2021-03-01 15:06:11 +08:00

89 lines
2.2 KiB
JavaScript

/**
* Dependencies
*/
const { URL } = require('url')
const HttpProxy = require('http-proxy')
const pathMatch = require('path-match')
/**
* Constants
*/
const proxy = HttpProxy.createProxyServer()
const route = pathMatch({
// path-to-regexp options
sensitive: false,
strict: false,
end: false
})
let eventRegistered = false
/**
* Koa Http Proxy Middleware
*/
module.exports = (path, options) => (ctx, next) => {
// create a match function
const match = route(path)
if (!match(ctx.path)) return next()
let opts = Object.assign({}, options)
if (typeof options === 'function') {
const params = match(ctx.path)
opts = options.call(options, params)
}
// object-rest-spread is still in stage-3
// https://github.com/tc39/proposal-object-rest-spread
const { logs, rewrite, events } = opts
const httpProxyOpts = Object.keys(opts)
.filter(n => ['logs', 'rewrite', 'events'].indexOf(n) < 0)
.reduce((prev, cur) => {
prev[cur] = opts[cur]
return prev
}, {})
return new Promise((resolve, reject) => {
ctx.req.oldPath = ctx.req.url
if (typeof rewrite === 'function') {
ctx.req.url = rewrite(ctx.req.url, ctx)
}
if (logs) {
typeof logs === 'function' ? logs(ctx, opts.target) : logger(ctx, opts.target)
}
if (events && typeof events === 'object' && !eventRegistered) {
Object.entries(events).forEach(([event, handler]) => {
proxy.on(event, handler)
})
eventRegistered = true
}
// Let the promise be solved correctly after the proxy.web.
// The solution comes from https://github.com/nodejitsu/node-http-proxy/issues/951#issuecomment-179904134
ctx.res.on('close', () => {
reject(new Error(`Http response closed while proxying ${ctx.req.oldPath}`))
})
ctx.res.on('finish', () => {
resolve()
})
proxy.web(ctx.req, ctx.res, httpProxyOpts, e => {
const status = {
ECONNREFUSED: 503,
ETIMEOUT: 504
}[e.code]
ctx.status = status || 500
resolve()
})
})
}
module.exports.proxy = proxy
function logger (ctx, target) {
console.log('%s - %s %s proxy to -> %s', new Date().toISOString(), ctx.req.method, ctx.req.oldPath, new URL(ctx.req.url, target))
}