Fixing Volley Request for Patch and PUT adding blank entry to JSON endpoints

VolleyPatchFix

/****
 * Using Volley to PUT or PATCH a JSON endpoint creates an empty entry in your JSON:
 * 
 * {
 *  "id": 7,
 *  "favorite": true,
 *  "": ""
 * }
 * 
 * The bug is in line 457 of Request.java in the Volley source: 
 * https://android.googlesource.com/platform/frameworks/volley/+/l-preview/src/com/android/volley/Request.java
 *     
  private byte[] encodeParameters(Map<String, String> params, String paramsEncoding) {
      StringBuilder encodedParams = new StringBuilder();
      try {
          for (Map.Entry<String, String> entry : params.entrySet()) {
              encodedParams.append(URLEncoder.encode(entry.getKey(), paramsEncoding));
              encodedParams.append('=');
              encodedParams.append(URLEncoder.encode(entry.getValue(), paramsEncoding));
              encodedParams.append('&');
          }
          return encodedParams.toString().getBytes(paramsEncoding);
      } catch (UnsupportedEncodingException uee) {
          throw new RuntimeException("Encoding not supported: " + paramsEncoding, uee);
      }
  }
*
* The loop is adding an extra '&' at the end. A quick hack to fix this is to create a static
* encodeParams() function in your VolleyManager singleton, which you call from getBody(), which
* you override in your request object.
* 
*/
  
/**
 * Place this file inside some globally accessible point such as your Volley singleton.
 * I've only changed line 47, which takes out the final '&'.
 */
public static byte[] encodeParameters(Map<String, String> params, String paramsEncoding) {
    StringBuilder encodedParams = new StringBuilder();
    try {
        for (Map.Entry<String, String> entry : params.entrySet()) {
            encodedParams.append(URLEncoder.encode(entry.getKey(), paramsEncoding));
            encodedParams.append('=');
            encodedParams.append(URLEncoder.encode(entry.getValue(), paramsEncoding));
            encodedParams.append('&');
        }
        encodedParams.replace(encodedParams.length()-1, encodedParams.length(), "");

        return encodedParams.toString().getBytes(paramsEncoding);
    } catch (UnsupportedEncodingException uee) {
        throw new RuntimeException("Encoding not supported: " + paramsEncoding, uee);
    }
}
  
/***
 * An example string request. The important piece is the getBody() function.
 */
VolleyManager.getInstance().addToRequestQueue(new StringRequest(Request.Method.PATCH, http://127.0.0.1/contacts/7,
        new Response.Listener<String>() {

            @Override
            public void onResponse(String response) {
                new AlertDialog.Builder(mContext)
                        .setMessage(response.substring(0, 200)).create().show();
            }
        }, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        Log.i("Volley", error.getMessage());
    }
}) {
    @Override
    protected Map<String, String> getParams() throws AuthFailureError {

        Map<String, String> params = new HashMap<String, String>();
        params.put("favorite", String.valueOf(false));

        return params;
    }

    /**
     * This will call our new encodeParams function, which doesn't add a blank entry in our JSON.
     * The code is pulled directly from Request.java only changing line 89 by calling our fixed encodeParams().
     */
    @Override
    public byte[] getBody() throws AuthFailureError {
        Map<String, String> params = getParams();
        if (params != null && params.size() > 0) {
            return VolleyManager.encodeParameters(params, getParamsEncoding());
        }
        return null;
    }
});