我试图从C#客户端(Outlook插件)填写php应用程序中的表单.我使用Fiddler从php应用程序中查看原始请求,并将表单作为multipart/form传输.不幸的是.Net没有为这种类型的表单提供本机支持(WebClient只有一种上传文件的方法).有人知道图书馆或有一些代码来实现这一目标吗？我想发布不同的值,另外(但有时只)发布一个文件.
谢谢你的帮助,塞巴斯蒂安
感谢大家的答案!我最近不得不让它工作,并大量使用你的建议.然而,有一些棘手的部分没有按预期工作,主要是与实际包括文件(这是问题的一个重要部分)有关.这里有很多答案,但我认为这可能对将来的某些人有用(我在网上找不到很多明确的例子).我写了一篇博文,解释了一下.
基本上,我首先尝试将文件数据作为UTF8编码的字符串传递,但我遇到了编码文件的问题(它对于纯文本文件工作正常,但是在上传Word文档时,例如,如果我试图保存使用Request.Files [0] .SaveAs()传递给已发布表单的文件,在Word中打开文件无法正常工作.我发现如果直接使用Stream(而不是StringBuilder)编写文件数据),它按预期工作.另外,我做了一些修改,让我更容易理解.
顺便说一下,如果任何人需要参考规范,那么Multipart Forms for Comments和W3C关于mulitpart/form-data的建议是一些有用的资源.
我将WebHelpers类更改为更小并且具有更简单的接口,现在调用它FormUpload.如果传递a FormUpload.FileParameter,则可以传递byte []内容以及文件名和内容类型,如果传递字符串,则会将其视为标准名称/值组合.
这是FormUpload类:
// Implements multipart/form-data POST in C# http://www.ietf.org/rfc/rfc2388.txt
// http://www.briangrinstead.com/blog/multipart-form-post-in-c
public static class FormUpload
{
private static readonly Encoding encoding = Encoding.UTF8;
public static HttpWebResponse MultipartFormDataPost(string postUrl, string userAgent, Dictionary postParameters)
{
string formDataBoundary = String.Format("----------{0:N}", Guid.NewGuid());
string contentType = "multipart/form-data; boundary=" + formDataBoundary;
byte[] formData = GetMultipartFormData(postParameters, formDataBoundary);
return PostForm(postUrl, userAgent, contentType, formData);
}
private static HttpWebResponse PostForm(string postUrl, string userAgent, string contentType, byte[] formData)
{
HttpWebRequest request = WebRequest.Create(postUrl) as HttpWebRequest;
if (request == null)
{
throw new NullReferenceException("request is not a http request");
}
// Set up the request properties.
request.Method = "POST";
request.ContentType = contentType;
request.UserAgent = userAgent;
request.CookieContainer = new CookieContainer();
request.ContentLength = formData.Length;
// You could add authentication here as well if needed:
// request.PreAuthenticate = true;
// request.AuthenticationLevel = System.Net.Security.AuthenticationLevel.MutualAuthRequested;
// request.Headers.Add("Authorization", "Basic " + Convert.ToBase64String(System.Text.Encoding.Default.GetBytes("username" + ":" + "password")));
// Send the form data to the request.
using (Stream requestStream = request.GetRequestStream())
{
requestStream.Write(formData, 0, formData.Length);
requestStream.Close();
}
return request.GetResponse() as HttpWebResponse;
}
private static byte[] GetMultipartFormData(Dictionary postParameters, string boundary)
{
Stream formDataStream = new System.IO.MemoryStream();
bool needsCLRF = false;
foreach (var param in postParameters)
{
// Thanks to feedback from commenters, add a CRLF to allow multiple parameters to be added.
// Skip it on the first parameter, add it to subsequent parameters.
if (needsCLRF)
formDataStream.Write(encoding.GetBytes("\r\n"), 0, encoding.GetByteCount("\r\n"));
needsCLRF = true;
if (param.Value is FileParameter)
{
FileParameter fileToUpload = (FileParameter)param.Value;
// Add just the first part of this param, since we will write the file data directly to the Stream
string header = string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}\";\r\nContent-Type: {3}\r\n\r\n",
boundary,
param.Key,
fileToUpload.FileName ?? param.Key,
fileToUpload.ContentType ?? "application/octet-stream");
formDataStream.Write(encoding.GetBytes(header), 0, encoding.GetByteCount(header));
// Write the file data directly to the Stream, rather than serializing it to a string.
