Convert raw image data to base64 encoded string

Question

I am downloading a thumbnail from dropbox using the following API:

https://www.dropbox.com/developers/documentation/http/documentation#files-get_thumbnail

This is part of my function from cloud code:

  }).then(function(oauthToken){
    /* Retrieve thumbnail image from dropbox */
    return Parse.Cloud.httpRequest({
      method: 'POST',
      url: 'https://content.dropboxapi.com/2/files/get_thumbnail',
      headers: {
        'Authorization': 'Bearer ' + oauthToken.get("accessToken"),
        'Dropbox-API-Arg': JSON.stringify({"path": dropboxFileId})
      }
    });

  }).then(function(imageResponse){
    if (log) {console.log(imageResponse);}
    var imageBuffer = imageResponse.buffer;
    var image = imageBuffer.toString("base64");
    response.success(image);
  }, function(error){
    response.error(error.text);
  });

Following is my imageResponse:

{ status: 200,
  headers: 
   { server: 'nginx',
     date: 'Wed, 16 Mar 2016 04:30:54 GMT',
     'content-type': 'application/octet-stream',
     'content-length': '906',
     connection: 'close',
     'accept-ranges': 'bytes',
     pragma: 'no-cache',
     'cache-control': 'no-cache',
     'original-content-length': '906',
     'dropbox-api-result': '{"name": "HTS-logo-low-res.png", "path_lower": "/hts-logo-low-res.png", "path_display": "/HTS-logo-low-res.png", "id": "id:hrkr_mV5FYAAAAAAAAAAHw", "client_modified": "2015-04-05T04:16:15Z", "server_modified": "2016-02-13T06:08:02Z", "rev": "2a043d0c726", "size": 10506}',
     'x-server-response-time': '190',
     'x-dropbox-request-id': '04bb8d6b45511f2b2d7a278e230ea572',
     'x-robots-tag': 'noindex, nofollow, noimageindex' },
  buffer: <Buffer ef bf bd ef bf bd ef bf bd ef bf bd 00 10 4a 46 49 46 00 01 01 00 00 01 00 01 00 00 ef bf bd ef bf bd 00 43 00 06 04 05 06 05 04 06 06 05 06 07 07 06 ... >,
  cookies: undefined,
  text: '����\u0000\u0010JFIF\u0000\u0001\u0001\u0000\u0000\u0001\u0000\u0001\u0000\u0000��\u0000C\u0000\u0006\u0004\u0005\u0006\u0005\u0004\u0006\u0006\u0005\u0006\u0007\u0007\u0006\b\n\u0010\n\n\t\t\n\u0014\u000e\u000f\f\u0010\u0017\u0014\u0018\u0018\u0017\u0014\u0016\u0016\u001a\u001d%\u001f\u001a\u001b#\u001c\u0016\u0016 , #&\')*)\u0019\u001f-0-(0%()(��\u0000C\u0001\u0007\u0007\u0007\n\b\n\u0013\n\n\u0013(\u001a\u0016\u001a((((((((((((((((((((((((((((((((((((((((((((((((((��\u0000\u0011\b\u0000\u0010\u0000@\u0003\u0001"\u0000\u0002\u0011\u0001\u0003\u0011\u0001��\u0000\u001f\u0000\u0000\u0001\u0005\u0001\u0001\u0001\u0001\u0001\u0001\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\b\t\n\u000b��\u0000�\u0010\u0000\u0002\u0001\u0003\u0003\u0002\u0004\u0003\u0005\u0005\u0004\u0004\u0000\u0000\u0001}\u0001\u0002\u0003\u0000\u0004\u0011\u0005\u0012!1A\u0006\u0013Qa\u0007"q\u00142���\b#B��\u0015R��$3br�\t\n\u0016\u0017\u0018\u0019\u001a%&\'()*456789:CDEFGHIJSTUVWXYZcdefghijstuvwxyz���������������������������������������������������������������������������\u0000\u001f\u0001\u0000\u0003\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0001\u0000\u0000\u0000\u0000\u0000\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\b\t\n\u000b��\u0000�\u0011\u0000\u0002\u0001\u0002\u0004\u0004\u0003\u0004\u0007\u0005\u0004\u0004\u0000\u0001\u0002w\u0000\u0001\u0002\u0003\u0011\u0004\u0005!1\u0006\u0012AQ\u0007aq\u0013"2�\b\u0014B����\t#3R�\u0015br�\n\u0016$4�%�\u0017\u0018\u0019\u001a&\'()*56789:CDEFGHIJSTUVWXYZcdefghijstuvwxyz��������������������������������������������������������������������������\u0000\f\u0003\u0001\u0000\u0002\u0011\u0003\u0011\u0000?\u0000�;ŷ��鱘\'[s,�\u0013L�\n���{\f�g޹\u000f��I�\\.�w\u0013��H~̡���\u0002�\u001b���\u000f\u0001���@�%�&�O��\u0004z����6�Z:X�"G;�GB}M%N�3��ͧ]4��̪��9`�������0�֕�+\u000b�t \u0006P�\u0001%�z��\u0003�R=ި�G$.� �U��h]���d�\u001d9����u���*O����q��|�\u0007\u0005\\�N\u000e\u0017\u0003�\u0000C�q��;�K���1\u001e��HR��z��~�N+���uy��d�بS咕�0e��91�\u001fC�\u0014���}z����.u\u0019Y�I\u0012�T.�\u0019~�\u0007ߦ\b��+���ߝ��W���_q��'
}

My code in XCode:

if let imageInBase64 = response as? String {
    print(imageInBase64)
    let decodedImage = NSData(base64EncodedString: imageInBase64, options: NSDataBase64DecodingOptions())
    imageView.image = UIImage(data: decodedImage!)
}

Following is the output for imageInBase64:

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

When I run this, I do not get an image displayed. I suspect that I am not properly handling the response from Dropbox before converting it to base64 string. Dropbox state that their responses are raw image data.

Any help will be much appreciated. Thanks.

http://stackoverflow.com/questions/29365145/how-to-encode-string-to-base64-in-swift — Awesome.Apple, Mar 16 '16 at 04:59
I think your `options` might be wrong. Try `base64EncodedString: encodedImageData options: .allZeros` instead. — sschale, Mar 16 '16 at 05:05

score 2 · Answer 1 · answered Mar 17 '16 at 06:32

Figured it out & thanks for those who answered. The issue was with Parse.com module Parse.Cloud.httpRequest which works slightly different when you are self-hosting parse-server vs Parse.com. I just needed to include encoding: null as an option in the module and everything works fine. Code below:

  }).then(function(oauthToken){
    /* Retrieve thumbnail image from dropbox */
    return Parse.Cloud.httpRequest({
      method: 'POST',
      url: 'https://content.dropboxapi.com/2/files/get_thumbnail',
      headers: {
        'Authorization': 'Bearer ' + oauthToken.get("accessToken"),
        'Dropbox-API-Arg': JSON.stringify({"path": dropboxFileId})
      },
      encoding: null
    });

  }).then(function(imageResponse){
    if (log) {console.log(imageResponse);}
    var imageBuffer = imageResponse.buffer;
    var image = imageBuffer.toString("base64");
    response.success(image);
  }, function(error){
    response.error(error.text);
  });

Convert raw image data to base64 encoded string

1 Answers1