Think about the role of some documents

1： Cross domain problem solving ？

In this project, I solve the cross domain problem caused by front-end access to the back-end , It's through proxy agent , stay vue.config Configuration inside proxy, In the development environment variable, I configured a VUE_BASE_URL_API=“lili“   At the same time, set the background port of his agent VUE_APP_SERVICE_URL
“http：//local host：3000”. Then I am proxy Pass through [prosses.env.VUE_BASE_URL_API] Get this proxy ID , Then here I set This target： And then in target It says the target address of my agent , That is, what I configured in the development environment VUE_APP_SERVICE_URL
And then in axios Inside, I also want to put the basic path baseurl become ”lili”, As soon as my front-end port is opened, I can access , Will bring /lili This logo , And then this proxy The proxy environment variable will send me to this target address

2： Why should the backstage pass npm init -y To install package.json ?

Defines the various modules required for this project , And the configuration information for the project （ Such as the name 、 edition 、 License and other data ）.npm install Command according to this configuration file , Automatically download the required modules , This is to configure the running and development environment required for the project .package.json Document enable npm You can start your project 、 Run script 、 Install dependencies 、 Publish to NPM Registry and many other useful tasks

3： install express,blueimp-md5 body-paser mongoose What's the use of backstage ？

express yes node.js The core framework of , Can quickly help us build web The server （ Interface ） To render the project for the backend ,api The server is to create an interface for the front end

blueimp-md5： Make a password md5 encryption

body-paser：express middleware , obtain post Request the submitted data

Then ask again what is a framework ？

An excellent framework , It is equivalent to a template code base , Many basic functions , The underlying functions and operations have been implemented for us , We just need to concentrate on implementing the required business logic .

4,node-modules What's in it ？

npm install After execution , We can do it in node_modules See all dependent packages , what express,mongodb,body-paser,webpack It's all here . To move / Copy / Packaging projects is relatively simple , For development 、 Deployment has benefits

Then I will open it backstage , Because there are many middleware , It's useless if it's not open

app.use("/node-module."express.static(path.join(__dirname,"./node-modules")))

5：post and get When to use ？

post For common resources , Processing forms , Add new data to the database , When adding data rows, use modify and write

get It is used when there are no side effects , It is conducive to adding data rows . For resource acquisition , Read