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'use strict'
const path = require('path')
const http = require('http')
const url = require('url')
const Koa = require('koa')
const convert = require('koa-convert')
const cors = require('kcors')
const _ = require('koa-route')
const pathToRegexp = require('path-to-regexp')
/**
* @module local-web-server
*/
module.exports = localWebServer
/**
* Returns a Koa application
*
* @param [options] {object} - options
* @param [options.static] {object} - koa-static config
* @param [options.static.root] {string} - root directory
* @param [options.static.options] {string} - [options](https://github.com/koajs/static#options)
* @param [options.serveIndex] {object} - koa-serve-index config
* @param [options.serveIndex.path] {string} - root directory
* @param [options.serveIndex.options] {string} - [options](https://github.com/expressjs/serve-index#options)
* @param [options.forbid] {string[]} - A list of forbidden routes, each route being an [express route-path](http://expressjs.com/guide/routing.html#route-paths).
* @param [options.spa] {string} - specify an SPA file to catch requests for everything but static assets.
* @param [options.log] {object} - [morgan](https://github.com/expressjs/morgan) config
* @param [options.log.format] {string} - [log format](https://github.com/expressjs/morgan#predefined-formats)
* @param [options.log.options] {object} - [options](https://github.com/expressjs/morgan#options)
* @param [options.compress] {boolean} - Serve gzip-compressed resources, where applicable
* @param [options.mime] {object} - A list of mime-type overrides, passed directly to [mime.define()](https://github.com/broofa/node-mime#mimedefine)
* @param [options.rewrite] {module:local-web-server~rewriteRule[]} - One or more rewrite rules
* @param [options.verbose] {boolean} - Print detailed output, useful for debugging
*
* @alias module:local-web-server
* @example
* const localWebServer = require('local-web-server')
* localWebServer().listen(8000)
*/
function localWebServer (options) {
options = Object.assign({
static: {},
serveIndex: {},
spa: null,
log: {},
compress: false,
mime: {},
forbid: [],
rewrite: [],
verbose: false
}, options)
const log = options.log
log.options = log.options || {}
const app = new Koa()
const _use = app.use
app.use = x => _use.call(app, convert(x))
function verbose (category, message) {
if (options.verbose) {
process.nextTick(() => app.emit('verbose', category, message))
}
}
app._verbose = verbose
if (options.verbose && !log.format) {
log.format = 'none'
}
/* CORS: allow from any origin */
app.use(cors())
/* rewrite rules */
if (options.rewrite && options.rewrite.length) {
options.rewrite.forEach(route => {
if (route.to) {
if (url.parse(route.to).host) {
verbose('proxy rewrite', `${route.from} -> ${route.to}`)
app.use(_.all(route.from, proxyRequest(route, app)))
} else {
const rewrite = require('koa-rewrite')
verbose('local rewrite', `${route.from} -> ${route.to}`)
app.use(rewrite(route.from, route.to))
}
}
})
}
/* path blacklist */
if (options.forbid.length) {
verbose('forbid', options.forbid.join(', '))
app.use(blacklist(options.forbid))
}
/* Cache */
if (!options['no-cache']) {
const conditional = require('koa-conditional-get')
const etag = require('koa-etag')
verbose('etag caching', 'enabled')
app.use(conditional())
app.use(etag())
}
/* mime-type overrides */
if (options.mime) {
verbose('mime override', JSON.stringify(options.mime))
app.use((ctx, next) => {
return next().then(() => {
const reqPathExtension = path.extname(ctx.path).slice(1)
Object.keys(options.mime).forEach(mimeType => {
const extsToOverride = options.mime[mimeType]
if (extsToOverride.indexOf(reqPathExtension) > -1) ctx.type = mimeType
})
})
})
}
/* compress response */
if (options.compress) {
const compress = require('koa-compress')
verbose('compression', 'enabled')
app.use(compress())
}
/* Logging */
if (log.format !== 'none') {
const morgan = require('koa-morgan')
if (!log.format) {
const streamLogStats = require('stream-log-stats')
log.options.stream = streamLogStats({ refreshRate: 500 })
app.use(morgan.middleware('common', log.options))
} else if (log.format === 'logstalgia') {
morgan.token('date', logstalgiaDate)
app.use(morgan.middleware('combined', log.options))
} else {
app.use(morgan.middleware(log.format, log.options))
}
}
/* serve static files */
if (options.static.root) {
const serve = require('koa-static')
verbose('static', `root: ${options.static.root} options: ${JSON.stringify(options.static.options)}` )
app.use(serve(options.static.root, options.static.options))
}
/* serve directory index */
if (options.serveIndex.path) {
const serveIndex = require('koa-serve-index')
verbose('serve-index', `root: ${options.serveIndex.path} options: ${JSON.stringify(options.serveIndex.options)}` )
app.use(serveIndex(options.serveIndex.path, options.serveIndex.options))
}
/* for any URL not matched by static (e.g. `/search`), serve the SPA */
if (options.spa) {
const send = require('koa-send')
verbose('SPA', options.spa)
app.use(_.all('*', function * () {
yield send(this, options.spa, { root: path.resolve(options.static.root) || process.cwd() })
}))
}
return app
}
function logstalgiaDate () {
var d = new Date()
return (`${d.getDate()}/${d.getUTCMonth()}/${d.getFullYear()}:${d.toTimeString()}`).replace('GMT', '').replace(' (BST)', '')
}
function proxyRequest (route, app) {
const httpProxy = require('http-proxy')
const proxy = httpProxy.createProxyServer({
changeOrigin: true
})
return function * proxyMiddleware () {
const next = arguments[arguments.length - 1]
const keys = []
route.re = pathToRegexp(route.from, keys)
route.new = this.path.replace(route.re, route.to)
keys.forEach((key, index) => {
const re = RegExp(`:${key.name}`, 'g')
route.new = route.new
.replace(re, arguments[index] || '')
})
/* test no keys remain in the new path */
keys.length = 0
pathToRegexp(route.new, keys)
if (keys.length) {
this.throw(500, `[PROXY] Invalid target URL: ${route.new}`)
return next()
}
this.response = false
app._verbose('proxy request', `from: ${this.path}, to: ${url.parse(route.new).href}`)
proxy.once('error', err => {
this.throw(500, `[PROXY] ${err.message}: ${route.new}`)
})
proxy.once('proxyReq', function (proxyReq) {
proxyReq.path = url.parse(route.new).path
})
proxy.web(this.req, this.res, { target: route.new })
}
}
function blacklist (forbid) {
return function blacklist (ctx, next) {
if (forbid.some(expression => pathToRegexp(expression).test(ctx.path))) {
ctx.throw(403, http.STATUS_CODES[403])
} else {
return next()
}
}
}
process.on('unhandledRejection', (reason, p) => {
throw reason
})
/**
* The `from` and `to` routes are specified using [express route-paths](http://expressjs.com/guide/routing.html#route-paths)
*
* @example
* ```json
* {
* "rewrite": [
* { "from": "/css/*", "to": "/build/styles/$1" },
* { "from": "/npm/*", "to": "http://registry.npmjs.org/$1" },
* { "from": "/:user/repos/:name", "to": "https://api.github.com/repos/:user/:name" }
* ]
* }
* ```
*
* @typedef rewriteRule
* @property from {string} - request route
* @property to {string} - target route
*/