aaac7fed
 liuqimichale
add
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var _ = require('lodash');
var httpProxy = require('http-proxy');
var configFactory = require('./config-factory');
var handlers = require('./handlers');
var contextMatcher = require('./context-matcher');
var PathRewriter = require('./path-rewriter');
var Router = require('./router');
var logger = require('./logger').getInstance();
var getArrow = require('./logger').getArrow;
module.exports = HttpProxyMiddleware;
function HttpProxyMiddleware(context, opts) {
// https://github.com/chimurai/http-proxy-middleware/issues/57
var wsUpgradeDebounced = _.debounce(handleUpgrade);
var wsInitialized = false;
var config = configFactory.createConfig(context, opts);
var proxyOptions = config.options;
// create proxy
var proxy = httpProxy.createProxyServer({});
logger.info('[HPM] Proxy created:', config.context, ' -> ', proxyOptions.target);
var pathRewriter = PathRewriter.create(proxyOptions.pathRewrite); // returns undefined when "pathRewrite" is not provided
// attach handler to http-proxy events
handlers.init(proxy, proxyOptions);
// log errors for debug purpose
proxy.on('error', logError);
// https://github.com/chimurai/http-proxy-middleware/issues/19
// expose function to upgrade externally
middleware.upgrade = wsUpgradeDebounced;
return middleware;
function middleware(req, res, next) {
if (shouldProxy(config.context, req)) {
var activeProxyOptions = prepareProxyRequest(req);
proxy.web(req, res, activeProxyOptions);
} else {
next();
}
if (proxyOptions.ws === true) {
// use initial request to access the server object to subscribe to http upgrade event
catchUpgradeRequest(req.connection.server);
}
}
function catchUpgradeRequest(server) {
// subscribe once; don't subscribe on every request...
// https://github.com/chimurai/http-proxy-middleware/issues/113
if (!wsInitialized) {
server.on('upgrade', wsUpgradeDebounced);
wsInitialized = true;
}
}
function handleUpgrade(req, socket, head) {
// set to initialized when used externally
wsInitialized = true;
if (shouldProxy(config.context, req)) {
var activeProxyOptions = prepareProxyRequest(req);
proxy.ws(req, socket, head, activeProxyOptions);
logger.info('[HPM] Upgrading to WebSocket');
}
}
/**
* Determine whether request should be proxied.
*
* @private
* @return {Boolean}
*/
function shouldProxy(context, req) {
var path = (req.originalUrl || req.url);
return contextMatcher.match(context, path, req);
}
/**
* Apply option.router and option.pathRewrite
* Order matters:
Router uses original path for routing;
NOT the modified path, after it has been rewritten by pathRewrite
*/
function prepareProxyRequest(req) {
// https://github.com/chimurai/http-proxy-middleware/issues/17
// https://github.com/chimurai/http-proxy-middleware/issues/94
req.url = (req.originalUrl || req.url);
// store uri before it gets rewritten for logging
var originalPath = req.url;
var newProxyOptions = _.assign({}, proxyOptions);
// Apply in order:
// 1. option.router
// 2. option.pathRewrite
__applyRouter(req, newProxyOptions);
__applyPathRewrite(req, pathRewriter);
// debug logging for both http(s) and websockets
if (proxyOptions.logLevel === 'debug') {
var arrow = getArrow(originalPath, req.url, proxyOptions.target, newProxyOptions.target);
logger.debug('[HPM] %s %s %s %s', req.method, originalPath, arrow, newProxyOptions.target);
}
return newProxyOptions;
}
// Modify option.target when router present.
function __applyRouter(req, options) {
var newTarget;
if (options.router) {
newTarget = Router.getTarget(req, options);
if (newTarget) {
logger.debug('[HPM] Router new target: %s -> "%s"', options.target, newTarget);
options.target = newTarget;
}
}
}
// rewrite path
function __applyPathRewrite(req, pathRewriter) {
if (pathRewriter) {
var path = pathRewriter(req.url, req);
if (typeof path === 'string') {
req.url = path;
} else {
logger.info('[HPM] pathRewrite: No rewritten path found. (%s)', req.url);
}
}
}
function logError(err, req, res) {
var hostname = (req.headers && req.headers.host) || (req.hostname || req.host); // (websocket) || (node0.10 || node 4/5)
var target = proxyOptions.target.host || proxyOptions.target;
var errReference = 'https://nodejs.org/api/errors.html#errors_common_system_errors'; // link to Node Common Systems Errors page
logger.error('[HPM] Error occurred while trying to proxy request %s from %s to %s (%s) (%s)', req.url, hostname, target, err.code, errReference);
}
};
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