HTTP protocol Overview

Testing industry from the initial manual testing development to today basically has formed two major directions, one is the direction of business experts, the second is the direction of testing development, business experts require the overall framework of the system and data flow industry is very familiar with the test development requirements can be self-developed testing tools, build a test framework to replace pure manual testing, To achieve such a level of at least three years development experience, in the test development of this piece of fire or popular is the interface Automation testing, the next series of essays will tell the Python interface automation testing needs to master the knowledge, will also add some actual combat content, I hope you have patience to see.

Today's Web program development technology is a great contention, Asp.net,php,jsp,perl,ajax, there are now more popular Python,django. But regardless of how web technologies evolve in the future, it is important to understand the basic protocols for communicating between web programs, because it gives us an understanding of how the Web application works internally. Understand the Web program working principle is to carry out the basis of interface testing, this article mainly on the HTTP protocol detailed strength to explain, the content is more complex, I hope you look patiently, but also hope that everyone's testing work is helpful, using the Fiddler tool is very convenient to capture the HTTP Request and HTTP Response, about the use of the Fiddler tool, will be detailed in the following articles, in this article with you in conjunction with fiddler tools to learn the HTTP protocol.

First, what is the HTTP protocol

So, so many people will ask what is the HTTP protocol? Protocol refers to the rules or rules that must be adhered to in communication between two computers in a computer communication network, Hypertext Transfer Protocol (HTTP) is a communication protocol that allows Hypertext Markup Language (HTML) documents to be delivered from a Web server to the client's browser. In order to let everyone better understand, the following approximate introduction of the network communication Five layer architecture:

The above is just a simple introduction, want to learn more about Baidu can be their own, haha, in fact, I do not understand.

As can be seen above, HTTP is the Web Application Layer Hypertext Transfer Protocol, currently we are using the http/1.1 version

Second, Web server, browser, proxy server

Why do we open the browser while surfing the Internet, enter the URL in the Address bar, and then we can see the page, what is the principle?

In fact, after we enter the URL, our browser sends a Request,web server to the Web server to process the request, generate the response, then send it to the browser, the browser parses the HTML in response, so we can see the page , as shown in the procedure

It is possible that our request was passed through a proxy server and finally arrived at the Web server, as shown in the following procedure:

Proxy Server is a transit point of network information, what is the function?

1. Improve access speed, most of the proxy server has the cache function.

2. Break the limit, that's FQ.

3. Hide identities.

HTTP protocol Overview