jack2/middleware/proxy.js

HTTP middleware for Node.js/Q-JSGI/JSGI2

var Q = require("q");
var Q_HTTP = require("q-http");

var LOG_REQUEST_PROPS = ["method", "host", "port", "path", "headers"];
var LOG_RESPONSE_PROPS = ["status", "headers"];

function logProperties(string, object, properties) {
    var items = [string];
    properties.forEach(function(name) { items.push(name, object[name]) })
    console.log.apply(console, items);
}

function Log(app) {
    return function(request) {
        logProperties("> ", request, LOG_REQUEST_PROPS);
        delete request.url;
        return Q.when(app(request), function(response) {
            logProperties("< ", response, LOG_RESPONSE_PROPS);
            return response;
        });
    }
}

var server = Q_HTTP.Server(Log(Cache(StripHopByHopHeaders(Q_HTTP.request))));
server.listen(4444);

function Cache(app) {
    var cache = {};
    return function(request) {
        // if (request.path in cache) {
        //     return cache[request.path];
        // } else {
            return Q.when(app(request), function(response) {
                var body = "";
                return Q.when(response.body.forEach(function(chunk) {
                    body += chunk;
                }), function() {
                    return cache[request.path] = {
                        status: response.status,
                        headers: response.headers,
                        body: [body]
                    };
                });
            });
        // }
    }
}

function StripHopByHopHeaders(app) {
    return function(request) {
        return Q.when(app(request), function(response) {
            HOP_BY_HOP_HEADERS.forEach(function(header) {
                delete response.headers[header];
            });
            return response;
        });
    }
}

var HOP_BY_HOP_HEADERS = [
    "Connection",
    "Keep-Alive",
    "Proxy-Authenticate",
    "Proxy-Authorization",
    "TE",
    "Trailers",
    "Transfer-Encoding",
    "Upgrade"
].map(function(header) { return header.toLowerCase(); });