如何从客户端获取 firebase 存储 json 文件

Question

I saved a json file in google cloud storage, I want to fetch the file, read the json content and save the content to client indexeddb.

loadJSON(function(json) {
   console.log(json); // this will log out the json object
 });

var fileUrl ="https://firebasestorage.googleapis.com/v0/b/rwrwr-rwr.appspot.com/o/TestCatalog.json?alt=media&token=r545-54-54-54-45455"


function loadJSON() {

  var request = new Request(fileUrl);

  fetch(request, {mode: 'cors'}).then(function(response) {
    // Convert to JSON
    return response.json();
   }).then(function(j) {
  // Yay, `j` is a JavaScript object
   console.log(JSON.stringify(j));
  }).catch(function(error) {
   console.log('Request failed', error)
  });
  }

The fetch is producing this error

from origin 'null' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

How could I fetch the firebase storage json file ?

Answer 1

If you're running this code form the browser you have to enable cross-origin access on your Cloud Storage bucket.
For that you can use the gsutil tool und run

gsutil cors set cors.json gs://<your-cloud-storage-bucket>

The cors.json file should contain the following content:

[
  {
    "origin": ["*"],
    "method": ["GET"],
    "maxAgeSeconds": 3600
  }
]

You can find the documentation on that here .