How to create a File object from binary data in JavaScript

问题

I'm probably missing something simple here, but how would I create a File object in JavaScript given the binary data as received from an AJAX request?

$.ajax({
  url: "http://example.com/image.jpg",
  success: function(data) {
    // Convert binary data to File object
  }
});

回答1:

I finally figured this out. In order to avoid cross-site scripting issues, I created a proxy endpoint on my server. Then I can pass the image URL to my server, which then executes a GET request on the remote file, converts the response to Base64, and sends it back to the browser. The browser can then convert the data back to binary and create a Blob (which is as good as a File for my purposes).

$.ajax({
  url: apiRoot + "/proxy",
  data: {url: "http://example.com/image.jpg"},
  success: function(data) {
    var binary = atob(data.split(',')[1]);
    var array = [];
    for (var i = 0; i < binary.length; i++) {
      array.push(binary.charCodeAt(i));
    }
    var file = new Blob([new Uint8Array(array)], {type: 'image/jpeg'});
  }
});

来源：https://stackoverflow.com/questions/18283772/how-to-create-a-file-object-from-binary-data-in-javascript