开源的反向代理项目推荐

àì夳堔傛蜴生んèń 2022-09-26 02:19 239阅读 0赞

ttps://bitbucket.org/tebeka/seamless是一个开源的反向代理项目，可将用户访问通过代理分流给多个后端服务器。可通过http接口动态增加删除后端服务。  
项目主要文件有两个：seamless.go和backends.go，简单，易于阅读学习。  
其中最主要的一个函数forward用于转发请求：

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 func forward 
 (local net. 
 Conn 
 , remoteAddr string 
 ) 
 { 
 &nbsp; &nbsp; remote 
 , err 
 := net. 
 Dial 
 ( 
 "tcp" 
 , remoteAddr 
 ) 
 &nbsp; &nbsp; 
 if err 
 != nil 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; 
 <a href="http://www.opengroup.org/onlinepubs/009695399/functions/log.html" rel="nofollow"> log</a>. 
 Printf 
 ( 
 "remote dial failed: %v\n" 
 , err 
 ) 
 &nbsp; &nbsp; &nbsp; &nbsp; local. 
 Close 
 ( 
 ) 
 &nbsp; &nbsp; &nbsp; &nbsp; 
 return 
 &nbsp; &nbsp; 
 } 
 &nbsp; &nbsp; go io. 
 Copy 
 (local 
 , remote 
 ) 
 &nbsp; &nbsp; go io. 
 Copy 
 (remote 
 , local 
 ) 
 
 } 
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io.Copy一句是精隨。  
local和remote均是一个网络连接，类型为net.Conn,关于Conn接口的定，在Go官方源码中有：

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 type Conn interface 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; Read 
 (b 
 [ 
 ]byte 
 ) 
 (n 
 int 
 , err error 
 ) 
 &nbsp; &nbsp; &nbsp; &nbsp; Write 
 (b 
 [ 
 ]byte 
 ) 
 (n 
 int 
 , err error 
 ) 
 &nbsp; &nbsp; &nbsp; &nbsp; Close 
 ( 
 ) error 
 &nbsp; &nbsp; &nbsp; &nbsp; LocalAddr 
 ( 
 ) Addr 
 &nbsp; &nbsp; &nbsp; &nbsp; RemoteAddr 
 ( 
 ) Addr 
 &nbsp; &nbsp; &nbsp; &nbsp; SetDeadline 
 (t 
 <a href="http://www.opengroup.org/onlinepubs/009695399/functions/time.html" rel="nofollow"> time</a>. 
 Time 
 ) error 
 &nbsp; &nbsp; &nbsp; &nbsp; SetReadDeadline 
 (t 
 <a href="http://www.opengroup.org/onlinepubs/009695399/functions/time.html" rel="nofollow"> time</a>. 
 Time 
 ) error 
 &nbsp; &nbsp; &nbsp; &nbsp; SetWriteDeadline 
 (t 
 <a href="http://www.opengroup.org/onlinepubs/009695399/functions/time.html" rel="nofollow"> time</a>. 
 Time 
 ) error 
 &nbsp; &nbsp; 
 } 
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io.Copy(dst Writer, src Reader)，则实现从src复制到dst。  
io.Copy的实现代码有：

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 buf 
 := make 
 ( 
 [ 
 ]byte 
 , 
 32 
 * 
 1024 
 ) 
 &nbsp; &nbsp; 
 for 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; nr 
 , er 
 := src. 
 Read 
 (buf 
 ) 
 &nbsp; &nbsp; &nbsp; &nbsp; 
 if nr 
 &gt; 
 0 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; nw 
 , ew 
 := dst. 
 Write 
 (buf 
 [ 
 0 
 :nr 
 ] 
 ) 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 if nw 
 &gt; 
 0 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; written 
 += 
 int64 
 (nw 
 ) 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 } 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 if ew 
 != nil 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; err 
 = ew 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 break 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 } 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 if nr 
 != nw 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; err 
 = ErrShortWrite 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 break 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 } 
 &nbsp; &nbsp; &nbsp; &nbsp; 
 } 
 &nbsp; &nbsp; &nbsp; &nbsp; 
 if er 
 == EOF 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 break 
 &nbsp; &nbsp; &nbsp; &nbsp; 
 } 
 &nbsp; &nbsp; &nbsp; &nbsp; 
 if er 
 != nil 
 { 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; err 
 = er 
 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
 break 
 &nbsp; &nbsp; &nbsp; &nbsp; 
 } 
 &nbsp; &nbsp; 
 } 
 &nbsp; &nbsp; 
 return written 
 , err 
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可以看到调用了Read和Write方法，而这个方法刚好net.Conn中定义了。这就实现了将一个连接的数据复制到另一个连接。