Invalid JSON payload received. Unable to parse number (Google Vision API) - json

Question

I'm getting the error:
Invalid JSON payload received. Unable to parse number. INVALID_ARGUMENT
I got the key and everything and I'm still having the same error return. A few suggestions are resizing the image first to less fit the 4MB image limit.
I also tried emulating the same JSON request coming from their docs. But still have the same issue.
https://cloud.google.com/vision/docs/drag-and-drop
Here's the code I'm using: (I got the sample from Akshay Kadam)
me.detection_types = {
LABEL_DETECTION: 'label',
DOCUMENT_TEXT_DETECTION: 'text',
LOGO_DETECTION: 'logo',
LANDMARK_DETECTION: 'landmark'
};
var api_key = '';
$scope.takePicture = function(){
var options = {
destinationType: Camera.DestinationType.DATA_URL,
sourceType: Camera.PictureSourceType.CAMERA,
targetWidth: 150,
targetHeight: 150,
correctOrientation: true,
cameraDirection: 0,
allowEdit: true,
encodingType: Camera.EncodingType.JPEG,
quality: 25
};
$cordovaCamera.getPicture(options).then(function(imagedata){
me.current_image = "data:image/jpeg;base64," + imagedata;
me.image_description = '';
me.locale = '';
var vision_api_json = {
"requests":[
{
"image":{
"content": imagedata
},
"imageContext": {
"cropHintsParams": {
"aspectRatios": [
0.8,
1,
1.2
]
}
},
"features":[
{
"type": me.detection_type,
"maxResults": 1
}
]
}
]
}
var file_contents = JSON.stringify(vision_api_json);
$cordovaFile.writeFile(
cordova.file.applicationStorageDirectory,
'file.json',
file_contents,
true
).then(function(result){
var headers = {
'Content-Type': 'application/json'
};
options.headers = headers;
var server = 'https://vision.googleapis.com/v1/images:annotate?key=' + api_key;
var filePath = cordova.file.applicationStorageDirectory + 'file.json';
$cordovaFileTransfer.upload(server, filePath, options, true)
.then(function(result){
alert(JSON.stringify(result))
var res = JSON.parse(result.response);
var key = me.detection_types[me.detection_type] + 'Annotations';
me.image_description = res.responses[0][key][0].description;
}
Need help. Thank you!
UPDATE:
I tried adding Content-Length and was still having the same problem.