使用HttpWebRequest的使用多/ form-data的POST数据/上传图片 [英] Using HttpWebRequest to POST data/upload image using multipart/form-data

问题描述

我试图使用ImageShack API来上传图片。要使用它，我应该 POST 使用图像的multipart / form-data的。我喜欢它...

  VAR POSTDATA =;
VAR REQ = HttpWebRequest.Create（http://www.imageshack.us/upload_api.php）;
req.Method =POST;
req.Co​​ntentType =的multipart / form-data的;
POSTDATA + =键= my_key_here＆安培;;
POSTDATA + =类型的base64 =＆安培;;//从图像数据的base64
字节[]字节= File.ReadAllBytes（@D：\\ tmp目录\\ WpfApplication1 \\ WpfApplication1 \\图片\\ Icon128.gif）;
字符串连接codeD = Convert.ToBase64String（字节）;
POSTDATA + =文件上传=EN + codeD;字节[] = reqData Encoding.UTF8.GetBytes（POSTDATA）;
使用（流数据流= req.GetRequestStream（））
{
    dataStream.Write（reqData，0，reqData.Length）;
}VAR解析度=（HttpWebResponse）req.GetResponse（）;
变种resStream = res.GetResponseStream（）;
VAR读者=新的StreamReader（resStream）;
字符串resString = reader.ReadToEnd（）;
txt1.Text = resString;
 

但ImageShack的抱怨

 ＆LT;链接和GT;
    ＆LT;错误ID =parameter_missing＆GT;对不起，但我们检测到意外的数据被接收。必要参数'文件上传'丢失或您的文章没有的multipart / form-data的＆LT; /错误＆GT;
＆LT; /链接和GT;
 

文件上传为present和我使用的multipart / form-data的什么是错？

更新：

新的code http://pastebin.com/TN6e0CD8

发表的数据 http://pastebin.com/fYE9fsxs

更新2

我看了看其他的问题<一href=\"http://stackoverflow.com/questions/219827/multipart-forms-from-c-client\">http://stackoverflow.com/questions/219827/multipart-forms-from-c-client.修改了我的code。与边界，去掉​​了预期100头还是我不能得到它的工作...

  ServicePointManager.Expect100Continue = FALSE;
VAR边界=----------------------------- 28520690214962;
VAR NEWLINE = Environment.NewLine;
VAR propFormat =边界+换行+
                    内容处置：表格数据;名称= \\{0} \\+换行+换行+
                    {1}+换行+换行;
VAR fileHeaderFormat =边界+换行+
                        内容处置：表格数据;名称= \\{0} \\;文件名= \\{1} \\+换行;VAR REQ =（HttpWebRequest的）HttpWebRequest.Create（HTTP：//jm/php/upload.php）;
req.Method = WebRequestMethods.Http.Post;
req.Co​​ntentType =的multipart / form-data的;边界=+边界;使用（VAR reqStream = req.GetRequestStream（））{
    VAR reqWriter =新的StreamWriter（reqStream）;
    VAR TMP =的String.Format（propFormat，STR1，世界你好）;
    reqWriter.Write（TMP）;
    TMP =的String.Format（propFormat，STR2赛车，世界你好2）;
    reqWriter.Write（TMP）;
    reqWriter.Write（边界+ - ）;
    reqWriter.Flush（）;
}
VAR解析度= req.GetResponse（）;
使用（VAR resStream = res.GetResponseStream（））{
    VAR读者=新的StreamReader（resStream）;
    txt1.Text = reader.ReadToEnd（）;
}
 

解决方案

我相信你没有正确建立请求主体。
首先，你需要在内容类型头部分边界（随机文本）。例如，

  

