JavaScript and Services: JSON Server + JSON + JSONP // + MooTools // Discussions

This works beautifully, but last night I ran into a challenge in sending JSON strings. I'm working on it right now and will update once I know what's wrong. In the meantime, if anyone picks this up and has insight, I'd love to hear it.

Problem

I can store regular strings without problem. I can receive JSON strings from services/database, no problem.

I can ~send JSON strings, no problem. (The string appears fine in the post (via Firebug)).

No errors are reported.

HOWEVER, the JSON string does not write to the database via JSON server.

The exact same string DOES write to the database, if using the admin/build/services drupal interface. It appears as though JSON server is choking on the string somewhere during the process.

An attempt to be clearer:

I'm passing data from my JS app back and forth from the database. No problem.

However -- as well as sending regular string arguments in the POST object, I'd like to include a JSON string argument.

The regular arguments write to corresponding table fields in the DB as normal. ** The JSON argument (containing a lengthy string of fields) would write and be called to a single table field in the DB.

I'm running into a problem with the parsing of the JSON server data object. It seems to choke when it contains a sub object such as my JSON string.

I'm working on it. Any ideas in the meantime would be appreciated.

Update

Cataloging this process is helping me think through it. Here's what I've got so far...

After encoding the object into a string, it seems mandatory to escape the first curly bracket with another character. Anything other than ' [ ' or ' { ' which confuse the JSON parser.

So, as of now I'm writing strings like:

and it's working but not overly ideal.

Hi Mike

Thanks for taking the time. I'm not mistaking anything.

MooTools' encode function takes a JavaScript OBJECT and converts it to a JSON STRING. The function I'm using is the correct one. Not knowing if you are familiar with JS, let me give you a quick example.

The string that it returns is a JSON string. It's my expectation that this string should be able to be passed as an argument.

However, this fails, hence the need to escape the curly bracket.

Since writing this I've discovered that MooTools has a function to do this properly.

Escaping it is fine. I simply think it is an unexpected and unnecessary step.

PS: Conversely, to decode a string is to convert a JSON STRING to a JS OBJECT. To anyone reading, these are the exact functions you would want to use to convert objects to strings and vice versa.

Hey Alex,

I just responded via email with my solution. I see here that you've tested pretty much the same thing I've sent you.

Mine works fine however...

Hmm... I'm also using 1.2.3-core. Have you tested your services setup through the Drupal admin? Or any other service method?

I will swap out my Services and JSON_Server mods with the one's you sent me, and will let you know how that goes. Should I expect this to work crossdomain (JSON/P), or was that not originally supported? I'm not totally sure on this, but i did test JSON server on the same domain that my drupal instance is installed on and it seemed to work fine. However, if I run the same script and make an HTTP request from outside of the domain then i start to see issues. I was hoping that it would be possible to pass (callback=CALLBACK) similar to the way that Del.icio.us handles it

http://del.icio.us/feeds/json/singpolyma.techblog/
http://del.icio.us/feeds/json/singpolyma.techblog/?callback=CALLBACK

As side note question regarding JSON/P: Since i am a bit of a noob in the Drupal world, how would Drupal deal with (?callback=CALLBACK) when cleanURLs are setup? Just curious and wanted to make sure that wasn't the source of my issues also.

I modified the JSON server module to handle JSONP and GET/POST. When I was about to post the code, dmitrig01 asked me not to. Unfortunatelly my emails have gone unanswered and I wasn't able to convince him to update the changes to the JSON server module. Anyhow, the code lives here:

http://drupal.org/node/477012#comment-2050614

It's very basic and doesn't change anything fundamental. But if you need help, let me know.

Very appreciative for both of your your help just to sum up for anyone else's benefit.

Here is the MooTools JS i used:

window.addEvent('domready', function() {
$('myElement').addEvent('click', function(){
new JsonP('http://ExternalDomain.com/services/json', {
data: {
method: 'system.connect'
},
onComplete: function(data){
var results = eval(data);
alert(results["#data"].sessid)
}
}).request(); //alerts 8.3 - the rating of the ipod
});
});

Here is my edit as per nick's advice using json_server.module,v 1.6

function json_server_server() {
if (!isset($_REQUEST)) {
return drupal_to_js(array('#error' => TRUE, '#data' => "JSON server accepts GET requests only."));
}

//GET CALLBACK
$callback = $_REQUEST['callback'];

$methods = services_get_all();
$request = drupal_parse_json($_REQUEST['method']);
$args = array();


foreach ($methods as $method) {
    if ($method['#method'] == $request) {
        unset($_REQUEST['q']);
        unset($_REQUEST['method']);
        $args = array();
        foreach($method['#args'] as $arg) {
            if(isset($_REQUEST[$arg['#name']])) {
                $args[] = drupal_parse_json($_REQUEST[$arg['#name']]);
            }
            elseif($arg['#optional'] == 0) {
                return drupal_to_js(array("#error" => TRUE, "#data" => "Argument ". $arg['#name'] ." not recieved"));
            }
            else {
                $args[$arg['#name']] = NULL;
            }
        }

        $result = services_method_call($method['#method'], $args);

        if (is_array($result) && $result['#error'] === TRUE){
            return $jsondrupal_to_js(array('#error' => TRUE, '#data' => $result['#message']));
        }

        //ADD IN CALLBACK JSON/P SUPPORT

        $json = drupal_to_js(array('#error' => FALSE, '#data' => $result))

        if ($callback) {
            header("Content-type: text/javascript");
            return $callback ."(". $json .");";
        } else {
            header("Content-type: application/json");
            return $json;
        }      
    }
}
return drupal_to_js(array('#error' => TRUE, '#data' => "Invalid method $request"));

}

IMPORTANT NOTE FOR ALL

As of November 2009

The code shown here is not an official contribution to the JSON Server module, as noted in the comments above. If anyone finds it useful, perhaps you can chime in on the discussion to have it recognized by the maintainer.

http://drupal.org/node/477012#comment-2050614

I posted tips for:

• Node.Save (JavaScript)

• Node.Save (EDIT) (JavaScript)

• Processing the request w/ JSONP (MooTools)

  --> http://drupal.org/node/774116

Thanks for the updates on this . However i'm still having difficulty understanding some of it.

I have been trying to find an example of a simple standalone html/javascript form that can submit a JSON/JSONP post to Drupal, as I think this would help illustrate the whole process to me rather than snippets. I've been googling a lot and still haven't found anything like this yet - so if you could point me in the right direction or be kind enough to show me this process I would be most grateful.

Cheers.

// + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

UPDATE: This has been posted to http://drupal.org/node/776122

That version will be maintained more actively. Please consult there.

// + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

// Original Post

Required Reading:

http://drupal.org/node/774116

Understand these objects: "data" and "node_object"

Continue :)

///////// SIMPLE CCK FIELDS

In the code box below refer to:

custom_field_a = [{ value: 'custom field a' }]

// Which translates to:

// custom_field_a = [];
// custom_field_a[0] = {};
// custom_field_a[0].value = 'custom field a';

This is how simple CCK fields must be formatted.

// + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

UPDATE: This has been posted to http://drupal.org/node/776122

That version will be maintained more actively. Please consult there.

// + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

Looking for some JSON help when dealing with the views.get method. No matter what I have tried, I always get "Missing required arguments".

I've been able to grab nodes and session ID's just fine, but the views.get is making me pull my hair out!

What argument am I missing exactly?! The only required one is "view_name" correct?

Thanks!