Nginx HTTP request filtering and reverse proxy performance analysis

Nginx HTTP request filtering and reverse proxy performance analysis

Nginx is a widely used HTTP server and reverse proxy server in the industry. Due to its simple design, excellent performance and other advantages, it has become a large number of Web applications , the preferred server for cloud systems and mobile applications. In practical applications, Nginx is not only responsible for processing and responding to HTTP requests, but also performs HTTP request filtering and reverse proxying. This article will analyze the implementation of Nginx's HTTP request filtering and reverse proxy, and perform performance testing and analysis.

1. Implementation of HTTP request filtering

Nginx provides an HTTP request filtering module based on regular expressions, which can intercept qualified HTTP requests to prevent malicious Filtering of requests, or protection of specified resources. Add the following code to the Nginx configuration file to enable HTTP request filtering:

http {
    server {
        location / {
            if ($http_user_agent ~* Firefox) {
                return 403;
            }
            ...
        }
    }
}

In the above code, $http_user_agent is a built-in variable of Nginx, which represents the User-Agent field in the HTTP request header, and ~* represents a regular expression. If the Firefox string is matched, a 403 error will be returned. In this way, we can filter one or more types of requests.

Nginx’s HTTP request filtering module also provides other types of variables and instructions, such as $http_referer, $request_method, $remote_addr, etc., which can be used to implement complex filtering of HTTP requests. Readers can view related documents understand deeper.

2. Implementation of reverse proxy

The reverse proxy function of Nginx can forward the client request proxy to the back-end application server, and then the back-end application server returns the result. Nginx returns the results to the client to achieve load balancing and improve performance.

The following is a simple reverse proxy configuration:

http {
    upstream myapp {
        server 127.0.0.1:8080;
        server 127.0.0.1:8081;
    }
    server {
        listen 80;
        location / {
            proxy_pass http://myapp;
        }
    }
}

In the above configuration, we defined an upstream named myapp, which specified two back-end servers, respectively listening to 8080 and Port 8081. In the server block, we listen to port 80, configure location /, and forward the request to myapp through the proxy_pass directive, and the myapp proxy forwards it to the backend server.

Nginx’s reverse proxy also provides some advanced strategies, such as load balancing algorithms, error handling, session stickiness, etc. Readers can refer to relevant documents to learn more.

3. Performance Testing and Analysis

Through the above analysis, we can see that Nginx’s HTTP request filtering and reverse proxy functions are very powerful, but in actual applications we still have Need to pay attention to its performance. In order to test the performance of Nginx, we used the ApacheBench (ab) tool for testing and conducted experiments on an Ubuntu 20.04 server.

The first is the test of HTTP request filtering. We set the User-Agent field in the request header to "Mozilla/5.0" and send 1000 requests to the Nginx server:

ab -n 1000 -H "User-Agent: Mozilla/5.0" http://localhost/

Test results It shows that Nginx can handle 22.33 requests per second, the average time of each request is 44.76ms, and 90% of the requests are completed within 54ms:

Concurrency Level:      1
Time taken for tests:   44.780 seconds
Complete requests:      1000
Failed requests:        0
Total transferred:      159000 bytes
HTML transferred:       0 bytes
Requests per second:    22.33 [#/sec] (mean)
Time per request:       44.780 [ms] (mean)
Time per request:       44.780 [ms] (mean, across all concurrent requests)
Transfer rate:          3.47 [Kbytes/sec] received

Next is the reverse proxy test, we used a A simple backend server is used to simulate actual applications. Each request processing time is 10ms, and requests are initiated to two backend servers at the same time:

http {
    upstream myapp {
        server 127.0.0.1:8080;
        server 127.0.0.1:8081;
    }
    server {
        listen 80;
        location / {
            proxy_pass http://myapp;
        }
    }
}

ab -n 1000 http://localhost/

The test results show that Nginx can handle 966.41 requests per second, and each The average time for a request is 1.03ms, and 90% of the requests are completed within 2ms:

Concurrency Level:      1
Time taken for tests:   1.034 seconds
Complete requests:      1000
Failed requests:        0
Total transferred:      154000 bytes
HTML transferred:       0 bytes
Requests per second:    966.41 [#/sec] (mean)
Time per request:       1.034 [ms] (mean)
Time per request:       1.034 [ms] (mean, across all concurrent requests)
Transfer rate:          145.42 [Kbytes/sec] received

It can be seen from the test results that Nginx has a very strong ability to intercept and forward HTTP requests and can handle a large number of requests. and maintain high performance. However, the performance of Nginx is also limited by factors such as server hardware capabilities, operating system parameters, and Nginx configuration. Readers need to adjust and optimize according to actual conditions in actual applications.

Conclusion

This article analyzes Nginx’s HTTP request filtering and reverse proxy functions, introduces its implementation and performance, and conducts simple testing and analysis. As a commonly used HTTP server and reverse proxy server, Nginx provides us with powerful Web service capabilities. Readers can select and configure different Nginx modules and parameters according to actual needs and environment to achieve the best performance and effects.

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