HTTP
What is HTTP
HTTP, Hypertext Transfer Protocol, is a response protocol that implements communication between a client and a server, and it is used as a request between a client and a server.
The client (browser) submits an HTTP request to the server; the server then returns a response to the client; the response contains status information about the request and may also contain the content of the request.
HTTP request method
Eight methods (sometimes called "actions") are defined in the HTTP/1.1 protocol to indicate different operation modes of resources specified by Request-URL
Among them:
HTTP1.0 defines three request methods: GET , POST and HEAD methods.
HTTP1.1 adds five new request methods: OPTIONS , PUT , DELETE , TRACE and CONNECT methods
The four most commonly used request methods: GET , POST , PUT , DELETE .
Get HTTP request parameters
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get get request
Choose one of the following two ways
let { id } = ctx.request.query
let { id } = ctx.query
example
const router = new Router({
prefix: '/user'
})
router.get('/del', async (ctx) => {
let { id } = ctx.request.query
console.log(id)
ctx.body = "删除用户"
})
send request
result
Example 2
const router = new Router({
prefix: '/user'
})
router.get('/del', async (ctx) => {
let { id } = ctx.query
console.log(id)
ctx.body = "删除用户"
})
send request
result
get post request
Use ctx.request.body (this method is wrong)
router.post('/add', async (ctx) => {
let {username,pwd} = ctx.request.body
console.log(username,pwd)
ctx.body = '添加用户'
})
send request
Note: It is obvious that a 500 error is reported here. Check the console and the error is as follows:
console display
Reason : ctx.request.body , this one doesn't exist.
Solution : Get the post request parameters. It is cumbersome to use native ones and needs to be converted. Use the middleware [ koa-bodyparser ] to get the post request parameters.
Use the middleware koa-bodyparser
Install middleware koa-bodyparser
npm install koa-bodyparser --save
Introduce the use of middleware
const bodyParser = require('koa-bodyparser')
app.use(bodyParser())
send request
result
Get routing parameters
let id = ctx.params.id
example
router.get('/find/:id', async (ctx) => {
let id = ctx.params.id
console.log(id)
ctx.body = '这是用户首页'
}
send request
result
full code
const koa = require('koa')
const bodyparser = require('koa-bodyparser')
const Router = require('koa-router')
const app = new koa()
const router = Router({
prefix: '/user'
})
app.use(bodyparser())
app.use(router.routes())
router.get('/', async (ctx) => {
ctx.set("Allow","GET,POST")
ctx.status = 301
ctx.body = {
code: 200,
msg: '这是请求首页的信息'
}
})
// 获取路由参数
router.get('/find/:id', async (ctx) => {
let id = ctx.params.id
console.log(id)
ctx.body = '这是用户首页'
})
// 获取get请求参数
router.get('/del', async (ctx) => {
let {id} = ctx.request.query
console.log(id)
ctx.body = '删除用户'
})
router.get('/del2', async (ctx) => {
let {id} = ctx.query
console.log(id)
ctx.body = '删除用户'
})
// 获取post请求参数
router.post('/add', async (ctx) => {
let {username,pwd} = ctx.request.body
console.log(username,pwd)
ctx.body = '添加用户'
})
app.listen(3000)
Summarize
- Get get request parameters:
ctx.request.queryorctx.query - Get post request parameters: use middleware [ koa-bodyparser ]
- Get routing parameters: use
ctx.params.xx to represent the required parameters