Json – GWT RequestBuilder POST JSON application/json

gwtjsonpost

I'm trying to send JSON data to a server.

RequestBuilder builder = new RequestBuilder(RequestBuilder.POST, url);
builder.setHeader("Content-Type", "application/json");
builder.setRequestData(getJSONString());
builder.setCallback(myCallbackObject);
builder.send();

I do this in eclipse and I saw in the TCP/IP Monitor that my JSON Data is not transmitted as post in the request. If I ask for

builder.getRequestData();

I can see the JSON data is right there.

What do I need for the data to get on the server?

Best Answer

You might be running into the browser's same-origin policy if the url that you are attempting to connect to is not from the same origin as your GWT nocache.js file. Is your callback's onFailure() being called? Also, see if Request.getSatusCode() returns 0, which is indicative of SOP problems.

Dynamically create `<input>`s in a form and submit it

/**
 * sends a request to the specified url from a form. this will change the window location.
 * @param {string} path the path to send the post request to
 * @param {object} params the parameters to add to the url
 * @param {string} [method=post] the method to use on the form
 */

function post(path, params, method='post') {

  // The rest of this code assumes you are not using a library.
  // It can be made less verbose if you use one.
  const form = document.createElement('form');
  form.method = method;
  form.action = path;

  for (const key in params) {
    if (params.hasOwnProperty(key)) {
      const hiddenField = document.createElement('input');
      hiddenField.type = 'hidden';
      hiddenField.name = key;
      hiddenField.value = params[key];

      form.appendChild(hiddenField);
    }
  }

  document.body.appendChild(form);
  form.submit();
}

Example:

post('/contact/', {name: 'Johnny Bravo'});

EDIT: Since this has gotten upvoted so much, I'm guessing people will be copy-pasting this a lot. So I added the hasOwnProperty check to fix any inadvertent bugs.

Json – Can comments be used in JSON

No.

The JSON is data only, and if you include a comment, then it will be data too.

You could have a designated data element called "_comment" (or something) that should be ignored by apps that use the JSON data.

You would probably be better having the comment in the processes that generates/receives the JSON, as they are supposed to know what the JSON data will be in advance, or at least the structure of it.

But if you decided to:

{
   "_comment": "comment text goes here...",
   "glossary": {
      "title": "example glossary",
      "GlossDiv": {
         "title": "S",
         "GlossList": {
            "GlossEntry": {
               "ID": "SGML",
               "SortAs": "SGML",
               "GlossTerm": "Standard Generalized Markup Language",
               "Acronym": "SGML",
               "Abbrev": "ISO 8879:1986",
               "GlossDef": {
                  "para": "A meta-markup language, used to create markup languages such as DocBook.",
                  "GlossSeeAlso": ["GML", "XML"]
               },
               "GlossSee": "markup"
            }
         }
      }
   }
}

Best Answer

Related Solutions

JavaScript post request like a form submit

Dynamically create <input>s in a form and submit it

Json – Can comments be used in JSON

Related Topic

Dynamically create `<input>`s in a form and submit it