3.koa2请求数据

GET请求数据获取

koa获取GET请求数据是request对象中的query方法或者querystring方法，query返回是格式化好的参数对象，querystring返回的是请求的字符串。

• 1.从上下文中直接获取
  请求对象ctx.query
  请求字符串ctx.querystring
• 2.从上下文的request对象中获取
  请求对象ctx.request.query
  请求字符串ctx.request.querystring

const Koa = require('koa');
const app = new Koa();

app.use(async(ctx)=>{
    let url = ctx.url;
    let request = ctx.request;
    //从上下文的request对象中获取
    let req_query = request.query;
    let req_querystring = request.querystring
    //从上下文获取
    let ctx_query = ctx.query;
    let ctx_querystring = ctx.querystring
    ctx.body = {
        url,
        req_query,
        req_querystring,
        ctx_query,
        ctx_querystring
    }
})

app.listen(3000,()=>{
    console.log('get starting at 3000')
})

POST请求参数

需要解析上下文请求对象req，将POST表单解析成querystring，再讲querystring解析成json

//将POST请求参数字符串解析成JSON
const Koa = require('koa');
const app = new Koa();

app.use(async(ctx)=>{
    if(ctx.url === '/' && ctx.method === 'GET'){
        let html = `
            <h1>koa2 request post demo</h1>
            <form action="/" method='POST'>
                <p>userName</p>
                <input type="userName"/><br />
                <p>nickName</p>
                <input type="nickName"/><br/>
                <p>email</p>
                <input type="email"/><br />
                <button type='submit'>submit</button>
            </form>
        `;
        ctx.body = html;
    }else if(ctx.url === '/' && ctx.method === 'POST'){
        console.log(ctx);
        let poseData = await parsePostData(ctx);
        ctx.body = poseData;
    }else{
        ctx.body = '<h1>404!!!</h1>'
    }
})

app.listen(3000,()=>{
    console.log('starting 3000')
})


function parseQueryStr(querystr){
    let queryData = {};
    let queryStrList = querystr.split('&');
    console.log(queryStrList);

    for(let [index,querystr] of queryStrList.entries()){
        let itemList = querystr.split('=');
        console.log(itemList)
        queryData[itemList[0]]=decodeURIComponent(itemList[0])
    }
    return queryData
}


function parsePostData(ctx){
    return new Promise((resolve,reject)=>{
        try{
            let postdata = '';
            ctx.req.addListener('data',(data)=>{
                postdata+=data;
            })
            ctx.req.addListener('end',function(){
                let parseData = parseQueryStr(postdata)
                resolve(parseData);
            })
        }catch(err){
            reject(err)
        }
    })
}