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This article mainly introduces "detailed introduction of HTTP and HTTP collaboration Web server access process". In daily operation, I believe many people have doubts about the detailed introduction of HTTP and HTTP collaboration Web server access process. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "detailed introduction of Web server access process of HTTP and HTTP collaboration". Next, please follow the editor to study!

A web server can build web websites with multiple independent domain names, and it can also be used as a transit server on the communication path to improve transmission efficiency.

1. Using a single virtual host to realize multiple domain names

The HTTP/1.1 specification allows one HTTP server to build multiple web sites.

Even if there is only one server at the physical level, as long as you use the function of a virtual host, you can assume that you already have multiple servers.

On the Internet, the domain name is mapped to the IP address (domain name resolution) through the DNS service and then visits the target website. It can be seen that when the request is sent to the server, it is already accessed in the form of an IP address.

So, if the two domain names www.tricorder.jp and www.hackr.jp are hosted on a server, you need to figure out which domain name to access when you receive a request.

Under the same IP address, because the virtual host can host multiple web websites with different host names and domain names, when sending HTTP requests, the URI of the host name or domain name must be fully specified in the header of the Host.

Communication data forwarding programs: agents, gateways, tunnels

These applications and servers can forward the request to the next station server on the communication line and receive the response from that server and forward it to the client.

① proxy: the basic behavior of a proxy server is to receive a request from a client and forward it to another server. The agent does not change the request URI and will send it directly to the target server that holds the resource ahead. The server that holds the resource entity is called the source server. The response returned from the source server passes through the proxy server and then passes to the client.

The reasons for using the proxy server are: the use of caching technology to reduce network bandwidth traffic, the organization's internal access control for specific websites, access logs as the main purpose, and so on.

Proxies can be used in several ways:

Cache proxy:

When the agent forwards the response, the cache agent saves a copy of the resource on the proxy server in advance. When the agent receives a request for the same resource again, it can return the previously cached resource as a response instead of getting the resource from the source server.

Transparent proxy:

When forwarding a request or response, the type of agent that does not do any processing on the message is called a transparent proxy. On the contrary, the agent that processes the content of the message is called an opaque agent.

② gateways: gateways work very much like proxies. The gateway enables the server on the communication line to provide non-HTTP protocol services. The use of the gateway can provide communication security because it can be encrypted on the communication line between the client and the gateway to ensure the security of the connection.

③ tunnel: the tunnel can establish a communication line with other servers as required, and then use encryption methods such as SSL to communicate. The purpose of the tunnel is to ensure that the client can communicate securely with the server.

The tunnel itself does not parse the HTTP request. That is, the request is left intact and transferred to the later server. The tunnel ends when both sides of the communication are disconnected.

Third, save the cache of resources

Caching refers to a copy of a resource saved on the local disk of a proxy server or client. Caching reduces access to the server, thus saving traffic and communication time.

The cache server is one of the proxy servers and is classified as a cache proxy type.

The validity period of the ① cache

Caching for ② clients

At this point, the study on the "detailed introduction of the Web server access process of HTTP and HTTP collaboration" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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