table of Contents
principle:
For processing POST request, koa2 no method for acquiring parameters of the package, need to request the object req by parsing the context as the native Node.js, a POST form data parsed into query string (for example: a = 1 & b = 2 & c = 3), then parse the query string into JSON format (e.g.: { "a": "1", "b": "2", "c": "3"})
note:
ctx.request request object is encapsulated in context, ctx.req native node.js is the HTTP request object to provide context, a context Similarly ctx.response response object after encapsulation, ctx.res context is provided native node.js HTTP request object.
Example:
const Koa = require('koa')
const app = new Koa()
app.use( async ( ctx ) => {
if ( ctx.url === '/' && ctx.method === 'GET' ) {
// 当GET请求时候返回表单页面
let html = `
<h1>koa2 request post demo</h1>
<form method="POST" action="/">
<p>userName</p>
<input name="userName" /><br/>
<p>nickName</p>
<input name="nickName" /><br/>
<p>email</p>
<input name="email" /><br/>
<button type="submit">submit</button>
</form>
`
ctx.body = html
} else if ( ctx.url === '/' && ctx.method === 'POST' ) {
// 当POST请求的时候,解析POST表单里的数据,并显示出来
let postData = await parsePostData( ctx )
ctx.body = postData
} else {
// 其他请求显示404
ctx.body = '<h1>404!!! o(╯□╰)o</h1>'
}
})
/**
* 解析上下文里node原生请求的post参数
* */
function parsePostData(ctx){
return new Promise((resolve,reject)=>{
try {
console.log(ctx.req === ctx.request)
let postData = '';
ctx.req.addListener('data',(data)=>{
postData += data;
})
ctx.req.addListener('end',()=>{
let parseData = parseQueryStr(postData);
resolve(parseData)
})
}catch (err) {
reject(err)
}
})
}
/**
* 将POST请求的参数字符串解析成json
*/
function parseQueryStr(queryStr) {
console.log('queryStr',queryStr)
let queryData = {};
let queryStrList = queryStr.split('&');
console.log(queryStrList);
for(let [index,queryStr] of queryStrList.entries()){
console.log(index,queryStr)
let itemList = queryStr.split('=');
queryData[itemList[0]] = decodeURIComponent(itemList[1]);
}
return queryData
}
app.listen(3000, () => {
console.log('[demo] request post is starting at port 3000')
})