proxy.js

var request = require('request');
var http = require('http');
var cacheDir = __dirname + '/fileCache';
var fs = require('fs-extra');
var url = require('url');
var path = require('path');
var mime = require('mime');
mime.default_type = -1;
var server = http.createServer(function (req, resp) {
    var urlparse = url.parse(req.url);
    var modTime = req.headers['If-Modified-Since'] || req.headers['if-modified-since'];
    if (urlparse.pathname === '/cleanCache') {
        cleanAllCache(function () {
            resp.writeHead(200);
            resp.end('ok');
        });
        return;
    }
    if (urlparse.pathname.lastIndexOf('/') !== urlparse.pathname.length - 1) {
        var lastPath = urlparse.pathname.split('/').pop();
        var a = mime.lookup(lastPath);
        console.log(lastPath, a);
        if (a === -1) {
            resp.writeHead(302, {
                'Location': urlparse.pathname + '/'
            });
            resp.end();
            return;
        }
    }
    checkMod(urlparse.pathname, modTime, function (hasMod) {
        if (!hasMod) {
            resp.writeHead(304);
            resp.end();
            return;
        }
        getCache(urlparse.pathname, function (err, stream) {
            if (err) {
                var content = [];
                var x = request({
                    url: 'http://fex-team.github.io' + urlparse.pathname,
                    method: req.method,
                    qs: urlparse.query
                }, function (error, response, body) {
                    if (error) {
                        resp.statusCode = 500;
                        resp.end('remote fetch failed');
                        return;
                    }
                    //console.log(urlparse.pathname, response.statusCode);
                    if (response.statusCode === 200) {
                        setCache(urlparse.pathname, Buffer.concat(content), function (err) {
                            err && console.log('set cache err', err);
                        });
                        setCacheHeaders(urlparse.pathname, response.headers, function (err) {
                            err && console.log('set cache header err', err);
                        });
                    }
                }).on('error', function (error) {
                    resp.statusCode = 500;
                    resp.end('remote fetch failed');
                }).on('response', function (response) {
                    //console.log(urlparse.pathname, response.statusCode);
                    if (response.statusCode === 200) {
                        response.on('data', function (data) {
                            content.push(data);
                        });
                    }
                });
                delete req.headers['If-Modified-Since'];
                delete req.headers['if-modified-since'];
                delete req.headers.host;
                req.pipe(x);
                x.pipe(resp);
            } else {
                getCacheHeaders(urlparse.pathname, function (err, headers) {
                    if (err) {
                        cleanCache(urlparse.pathname);
                        resp.statusCode = 500;
                        resp.end('cache fetch failed');
                        return;
                    }
                    //console.log(urlparse.pathname, 'pipe cache');
                    headers['bae_cache'] = 1;
                    resp.writeHead(200, headers);
                    stream.pipe(resp);
                });
            }
        });
    });
});

server.listen(18080);

function cleanAllCache(cb) {
    fs.remove(cacheDir, cb);
}

function cleanCache(url, cb) {
    url = fixName(url);
    var file = cacheDir + url;
    fs.remove(file);
}

function checkMod(url, mod, cb) {
    url = fixName(url);
    var file = cacheDir + url;
    fs.readJson(file + '.headers', function (err, headers) {
        if (err) {
            cb(true);
            return;
        }
        var modTime = headers['Last-Modified'] || headers['last-modified'];
        if (modTime === mod) {
            cb(false);
        } else {
            cb(true);
        }
    });
}

function getCache(url, cb) {
    url = fixName(url);
    var file = cacheDir + url;
    fs.stat(file, function (err, stats) {
        if (err) return cb(true);
        if (stats.isDirectory()) {
            console.log(file + ' is directory');
            cb(true);
        } else {
            cb(null, fs.createReadStream(file));
        }
    });
}

function setCache(url, content, cb) {
    url = fixName(url);
    var file = cacheDir + url;
    fs.outputFile(file, content, cb);
}

function setCacheHeaders(url, headers, cb) {
    url = fixName(url);
    var file = cacheDir + url;
    fs.outputJson(file + '.headers', headers, cb);
}

function getCacheHeaders(url, cb) {
    url = fixName(url);
    var file = cacheDir + url;
    fs.readJson(file + '.headers', cb);
}

function fixName(url) {
    if (url.lastIndexOf('/') === url.length - 1) {
        return url + path.sep + 'index.html';
    } else {
        return url;
    }
}