Properly Create and Serve PDF Blob via HTML5 File

问题:

Ok, Let's say I have document data stored somewhere, let's arbitrarily take this pdf.

Issue #1. What I want to do is make an AJAX call to this URL (because I need to pass some authentication headers and it is cross domain). Then take the returned data, create a blob url for it, append an iFrame to the DOM, and direct the src to the blob url.

Currently my code looks like this:

$.ajax({
  url:'http://www.grida.no/climate/ipcc_tar/wg1/pdf/tar-01.pdf'
}).done(function(data){
   var file = new Blob([data], {type:'application/pdf'}),
       url = URL.createObjectURL(file),
       _iFrame = document.createElement('iframe');
      _iFrame.setAttribute('src', url);
      _iFrame.setAttribute('style', 'visibility:hidden;');
      $('#someDiv').append(_iFrame);
});

Unfortunately, I am getting a 'Failed to Render PDF' in the iFrame.

Issue #2. I'd like this to result in a file download prompt. Not sure how to guarantee this given that PDF's will naturally just display in the iFrame.

回答1:

jQuery.ajax does not currently support blobs, see this bug report #7248 which is closed as wontfix.

However it's easy to do XHR for blobs without jQuery:

var xhr = new XMLHttpRequest();
xhr.open('GET', 'http://www.grida.no/climate/ipcc_tar/wg1/pdf/tar-01.pdf', true);
xhr.responseType = 'blob';

xhr.onload = function(e) {
  if (this.status == 200) {
    // Note: .response instead of .responseText
    var blob = new Blob([this.response], {type: 'application/pdf'}),
        url = URL.createObjectURL(blob),
        _iFrame = document.createElement('iframe');

    _iFrame.setAttribute('src', url);
    _iFrame.setAttribute('style', 'visibility:hidden;');
    $('#someDiv').append(_iFrame)        
  }
};

xhr.send();

Shamelessly copied from HTML5rocks.

If jQuery did support the Blob type, it could be as simple as:

$.ajax({
  url:'http://www.grida.no/climate/ipcc_tar/wg1/pdf/tar-01.pdf',
  dataType:'blob'
})...