> For the complete documentation index, see [llms.txt](https://yangsx95.gitbook.io/notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yangsx95.gitbook.io/notes/distributed/web-fu-wu-qi/nginx/dai-li-fu-wu.md).

# 代理服务

Nginx可以作为多种代理服务：

![1556094884828](/files/gmcDulamhwFmKvApbudo)

## proxy\_pass

```nginx
# 进入到location后，发现此配置，将会把请求转发给指定的URL，再由nginx接收响应，再响应给客户端
Syntax: proxy_pass URL;
Default:
Context: location, if in location, limit_except

# 支持的URL：
# http://localhost:8080/uri/
# https://test.com/uri/
# http://unix:/tmp/backend.socket:/uri/
```

## 反向代理

反向代理，比如nginx代理内网中的某个tomcat，代理的是服务端

```nginx
# 将admin.html的请求反向代理交给服务器的tomcat处理(8080是tomcat端口)
location ~ /admin.html$ {
    proxy_pass http://127.0.0.1:8080;
}
```

## 正向代理

正向代理，比如VPN，代理的是客户端

```nginx
# 定义DNS server，这是google的dns server
resolver 8.8.8.8;
# 请求这台代理服务器，这台服务器会代替我们请求，并响应
location / {
    proxy_pass http://$http_host$request_uri;
}
```

可以通过代理软件，设置代理。

## http\_proxy\_module

`http_proxy_module`是代理模块，包含了很多代理指令，详细可以了解[官方文档](http://nginx.org/en/docs/http/ngx_http_proxy_module.html)。下面是需要了解的常用配置：

```nginx
#### 信息修改

# 重写客户端请求的请求头
Syntax:	proxy_set_header field value;
Default:	
proxy_set_header Host $proxy_host;
proxy_set_header Connection close;
Context:	http, server, location

# 重写客户端请求的请求体
Syntax:	proxy_set_body value;
Default:	—
Context:	http, server, location

### 超时时间

# 与代理服务器连接的超时时间，通常不会超过75s
Syntax:	proxy_connect_timeout time;
Default:	proxy_connect_timeout 60s;
Context:	http, server, location

# 接收服务器响应的数据的超时时间	
Syntax:	proxy_send_timeout time;
Default:	proxy_send_timeout 60s;
Context:	http, server, location

# 读取代理服务器响应超时时间
Syntax:	proxy_read_timeout time;
Default:	proxy_read_timeout 60s;
Context:	http, server, location


### 缓冲区配置
# 开启后，当nginx接收到目标服务器的响应时，会将其保存到 proxy_buffers 设置的缓冲区中
# 缓冲区的大小由proxy_buffer_size设定
# 当响应过大，缓冲区装不下时，可以将一部分放入到磁盘的临时文件中
# 这个临时文件由proxy_max_temp_file_size和proxy_temp_file_write_size配置项配置。

# 开启，关闭代理服务器缓冲区
Syntax:	proxy_buffering on | off;
Default:	proxy_buffering on;
Context:	http, server, location

# 配置缓冲区大小	
Syntax:	proxy_buffer_size size;
Default:	
proxy_buffer_size 4k|8k;
Context:	http, server, location

### 跳转重定向
# 当后端返回301重定向的地址是需要代理的地址的时候，就可以使用此种方式重写跳转地址的url，防止客户端访问不到目标地址
# 默认使用default即可
Syntax:	proxy_redirect default;
	proxy_redirect off;
	proxy_redirect redirect replacement;
Default:	proxy_redirect default;
Context:	http, server, location
```

## 企业应用nginx作为代理通常所要配置的参数

```nginx
location / {
    proxy_pass http://127.0.0.1:8080;
    proxy_redirect default;
    
	# 代理添加的头信息,需要服务端直到客户端的真实ip
    proxy_set_header Host $http_host;
    proxy_set_header X-Real-IP $remote_addr;

    # 超时时间设置
    proxy_connect_timeout 30;
    proxy_send_timeout 60;
    proxy_read_timeout 60;

    # 缓冲配置，用以减少频繁的IO
    proxy_buffer_size 32k; # 页面通常不会超过32k
    proxy_buffering on;
    proxy_buffers 4 128k;
    proxy_busy_buffers_size 256k;
    proxy_max_temp_file_size 256k; # 当buffer与busy_buffers都用完的时候，就需要文件缓冲 
    # 可以使用 nginx -V 查看 --http-proxy-temp-path 变量，查看临时文件位置
}
```

通常proxy的配置是很长很冗余的，可以将其拆分为文件，并引入：

```nginx
# proxy_params 文件
proxy_redirect default;

proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;

proxy_connect_timeout 30;
proxy_send_timeout 60;
proxy_read_timeout 60;

proxy_buffer_size 32k;
proxy_buffering on;
proxy_buffers 4 128k;
proxy_busy_buffers_size 256k;
proxy_max_temp_file_size 256k;

# conf文件
location / {
    proxy_pass http://127.0.0.1:8080;
    include proxy_params;
}
```


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