chushihua

node_modules/http-proxy-middleware/lib/handlers.js

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+var _ = require('lodash')
+var logger = require('./logger').getInstance()
+
+module.exports = {
+  init: init,
+  getHandlers: getProxyEventHandlers
+}
+
+function init(proxy, opts) {
+  var handlers = getProxyEventHandlers(opts)
+
+  _.forIn(handlers, function(handler, eventName) {
+    proxy.on(eventName, handlers[eventName])
+  })
+
+  logger.debug('[HPM] Subscribed to http-proxy events: ', _.keys(handlers))
+}
+
+function getProxyEventHandlers(opts) {
+  // https://github.com/nodejitsu/node-http-proxy#listening-for-proxy-events
+  var proxyEvents = [
+    'error',
+    'proxyReq',
+    'proxyReqWs',
+    'proxyRes',
+    'open',
+    'close'
+  ]
+  var handlers = {}
+
+  _.forEach(proxyEvents, function(event) {
+    // all handlers for the http-proxy events are prefixed with 'on'.
+    // loop through options and try to find these handlers
+    // and add them to the handlers object for subscription in init().
+    var eventName = _.camelCase('on ' + event)
+    var fnHandler = _.get(opts, eventName)
+
+    if (_.isFunction(fnHandler)) {
+      handlers[event] = fnHandler
+    }
+  })
+
+  // add default error handler in absence of error handler
+  if (!_.isFunction(handlers.error)) {
+    handlers.error = defaultErrorHandler
+  }
+
+  // add default close handler in absence of close handler
+  if (!_.isFunction(handlers.close)) {
+    handlers.close = logClose
+  }
+
+  return handlers
+}
+
+function defaultErrorHandler(err, req, res) {
+  var host = req.headers && req.headers.host
+  var code = err.code
+
+  if (res.writeHead && !res.headersSent) {
+    if (/HPE_INVALID/.test(code)) {
+      res.writeHead(502)
+    } else {
+      switch (code) {
+        case 'ECONNRESET':
+        case 'ENOTFOUND':
+        case 'ECONNREFUSED':
+          res.writeHead(504)
+          break
+        default:
+          res.writeHead(500)
+      }
+    }
+  }
+
+  res.end('Error occured while trying to proxy to: ' + host + req.url)
+}
+
+function logClose(req, socket, head) {
+  // view disconnected websocket connections
+  logger.info('[HPM] Client disconnected')
+}