Ios 将原始图像数据转换为base64编码字符串

我正在使用以下API从dropbox下载缩略图：

这是我的云代码功能的一部分：

  }).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);
  });

以下是我的

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��'
}

以下是

imageInBase64

的输出：

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

运行此操作时，不会显示图像。我怀疑在将Dropbox转换为base64字符串之前，我没有正确处理它的响应。Dropbox声明它们的响应是原始图像数据

---

任何帮助都将不胜感激。谢谢。

想明白了&谢谢那些回答的人。问题是Parse.com模块Parse.Cloud.httpRequest在自托管Parse服务器和Parse.com时的工作方式略有不同。我只需要在模块中包含

encoding:null

作为选项，一切正常。代码如下：

  }).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);
  });

---

我认为您的

选项可能是错误的。请尝试
base64EncodedString:encodedImageData选项：。改为allZeros
。
  }).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);
  });