node.js 文件操作

既然到了后台，只要你有权限就可以为所欲为了！

创建文件夹

//fs.js
var fs = require('fs');
fs.mkdirSync('a', 0755);
fs.mkdirSync('a/b', 0755);
fs.mkdirSync('a/b/c', 0755);

那么它会在fs.js所在目录中创建一个a目录，a目录下再创建b目录，b目录下创建c目录。mkdirSync是一个同步方法，拥有三个参数，第一个是路径，第二个是目录权限，第三个是回调

但这样做有点不妥，如果指定目录已存在，就报错。如果要建立多级目录，一层层判定此目录是否存在，立即会陷入“回调地狱”的境地。虽然node.js对于IO操作的方法都提供了两个版本，一个是同步的，一个是异步的。想了想，搞出我自己的mkdirSync函数，实现比mkdirp的作者好很多。

var fs = require('fs');
 
function mkdirSync(url,mode,cb){
    var path = require("path"), arr = url.split("/");
    mode = mode || 0755;
    cb = cb || function(){};
    if(arr[0]==="."){//处理 ./aaa
        arr.shift();
    }
    if(arr[0] == ".."){//处理 ../ddd/d
        arr.splice(0,2,arr[0]+"/"+arr[1])
    }
    function inner(cur){
        if(!path.existsSync(cur)){//不存在就创建一个
            fs.mkdirSync(cur, mode)
        }
        if(arr.length){
            inner(cur + "/"+arr.shift());
        }else{
            cb();
        }
    }
    arr.length && inner(arr.shift());
}
//测试代码
mkdirSync("aaa/ddd/dd",0,function(e){
    if(e){
        console.log('出错了');
    }else{
        console.log("创建成功")
    }
});

有关目录的创建的讨论，详见这里

创建文件与写入内容

创建文件的方法fs.open(path, flags, [mode], [callback])好像所有语言都很一致，可能是想与最原始的C语言的方法保持一致。这是个异步方法，其同步版本，与其他同步方法一样，就是少了个回调。说一下flags中w与a的不同，w会把已存在的同名文件删除再创建一个，因此要注意。

fs.open("test.txt", "w");

写入内容。这有几种方法，比如fs.write，不过它的第一个参数要求类型为Buffer，而fs.openSync不是返回一个Buffer，因此它不能与fs.write配合使用。

//fs.js
var fs = require('fs');
 
fs.open("test.txt","w",0644,function(e,fd){
    if(e) throw e;
    fs.write(fd,"first fs!",0,'utf8',function(e){
        if(e) throw e;
        fs.closeSync(fd);
    })
});

这时，我们就创建一个文本文件，里面写入"first fs"。不过open中间那两个参数的不是必要的。我们可以再搞一个fs2.js脚本

//fs2.js
var fs = require('fs');
fs.open("test.txt","a",0644,function(e,fd){
    if(e) throw e;
    fs.write(fd,"second fs!",function(e){
        if(e) throw e;
        fs.closeSync(fd);
    })
});

执行它，它会在test.txt追加"second fs"这句话。

fs的open, write, close有点像我们在浏览器对document的操作。此外，还有fs.writeFile与fs.writeFileSync，可惜它们不能做追加内容的操作。

var fs = require('fs');
 
fs.writeFile("test.txt","third fs!",function(e){//会先清空原先的内容
    if(e) throw e;
})

删除目录或文件

var fs = require('fs');
fs.rmdir("aaa",function(e){
    if(e){
        console.log(e)
    }
})
/**
{ stack: [Getter/Setter],
  arguments: undefined,
  type: undefined,
  message: 'ENOTEMPTY, Directory not empty \'aaa\'',
  errno: 39,
  code: 'ENOTEMPTY',
  path: 'aaa' }
*/

