The actual combat of the beego framework of goweb development: Section III program execution process analysis

Perform process analysis

Go When a language executes, it executes main Under the bag init function ,main Function in turn . therefore , First find main.go file .

As shown above main.go The contents of the document , So how does the code execute ？ First ,import Imported two packages , One is routers, One is beego. And in the routers In front of the bag , You can see there's one “_”, This indicates the introduction of routers package , And implement init Method . Here is a knowledge point , Namely Go The execution of language , Here is a program execution flow chart ：

According to the picture above , We can know that the program first arrives at routers Package execution init Method . To router.go Take a look at the specific code ：

You can see in the router.go There's one in the file init Method , notice beego.Router() This code .router It means routing , The function of this function is to map URL To controller, The first parameter is URL ( The address requested by the user ), It's registered here /, That is, access without any parameters URL, The second parameter corresponds to Controller, The request will be distributed to that controller to execute the corresponding logic , Now go here and set up MainController Go and see what method there is ：

MainController Structures and functions are declared in default.go In file . And here's one Get Method , There are three lines of code in the method .

Accessed in the browser above is ：http://localhost:8080, This is a get request , When the request goes backstage , There are no request parameters , therefore , Will be “/” Intercept , Execute to MainController The code in , the reason being that get request , So here we automatically find Get Function and execute .

stay get In the function , There are three codes , The first two sentences c.Data[]= "" Indicates the data fields and contents returned by setting , The last sentence c.TplName Indicates that the setting handles the request and points to a template file , It points to index.tpl, that index.tpl Where are the documents ？ You can view the project directory structure , stay views below ,views Here are some template files .

• Template file
  A brief explanation , Most pages are static html+css+js Wait for these static code to layout the page , Page effect control, etc , The data of the page is represented by variables , such , When displaying the page , It can automatically fill in the value of the variable in the page ; These static code files are collectively referred to as template files . Each template file is just like a template , The style and effect are fixed , Just render and display according to different data .

beego.Run() Logic

init After the method analysis , The program will continue to run down , That's it main function , stay main Execute in function ：beego.Run() Code . Look at the Run Logic of code , stay Run Methods the internal , I did a few things ：

• 1） Parse configuration file , That's our app.conf file , Like ports , Application name and other information .
• 2） Check if it's on session, If open session, It initializes a session object .
• 3） Whether to compile templates ,beego When the project starts, the framework will change the configuration according to the configuration views All templates in the directory are precompiled , Then store it in map in , This can effectively improve the efficiency of template operation , There is no need to compile multiple times .
• 4） Listen to the service port . according to app.conf Port configuration in file , Start listening .