node.js 复制文件夹

思路:

1、callback 驱动

2、递归所有需要复制文件

3、在一定阀值下并发复制文件

var async = require("async"); var fs = require("fs"); var path = require("path"); // cursively make dir function mkdirs(p, mode, f, made) { if (typeof mode === 'function' || mode === undefined) { f = mode; mode = 0777 & (~process.umask()); } if (!made) made = null; var cb = f || function () {}; if (typeof mode === 'string') mode = parseInt(mode, 8); p = path.resolve(p); fs.mkdir(p, mode, function (er) { if (!er) { made = made || p; return cb(null, made); } switch (er.code) { case 'ENOENT': mkdirs(path.dirname(p), mode, function (er, made) { if (er) { cb(er, made); } else { mkdirs(p, mode, cb, made); } }); break; // In the case of any other error, just see if there's a dir // there already. If so, then hooray! If not, then something // is borked. default: fs.stat(p, function (er2, stat) { // if the stat fails, then that's super weird. // let the original error be the failure reason. if (er2 || !stat.isDirectory()) { cb(er, made); } else { cb(null, made) }; }); break; } }); } // single file copy function copyFile(file, toDir, cb) { async.waterfall([ function (callback) { fs.exists(toDir, function (exists) { if (exists) { callback(null, false); } else { callback(null, true); } }); }, function (need, callback) { if (need) { mkdirs(path.dirname(toDir), callback); } else { callback(null, true); } }, function (p, callback) { var reads = fs.createReadStream(file); var writes = fs.createWriteStream(path.join(path.dirname(toDir), path.basename(file))); reads.pipe(writes); //don't forget close the when all the data are read reads.on("end", function () { writes.end(); callback(null); }); reads.on("error", function (err) { console.log("error occur in reads"); callback(true, err); }); } ], cb); } // cursively count the files that need to be copied function _ccoutTask(from, to, cbw) { async.waterfall([ function (callback) { fs.stat(from, callback); }, function (stats, callback) { if (stats.isFile()) { cbw.addFile(from, to); callback(null, []); } else if (stats.isDirectory()) { fs.readdir(from, callback); } }, function (files, callback) { if (files.length) { for (var i = 0; i < files.length; i++) { _ccoutTask(path.join(from, files[i]), path.join(to, files[i]), cbw.increase()); } } callback(null); } ], cbw); } // wrap the callback before counting function ccoutTask(from, to, cb) { var files = []; var count = 1; function wrapper(err) { count--; if (err || count <= 0) { cb(err, files) } } wrapper.increase = function () { count++; return wrapper; } wrapper.addFile = function (file, dir) { files.push({ file : file, dir : dir }); } _ccoutTask(from, to, wrapper); } function copyDir(from, to, cb) { if(!cb){ cb=function(){}; } async.waterfall([ function (callback) { fs.exists(from, function (exists) { if (exists) { callback(null, true); } else { console.log(from + " not exists"); callback(true); } }); }, function (exists, callback) { fs.stat(from, callback); }, function (stats, callback) { if (stats.isFile()) { // one file copy copyFile(from, to, function (err) { if (err) { // break the waterfall callback(true); } else { callback(null, []); } }); } else if (stats.isDirectory()) { ccoutTask(from, to, callback); } }, function (files, callback) { // prevent reaching to max file open limit async.mapLimit(files, 10, function (f, cb) { copyFile(f.file, f.dir, cb); }, callback); } ], cb); } var start = new Date().getTime(); copyDir("F:\\gear", "F:\\gear2", function (err) { if (err) { console.log("error ocur"); console.dir(err); } else { console.log("copy ok"); console.log("consume time:" + (new Date().getTime() - start)) } });

总结

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