如何设置独立的附件内容类型

Question

我已经能够创建一个独立的附件，但是content_type最终以乘数/form-data结束。我在做什么错？该代码之后是帖子的响应，然后是请求；您可以在请求中看到内容类型在请求有效载荷中是正确的。

代码：

 function uploadFile() {
    var fd = new FormData();
    var file = document.getElementById('fileToUpload').files[0];
    fd.append("fileToUpload", document.getElementById('fileToUpload').files[0]);
    var xhr = new XMLHttpRequest();
    xhr.upload.addEventListener("progress", uploadProgress, false);
    xhr.addEventListener("load", uploadComplete, false);
    xhr.addEventListener("error", uploadFailed, false);
    xhr.addEventListener("abort", uploadCanceled, false);
    xhr.open("PUT", "http://usr:pswd@localhost:5984/db_test/testdoc7/"+ file.name +"?rev=1-967a00dff5e02add41819138abb3284d");
    xhr.send(fd);
  }

响应：

{
   "_id": "testdoc7",
   "_rev": "2-2841dcd640adb94de525e486be34052e",
   "_attachments": {
       "P9025287.JPG": {
           "content_type": "multipart/form-data; boundary=----WebKitFormBoundary9QNXLDTeW13Gc1ip",
           "revpos": 2,
           "digest": "md5-VcoscthaPUYoWHBmCBaAnA==",
           "length": 3083669,
           "stub": true
       }
   }
}

请求：

Request URL:http://usr:pswd@localhost:5984/db_test/testdoc7/P9025287.JPG?rev=1-967a00dff5e02add41819138abb3284d
Request Method:PUT
Status Code:201 Created
Request Headersview source
Accept:*/*
Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Connection:keep-alive
Content-Length:3083669
Content-Type:multipart/form-data; boundary=----WebKitFormBoundary9QNXLDTeW13Gc1ip
Cookie:AuthSession=YmRyaG9hOjUwOUFFNDg3OnR23NsQsqdQvnKp7HX_0g90grXw
Host:localhost:5984
Origin:http://localhost:5984
Referer:http://localhost:5984/estante_test/_design/library/html5/html5test.html
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11
Query String Parametersview URL encoded
rev:1-967a00dff5e02add41819138abb3284d
Request Payload
------WebKitFormBoundary9QNXLDTeW13Gc1ip
Content-Disposition: form-data; name="fileToUpload"; filename="P9025287.JPG"
Content-Type: image/jpeg

------WebKitFormBoundary9QNXLDTeW13Gc1ip--
Response Headersview source
Cache-Control:must-revalidate
Content-Length:71
Content-Type:text/plain; charset=utf-8
Date:Wed, 07 Nov 2012 22:45:40 GMT
ETag:"2-2841dcd640adb94de525e486be34052e"
Location:http://localhost:5984/estante_test/testdoc7/P9025287.JPG
Server:CouchDB/1.2.0 (Erlang OTP/R15B)

Answer 1

您的代码将整个表格的主体放在couchdb上。我怀疑如果您查看附件，您会发现不仅内容类型不正确。这样的事情应该更好地工作：

function uploadFile() {
  var file = document.getElementById('fileToUpload').files[0];
  var xhr = new XMLHttpRequest();
  xhr.upload.addEventListener("progress", uploadProgress, false);
  xhr.addEventListener("load", uploadComplete, false);
  xhr.addEventListener("error", uploadFailed, false);
  xhr.addEventListener("abort", uploadCanceled, false);
  xhr.open("PUT", "http://usr:pswd@localhost:5984/db_test/testdoc7/"+ file.name +"?rev=1-967a00dff5e02add41819138abb3284d");
  xhr.send(file);
}

此起作用是因为文件接口从blob继承，因此XHR2发送算法将提交文件的原始数据，并根据您的文件条目的.Type属性设置MIME类型。

请注意，至少有些浏览器不能为文件提供良好的Mime类型猜测，因此您仍然可能会以"应用程序/八位八分路"为类型，除非您通过xhr.setrequestheader（）为自己提供覆盖率（）。