xml – vb.net中的REST调用：如何传递在cURL中工作的密钥“文件”

我已经在这个问题上苦苦挣扎了差不多一个月了,我在网上找到了所有可以找到的东西,没有任何解决方案.这是我的问题：我正在为RESTful API服务实现一个客户端,该服务必须通过POST调用在vb.net中发送 XML文件.我能够以xml格式获取一些数据,但是当发送这个Xml文件时,我总是得到“400错误的请求错误”.

我已经发现它必须是必须传递给服务器的密钥的问题(显然只接受POST的文件上传,我不能将其作为字符串发送).

基本上这个调用与cURL一起使用,但我正在努力在vb.net中实现我自己的调用,传递正确的值.

工作cURL调用:(成功传输XML)

c:>curl -u username:password -F "file=@filename.xml" -X POST http://hostname.com/URI?parameters

不工作的Vb.net代码:(这给了我400 Bad Request)

Dim ss As String = "" 'server says...
Dim S As String = txb_username.Text & ":" & txb_password.Text
Dim EncodedString As String = System.Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(S))
Dim req As HttpWebRequest = Nothing
Dim res As HttpWebResponse = Nothing

Try
    Dim xmlDoc As System.Xml.XmlDocument = New System.Xml.XmlDocument
    xmlDoc.XmlResolver = Nothing

    xmlDoc.Load("c:\path\file4.xml")

    Dim sXML As String = "file" & xmlDoc.InnerXml '<- This is where I try to put the "KEY"

    Dim url As String = "http:/host.com+URI"

    req = CType(WebRequest.Create(url), Net.HttpWebRequest) 'or Directcast ... 
    req.Method = "POST"
    req.Headers.Add("Authorization: Basic " & EncodedString)
    req.ContentType = "multipart/form-data"
    req.ContentLength = sXML.Length 
    req.Accept = "*/*"

    System.Windows.Forms.Application.DoEvents()

    Dim sw As System.IO.StreamWriter = New System.IO.StreamWriter(req.GetRequestStream)
    StatusUpdate(sXML)
    sw.Write(sXML)
    sw.Close()
    ss = "server says: "
    res = CType(req.GetResponse, HttpWebResponse)
     StatusUpdate(req.ToString)
    Catch ex As Exception
        StatusUpdate(ss & ex.Message)
    Finally

End Try

是因为我想把它作为字符串发送吗？ (但我怎么能把它作为文件发送？)
为此,我做了另一个发送数据字节的过程,但是这个也给了我“400”,因为(我假设)我没有放“文件”键.

Dim requestStream As Stream = Nothing
    Dim fileStream As FileStream = Nothing
    Dim uploadResponse As Net.HttpWebResponse = Nothing

    Try

        Dim uploadRequest As Net.HttpWebRequest = CType(Net.HttpWebRequest.Create(URI.Text & Uri_part2.text), Net.HttpWebRequest)

        uploadRequest.Method = Net.WebRequestMethods.Http.Post
        uploadRequest.ContentType = "text/xml; charset=utf-8"
        uploadRequest.Credentials = New NetworkCredential("user", "pass")
        uploadRequest.KeepAlive = True
        uploadRequest.UserAgent = "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.0.10) Gecko/2009042316 Firefox/3.0.10"
        uploadRequest.Accept = ("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
        uploadRequest.Headers.Add("Accept-Language: en-us,en;q=0.5")
        uploadRequest.Headers.Add("Accept-Encoding: gzip,deflate")
        uploadRequest.Headers.Add("Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7")
        uploadRequest.Headers.Add("Content-Disposition: form-data; name=""file"";")
        uploadRequest.ContentType = "application/xml; charset=utf-8"

        requestStream = uploadRequest.GetRequestStream()
        fileStream = File.Open("C:\example.xml", FileMode.Open)

        Dim a As Integer

        Dim buffer(1024) As Byte
        Dim bytesRead As Integer
        While True
            a = a + 1
            bytesRead = fileStream.Read(buffer, 0, buffer.Length)
            StatusUpdate(buffer(a))

            If bytesRead = 0 Then
                Exit While
            End If
            requestStream.Write(buffer, 0, bytesRead)

        End While

       requestStream.Close()

        uploadResponse = uploadRequest.GetResponse()
        Dim responseReader As StreamReader = New StreamReader(uploadRequest.GetResponse.GetResponseStream())
        Dim x As String = responseReader.ReadToEnd()
        responseReader.Close()
        StatusUpdate(x)


    Catch ex As UriFormatException
        StatusUpdate("UriFormatException: " & ex.Message)
    Catch ex As IOException
        StatusUpdate("IOException: " & ex.Message)
    Catch ex As Net.WebException
        StatusUpdate("Net.WebException: " & ex.Message)

    Finally

        If uploadResponse IsNot Nothing Then
            uploadResponse.Close()
        End If

        If fileStream IsNot Nothing Then
            fileStream.Close()
        End If

        If requestStream IsNot Nothing Then
            requestStream.Close()
        End If

    End Try

无论如何,我还尝试了其他2个客户端(POSTMAN和REST控制台,2个Google Chrome扩展程序),只有将值“file”添加到“key”字段中我才能使用它.我必须插入特定的4个字符“文件”才能使其正常工作.所以,问题是：如何在Vb.net调用中添加相同的值？如何在工作的Vb.net代码中翻译cURL调用的代码？非常感谢您的时间和帮助！

找到我想在这里添加的东西的图像,

附：我不能使用PUT,我必须使用POST(服务器限制)

我还添加了适用于我的目的的HTML代码,使用我的电脑上的服务器(再次参见“文件”键)

<html>
<body>
<form enctype="multipart/form-data" action="http://URI" method="POST">
<table border=0>

<tr>
<td align="right">File&nbsp;</td>
<td><input type="FILE" name="file"></td>
</tr>
<tr>
<td>&nbsp;</td>
<td><input type="submit"></td>
</tr>
</table>
</form>
</body>
</html>

此外,我还在PERL中粘贴了一个脚本,该脚本也可以在我的计算机上与服务器一起使用.

  

#!perl

use strict;
use LWP; # Loads all important LWP classes

my $client_id         = 1234;
my $filename          = "new_file.xml";

### Prepare to make a request

my $browser = LWP::UserAgent->new;

my $url = "http://uri.com?&xx=$client_id";

my @post_pairs = (
    #'client_id_in' => $client_id,
    'file' => [$filename],
);

my @ns_headers = (
    'User-Agent' => 'Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.0.10) Gecko/2009042316 Firefox/3.0.10',
    'Accept' => 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
    'Accept-Language' => 'en-us,en;q=0.5',
    'Accept-Encoding' => 'gzip,deflate',
    'Accept-Charset' => 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
    'Authorization' => 'Basic base64EncodedCredentialsHere',
    'Content_Type' => 'form-data',
);

### Make a request
my $response = $browser->post($url, \@post_pairs, @ns_headers);
die "Can't get $url -- ", $response->status_line
        unless $response->is_success;

### Display the response
print STDOUT $response->content;

我认为你的问题是你真的不知道请求应该是什么样的,请使用fiddler来查看cURL发送的请求,并尝试使用vb.net实现相同的请求.在我看来,你的secons代码段(使用缓冲区,而不是xml序列化程序)应该可以工作……但只有在服务器端可以理解这种结构.