FineUploader Failing to parse incoming JSON - json

Question

I'm using play/scala for a webapp and a scala API, currently running simply on two different ports on localhost:9000 and localhost:8080 respectively. I have the basic page from the fine-uploader.com website docs, and a simple test page build in Play. (FWIW, i don't think much of the above is relevant)
When i post a file, chunked or not, Fine uploader receives a 200 from the API and valid JSON, but JSON.parse returns a failure. The logging from fine-uploader is below. If i take this output and run it through (in the console)
JSON.parse(JSON.stringify(json))
a valid object is returned. I can't just JSON.parse(json) directly in the browser tools b/c its already an object. I have checked the types by console.log'ing typeOf json in the qq.parseJson method and it returns string, so no conversion should be required, though i have tried it with the same results.
fine-uploader console logs:
[Fine Uploader 5.5.1] Sending simple upload request for 0 fine-uploader.js:251
[Fine Uploader 5.5.1] xhr - server response received for 0 fine-uploader.js:251
[Fine Uploader 5.5.1] responseText = {"code":"UPLOAD_COMPLETE","response":{"MediaModel":{"id":1103,"publicUri":"http://localhost:8080/media/Archive.zip","fileLocation":"/src/services/api/src/main/webapp/media/Archive.zip","mediaDate":{"year":2016,"month":2,"day":28},"mediaOrder":1,"viewName":"","caption":"","altText":"","isPublic":1,"fileSize":1107080,"created":"2016-02-28T14:58:43Z"},"UserMediaModel":{"id":1,"userId":24,"mediaId":3,"created":"2016-02-17T12:48:18Z"}},"errors":[]} fine-uploader.js:251
[Fine Uploader 5.5.1] Received response status 200 with body: {"code":"UPLOAD_COMPLETE","response":{"MediaModel":{"id":1103,"publicUri":"http://localhost:8080/media/Archive.zip","fileLocation":"/src/services/api/src/main/webapp/media/Archive.zip","mediaDate":{"year":2016,"month":2,"day":28},"mediaOrder":1,"viewName":"","caption":"","altText":"","isPublic":1,"fileSize":1107080,"created":"2016-02-28T14:58:43Z"},"UserMediaModel":{"id":1,"userId":24,"mediaId":3,"created":"2016-02-17T12:48:18Z"}},"errors":[]} fine-uploader.js:251
[Fine Uploader 5.5.1] Simple upload request failed for 0
The server is responding with a 200 per the API logs and i can see the exact response object in the Response tab of Chrome Dev tools.
I added a custom error handler, but not more more information was provided, just that the error is the text output
Error on file number 0 - Archive.zip. Reason: {"code":"UPLOAD_COMPLETE",....same as above
Lastly, all rows are propery inserted into the database as you see from the id's created above. And all logging points to an equally successful action.
Thanks for any pointers. I've also put this output in http://jsonlint.com/ and it parses fine.
Thanks! (sorry for the lack of JSON formatting, i can change it, but this seemed long enough already)
EDIT
It seems that i have satisfied the requirements stated in the other question with "success":true and Content-Type=text/plain. The following, per request is the JSON output and the headers
Headers:
Key: Access-Control-Allow-Origin Value: http://localhost:9000
Key: Date Value: Mon, 29 Feb 2016 00:55:19 GMT
Key: Access-Control-Allow-Credentials Value: true
Key: Content-Type Value: text/plain; charset=UTF-8
{
"code": "UPLOAD_COMPLETE",
"response": {
"MediaModel": {
"id": 1169,
"publicUri": "http://localhost:8080/media/Archive.zip",
"fileLocation": "/src/services/api/src/main/webapp/media/Archive.zip",
"mediaDate": {
"year": 2016,
"month": 2,
"day": 28
},
"mediaOrder": 1,
"viewName": "",
"caption": "",
"altText": "",
"isPublic": 1,
"fileSize": 1107080,
"created": "2016-02-29T00:55:19Z"
},
"UserMediaModel": {
"id": 1,
"userId": 24,
"mediaId": 3,
"created": "2016-02-17T12:48:18Z"
}
},
"errors": [],
"success": true
}
I'm sure this will end up being something silly, so i appreciate the input.

Answer 1

Based on the error reported by Fine Uploader, your response is not properly formatted. If you look closely at the response in your browser's network tab (such as with Chrome dev tools), you'll likely see a JSON string that, once parsed using JSON.parse results in another JSON string instead of a JavaScript object containing the expected properties. I can't confirm this as you haven't posted the exact response from your server, but I'm certain that this is the case. This is most likely caused by an encoding issue server-side. For example, your server should return this: {"foo": "bar", "success": true} instead of this: "{\"foo\": \"bar\", \"success\": true}". I suspect your server is returning the latter.