Manifest error. Line: 1, column: 1, Syntax error in Flask

0
votes
  • I am trying to link manifest.json file to the website I built to convert it to PWA. Have used html/css and python flask for the backend.
  • I am not getting whether it is the issue of the path or something else. Service worker is being detected and that is working absolutely fine.
  • But in the Application manifest I am getting this error Manifest is not valid JSON. Line: 1, column: 1, Unexpected token enter image description here
  • manifest.json file

{
  "name": "Flask-PWA",
  "short_name": "Flask-PWA",
  "description": "A progressive webapp template built with Flask",
  "theme_color": "transparent",
  "background_color": "transparent",
  "display": "standalone",
  "orientation": "portrait",
  "scope": "/",
  "start_url": "../templates/login_user.html",
  "icons": [
    {
      "src": "images/icons/icon-72x72.png",
      "sizes": "72x72",
      "type": "image/png"
    },
    {
      "src": "images/icons/icon-96x96.png",
      "sizes": "96x96",
      "type": "image/png"
    },
    {
      "src": "images/icons/icon-128x128.png",
      "sizes": "128x128",
      "type": "image/png"
    },
    {
      "src": "images/icons/icon-144x144.png",
      "sizes": "144x144",
      "type": "image/png"
    },
    {
      "src": "images/icons/icon-152x152.png",
      "sizes": "152x152",
      "type": "image/png"
    },
    {
      "src": "images/icons/icon-192x192.png",
      "sizes": "192x192",
      "type": "image/png"
    },
    {
      "src": "images/icons/icon-384x384.png",
      "sizes": "384x384",
      "type": "image/png"
    },
    {
      "src": "images/icons/icon-512x512.png",
      "sizes": "512x512",
      "type": "image/png"
    }
  ]
}
  • This is the file structure for the manifest

enter image description here

1
pythonhtmlflaskprogressive-web-appsmanifest.json

1 Answers

0
votes

change content type

Check your network tab in the developer console and look for the manifest.json request. If the content type of the response is text/html, then you might need to add an additional header changing Content-Type to application/json in your flask route.

use python object

If changing the content type doesn't work, you can write your entire manifest as a python object then jsonify it before returning it to the browser.

from flask import jsonify
@app.route('/manifest.json')
def manifest():
    return jsonify(manifest_python_object)