Json RPC request via jquery getJSON

Question

I am trying to send json-rpc request to remote server with jquery getJSON method. Here is my code:

json_string=JSON.stringify(obj);
var jqxhr = $.getJSON("https://91.199.226.106/ssljson.php?jsoncallback=?", json_string, function(data){
    alert("aaaaaa");
});
jqxhr.error(function() { alert("error"); })

Here is my json-rpc string example:

{"jsonrpc":"2.0","method":"merchant_check","params":[{"hostID":150999,"orderID":116,"amount":"150","currency":"051","mid":15001038,"tid":15531038,"mtpass":"12345","trxnDetails":""}],"id":116}

And here is the error I get:

{"jsonrpc":"2.0","id":null,"error":{"code":-32600,"message":"Invalid JSON-RPC 2.0 request error (-32600)"}}

I can`t get what is the issue. Am I doing something wrong? Maybe I need to send request with php and not jquery? Then how should I do it?

Answer 1

The getJSON as the name say will send GET request if you want to use JSON-RPC you need to use POST like:

var json_string = JSON.stringify(obj);
$.post('https://91.199.226.106/ssljson.php', json_string, function(response) {
   // process response
}, 'json');

but this will only work if your page is on the same server, unless you use CORS.

Answer 2

That specific error message is supposed to tell you that the message envelope is invalid per the JSON-RPC 2.0 spec, or that there's a parse error in the JSON itself.

Unfortunately, in practice, many services return this error under a much wider variety of circumstances. (e.g.: missing authentication token, etc)

Specific problems with your example message?

Does the web-service accept GET requests? (i.e: should this be a POST instead?)

Does the web-service actually require the ?jsoncallback=? bit? That's normally for a JSONP request rather than JSON-RPC. The service is returning a real JSON-RPC error status, so I'd be really surprised if it needed that GET parameter, and (depending on the web-service configuration) might be interpreted as part of the envelope, which would make it an invalid JSON-RPC request!

Does merchant_check take an array of one-or-more transactions as its only parameter? If not, then you've got the syntax wrong for params. Some services want params to be an Array, some services want it to be an Object. Consult the SMD/documentation to determine which is the case.

The service might require text/json (or something else) as the mime-type for the request.

Recommended Approach:

To avoid these issues, you should probably start by using a purpose-built JSON-RPC library, like the one provided in Dojo toolkit, and use the SMD published by the web-service if it has one. (I recommend against hand-constructing JSON-RPC messages).