What is nginx?

nginx application scenario

Installing Nginx in Windows

Advantages and disadvantages of nginx

nginx implements reverse proxy

http {
    include       mime.types;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;

    server {
        listen       80; //port number
        server_name  localhost; //Together, they mean that as long as they are accessed through localhost:80, I will intercept them to the location address.

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            proxy_pass: https://www.baidu.com; //The address of the jump. Note that there's another number at the end of the jump.
            index  index.html index.htm; //// Intercept files that go by default
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

        # proxy the PHP scripts to Apache listening on 127.0.0.1:80
        #
        #location ~ \.php$ {
        #    proxy_pass   http://127.0.0.1;
        #}

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ \.php$ {
        #    root           html;
        #    fastcgi_pass   127.0.0.1:9000;
        #    fastcgi_index  index.php;
        #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
        #    include        fastcgi_params;
        #}

        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        #location ~ /\.ht {
        #    deny  all;
        #}
    }

What is Load Balancing

Load Balancing Strategy

1,Polling (default)
//Each request is allocated to different back-end servers in chronological order. If the back-end server down s, it can be automatically eliminated.
upstream backserver {
server 192.168.0.14;
server 192.168.0.15;
}
2,Designated weight
//Specify polling probability, weight proportional to access ratio, for uneven performance of back-end servers.
upstream backserver {
server 192.168.0.14 weight=10;
server 192.168.0.15 weight=10;
}
3,IP binding ip_hash
//Each request is allocated according to the hash result of accessing ip, so that each visitor can access a back-end server regularly, which can solve the session problem.
upstream backserver {
ip_hash;
server 192.168.0.14:88;
server 192.168.0.15:80;
}

nginx for load balancing

upstream is the address where the load balancing server is configured.
Implementing access to localhost:80 for load balancing access to 8080 and 8081 servers

upstream backserver { 
     server 127.0.0.1:8080; 
     server 127.0.0.1:8081; 
    } 

    server {
        listen       80;
        server_name localhost;
        location / {
		    proxy_pass  http://backserver; // This address should have the same name as the updatestream definition
			index  index.html index.htm;
        }
    }

Because nginx defaults to the load balancing strategy of rotation training, when visiting, each time visiting, visiting in turn is 8080 - > 8081 - 8080 - >. Server

nginx implements specified weights

Advantages of assigning weights: more work for the able

upstream backserver { 
     server 127.0.0.1:8080 weight=1; 
     server 127.0.0.1:8081 weight=3;
    } 

    server {
        listen       80;
        server_name  www.itmayiedu.com;
        location / {
		    proxy_pass  http://backserver;
			index  index.html index.htm;
        }
    }

The ratio of visits to nginx 8080 and 8081 is 1 to 3

Downtime fault tolerance of nginx

We have two servers in front of us, so there may be a situation that when we access 8080 server, the server is down, but in order to achieve the availability of the server, we can let him access 8081 instead of work at this time.
For example, the architect is ill today, and as a result, you are responsible for all the project problems.

 upstream backserver { 
         server 127.0.0.1:8080 weight=1; 
         server 127.0.0.1:8081 weight=3;
        } 
    
        server {
            listen       80;
            server_name  www.itmayiedu.com;
            location / {
    		    proxy_pass  http://backserver;
    			index  index.html index.htm;
    			proxy_connect_timeout 1; //Connection timeout
    			proxy_send_timeout 1; //Delivery timeout
    			proxy_read_timeout 1; // Read timeout
            }
        }

At this point in the access, there will be no matter how access, access servers are 8081 servers

nginx solves cross-domain problems

What is a cross-domain problem
When I was working in the company, I heard the interviewer next door ask this question, but the interviewer didn't seem to understand the cross-border problem very well. Instead, he asked the interviewer to explain it to him.
Simple cross-domain: Simply speaking, page a wants to obtain b page resources. If the protocol, domain name, port and sub-domain name of a and b pages are different, the access actions are cross-domain. For security reasons, browsers generally restrict cross-domain access, that is, cross-domain requests for resources are not allowed. Note: Cross-domain access restrictions are actually browser restrictions. It's important to understand this!!!
For example, now these two websites http://a.a.com:81/A and http://b.b.com:81/B conform to the above cross-domain problem. If the protocols, domain names, ports and sub-domain names of a and B pages are different, how can nginx be used to solve the cross-domain problem?

For example, one request is www.baidu.com/A and www.baidu.com/B.

server {
        listen       80;
        server_name  www.baidu.com;
        location /A {  //Note that there is a / a here.
		    proxy_pass  http://a.a.com:81/A;
			index  index.html index.htm;
        }
		location /B {
		    proxy_pass  http://b.b.com:81/B;
			index  index.html index.htm;
        }
    }

At www.baidu.com/A, you can visit http://a.a.com:81/A.
www.baidu.com/B has access to http://b.b.com:81/B;
How can we access http://b.b.com:81/B at www.baidu.com/A?

The answer is simple, although http://a.a.com:81/A; and http://b.b.com:81/B; cross-domain, but www.baidu.com/A and www.baidu.com/B do not exist.
When I visit www.baidu.com/A, I can directly request www.baidu.com/B to achieve cross-domain solutions.

nginx anti-theft chain

** Anti-theft Chain ** In order to protect website resources from theft, such as website videos and pictures, the general solution is to use F12 browser to find links directly for theft, how to solve this problem is the anti-theft chain to do.

For example, in my project, an image can be embezzled directly with the label < img href= "wwww.baidu.com/iamg.jpg">.

We only need to configure these in nginx

location ~ .*\.(jpg|jpeg|JPG|png|gif|icon)$ { //The main thing is that when accessing these suffixes, the world returns 403 to them.
        valid_referers blocked http://www.baidu.com www.baidu.com;
        if ($invalid_referer) {
            return 403;
        }
}