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This article mainly explains "how C # uses the http protocol to communicate with the server". The explanation in the article is simple and clear, and is easy to learn and understand. Please follow the editor's train of thought to study and learn "how C # uses the http protocol to communicate with the server".

Using System

Using System.Collections.Generic

Using System.Linq

Using System.Text

Using System.Collections

Using System.Net

Using System.IO

Namespace www.xinduofen.cn

{

/ / /

/ C # tool class for interfacing with http server

/ / /

Class HttpWebTool

{

/ / /

/ / used to cache SESSIONID or JSESSIONID transferred from the server to the client

/ / /

Private Cookie sessionidCookie = null

/ / /

/ / get data from HttpWebServer (using "post" mode)

/ / /

/ / request URL

/ / request parameter collection. Null value is passed when no parameter is needed.

/ / request cookie collection. Pass a null value when no cookie is required.

/ / return the request result string, which means that the request failed if returned as null

Public String getDatafromHttpWebServer (String url, Hashtable data,CookieCollection cookies)

{

String result = null

If (string.IsNullOrEmpty (url))

{

Return null;// input parameter exception

}

Byte [] data_stream = null;// the contents of the data stream to be transmitted to the server

If (data! = null & & data.Count > 0)

{

String transportData = ""; / / the string content to be transmitted to the server

Foreach (DictionaryEntry de in data)

{

TransportData = transportData + de.Key.ToString () + "=" + de.Value.ToString () + "&"; / / Demodulate the key-value pair data

}

TransportData = transportData.TrimEnd ('&'); / / remove the & at the end of the string

If (! string.IsNullOrEmpty (transportData))

{

Data_stream = Encoding.UTF8.GetBytes (transportData); / / package uploaded string data into a data stream

}

}

Try

{

HttpWebRequest req = (HttpWebRequest) HttpWebRequest.Create (url)

/ / request method

Req.Method = "POST"

/ / declare that the client only receives content of type txt

Req.Accept = "text/plain"

/ / pass parameters to the server in the form of key-value pairs

Req.ContentType = "application/x-www-form-urlencoded"

/ / set the cookie box (the cookie requested by the client and the cookie returned by the server are placed in this box)

CookieContainer cookieContainer = new CookieContainer ()

If (sessionidCookie! = null & &! string.IsNullOrEmpty (sessionidCookie.Domain))

{

CookieContainer.Add (sessionidCookie)

}

If (cookies created null)

{

CookieContainer.Add (cookies); / / add the cookie collection passed in by the caller

}

Req.CookieContainer = cookieContainer

If (data_stream! = null & & data_stream.Length > 0)

{

/ / request the length of the data stream

Req.ContentLength = data_stream.Length

Using (Stream requestStream = req.GetRequestStream ()) {

/ / write request entity stream

RequestStream.Write (data_stream, 0, data_stream.Length)

}

}

/ / receive the return value

Using (HttpWebResponse myResponse = (HttpWebResponse) req.GetResponse ()) {

Using (StreamReader reader = new StreamReader (myResponse.GetResponseStream (), Encoding.UTF8))

{

Result = reader.ReadToEnd () .Trim ()

}

If (myResponse.Cookies ["SESSIONID"]! = null)

{

SessionidCookie = myResponse.Cookies ["SESSIONID"]

}

Else

{

If (myResponse.Cookies ["JSESSIONID"]! = null)

{

SessionidCookie = myResponse.Cookies ["JSESSIONID"]

}

}

}

} catch (Exception) {

Console.WriteLine ("Please check whether the incoming parameters are correct or whether the server is down")

}

Return result

}

/ / /

/ / get the message data flow for the parameter data, ending with "\ r\ n"

/ / /

/ / request parameter collection. Null value is passed when no parameter is needed.

/ / message delimiter

/ / return the data flow of the parameter data. If it is empty, it means the acquisition failed.

Private byte [] getParameterBytes (Hashtable data, String boundary)

{

Byte [] parameterBytes = null

/ / if there are request parameters

If (data! = null & & data.Count > 0)

{

String parameterStr = ""

Foreach (DictionaryEntry de in data)

{

ParameterStr + = "-" + boundary

ParameterStr + = "\ r\ n" + "Content-Disposition: form-data;name=\"+ de.Key.ToString () +"\ ""

ParameterStr + = "\ r\ n" + "Content-Type: text/plain; charset=UTF-8"

ParameterStr + = "\ r\ n\ r\ n" + de.Value.ToString ()

ParameterStr + = "\ r\ n"

}

If (! string.IsNullOrEmpty (parameterStr))

{

ParameterBytes = Encoding.UTF8.GetBytes (parameterStr); / / package uploaded string data into a data stream

}

}

Return parameterBytes

}

/ / /

/ / get the header character stream of the uploaded file, ending with "\ r\ n\ r\ n"

/ / /

/ / upload file "control name, location where the uploaded file is saved (including" file name "." extension ")"

/ / message delimiter

/ / return the character stream of the header part of the uploaded file. The return will fail for the null representative.

Private byte [] getUploadFileDeclareBytes (DictionaryEntry de, String boundary)

{

Byte [] uploadFileDeclareBytes = null

/ / the header description part of the uploaded file

String uploadFileDeclareStr = ""

UploadFileDeclareStr + = "-" + boundary

UploadFileDeclareStr + = "\ r\ n" + "Content-Disposition: form-data;name=\"+ de.Key.ToString () +"\ "; filename=\"+ de.Value.ToString () +"\ ""

UploadFileDeclareStr + = "\ r\ n" + "Content-Type: application/octet-stream"

UploadFileDeclareStr + = "\ r\ n\ r\ n"

If (! string.IsNullOrEmpty (uploadFileDeclareStr))

{

UploadFileDeclareBytes = Encoding.UTF8.GetBytes (uploadFileDeclareStr); / / package uploaded string data into a data stream

}

Return uploadFileDeclareBytes

}

}

}

Thank you for your reading, the above is the content of "how C # uses http protocol to communicate with server". After the study of this article, I believe you have a deeper understanding of how C # uses http protocol to communicate with server, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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