HTTP (Hypertext Transfer Protocol) is a protocol used to transmit hypertext on the Internet. It defines the communication rules between the client and the server. The HTTP protocol has evolved through multiple versions, of which HTTP1.0 and HTTP1.1 are two important versions. This article will explain the differences between them and why HTTP1.1 is more commonly used.
1. Persistent connection
In HTTP1.0, by default, each request/response needs to establish a separate connection, and the connection is closed immediately after the request is completed. This means that each request requires additional time to establish and close the connection, which is less efficient.
HTTP1.1 introduced the concept of persistent connections (Keep-Alive Connection), which allows multiple requests and responses to be transmitted on the same connection. This significantly reduces the overhead of connection establishment and closing, improving performance.
2. Pipeline
HTTP 1.1 also introduced a pipeline mechanism, allowing the client to send multiple requests without waiting for a response. This improves the efficiency of parallel requests and reduces latency.
// 代码
GET /page1 HTTP/1.1
Host: example.com
GET /page2 HTTP/1.1
Host: example.com
3. Caching
Cache control in HTTP1.0 is weak and usually relies on the Pragma header and Cache-Control header for control.
HTTP1.1 introduced a more powerful cache control mechanism, including the ETag and If-None-Match headers, as well as the Last-Modified and If-Modified-Since headers. These headers allow clients and servers to manage the caching of resources more efficiently.
// 代码
GET /page HTTP/1.1
Host: example.com
If-None-Match: "686897696a7c876b7e"
4. Error handling
HTTP1.1 provides more status codes to more accurately represent different response situations. For example, HTTP 1.1 introduced 100 Continue to indicate that the client can continue sending the request body without waiting for the server to fully process the request.
// 代码
HTTP/1.1 100 Continue
5. Host header
In HTTP1.0, the requested host information is usually included in the URL, for example:
// 代码
GET http://example.com/page HTTP/1.0
HTTP1.1 introduced the Host header, allowing multiple domain names to share the same IP address, thus realizing support for virtual hosts.
// 代码
GET /page HTTP/1.1
Host: example.com
in conclusion
HTTP1.1 brings many improvements over HTTP1.0, including persistent connections, pipelining, more powerful cache control, more status codes, and virtual host support. These improvements make HTTP1.1 more suitable for modern network environments and therefore more commonly used in practical applications. However, it should be noted that HTTP2 and HTTP3 have been launched, which have further improved performance and security, so these new versions should also be taken into consideration when choosing a protocol.