nginx main application scenarios

1. Reverse proxy

(Recommended tutorial: nginx tutorial)

Reverse proxy should be the most common thing Nginx does. What is a reverse proxy? The following is what Baidu Encyclopedia says: The reverse proxy (Reverse Proxy) method refers to using a proxy server to accept the Internet. The connection request is then forwarded to the server on the internal network, and the result obtained from the server is returned to the client requesting the connection on the Internet. At this time, the proxy server appears as a reverse proxy server to the outside world. To put it simply, the real server cannot be directly accessed by the external network, so a proxy server is needed. The proxy server can be accessed by the external network and is in the same network environment as the real server. Of course, it may also be the same server and port. Just different.

Key command: proxy_pass; For example, transfer localhost port 80 to localhost port 8080

<span style="color: #000000;">server { 
　　 listen 80; 
    server_name localhost; 

    location / {
        proxy_pass http://localhost:8080;
        proxy_set_header Host $host:$server_port;
　　}<br>}    </span>

2. Load balancing

Load balancing is also a commonly used function of Nginx. Simply put, when there are 2 or more servers, requests are randomly distributed to designated servers for processing according to rules. Load balancing configuration generally needs to be configured at the same time. Reverse proxy, jump to load balancing through reverse proxy. Nginx currently supports 3 built-in load balancing strategies, as well as 2 commonly used third-party strategies

Key commands: upstream; such as allocating requests from localhost port 80 to localhost 8080 and localhost 8081

Load scheme:

1), weight weight: session sharing must be implemented, otherwise the user session will be out of sync, causing the user to log in again

    upstream test {
        server localhost:8080 weight=9;  #请求的 90% 进入到8080服务器
        server localhost:8081 weight=1;  #请求的 10% 进入到8081服务器
    }

2), ip_hash: Each request is allocated according to the hash result of the accessed IP, so that each visitor has a fixed access to a back-end server, which can solve the session problem

upstream test {        ip_hash;
        server localhost:8080;
        server localhost:8081;
    }

3), fair (third party): press Requests are allocated based on the response time of the backend server, and those with shorter response times are allocated first.

upstream test {        fair;
        server localhost:8080;
        server localhost:8081;
}

4), url_hash (third party): Ask the hash result of the URL to allocate requests so that each URL is directed to the same back-end server. It is more effective when the back-end server is cached

upstream backend {        hash $request_uri;
        hash_method crc32;
        server localhost:8080;
        server localhost:8081;
    }

5), Default: allocate to different machines at once according to time

upstream test {
        server localhost:8080;
        server localhost:8081;
    }
    server {
        listen       80;                                                        
        server_name  localhost;                                              
        client_max_body_size 1024M;

        location / {
            proxy_pass http://test;
            proxy_set_header Host $host:$server_port;
        }
    }

3, WEB server

Nginx itself is also a static resource server. When there are only static resources, You can use Nginx as a server. At the same time, it is also very popular now to separate static and dynamic resources, which can be achieved through Nginx. First, let’s take a look at Nginx as a static resource server.

In this way, if you access http://localhost, you will access it by default #index.html under the ##E://www/data directory, if a website is just a static page, then it can be deployed in this way

Key Command:

root When there are only static resources, you can use Nginx as the server

server {
        listen       80;                                                        
        server_name  localhost;                                              

        location / {
               root   e:/www/data;
               index  index.html;
           }
    }

4. Forward proxy does not support HTTPS

Forward proxy , meaning a server located between the client and the origin server (origin server). In order to obtain content from the origin server, the client sends a request to the proxy and specifies the target (origin server), and then the proxy forwards the request to the origin server and The obtained content is returned to the client. Only clients can use forward proxies. When you need to use your server as a proxy server, you can use Nginx to implement forward proxy, but currently Nginx has a problem, that is, it does not support HTTPS

5, static separation

Separation of dynamic and static resources allows dynamic web pages in dynamic websites to distinguish constant resources from frequently changing resources according to certain rules. After dynamic and static resources are split, we can cache them according to the characteristics of static resources. This is the core idea of ​​static website processing.

upstream test{  
       server localhost:8080;  
       server localhost:8081;  
    }  

    server {  
        listen       80;  
        server_name  localhost;  

        location / {  
            root   e:/wwwroot;  
            index  index.html;  
        }  

        # 所有静态请求都由nginx处理，存放目录为html  
        location ~ .(gif|jpg|jpeg|png|bmp|swf|css|js)$ {  
            root    e:/wwwroot;  
        }  

        # 所有动态请求都转发给tomcat处理  
        location ~ .(do)$ {  
            proxy_pass  http://test;  
        }  

        error_page   500 502 503 504  /50x.html;  
        location = /50x.html {  
            root   e:/wwwroot;  
        }  
    }

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