我正在尝试下载、搜索 bing 页面,并询问是否使用套接字,我决定使用套接字,而不是 webclient。
在 bing、yahoo、google 的情况下,socket.Receive(); 在几个循环后挂起,但适用于询问。 for google loop 将接收 4 - 5 次,然后停止调用。
我不知道为什么?
public string Get(string url)
{
Uri requestedUri = new Uri(url);
string fulladdress = requestedUri.Host;
IPHostEntry entry = Dns.GetHostEntry(fulladdress);
StringBuilder sb = new StringBuilder();
try
{
using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP))
{
socket.Connect(entry.AddressList[0], 80);
NetworkStream ns = new NetworkStream(socket);
string part_request = string.Empty;
string build_request = string.Empty;
if (jar.Count != 0)
{
part_request = "GET {0} HTTP/1.1\r\nHost: {1} \r\nUser-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\nAccept-Language: en-us,en;q=0.5\r\nAccept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\nCookie: {2}\r\nConnection: keep-alive\r\n\r\n";
build_request = string.Format(part_request, requestedUri.PathAndQuery, requestedUri.Host, GetCookies(requestedUri));
}
else
{
part_request = "GET {0} HTTP/1.1\r\nHost: {1} \r\nUser-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\nAccept-Language: en-us,en;q=0.5\r\nAccept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\nConnection: keep-alive\r\n\r\n";
build_request = string.Format(part_request, requestedUri.PathAndQuery, requestedUri.Host);
}
byte[] data = Encoding.UTF8.GetBytes(build_request);
socket.Send(data, data.Length, 0);
byte[] bytesReceived = new byte[102400];
int bytes = 0;
do
{
bytes = socket.Receive(bytesReceived, bytesReceived.Length, 0);
sb.Append(Encoding.ASCII.GetString(bytesReceived, 0, bytes));
}
while (bytes > 0);
List<String> CookieHeaders = new List<string>();
foreach (string header in sb.ToString().Split("\n\r".ToCharArray(), StringSplitOptions.RemoveEmptyEntries))
{
if (header.StartsWith("Set-Cookie"))
{
CookieHeaders.Add(header.Replace("Set-Cookie: ", ""));
}
}
this.AddCookies(CookieHeaders, requestedUri);
socket.Close();
}
}
catch (Exception ex)
{
string errorMessage = ex.Message;
}
return sb.ToString();
}
CookieContainer jar = new CookieContainer();
public string GetCookies(Uri _uri)
{
StringBuilder sb = new StringBuilder();
CookieCollection collection = jar.GetCookies(_uri);
if (collection.Count != 0)
{
foreach (Cookie item in collection)
{
sb.Append(item.Name + "=" + item.Value + ";");
}
}
return sb.ToString();
}
最佳答案
这是因为您已经读完了内容,但您仍在请求更多...
do
{
bytes = socket.Receive(bytesReceived, bytesReceived.Length, 0);
sb.Append(Encoding.ASCII.GetString(bytesReceived, 0, bytes));
}
while (bytes > 0);
这假设只要最后一个请求返回的字节数大于 0,就会有更多可用字节,而实际上当网络流到达末尾时,您很可能会在最后一个循环中填充一些缓冲区。 (例如 bytes > 0 但仅此而已)...所以服务器关闭连接。
尝试这样的事情......
do
{
bytes = socket.Receive(bytesReceived, bytesReceived.Length, 0);
sb.Append(Encoding.ASCII.GetString(bytesReceived, 0, bytes));
}
while (bytes == bytesReceived.Length);
一些服务器(ask 可能是其中之一)显然不会像您期望的那样自动关闭连接,因此它不会总是失败的原因。
:::编辑:::
我的测试样本:
加载 visual studio,创建一个新的控制台应用程序,然后将以下内容粘贴到生成的程序类中(代替所有现有代码):
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
string test = Get("http://www.google.co.uk/search?q=test&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a");
Console.Read();
}
public static string Get(string url)
{
Uri requestedUri = new Uri(url);
string fulladdress = requestedUri.Host;
IPHostEntry entry = Dns.GetHostEntry(fulladdress);
StringBuilder sb = new StringBuilder();
try
{
using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP))
{
socket.Connect(entry.AddressList[0], 80);
NetworkStream ns = new NetworkStream(socket);
string part_request = string.Empty;
string build_request = string.Empty;
if (jar.Count != 0)
{
part_request = "GET {0} HTTP/1.1\r\nHost: {1} \r\nUser-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\nAccept-Language: en-us,en;q=0.5\r\nAccept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\nCookie: {2}\r\nConnection: keep-alive\r\n\r\n";
build_request = string.Format(part_request, requestedUri.PathAndQuery, requestedUri.Host, GetCookies(requestedUri));
}
else
{
part_request = "GET {0} HTTP/1.1\r\nHost: {1} \r\nUser-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\nAccept-Language: en-us,en;q=0.5\r\nAccept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\nConnection: keep-alive\r\n\r\n";
build_request = string.Format(part_request, requestedUri.PathAndQuery, requestedUri.Host);
}
byte[] data = Encoding.UTF8.GetBytes(build_request);
socket.Send(data, data.Length, 0);
byte[] bytesReceived = new byte[4096];
int bytes = 0;
string currentBatch = "";
do
{
bytes = socket.Receive(bytesReceived);
currentBatch = Encoding.ASCII.GetString(bytesReceived, 0, bytes);
Console.Write(currentBatch);
sb.Append(currentBatch);
}
while (bytes == bytesReceived.Length);
List<String> CookieHeaders = new List<string>();
foreach (string header in sb.ToString().Split("\n\r".ToCharArray(), StringSplitOptions.RemoveEmptyEntries))
{
if (header.StartsWith("Set-Cookie"))
{
CookieHeaders.Add(header.Replace("Set-Cookie: ", ""));
}
}
//this.AddCookies(CookieHeaders, requestedUri);
socket.Close();
}
}
catch (Exception ex)
{
string errorMessage = ex.Message;
}
return sb.ToString();
}
static CookieContainer jar = new CookieContainer();
public static string GetCookies(Uri _uri)
{
StringBuilder sb = new StringBuilder();
CookieCollection collection = jar.GetCookies(_uri);
if (collection.Count != 0)
{
foreach (Cookie item in collection)
{
sb.Append(item.Name + "=" + item.Value + ";");
}
}
return sb.ToString();
}
}
}
我减少了缓冲区以确保它不止一次被填充......从我的角度来看似乎没问题 这篇文章附带了我电脑上的典型作品保证:)
关于c# - 套接字接收挂起,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/6775065/