内容类型：多重/ form-data的;
  边界= ---- WebKitFormBoundarySkAQdHysJKel8YBM

现在请求主体的格式将是这样

  ------ WebKitFormBoundarySkAQdHysJKel8YBM
内容处置：表格数据;名称=钥匙KeyValueGoesHere
------ WebKitFormBoundarySkAQdHysJKel8YBM
内容处置：表格数据;名称=参数2ValueHere
------ WebKitFormBoundarySkAQdHysJKel8YBM
内容处置：表格数据;名称=文件上传;文件名=y1.jpg
内容类型：图像/ JPEG[图像数据放在这里]
 

我会建议你使用的工具，如提琴手了解这些请求是如何构建的。

I am trying to use the ImageShack API to upload images. To use it, I am supposed to POST the image using multipart/form-data. I did it like ...

var postData = "";
var req = HttpWebRequest.Create("http://www.imageshack.us/upload_api.php");
req.Method = "POST";
req.ContentType = "multipart/form-data";
postData += "key=my_key_here&";
postData += "type=base64&";

// get base64 data from image
byte[] bytes = File.ReadAllBytes(@"D:\tmp\WpfApplication1\WpfApplication1\Images\Icon128.gif");
string encoded = Convert.ToBase64String(bytes);
postData += "fileupload=" + encoded;

byte[] reqData = Encoding.UTF8.GetBytes(postData);
using (Stream dataStream = req.GetRequestStream())
{
    dataStream.Write(reqData, 0, reqData.Length);
}

var res = (HttpWebResponse)req.GetResponse();
var resStream = res.GetResponseStream();
var reader = new StreamReader(resStream);
string resString = reader.ReadToEnd();
txt1.Text = resString;

but ImageShack is complaining that

<links>
    <error id="parameter_missing">Sorry, but we've detected that unexpected data is received. Required parameter 'fileupload' is missing or your post is not multipart/form-data</error>
</links>

FileUpload is present and I am using multipart/form-data whats wrong?

UPDATE:

New Code http://pastebin.com/TN6e0CD8

Post data http://pastebin.com/fYE9fsxs

UPDATE 2

i looked at the other question http://stackoverflow.com/questions/219827/multipart-forms-from-c-client. modified my code with boundary, removed the expect 100 header still i cant get it working ...

ServicePointManager.Expect100Continue = false;
var boundary = "-----------------------------28520690214962";
var newLine = Environment.NewLine;
var propFormat = boundary + newLine +
                    "Content-Disposition: form-data; name=\"{0}\"" + newLine + newLine + 
                    "{1}" + newLine + newLine;
var fileHeaderFormat = boundary + newLine +
                        "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"" + newLine;

var req = (HttpWebRequest)HttpWebRequest.Create("http://jm/php/upload.php");
req.Method = WebRequestMethods.Http.Post;
req.ContentType = "multipart/form-data; boundary=" + boundary;

using (var reqStream = req.GetRequestStream()) {
    var reqWriter = new StreamWriter(reqStream);
    var tmp = string.Format(propFormat, "str1", "hello world");
    reqWriter.Write(tmp);
    tmp = string.Format(propFormat, "str2", "hello world 2");
    reqWriter.Write(tmp);
    reqWriter.Write(boundary + "--");
    reqWriter.Flush();
}
var res = req.GetResponse();
using (var resStream = res.GetResponseStream()) {
    var reader = new StreamReader(resStream);
    txt1.Text = reader.ReadToEnd();
}

解决方案

I believe that you are not building the request body correctly. First, you need to include part boundary (random text) in content type header. For example,

Content-Type: multipart/form-data; boundary=----WebKitFormBoundarySkAQdHysJKel8YBM

Now format of request body will be something like

------WebKitFormBoundarySkAQdHysJKel8YBM 
Content-Disposition: form-data;name="key"

KeyValueGoesHere
------WebKitFormBoundarySkAQdHysJKel8YBM 
Content-Disposition: form-data;name="param2"

ValueHere
------WebKitFormBoundarySkAQdHysJKel8YBM 
Content-Disposition: form-data;name="fileUpload"; filename="y1.jpg"
Content-Type: image/jpeg 

[image data goes here]

I will suggest you to use tool such as Fiddler to understand how these requests are built.

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