node-folder-mirroring.js

var fuse = require('fuse-bindings');
var fs = require('fs');
var mknod = require('mknod');
var pt = require('path');
var statvfs = require('statvfs');
var argv = require('minimist')(process.argv.slice(2));

if (argv._.length != 2){
    console.log("Usage: node node-folder-mirroring.js <original_folder> <mirror_folder> [-o <option> ...]");
    console.log("Note that additional fuse options can be passed using -o. See man mount.fuse for the available options.");
    process.exit(-1);
}

var original_folder = argv._[0];
var mirror_folder = argv._[1];
var fuse_options = argv.o;

if (!pt.isAbsolute(original_folder) || !pt.isAbsolute(mirror_folder)){
    console.log("Please use absolute paths!");
    process.exit(-1);
}

console.log("Mounting folder " + original_folder + " in folder " + mirror_folder);
if(fuse_options != undefined)
    console.log("Fuse options: " + fuse_options);

    var getattr_function = function(path, cb){
        console.log('getattr(%s)',path);
        fs.lstat(pt.join(original_folder, path), function(err, stats){
            if(err){
                //console.log('error: ', err);                
                cb(fuse[err.code]);
            }
            else{
                cb(null,stats);
            }
        });
    }
    
    var access_function = function(path, mode, cb){
        console.log('access(%s)', path);
        fs.access(pt.join(original_folder, path), mode, function(err){
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            }
        });
    }
    
    var readlink_function = function(path, cb){
        console.log('readlink(%s)', path);
        fs.readlink(pt.join(original_folder, path), function(err, linkString){
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(null, linkString);
            }
        });        
    }
    
    var readdir_function = function(path, cb){
        console.log('readdir(%s)', path);
        fs.readdir(pt.join(original_folder, path), function(err, files){
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                console.log('files: ', files);
                cb(null,files);
            }
        });                
    }
    
    var mknod_function = function(path, mode, dev, cb){
        console.log('mknod(%s)', path);
        mknod(pt.join(original_folder, path), mode, dev, function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            }            
        });
    }
    
    var mkdir_function = function(path, mode, cb){
        console.log('mkdir(%s)', path);
        fs.mkdir(pt.join(original_folder, path), mode, function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });        
    }
    
    var unlink_function = function(path, cb){
        console.log('unlink(%s)', path);
        fs.unlink(pt.join(original_folder, path), function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });        
    }
    
    var rmdir_function = function(path, cb){
        console.log('rmdir(%s)', path);
        fs.rmdir(pt.join(original_folder, path), function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });                
    }
    
    var symlink_function = function(src, dest, cb){
        console.log('symlink(%s,%s)', src, dest);
        fs.symlink(pt.join(original_folder, src), pt.join(original_folder, dest), function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });        
    }
    
    var rename_function = function(src, dest, cb){
        console.log('rename(%s,%s)', src, dest);
        fs.rename(pt.join(original_folder, src), pt.join(original_folder, dest), function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });                
    }
    
    var link_function = function(src, dest, cb){
        console.log('link(%s,%s)', src, dest);
        fs.link(pt.join(original_folder, src), pt.join(original_folder, dest), function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });                        
    }
    
    var chmod_function = function(path, mode, cb){
        console.log('chmod(%s)', path);
        fs.chmod(pt.join(original_folder, path), mode, function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });                                
    }
    
    var chown_function = function(path, uid, gid, cb){
        console.log('chown(%s)', path);
        fs.chown(pt.join(original_folder, path), uid, gid, function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });        
    }
    
    var truncate_function = function(path, size, cb){
        console.log('truncate(%s)', path);
        fs.truncate(pt.join(original_folder, path), size, function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });        
    }
    
    var utimens_function = function(path, atime, mtime, cb){
        console.log('utimens(%s)', path);
        fs.utimes(pt.join(original_folder, path), atime, mtime, function (err) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(0);
            } 
        });        
    }
    
    var open_function = function(path, flags, cb){
        console.log('open(%s)', path);
        fs.open(pt.join(original_folder, path), flags, function (err, fd) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(null, fd);
            } 
        });        
    }
    
    var read_function = function(path, fd, buffer, length, position, cb){
        console.log('read(%s)', path);
        fs.open(pt.join(original_folder, path), 'r', function (err, int_fd) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                fs.read(int_fd, buffer, 0, length, position, function(err, bytesRead, int_buffer){
                    if(err){
                        //console.log('error: ', err);
                        cb(fuse[err.code]);
                    }
                    else{
                        buffer.copy(int_buffer);
                        fs.close(int_fd, function(err){
                            if(err){
                                //console.log('error:', err);
                                cb(fuse[err.code]);
                            }
                            else{
                                cb(bytesRead);
                            }
                        });
                    }
                });
            } 
        });        
    }
    
    var write_function = function(path, fd, buffer, length, position, cb){
        console.log('write(%s)', path);
        fs.open(pt.join(original_folder, path), 'r+', function (err, int_fd) {
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                fs.write(int_fd, buffer, 0, length, position, function(err, written, int_buffer){
                    if(err){
                        //console.log('error: ', err);
                        cb(fuse[err.code]);
                    }
                    else{
                        fs.close(int_fd, function(err){
                            if(err){
                                //console.log('error:', err);
                                cb(fuse[err.code]);
                            }
                            else{
                                cb(written);
                            }
                        });
                    }
                });
            } 
        });        

    }
    
    var getxattr_function = function(path, name, buffer, length, offset, cb){
        console.log('getxattr_function(%s)', path);
        fs.lstat(pt.join(original_folder, path), function(err, stats){
            if(err){
                console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                console.log('stats: ', stats);
                cb(null,stats);
            }
        });
        
    }
    
    var statfs_function = function(path, cb){
        console.log('statvfs(%s)', path);
        statvfs(pt.join(original_folder, path), function(err, stats){
            if(err){
                //console.log('error: ', err);
                cb(fuse[err.code]);
            }
            else{
                cb(null,stats);
            }
        });
    }
    
fuse.mount(mirror_folder, {
    getattr: getattr_function,
    access: access_function,
    readlink: readlink_function,
    readdir: readdir_function,
    mknod: mknod_function, //(not available in fs, using mknod module instead)
    mkdir: mkdir_function,
    unlink: unlink_function,
    rmdir: rmdir_function,
    symlink: symlink_function,
    rename: rename_function,
    link: link_function,
    chmod: chmod_function,
    chown: chown_function,
    truncate: truncate_function,
    utimens: utimens_function,
    open: open_function,
    read: read_function,
    write: write_function,
    statfs: statfs_function, //(not available in fs, using statvfs module instead)
    //setxattr: setxattr_function (not available in fs or other implementations)
    getxattr: getxattr_function, //(not available in fs or other implementations, using lstat instead)
    //listxattr: (not available in fuse-bindings)
    //removexattr: (not available in fuse-bindings)
    options: fuse_options
});

process.on('SIGINT', function () {
  fuse.unmount(mirror_folder, function () {
    process.exit()
  })
})