无法从google drive API检索文件内容

Question

我似乎无法通过google drive SDK检索文件的内容。为了重现这个问题，我使用API explorer来获取一个小文本文件的元数据：

200 OK

- Show headers -

{

 "kind": "drive#file",
 "id": "0B75zvzRT_NusaDBtSTVmWWk1cVk",
 "etag": "\"B6kWtzuiQYCrVi2MWyRaub0CRyo/MTM1NTgzNDEzMjU5MA\"",
 "selfLink": "https://www.googleapis.com/drive/v2/files/0B75zvzRT_NusaDBtSTVmWWk1cVk",
 "webContentLink": "https://docs.google.com/uc?id=0B75zvzRT_NusaDBtSTVmWWk1cVk&export=download",
 "alternateLink": "https://docs.google.com/file/d/0B75zvzRT_NusaDBtSTVmWWk1cVk/edit",
 "iconLink": "https://ssl.gstatic.com/docs/doclist/images/icon_10_text_list.png",
 "thumbnailLink":     "https://lh4.googleusercontent.com/ntOMGJ9Is5KigDUzpOe6xKRqVqHPyeeXPImG1vZTF2FDM5YOyeCZT62FsdBWTnetBA=s220",
 "title": "sync.txt",
 "mimeType": "text/plain",
 "description": "description",
 "labels": {
  "starred": false,
  "hidden": false,
  "trashed": false,
  "restricted": false,
  "viewed": true
 },
 "createdDate": "2012-12-18T11:49:21.710Z",
 "modifiedDate": "2012-12-18T12:35:32.590Z",
 "modifiedByMeDate": "2012-12-18T12:35:32.590Z",
 "lastViewedByMeDate": "2012-12-18T12:35:32.416Z",
 "parents": [
  {

   "kind": "drive#parentReference",
   "id": "0B75zvzRT_NusdVVJeGk2dVc2VHM",
   "selfLink": "https://www.googleapis.com/drive/v2/files/0B75zvzRT_NusaDBtSTVmWWk1cVk/parents/0B75zvzRT_NusdVVJeGk2dVc2VHM",
   "parentLink": "https://www.googleapis.com/drive/v2/files/0B75zvzRT_NusdVVJeGk2dVc2VHM",
   "isRoot": false
  }
 ],
 "downloadUrl": "https://doc-0g-0-docs.googleusercontent.com/docs/securesc/b2hod7vud4bdud0ju4mut5hh2assmdju/rmi0iqd62g0im724ngmc5uva7femfffo/1355832000000/00903399969355284739/00903399969355284739/0B75zvzRT_NusaDBtSTVmWWk1cVk?h=16653014193614665626&e=download&gd=true",
 "userPermission": {
  "kind": "drive#permission",
  "etag": "\"B6kWtzuiQYCrVi2MWyRaub0CRyo/kH0lkP-s4aFu1o5itR2fFqyLM6o\"",
  "id": "me",
  "selfLink": "https://www.googleapis.com/drive/v2/files/0B75zvzRT_NusaDBtSTVmWWk1cVk/permissions/me",
  "role": "owner",
  "type": "user"
 },
 "originalFilename": "sync.txt",
 "fileExtension": "txt",
 "md5Checksum": "ecd21579645508d1c206d5e6e20fd101",
 "fileSize": "156",
 "quotaBytesUsed": "156",
 "ownerNames": [
  "Sam Smith"
 ],
 "lastModifyingUserName": "Sam Smith",
 "editable": true,
 "writersCanShare": true
}

然后我点击downloadUrl链接，我总是得到一个空响应，即一个200个带有空正文的响应。如果我从Url末尾删除“gd=true”参数，它就可以下载。在我的程序中，除了删除“gd=true”也不起作用（可能是因为程序运行在服务器上，所以我没有登录到我的帐户中）之外，也会发生同样的事情。

Answer 1

好的，我终于算出来了。对于downloadURL上的GET请求，您似乎需要发送头部中的访问令牌，即发送一个“授权：承载{您的访问令牌}”头部。不要将访问令牌作为查询字符串的一部分发送。我在Drive SDK中使用的所有其他API调用都可以将访问令牌作为查询字符串的一部分--除了这个。