报错，缘由是之前我们还为aaa创建了子目录，必须逐个删除，实在不人性化，于是又造了一个轮子。

var fs = require('fs');
 
var rmdirSync = (function(){
    function iterator(url,dirs){
        var stat = fs.statSync(url);
        if(stat.isDirectory()){
            dirs.unshift(url);//收集目录
            inner(url,dirs);
        }else if(stat.isFile()){
            fs.unlinkSync(url);//直接删除文件
        }
    }
    function inner(path,dirs){
        var arr = fs.readdirSync(path);
        for(var i = 0, el ; el = arr[i++];){
            iterator(path+"/"+el,dirs);
        }
    }
    return function(dir,cb){
        cb = cb || function(){};
        var dirs = [];
 
        try{
            iterator(dir,dirs);
            for(var i = 0, el ; el = dirs[i++];){
                fs.rmdirSync(el);//一次性删除所有收集到的目录
            }
            cb()
        }catch(e){//如果文件或目录本来就不存在，fs.statSync会报错，不过我们还是当成没有异常发生
            e.code === "ENOENT" ? cb() : cb(e);
        }
    }
})();
 
rmdirSync("aaa",function(e){
    console.log("!!!"+e)
    console.log("删除aaa目录以及子目录成功")
})

上面的rmdirSync还可以分解出一个方法，取得给定目录下的所有目录与文件。

var fs = require('fs');
var getAllFolersAndFiles = (function(){
    function iterator(url, folders, files){
        var stat = fs.statSync(url);
        if(stat.isDirectory()){
            folders.unshift(url);//收集目录
            inner(url,folders, files);
        }else if(stat.isFile()){
            files.unshift(url);//收集文件
        }
    }
    function inner(path,folders,files){
        var arr = fs.readdirSync(path);
        for(var i = 0, el ; el = arr[i++];){
            iterator(path+"/"+el,folders,files);
        }
    }
    return function(dir){
        var folders = [], files = [];
        try{
            iterator(dir,folders,files);
        }catch(e){
        }finally{
            return {
                folders : folders,
                files   : files
            }
        }
    }
})()

如果我们只想取得指定目下的所有文件，还可以更精简些！

function getAllFiles(root) {
  var result = [], files = fs.readdirSync(root)
  files.forEach(function(file) {
    var pathname = root+ "/" + file
      , stat = fs.lstatSync(pathname)
    if (stat === undefined) return
 
    // 不是文件夹就是文件
    if (!stat.isDirectory()) {
      result.push(pathname)
    // 递归自身
    } else {
      result = result.concat(getAllFiles(pathname))
    }
  });
  return result
}

监听文件的改动

就是使用watchFile及其同步版本。

var fs = require("fs"),
sys = require("util");
fs.open("aaa.js","w",0644,function(e,fd){
    fs.writeSync(fd,"console.log(1111);");
    fs.closeSync(fd);
})
 
fs.watchFile("aaa.js", function(curr, prev) {
  sys.puts("\n\ttest_file.txt has been edited");
  sys.puts("\tThe current mtime is: " + curr.mtime);
  sys.puts("\tThe previous mtime was: " + prev.mtime + "\n");
});
 
fs.open("aaa.js","a",0644,function(e,fd){
    fs.writeSync(fd,"console.log(2222)");
    fs.closeSync(fd);
});

