waffle/lib/extensions/favicon.js

シンプルなWEBアプリケーションフレームワークです。(ALL YOUR NODE ARE BELONG TO US)

/*
 * Copyright 2012 Katsunori Koyanagi
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
/**
 * @overview 静的にfavicon.icoを返すコントローラのファクトリです。
 */

"use strict";

var crypto = require("crypto");
var fs = require("fs");

function md5(buf) {
	return crypto.createHash('md5').update(buf).digest('hex');
}

/**
 * 静的にfavicon.icoを返すコントローラを作成して返します。
 * 
 * @example <code>
 * var waffle = require("waffle");
 * config.router.on("/favicon", waffle.entensions.favicon("./public/favicon.ico"));
 * </code>
 * @function
 * @name Extensions#favicon
 * @param {String}
 *            path アプリケーションルートを起点としたfavicon.icoファイルのパス、省略時は内部のアイコンが使用される
 * @param {Number}
 *            maxAge キャッシュの生存時間を示すミリ秒の時間、省略時は1日(86400000ミリ秒)
 * @return {Function} コントローラ
 */
module.exports = function(path, maxAge) {
	var internal = false;
	if (!path) {
		path = fs.join(__dirname, "../assets/favicon.ico");
		internal = true;
	}
	maxAge = maxAge || 86400000;

	return (function(path, maxAge, internal) {
		var iconInfo = null;

		return function(context) {
			if (iconInfo !== null) {
				if (context.req.headers["if-none-match"] === iconInfo.headers.ETag
						|| Date.parse(context.req.headers['if-modified-since']) >= iconInfo.mtime) {
					context.res.writeHead(304, iconInfo.headers);
					context.complete();
					return;
				}

				context.res.writeHead(200, iconInfo.headers);
				context.res.end(iconInfo.data);
				context.complete();
				return;
			}

			var p = path;
			if (!internal) {
				p = fs.join(context.app.approot, path);
			}

			var stat = fs.stat(p, function(err, stats) {
				if (err) {
					context.error(404, err);
					return;
				}

				fs.readFile(p, function(err, buf) {
					if (err) {
						context.error(404, err);
						return;
					}

					iconInfo = {};
					iconInfo.headers = {
						"Content-Type" : "image/x-icon",
						"Content-Length" : buf.length,
						"ETag" : "\"" + md5(buf) + "\"",
						"Cache-Control" : "public, max-age=" + (maxAge / 1000)
					};
					iconInfo.mtime = stats.mtime.getTime();
					iconInfo.data = buf;
					context.res.writeHead(200, iconInfo.headers);
					context.res.end(iconInfo.data);
					context.complete();
				});
			});
		};
	})(path, maxAge, internal);
};