formDataStream.Write(fileToUpload.File, 0, fileToUpload.File.Length);
}
else
{
string postData = string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"\r\n\r\n{2}",
boundary,
param.Key,
param.Value);
formDataStream.Write(encoding.GetBytes(postData), 0, encoding.GetByteCount(postData));
}
}
// Add the end of the request. Start with a newline
string footer = "\r\n--" + boundary + "--\r\n";
formDataStream.Write(encoding.GetBytes(footer), 0, encoding.GetByteCount(footer));
// Dump the Stream into a byte[]
formDataStream.Position = 0;
byte[] formData = new byte[formDataStream.Length];
formDataStream.Read(formData, 0, formData.Length);
formDataStream.Close();
return formData;
}
public class FileParameter
{
public byte[] File { get; set; }
public string FileName { get; set; }
public string ContentType { get; set; }
public FileParameter(byte[] file) : this(file, null) { }
public FileParameter(byte[] file, string filename) : this(file, filename, null) { }
public FileParameter(byte[] file, string filename, string contenttype)
{
File = file;
FileName = filename;
ContentType = contenttype;
}
}
}
这是调用代码,它上传文件和一些普通的post参数:
// Read file data
FileStream fs = new FileStream("c:\\people.doc", FileMode.Open, FileAccess.Read);
byte[] data = new byte[fs.Length];
fs.Read(data, 0, data.Length);
fs.Close();
// Generate post objects
Dictionary postParameters = new Dictionary();
postParameters.Add("filename", "People.doc");
postParameters.Add("fileformat", "doc");
postParameters.Add("file", new FormUpload.FileParameter(data, "People.doc", "application/msword"));
// Create request and receive response
string postURL = "http://localhost";
string userAgent = "Someone";
HttpWebResponse webResponse = FormUpload.MultipartFormDataPost(postURL, userAgent, postParameters);
// Process response
StreamReader responseReader = new StreamReader(webResponse.GetResponseStream());
string fullResponse = responseReader.ReadToEnd();
webResponse.Close();
Response.Write(fullResponse);
这是从我写的一些示例代码中剪切和粘贴的,希望它应该给出基础知识.它目前仅支持文件数据和表单数据.
public class PostData
{
private List m_Params;
public List Params
{
get { return m_Params; }
set { m_Params = value; }
}
public PostData()
{
m_Params = new List();
// Add sample param
m_Params.Add(new PostDataParam("email", "MyEmail", PostDataParamType.Field));
}
///
/// Returns the parameters array formatted for multi-part/form data
///
///
要发送数据,您需要:
HttpWebRequest oRequest = null; oRequest = (HttpWebRequest)HttpWebRequest.Create(oURL.URL); oRequest.ContentType = "multipart/form-data"; oRequest.Method = "POST"; PostData pData = new PostData(); byte[] buffer = encoding.GetBytes(pData.GetPostData()); // Set content length of our data oRequest.ContentLength = buffer.Length; // Dump our buffered postdata to the stream, booyah oStream = oRequest.GetRequestStream(); oStream.Write(buffer, 0, buffer.Length); oStream.Close(); // get the response oResponse = (HttpWebResponse)oRequest.GetResponse();
希望这很清楚,我已经从几个来源切割和粘贴,以使得更整洁.
使用.NET 4.5,您当前可以使用System.Net.Http命名空间.下面是使用多部分表单数据上传单个文件的示例.
using System;
using System.IO;
using System.Net.Http;
namespace HttpClientTest
{
class Program
{
static void Main(string[] args)
{
var client = new HttpClient();
var content = new MultipartFormDataContent();
content.Add(new StreamContent(File.Open("../../Image1.png", FileMode.Open)), "Image", "Image.png");
content.Add(new StringContent("Place string content here"), "Content-Id in the HTTP");
var result = client.PostAsync("https://hostname/api/Account/UploadAvatar", content);
Console.WriteLine(result.Result.ToString());
}
}
}
以dnolans为例,这是我实际可以使用的版本(边界有一些错误,编码没有设置):-)
要发送数据:
HttpWebRequest oRequest = null;
oRequest = (HttpWebRequest)HttpWebRequest.Create("http://you.url.here");
oRequest.ContentType = "multipart/form-data; boundary=" + PostData.boundary;
oRequest.Method = "POST";
PostData pData = new PostData();
Encoding encoding = Encoding.UTF8;
Stream oStream = null;
/* ... set the parameters, read files, etc. IE:
pData.Params.Add(new PostDataParam("email", "example@example.com", PostDataParamType.Field));
pData.Params.Add(new PostDataParam("fileupload", "filename.txt", "filecontents" PostDataParamType.File));
*/
byte[] buffer = encoding.GetBytes(pData.GetPostData());
oRequest.ContentLength = buffer.Length;
oStream = oRequest.GetRequestStream();
oStream.Write(buffer, 0, buffer.Length);
oStream.Close();
HttpWebResponse oResponse = (HttpWebResponse)oRequest.GetResponse();
PostData类应如下所示:
public class PostData
{
// Change this if you need to, not necessary
public static string boundary = "AaB03x";
private List m_Params;
public List Params
{
get { return m_Params; }
set { m_Params = value; }
}
public PostData()
{
m_Params = new List();
}
///
/// Returns the parameters array formatted for multi-part/form data
///
///
在我使用的.NET版本中你也必须这样做:
System.Net.ServicePointManager.Expect100Continue = false;
如果不这样做,HttpWebRequest该类将自动添加Expect:100-continue请求标题,这会对所有内容造成污染.
另外,我学到了很难获得正确数量的破折号.无论你说什么,Content-Type标题中的"边界" 必须以两个破折号开头
--THEBOUNDARY
最后
--THEBOUNDARY--
与示例代码中的完全一样.如果您的边界是大量的破折号后跟一个数字,那么通过查看代理服务器中的http请求,这个错误将不会很明显
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