纯异步nodejs文件夹(目录)复制功能-创新互联

node.js 复制文件夹

坚守“ 做人真诚 · 做事靠谱 · 口碑至上 · 高效敬业 ”的价值观，专业网站建设服务10余年为成都成都三轮搅拌车小微创业公司专业提供成都企业网站定制营销网站建设商城网站建设手机网站建设小程序网站建设网站改版，从内容策划、视觉设计、底层架构、网页布局、功能开发迭代于一体的高端网站建设服务。

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)) 
  } 
});

文章名称：纯异步nodejs文件夹(目录)复制功能-创新互联
文章位置：http://shouzuofang.com/article/dgises.html