How does nginx distinguish between http and port proxying?

When we use nginx as a proxy server, sometimes we need to do different processing for different requests, such as distinguishing whether it is a http request or a port proxy. Then nginx how to realize this distinction? Next, I'll describe in detail how nginx can distinguish between http and port proxies.

Configuring the server block
First, we need to configure the server block in the nginx configuration file to distinguish between http requests and port proxies. Here is a simple example:
"`nginx
server {
listen 80.
server_name example.com.
location / {
proxy_pass http://backend.
}
}

server {
listen 8080;
server_name example.com.
location / {
proxy_pass http://backend:8080.
}
}
“`
In the configuration above, we configured two server blocks that listen on ports 80 and 8080. When a request is received on port 80, nginx proxies the request to http://backend; when a request is received on port 8080, nginx proxies the request to http://backend:8080.

Using the map module
In addition to configuring the server block, we can also use the nginx map module to differentiate between http requests and port proxies. map module can be mapped to another value based on the value of the variable, thus enabling different processing logic.

Here is an example of using the map module:
"`nginx
http {
map $server_port $backend {
default backend.
8080 backend:8080.
}

server {
listen 80.
server_name example.com.
location / {
proxy_pass http://$backend.
}
}
}
“`
In the configuration above, we used the map module to map to different $backend values based on the value of $server_port. When $server_port is 80, the value of $backend is backend; when $server_port is 8080, the value of $backend is backend:8080. this achieves the function of distinguishing between http requests and port proxies.

Using if Conditional Statements
In addition to the map module, we can also use nginx's if conditional statements to differentiate between http requests and port proxies. if conditional statements can perform different processing logic based on conditions.

Here is an example of using an if conditional statement:
"`nginx
server {
listen 80.
server_name example.com.
location / {
if ($server_port = 8080) {
proxy_pass http://backend:8080.
break;
}
proxy_pass http://backend.
}
}
“`
In the above configuration, we use the if conditional statement to determine whether the value of $server_port is 8080, if so then the request is proxied to http://backend:8080, otherwise the request is proxied to http://backend. By doing so, we can also realize the differentiation between the http request and the port proxying function.

summarize
Through the above introduction, we can see that nginx has a variety of ways to realize the function of distinguishing between http requests and port proxies, such as configuring server blocks, using the map module, using if conditional statements and so on. Different ways are applicable to different scenarios, we can choose the appropriate way to realize the function of distinguishing between http requests and port proxies according to the actual needs.

I hope the above is helpful, and if there are any other questions, please feel free to leave a comment to discuss.