此外，node.js还提供了修改了目录文件权限的操作，但这些都是不值一提。自己看看文档就会了。

//合并脚本
var fs = require("fs")
var path = require("path") //不同的操作系统，其 文件目录 分割符是不一样的，不能直接使用 + "/"来实现
var curDir = process.cwd() //当前目录
var otherDir = curDir.replace(/avalon[\/\\]src/, "")
console.log("otherDir " + otherDir)
var Buffer = require('buffer').Buffer
var now = new Date
var date = now.getFullYear() + "." + now.getMonth() + "." + now.getDate()
function directive(name) {
    return path.join("15 directive", name)
}
//avalon.js 所需要合并的子文件
var compatibleFiles = [
    "00 inter", "01 variable", "01 variable.share", "02 core", "03 es5.shim",
    "04 dom.polyfill", "05 configuration", "06 EventBus", "06 findNodes",
    "07 modelFactory", "07 modelFactory.shim", "08 Collection", "09 dispatcher",
    "10 HTML", "12 scan", "12 scanTag", "12 scanNode", "12 scanAttr", "12 scanText",
    "13 dom", "14 parser", "14 parser.share",
    directive("skip"), directive("controller"), directive("important"),
    directive("attr"), directive("include"), directive("class.hover.active"), directive("data"),
    directive("text"), directive("html"), directive("if"), directive("visible"), directive("on"),
    directive("widget"), directive("duplex.1"), directive("duplex.2"),
    directive("duplex.3"), directive("repeat.each.with"),
    "16 filter", "17 loader", "18 domReady", "19 outer"
]
//avalon.modern.js 所需要合并的子文件
var modernFiles = [
    "00 inter", "01 variable.modern", "01 variable.share", "02 core.modern",
    "04 dom.polyfill.modern", "05 configuration", "06 EventBus", "06 findNodes.modern",
    "07 modelFactory", "08 Collection", "09 dispatcher", "10 HTML.modern",
    "12 scan", "12 scanTag", "12 scanNode", "12 scanAttr.modern", "12 scanText",
    "13 dom.modern", "14 parser.modern", "14 parser.share",
    directive("skip"), directive("controller"), directive("important"),
    directive("attr"), directive("include"), directive("class.hover.active"), directive("data"),
    directive("text.modern"), directive("html"), directive("if"), directive("visible"), directive("on"),
    directive("widget"), directive("duplex.1"), directive("duplex.2.modern"),
    directive("duplex.3"), directive("repeat.each.with"),
    "16 filter", "17 loader", "18 domReady.modern", "19 outer"
]
//avalon.shim.js 所需要合并的子文件
var shimFiles = [
    "00 inter", "01 variable", "01 variable.share", "02 core", "03 es5.shim",
    "04 dom.polyfill", "05 configuration", "06 EventBus", "06 findNodes",
    "07 modelFactory", "07 modelFactory.shim", "08 Collection", "09 dispatcher",
    "10 HTML", "12 scan", "12 scanTag", "12 scanNode", "12 scanAttr", "12 scanText",
    "13 dom", "14 parser", "14 parser.share",
    directive("skip"), directive("controller"), directive("important"),
    directive("attr"), directive("include"), directive("class.hover.active"), directive("data"),
    directive("text"), directive("html"), directive("if"), directive("visible"), directive("on"),
    directive("widget"), directive("duplex.1"), directive("duplex.2"),
    directive("duplex.3"), directive("repeat.each.with"),
    "16 filter", "18 domReady.noop", "19 outer"
]
var writable = fs.createWriteStream(path.join(curDir, 'avalon.js'), {
    encoding: "utf8"
});
writable.setMaxListeners(100) //默认只有添加11个事件，很容易爆栈
 
compatibleFiles.forEach(function(fileName) {
    var filePath = path.join(curDir, fileName + ".js")
    var readable = fs.createReadStream(filePath)
    if (fileName == "00 inter") {
        readable.on('data', function(chunk) {
            var str = chunk.toString("utf8")
            var offset = (new Buffer(str.slice(0, str.indexOf("!!")), "utf8")).length
            chunk.write(" build in " + date + " \n", offset)
        })
    }
    //  readable.push("//都会插到新文件的最前面")
    //  writable.write("//都会插到新文件的最前面 ")
    readable.pipe(writable)
    readable.on("readable", function() {
        writable.write("\n")
        console.log("add " + filePath)
    })
    //更新avalon.test中的文件
    writable.on("finish", function() {
        var readable3 = fs.createReadStream(path.join(curDir, 'avalon.js'))
        var writable3 = fs.createWriteStream(path.join(otherDir, 'avalon.test', "src", "avalon.js"))
        readable3.pipe(writable3)
    });
})
var writable2 = fs.createWriteStream(path.join(curDir, 'avalon.modern.js'), {
    encoding: "utf8"
})
writable2.setMaxListeners(100) //默认只有添加11个事件，很容易爆栈
 
modernFiles.forEach(function(fileName) {
    var filePath = path.join(curDir, fileName + ".js")
    var readable = fs.createReadStream(filePath)
    if (fileName == "00 inter") {
        readable.on('data', function(chunk) {
            var str = chunk.toString("utf8")
            var offset = (new Buffer(str.slice(0, str.indexOf("!!")), "utf8")).length
            chunk.write(" build in " + date + " \n", offset)
        })
    }
    //  readable.push("//都会插到新文件的最前面")
    //  writable.write("//都会插到新文件的最前面 ")
    readable.pipe(writable2)
    readable.on("readable", function() {
        writable2.write("\n")
        console.log("add " + filePath)
    })
    //更新avalon.test中的文件
    writable2.on("finish", function() {
        var readable3 = fs.createReadStream(path.join(curDir, 'avalon.modern.js'))
        var writable3 = fs.createWriteStream(path.join(otherDir, 'avalon.test', "src", "avalon.modern.js"))
        readable3.pipe(writable3)
    });
})