Unable to Implement 'Content-Type' Header. about flask-cors HOT 6 CLOSED

#!/usr/bin/python

from flask import abort,Flask,jsonify,make_response,request
from flask.ext.cors import cross_origin
import redis
import uuid

app=Flask(__name__)
r=redis.StrictRedis(host='localhost',port='6379',db=0)

@app.route('/api/v1.0/assets',methods=['GET'])
@cross_origin(headers='Content-Type')
def get_assets():
  exists=r.exists('assets')
  if not exists:
    abort(404)
  else:
    members=r.smembers('assets')
    assets=[]
    for member in members:
      assets.append(member)
    return jsonify({'result':'success','data':assets})

@app.route('/api/v1.0/assets',methods=['POST','OPTIONS'])
@cross_origin(headers='Content-Type')
def post_assets():
  json=request.get_json()
  if not 'type' in json:
    abort(400)
  else:
    id=uuid.uuid4()
    r.sadd('assets',id)
    r.sadd('types',json['type'])
    r.sadd('types_'+json['type'],id)
    r.hset(id,'type',json['type'])
    for key,value in json.iteritems():
      if key != 'type':
        r.hset(id,key,value)
    return jsonify({'result':'success','data':id})

@app.route('/api/v1.0/assets',methods=['OPTIONS'])
@cross_origin()
def options_assets():
  return 200

@app.route('/api/v1.0/assets/<asset>',methods=['GET'])
@cross_origin()
def get_assets_asset(asset):
  exists=r.exists(asset)
  if not exists:
    abort(404)
  else:
    properties=r.hgetall(asset)
    hash={}
    hash[asset] = properties
    return jsonify({'result':'success','data':hash})

@app.route('/api/v1.0/assets/<asset>',methods=['DELETE'])
@cross_origin()
def delete_assets_asset(asset):
  exists=r.exists(asset)
  if not exists:
    abort(404)
  else:
    properties=r.hgetall(asset)
    r.srem('assets',asset)
    r.srem('types_'+properties['type'],asset)
    members = r.smembers('types_'+properties['type'])
    if not members:
      r.srem('types',properties['type'])
    r.delete(asset)
    return jsonify({'result':'success','data':'deleted'})

@app.route('/api/v1.0/types',methods=['GET'])
@cross_origin()
def get_types():
  exists=r.exists('types')
  if not exists:
    abort(404)
  else:
    members=r.smembers('types')
    types=[]
    for member in members:
      types.append(member)
    return jsonify({'result':'success','data':types})

@app.route('/api/v1.0/types/<type>', methods = ['GET'])
@cross_origin()
def get_types_type(type):
  exists=r.exists('types_'+type)
  if not exists:
    abort(404)
  else:
    members=r.smembers('types_'+type )
    assets=[]
    for member in members:
      assets.append(member)
    return jsonify({'result':'success','data':assets})

@app.errorhandler(400)
def not_found(error):
  return make_response(jsonify({'result':'error','data':'bad request'}),400)

@app.errorhandler(404)
def not_found(error):
  return make_response(jsonify({'result':'error','data':'url not found'}),404)

@app.errorhandler(500)
def not_found(error):
  return make_response(jsonify({'result':'error','data':'internal server error'}),500)

if __name__ == '__main__':
  app.run(host='0.0.0.0', debug=True)