headers == null
            || headers.equals(Collections.emptyMap())) {
        headers = new HashMap<String, String>();
    }

    headers.put("API_KEY", apiKey);

    return headers;
}