详解用node-images 打造简易图片服务器

var http = require('http'); var url = require('url'); var siteUrl = url.parse('http://img1.gtimg.com/view/pics/hv1/42/80/2065/134297067.jpg');  request = http.request({   method : 'HEAD',   port: siteUrl.port || 80,   host: siteUrl.host,   path : siteUrl.pathname }); request.on('response', function (response) {   response.setEncoding('utf8');   console.log(response.headers['content-length']); }); request.end(); 

npm install images 

// 配置对象。 var staticFileServer_CONFIG = {   'host': '127.0.0.1',      // 服务器地址   'port': 3000,        // 端口   'site_base': 'C:/project/bigfoot',   // 根目录，虚拟目录的根目录   'file_expiry_time': 480,    // 缓存期限 HTTP cache expiry time, minutes   'directory_listing': true    // 是否打开 文件 列表 }; 

const   HTTP = require('http'), PATH = require('path'), fs = require('fs'), CRYPTO = require('crypto'),   url = require("url"), querystring = require("querystring"),   Step = require('./step'), images = require("images");  // 配置对象。 var staticFileServer_CONFIG = {   'host': '127.0.0.1',      // 服务器地址   'port': 3001,            // 端口   'site_base': 'C:/project/bigfoot',     // 根目录，虚拟目录的根目录   'file_expiry_time': 480,    // 缓存期限 HTTP cache expiry time, minutes   'directory_listing': true    // 是否打开 文件 列表 };  const server = HTTP.createServer((req, res) => {   init(req, res, staticFileServer_CONFIG); });  server.listen(staticFileServer_CONFIG.port, staticFileServer_CONFIG.host, () => {   console.log(`Image Server running at http://${staticFileServer_CONFIG.host}:${staticFileServer_CONFIG.port}/`); });  // 当前支持的 文件类型，你可以不断扩充。 var MIME_TYPES = {   '.txt': 'text/plain',   '.md': 'text/plain',   '': 'text/plain',   '.html': 'text/html',   '.css': 'text/css',   '.js': 'application/javascript',   '.json': 'application/json',   '.jpg': 'image/jpeg',   '.png': 'image/png',   '.gif': 'image/gif' };  MIME_TYPES['.htm'] = MIME_TYPES['.html'];  var httpEntity = {   contentType: null,   data: null,   getHeaders: function (EXPIRY_TIME) {     // 返回 HTTP Meta 的 Etag。可以了解 md5 加密方法     var hash = CRYPTO.createHash('md5');     //hash.update(this.data);     //var etag = hash.digest('hex');      return {       'Content-Type': this.contentType,       'Content-Length': this.data.length,       //'Cache-Control': 'max-age=' + EXPIRY_TIME,       //'ETag': etag     };   } };  function init(request, response) {   var args = url.parse(request.url).query,     //arg => name=a&id=5      params = querystring.parse(args);    if (params.url) {     getRemoteImg(request, response, params);   } else {     load_local_img(request, response, params);   } }  // 加载远程图片 function getRemoteImg(request, response, params) {   var imgData = ""; // 字符串   var size = 0;   var chunks = [];    Step(function () {       HTTP.get(params.url, this);     },     function (res) {       var maxLength = 10; // 10mb       var imgData = "";       if (res.headers['content-length'] > maxLength * 1024 * 1024) {         server500(response, new Error('Image too large.'));       } else if (!~[200, 304].indexOf(res.statusCode)) {         server500(response, new Error('Received an invalid status code.'));       } else if (!res.headers['content-type'].match(/image/)) {         server500(response, new Error('Not an image.'));       } else {         // res.setEncoding("binary"); //一定要设置response的编码为binary否则会下载下来的图片打不开         res.on("data", function (chunk) {           // imgData+=chunk;           size += chunk.length;           chunks.push(chunk);         });          res.on("end", this);       }            },     function () {        imgData = Buffer.concat(chunks, size);            var _httpEntity = Object.create(httpEntity);       _httpEntity.contentType = MIME_TYPES['.png'];       _httpEntity.data = imgData;       // console.log('imgData.length:::' + imgData.length)       // 缓存过期时限       var EXPIRY_TIME = (staticFileServer_CONFIG.file_expiry_time * 60).toString();       response.writeHead(200);       response.end(_httpEntity.data);     }   );    }   // 获取本地图片 function load_local_img(request, response, params) {   if (PATH.extname(request.url) === '') {     // connect.directory('C:/project/bigfoot')(request, response, function(){});     // 如果 url 只是 目录 的，则列出目录     console.log('如果 url 只是 目录 的，则列出目录');     server500(response, '如果 url 只是 目录 的，则列出目录@todo');   } else {     var pathname = require('url').parse(request.url).pathname;     // 如果 url 是 目录 + 文件名 的，则返回那个文件     var path = staticFileServer_CONFIG.site_base + pathname;      Step(function () {       console.log('请求 url :' + request.url + ', path : ' + pathname);       fs.exists(path, this);     }, function (path_exists, err) {       if (err) {         server500(response, '查找文件失败！');         return;       }       if (path_exists) {         fs.readFile(path, this);       } else {         response.writeHead(404, { 'Content-Type': 'text/plain;charset=utf-8' });         response.end('找不到 ' + path + '/n');       }     }, function (err, data) {       if (err) {         server500(response, '读取文件失败！');         return;       }       var extName = '.' + path.split('.').pop();       var extName = MIME_TYPES[extName] || 'text/plain';        var _httpEntity = Object.create(httpEntity);       _httpEntity.contentType = extName;       var buData = new Buffer(data);       //images(buData).height(100);        var newImage;        if (params.w && params.h) {         newImage = images(buData).resize(Number(params.w), Number(params.h)).encode("jpg", { operation: 50 });       } else if (params.w) {         newImage = images(buData).resize(Number(params.w)).encode("jpg", { operation: 50 });       } else if (params.h) {         newImage = images(buData).resize(null, Number(params.h)).encode("jpg", { operation: 50 });       } else {         newImage = buData; // 原图       }        _httpEntity.data = newImage;        // 命中缓存，Not Modified返回 304       if (request.headers.hasOwnProperty('if-none-match') && request.headers['if-none-match'] === _httpEntity.ETag) {         response.writeHead(304);         response.end();       } else {         // 缓存过期时限         var EXPIRY_TIME = (staticFileServer_CONFIG.file_expiry_time * 60).toString();          response.writeHead(200, _httpEntity.getHeaders(EXPIRY_TIME));         response.end(_httpEntity.data);       }     });   } } function server500(response, msg) {   console.log(msg);   response.writeHead(404, { 'Content-Type': 'text/plain;charset=utf-8' });   response.end(msg + '/n'); } 加水印也是可以的。例子如下。var images = require('images'); var path = require('path'); var watermarkImg = images(path.join(__dirname, 'path/to/watermark.ext')); var sourceImg = images(path.join(__dirname, 'path/to/sourceImg.ext')); var savePath = path.join(__dirname, 'path/to/saveImg.jpg');  // 比如放置在右下角，先获取原图的尺寸和水印图片尺寸 var sWidth = sourceImg.width(); var sHeight = sourceImg.height(); var wmWidth = watermarkImg.width(); var wmWidth = watermarkImg.height();  images(sourceImg)  // 设置绘制的坐标位置，右下角距离 10px  .draw(watermarkImg, sWidth - wmWidth - 10, sHeight - wmHeight - 10)  // 保存格式会自动识别  .save(savePath);