Koa 代理http請求驱入,解決跨域問題
1昆烁、為什么用Koa做跨域代理吊骤?
"最初為了解決跨域問題,我把站點(diǎn)部署到了nginx上就解決了問題善玫。一次偶然的面試機(jī)會水援,面試官提出了一個(gè)假設(shè)我需要對提交api和api返回的數(shù)據(jù)進(jìn)行適配,那么nginx是不是就無法滿足了茅郎。當(dāng)然這個(gè)問題的提出蜗元,讓我考慮到其實(shí)如果自己搭一個(gè)站點(diǎn),通過這個(gè)站點(diǎn)進(jìn)行轉(zhuǎn)發(fā)系冗,適配第三方api的請求和應(yīng)答不就好了奕扣。那么要搭一個(gè)站點(diǎn)的語言其實(shí)有很多,例如.net,java,nodejs,php...掌敬,那為什么最后選擇nodejs呢惯豆?對于我來說最重要的原因池磁,應(yīng)該就是nodejs的輕量級和javascript語言親和性。
2楷兽、搭建nodejs應(yīng)用
由于Koa2剛出地熄,畢竟學(xué)技術(shù),那么就學(xué)最新的芯杀。
既然搭建程序那么就從程序的入口開始做端考,首先寫程序的路由
const fs = require('fs')
const Router = require('koa-router');
const {httpHandle} = require('../Infrastructure/httpHandle');
const koaBody = require('koa-body')({
multipart :true
});
const render = (page) => {
return new Promise((resolve, reject) => {
let viewUrl = `./view/${page}`
fs.readFile(viewUrl, "binary", (err, data) => {
if (err) {
reject(err)
} else {
resolve(data)
}
})
})
}
let api = new Router();
api.get('*', httpHandle)
.post('*', koaBody, httpHandle)
.put('*', koaBody, httpHandle).del('*', koaBody, httpHandle);
let common = new Router();
common.get('*', async (ctx) => {
ctx.body = await render('index.html');
})
let router = new Router();
router.use('/api', api.routes(), api.allowedMethods());
router.use('/', common.routes(), common.allowedMethods());
module.exports = router;
其次就是處理代理的請求
const httpRequest = (ctx) => {
return new Promise((resolve) => {
delete ctx.request.header.host;
const options = {
host,
port,
path: ctx.request.url.substr(4, ctx.request.url.length),
method: ctx.request.method,
headers: ctx.request.header
}
let requestBody='',
body,
head,
chunks = [],
fileFields,
files,
boundaryKey,
boundary,
endData,
filesLength,
totallength = 0;
if (ctx.request.body) {
console.log(ctx.request.header['content-type'])
if (ctx.request.header['content-type'].indexOf('application/x-www-form-urlencoded') > -1) {
requestBody = query.stringify(ctx.request.body);
options.headers['Content-Length'] = Buffer.byteLength(requestBody)
} else if (ctx.request.header['content-type'].indexOf('application/json') > -1) {
requestBody = JSON.stringify(ctx.request.body);
options.headers['Content-Length'] = Buffer.byteLength(requestBody)
} else if (ctx.request.header['content-type'].indexOf('multipart/form-data') > -1) {
fileFields = ctx.request.body.fields;
files = ctx.request.body.files;
boundaryKey = Math.random().toString(16);
boundary = `\r\n----${boundaryKey}\r\n`;
endData = `\r\n----${boundaryKey}--`;
filesLength = 0;
Object.keys(fileFields).forEach((key) => {
requestBody += `${boundary}Content-Disposition:form-data;name="${key}"\r\n\r\n${fileFields[key]}`;
})
Object.keys(files).forEach((key) => {
requestBody += `${boundary}Content-Type: application/octet-stream\r\nContent-Disposition: form-data; name="${key}";filename="${files[key].name}"\r\nContent-Transfer-Encoding: binary\r\n\r\n`;
filesLength += Buffer.byteLength(requestBody,'utf-8') + files[key].size;
})
options.headers['Content-Type'] = `multipart/form-data; boundary=--${boundaryKey}`;
options.headers[`Content-Length`] = filesLength + Buffer.byteLength(endData);
} else {
requestBody = JSON.stringify(ctx.request.body)
options.headers['Content-Length'] = Buffer.byteLength(requestBody)
}
}
const req = http.request(options, (res) => {
res.on('data', (chunk) => {
chunks.push(chunk);
totallength += chunk.length;
})
res.on('end', () => {
body = Buffer.concat(chunks, totallength);
head = res.headers;
resolve({head, body});
})
})
ctx.request.body && req.write(requestBody);
if (fileFields) {
let filesArr = Object.keys(files);
let uploadConnt = 0;
filesArr.forEach((key) => {
let fileStream = fs.createReadStream(files[key].path);
fileStream.on('end', () => {
fs.unlink(files[key].path);
uploadConnt++;
if (uploadConnt == filesArr.length) {
req.end(endData)
}
})
fileStream.pipe(req, {end: false})
})
} else {
req.end();
}
})
}
由此簡單的幾行代碼就實(shí)現(xiàn)了通過nodejs實(shí)現(xiàn)跨域的請求代理。 github鏈接
nginx代理config配置 如下
server {
listen 1024;
server_name tigrex:1024;
root home/TuoTuo.v2.UI;
index index.html;
access_log logs/tigrex.access.log;
error_log logs/tigrex.error.log;
charset utf-8;
location /api {
proxy_pass http://127.0.0.1:1023/;
proxy_set_header Host $host;
proxy_redirect off;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
location / {
try_files $uri $uri/ /index.html;
}
}