rewrite and examples.. refactor

lib/local-web-server.js

@@ -6,7 +6,6 @@ const Koa = require('koa')
 const convert = require('koa-convert')
 const cors = require('kcors')
 const _ = require('koa-route')
-const mount = require('koa-mount')
 const pathToRegexp = require('path-to-regexp')
 
 /**
@@ -43,63 +42,32 @@ function localWebServer (options) {
   const _use = app.use
   app.use = x => _use.call(app, convert(x))
 
-
-  /* Proxy routes */
-  if (options.proxyRoutes.length) {
-    const httpProxy = require('http-proxy')
-    const proxy = httpProxy.createProxyServer({
-      changeOrigin: true
-    })
-    options.proxyRoutes.forEach(route => {
-      app.use(_.all(route.from, function * () {
-        const keys = []
-        route.re = pathToRegexp(route.from, keys)
-        route.new = route.to
-
-        this.response = false
-        keys.forEach((key, index) => {
-          const re = {
-            token: RegExp('\\$\\{' + key.name + '\\}', 'g'),
-            index: RegExp('\\$\\{' + index + '\\}', 'g')
-          }
-          route.new = route.new
-            .replace(re.token, arguments[index] || '')
-            .replace(re.index, arguments[index] || '')
-        })
-        proxy.once('proxyReq', function (proxyReq) {
-          proxyReq.path = url.parse(route.new).path;
-        })
-        proxy.web(this.req, this.res, { target: route.new })
-      }))
-    })
-  }
-
-  /* Rewrite rules */
-  if (options.rewrite && options.rewrite.length) {
-    const rewrite = require('koa-rewrite')
-    options.rewrite.forEach(rule => {
-      app.use(rewrite(rule.from, rule.to))
-    })
-  }
-
   /* CORS: allow from any origin */
   app.use(cors())
 
-  /* path blacklist */
-  if (options.forbid.length) {
-    app.use(function blacklist (ctx, next) {
-      if (options.forbid.some(regexp => regexp.test(ctx.path))) {
-        ctx.throw(403, http.STATUS_CODES[403])
-      } else {
-        return next()
+  /* rewrite rules */
+  if (options.rewrite && options.rewrite.length) {
+    options.rewrite.forEach(route => {
+      if (route.to) {
+        if (url.parse(route.to).host) {
+          app.use(_.all(route.from, proxyRequest(route)))
+        } else {
+          const rewrite = require('koa-rewrite')
+          app.use(rewrite(route.from, route.to))
+        }
       }
     })
   }
 
+  /* path blacklist */
+  if (options.forbid.length) {
+    app.use(blacklist(options.forbid))
+  }
+
   /* Cache */
   if (!options['no-cache']) {
-    const conditional = require('koa-conditional-get');
-    const etag = require('koa-etag');
+    const conditional = require('koa-conditional-get')
+    const etag = require('koa-etag')
     app.use(conditional())
     app.use(etag())
   }
@@ -168,6 +136,54 @@ function logstalgiaDate () {
     .replace(' (BST)', '')
 }
 
+function proxyRequest (route) {
+  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}`)
+      yield next
+    }
+
+    this.response = false
+
+    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(regexp => regexp.test(ctx.path))) {
+      ctx.throw(403, http.STATUS_CODES[403])
+    } else {
+      return next()
+    }
+  }
+}
+
 process.on('unhandledRejection', (reason, p) => {
   throw reason
 })