关于使用fs.readdir进行异步目录搜索有什么想法吗?我意识到我们可以引入递归,并调用read目录函数来读取下一个目录,但我有点担心它不是异步的…
什么好主意吗?我已经看了node-walk,它很棒,但它不能像readdir那样只给我数组中的文件。虽然
寻找这样的输出…
['file1.txt', 'file2.txt', 'dir/file3.txt']
关于使用fs.readdir进行异步目录搜索有什么想法吗?我意识到我们可以引入递归,并调用read目录函数来读取下一个目录,但我有点担心它不是异步的…
什么好主意吗?我已经看了node-walk,它很棒,但它不能像readdir那样只给我数组中的文件。虽然
寻找这样的输出…
['file1.txt', 'file2.txt', 'dir/file3.txt']
当前回答
使用承诺(Q)以函数式风格解决此问题:
var fs = require('fs'),
fsPath = require('path'),
Q = require('q');
var walk = function (dir) {
return Q.ninvoke(fs, 'readdir', dir).then(function (files) {
return Q.all(files.map(function (file) {
file = fsPath.join(dir, file);
return Q.ninvoke(fs, 'lstat', file).then(function (stat) {
if (stat.isDirectory()) {
return walk(file);
} else {
return [file];
}
});
}));
}).then(function (files) {
return files.reduce(function (pre, cur) {
return pre.concat(cur);
});
});
};
它返回一个数组的promise,所以你可以这样使用它:
walk('/home/mypath').then(function (files) { console.log(files); });
其他回答
递归-readdir模块具有此功能。
There are basically two ways of accomplishing this. In an async environment you'll notice that there are two kinds of loops: serial and parallel. A serial loop waits for one iteration to complete before it moves onto the next iteration - this guarantees that every iteration of the loop completes in order. In a parallel loop, all the iterations are started at the same time, and one may complete before another, however, it is much faster than a serial loop. So in this case, it's probably better to use a parallel loop because it doesn't matter what order the walk completes in, just as long as it completes and returns the results (unless you want them in order).
一个平行循环看起来是这样的:
var fs = require('fs');
var path = require('path');
var walk = function(dir, done) {
var results = [];
fs.readdir(dir, function(err, list) {
if (err) return done(err);
var pending = list.length;
if (!pending) return done(null, results);
list.forEach(function(file) {
file = path.resolve(dir, file);
fs.stat(file, function(err, stat) {
if (stat && stat.isDirectory()) {
walk(file, function(err, res) {
results = results.concat(res);
if (!--pending) done(null, results);
});
} else {
results.push(file);
if (!--pending) done(null, results);
}
});
});
});
};
一个串行循环看起来像这样:
var fs = require('fs');
var path = require('path');
var walk = function(dir, done) {
var results = [];
fs.readdir(dir, function(err, list) {
if (err) return done(err);
var i = 0;
(function next() {
var file = list[i++];
if (!file) return done(null, results);
file = path.resolve(dir, file);
fs.stat(file, function(err, stat) {
if (stat && stat.isDirectory()) {
walk(file, function(err, res) {
results = results.concat(res);
next();
});
} else {
results.push(file);
next();
}
});
})();
});
};
并且在你的主目录中测试它(警告:如果你的主目录中有很多东西,结果列表将会非常大):
walk(process.env.HOME, function(err, results) {
if (err) throw err;
console.log(results);
});
编辑:改进的示例。
Filehound库是另一种选择。它将递归地搜索给定目录(默认为工作目录)。它支持各种过滤器、回调、承诺和同步搜索。
例如,搜索当前工作目录中的所有文件(使用回调):
const Filehound = require('filehound');
Filehound.create()
.find((err, files) => {
if (err) {
return console.error(`error: ${err}`);
}
console.log(files); // array of files
});
或承诺,并指定特定的目录:
const Filehound = require('filehound');
Filehound.create()
.paths("/tmp")
.find()
.each(console.log);
更多的用例和使用示例请参考文档:https://github.com/nspragg/filehound
声明:我是作者。
我必须将基于promise的砂光器库添加到列表中。
var sander = require('sander');
sander.lsr(directory).then( filenames => { console.log(filenames) } );
这就是我的答案。希望它能帮助到一些人。
我的重点是使搜索例程可以停在任何地方,对于找到的文件,告诉原始路径的相对深度。
var _fs = require('fs');
var _path = require('path');
var _defer = process.nextTick;
// next() will pop the first element from an array and return it, together with
// the recursive depth and the container array of the element. i.e. If the first
// element is an array, it'll be dug into recursively. But if the first element is
// an empty array, it'll be simply popped and ignored.
// e.g. If the original array is [1,[2],3], next() will return [1,0,[[2],3]], and
// the array becomes [[2],3]. If the array is [[[],[1,2],3],4], next() will return
// [1,2,[2]], and the array becomes [[[2],3],4].
// There is an infinity loop `while(true) {...}`, because I optimized the code to
// make it a non-recursive version.
var next = function(c) {
var a = c;
var n = 0;
while (true) {
if (a.length == 0) return null;
var x = a[0];
if (x.constructor == Array) {
if (x.length > 0) {
a = x;
++n;
} else {
a.shift();
a = c;
n = 0;
}
} else {
a.shift();
return [x, n, a];
}
}
}
// cb is the callback function, it have four arguments:
// 1) an error object if any exception happens;
// 2) a path name, may be a directory or a file;
// 3) a flag, `true` means directory, and `false` means file;
// 4) a zero-based number indicates the depth relative to the original path.
// cb should return a state value to tell whether the searching routine should
// continue: `true` means it should continue; `false` means it should stop here;
// but for a directory, there is a third state `null`, means it should do not
// dig into the directory and continue searching the next file.
var ls = function(path, cb) {
// use `_path.resolve()` to correctly handle '.' and '..'.
var c = [ _path.resolve(path) ];
var f = function() {
var p = next(c);
p && s(p);
};
var s = function(p) {
_fs.stat(p[0], function(err, ss) {
if (err) {
// use `_defer()` to turn a recursive call into a non-recursive call.
cb(err, p[0], null, p[1]) && _defer(f);
} else if (ss.isDirectory()) {
var y = cb(null, p[0], true, p[1]);
if (y) r(p);
else if (y == null) _defer(f);
} else {
cb(null, p[0], false, p[1]) && _defer(f);
}
});
};
var r = function(p) {
_fs.readdir(p[0], function(err, files) {
if (err) {
cb(err, p[0], true, p[1]) && _defer(f);
} else {
// not use `Array.prototype.map()` because we can make each change on site.
for (var i = 0; i < files.length; i++) {
files[i] = _path.join(p[0], files[i]);
}
p[2].unshift(files);
_defer(f);
}
});
}
_defer(f);
};
var printfile = function(err, file, isdir, n) {
if (err) {
console.log('--> ' + ('[' + n + '] ') + file + ': ' + err);
return true;
} else {
console.log('... ' + ('[' + n + '] ') + (isdir ? 'D' : 'F') + ' ' + file);
return true;
}
};
var path = process.argv[2];
ls(path, printfile);