方法说明:
获取真实路径。
可以使用process.cwd解决相对路径。
语法:
fs.realpath(path, [cache], [callback(err , resolvedPath)])
由于该方法属于fs模块,使用前需要引入fs模块(var fs= require(“fs”) )
接收参数:
path 路径
cache 可选,一个文字的映射路径可用于强制一个特定的路径解决或避免额外的fs.stat需要知道真正的路径对象。
callback 回调
err 异常
resolvedPath 真实地址
例子:
var cache = {'/etc':'/private/etc'}; fs.realpath('/etc/passwd', cache, function (err, resolvedPath) { if (err) throw err; console.log(resolvedPath); });
源码:
fs.realpath = function realpath(p, cache, cb) { if (!util.isFunction(cb)) { cb = maybeCallback(cache); cache = null; } // make p is absolute p = pathModule.resolve(p); if (cache && Object.prototype.hasOwnProperty.call(cache, p)) { return process.nextTick(cb.bind(null, null, cache[p])); } var original = p, seenLinks = {}, knownHard = {}; // current character position in p var pos; // the partial path so far, including a trailing slash if any var current; // the partial path without a trailing slash (except when pointing at a root) var base; // the partial path scanned in the previous round, with slash var previous; start(); function start() { // Skip over roots var m = splitRootRe.exec(p); pos = m[0].length; current = m[0]; base = m[0]; previous = ''; // On windows, check that the root exists. On unix there is no need. if (isWindows && !knownHard[base]) { fs.lstat(base, function(err) { if (err) return cb(err); knownHard[base] = true; LOOP(); }); } else { process.nextTick(LOOP); } } // walk down the path, swapping out linked pathparts for their real // values function LOOP() { // stop if scanned past end of path if (pos >= p.length) { if (cache) cache[original] = p; return cb(null, p); } // find the next part nextPartRe.lastIndex = pos; var result = nextPartRe.exec(p); previous = current; current += result[0]; base = previous + result[1]; pos = nextPartRe.lastIndex; // continue if not a symlink if (knownHard[base] || (cache && cache[base] === base)) { return process.nextTick(LOOP); } if (cache && Object.prototype.hasOwnProperty.call(cache, base)) { // known symbolic link. no need to stat again. return gotResolvedLink(cache[base]); } return fs.lstat(base, gotStat); } function gotStat(err, stat) { if (err) return cb(err); // if not a symlink, skip to the next path part if (!stat.isSymbolicLink()) { knownHard[base] = true; if (cache) cache[base] = base; return process.nextTick(LOOP); } // stat & read the link if not read before // call gotTarget as soon as the link target is known // dev/ino always return 0 on windows, so skip the check. if (!isWindows) { var id = stat.dev.toString(32) + ':' + stat.ino.toString(32); if (seenLinks.hasOwnProperty(id)) { return gotTarget(null, seenLinks[id], base); } } fs.stat(base, function(err) { if (err) return cb(err); fs.readlink(base, function(err, target) { if (!isWindows) seenLinks[id] = target; gotTarget(err, target); }); }); } function gotTarget(err, target, base) { if (err) return cb(err); var resolvedLink = pathModule.resolve(previous, target); if (cache) cache[base] = resolvedLink; gotResolvedLink(resolvedLink); } function gotResolvedLink(resolvedLink) { // resolve the link, then start over p = pathModule.resolve(resolvedLink, p.slice(pos)); start(); } };