c# 模拟web请求formdata webrequest

前言

在写代码中，我们常常需要去书写代码去请求一些东西，那么是不是可以模拟像web formdata一样请求。

正文

下面代码为模拟的:

public string SendRequest(string url, ref Dictionary<string, object> data, HttpMethod requestMethod,ref Dictionary<string, string> header, int timeOut, string localPath = null, long offset = -1, int sliceSize = 0)
{
	//url = "http://localhost:54257/Home/getdata";
	try
	{
		System.Net.ServicePointManager.Expect100Continue = false;
		if (requestMethod == HttpMethod.Get)
		{
			var paramStr = "";
			foreach (var key in data.Keys)
			{
				paramStr += string.Format("{0}={1}&", key, HttpUtility.UrlEncode(data[key].ToString()));
			}
			paramStr = paramStr.TrimEnd('&');
			url += (url.EndsWith("?") ? "&" : "?") + paramStr;
		}

		HttpWebRequest request;

		request = (HttpWebRequest)HttpWebRequest.Create(url);
		request.Accept = CosDefaultValue.ACCEPT;
		request.KeepAlive = true;
		request.UserAgent = CosDefaultValue.USER_AGENT_VERSION;
		request.Timeout = timeOut;
		foreach (var key in header.Keys)
		{
			if(key == "Content-Type")
			{
				request.ContentType = header[key];
			}
			else
			{
				request.Headers.Add(key, header[key]);
			}
		}
		if (requestMethod == HttpMethod.Post)
		{
			request.Method = requestMethod.ToString().ToUpper();
			var memStream = new MemoryStream();
			if (header.ContainsKey("Content-Type") && header["Content-Type"] == "application/json")
			{
				var json = JsonConvert.SerializeObject(data);
				var jsonByte = Encoding.GetEncoding("utf-8").GetBytes(json.ToString());
				memStream.Write(jsonByte, 0, jsonByte.Length);
			}
			else
			{
				var boundary = "---------------" + DateTime.Now.Ticks.ToString("x");
				var beginBoundary = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
				var endBoundary = Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
				request.ContentType = "multipart/form-data; boundary=" + boundary;                       

				var strBuf = new StringBuilder();
				foreach (var key in data.Keys)
				{
					strBuf.Append("\r\n--" + boundary + "\r\n");
					strBuf.Append("Content-Disposition: form-data; name=\"" + key + "\"\r\n\r\n");
					strBuf.Append(data[key].ToString());
				}
				var paramsByte = Encoding.GetEncoding("utf-8").GetBytes(strBuf.ToString());
				memStream.Write(paramsByte, 0, paramsByte.Length);
				if (localPath != null)
				{
					memStream.Write(beginBoundary, 0, beginBoundary.Length);
					var fileInfo = new FileInfo(localPath);
					using (var fileStream = new FileStream(localPath, FileMode.Open, FileAccess.Read))
					{
						const string filePartHeader =
							"Content-Disposition: form-data; name=\"fileContent\"; filename=\"{0}\"\r\n" +
							"Content-Type: application/octet-stream\r\n\r\n";
						var headerText = string.Format(filePartHeader, fileInfo.Name);
						var headerbytes = Encoding.UTF8.GetBytes(headerText);
						memStream.Write(headerbytes, 0, headerbytes.Length);

						if (offset == -1)
						{
							var buffer = new byte[1024];
							int bytesRead;
							while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
							{
								memStream.Write(buffer, 0, bytesRead);
							}
						}
						else
						{
							var buffer = new byte[sliceSize];
							int bytesRead;
							fileStream.Seek(offset, SeekOrigin.Begin);
							bytesRead = fileStream.Read(buffer, 0, buffer.Length);
							memStream.Write(buffer, 0, bytesRead);
						}
					}
				}
				memStream.Write(endBoundary, 0, endBoundary.Length);
			}
			request.ContentLength = memStream.Length;
			var requestStream = request.GetRequestStream();
			memStream.Position = 0;
			var tempBuffer = new byte[memStream.Length];
			memStream.Read(tempBuffer, 0, tempBuffer.Length);
			memStream.Close();

			requestStream.Write(tempBuffer, 0, tempBuffer.Length);
			requestStream.Close();

			//Console.WriteLine(strBuf.ToString());
		}
		//Console.WriteLine(request.ContentType.ToString());
		var response = request.GetResponse();
		using (var s = response.GetResponseStream())
		{
			var reader = new StreamReader(s, Encoding.UTF8);
			var rsp_data = reader.ReadToEnd();
			if (response != null) 
			{
				response.Close();
			}
			return rsp_data;
		}
	}
	catch (WebException we)
	{
		if (we.Status == WebExceptionStatus.ProtocolError)
		{
			using (var s = we.Response.GetResponseStream())
			{
				var reader = new StreamReader(s, Encoding.UTF8);
				return reader.ReadToEnd();
			}
		}
		else
		{
			throw we;
		}
	}
	catch (Exception e)
	{
		throw e;
	}
}
}
}