JSON POST request parsing in PHP

Question

I've generate an HTMLPost Request containing a JSON object in java and would like to parse it in PHP.

public static String transferJSON(JSONObject j) {
    HttpClient httpclient= new DefaultHttpClient();
    HttpResponse response;
    HttpPost httppost= new HttpPost(SERVERURL);
    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);  
    nameValuePairs.add(new BasicNameValuePair("json", j.toString()));

    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
    response = httpclient.execute(httppost);  
}

And on the server

<?php

if ($_SERVER['REQUEST_METHOD'] === 'POST') {

  // input = "json=%7B%22locations%22%3A%5B%7B%22..."
  $input = file_get_contents('php://input');

  // jsonObj is empty, not working
  $jsonObj = json_decode($input, true);

I guess this is because the JSON special characters are encoded.

The json_decode return empty response

Any idea why ?

Answer 1

Instead of POSTing an application/json entity, you are actually posting an HTTP form entity (application/x-www-form-urlencoded) with a single value pair json=(encoded json).

instead of

List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);  
nameValuePairs.add(new BasicNameValuePair("json", j.toString()));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

Try

 httppost.setEntity(new StringEntity(j.toString(),"application/json","UTF-8"));

Answer 2

That's by design: you are accessing the raw POST data, which needs to be URLencoded.

Use urldecode() on the data first.

Answer 3

Try this:

//remove json=
$input = substr($input, 5);

//decode the url encoding
$input = urldecode($input);

$jsonObj = json_decode($input, true);