Node.js fs。lchown()方法
fs.lchown()方法用于异步更改给定路径的所有者和组，但是，如果路径是一个，它不尊重符号链接，这与 fs.chown()方法不同，后者不将链接引用到它们的路径。该功能接受用户 id 和组 id，可用于设置各自的所有者和组。它不返回任何东西。
语法:
fs.lchown( fd, uid, gid, callback )
参数:该方法接受上述四个参数，描述如下:
- FD: is an integer, which indicates that the file descriptors of the owner and group files need to be changed.
- uid: is a number representing the user id corresponding to the owner to be set.
- Gid: is a number representing the group ID corresponding to the group to be set.
- Callback: is a function that will be called when the method is executed.
- err: If the method fails, this error will be thrown.
下面的例子说明了 Node.js 中的 fs.lchown()方法:
示例 1: 此示例显示了使用 lchown()方法设置所有者和组。
// Node.js program to demonstrate the
// fs.lchown() method
// Import the filesystem module
const fs = require('fs');
let filepath = "example_file.txt";
let symlinkpath = "symlinkFile";
// Create a symlink to the file
fs.symlinkSync(filepath, symlinkpath);
// Set the owner and group of the symbolic
// link to a new one
// New owner is "geeksforgeeks" with user id 1200
// New group is "editor" with group id 1201
fs.lchown(symlinkpath, 1200, 1201, (err) => {
if (err)
console.log(err);
else {
console.log("Given uid and gid set successfully");
}
});
运行代码前:
xubuntu@xubuntu: ~/Desktop/fs-lchown$ ls -l
total 4
-rw-rw--w- 1 xubuntu xubuntu 4 Apr 26 05:10 example_file.txt
-rw-rw-r-- 1 xubuntu xubuntu 290 Apr 26 05:15 index.js
代码输出:
Given uid and gid set successfully
运行代码后:
xubuntu@xubuntu: ~/Desktop/fs-lchown$ ls -l
total 4
-rw-rw--w- 1 xubuntu xubuntu 4 Apr 26 05:10 example_file.txt
-rw-rw-r-- 1 xubuntu xubuntu 290 Apr 26 05:15 index.js
lrwxrwxrwx 1 geeksforgeeks editor 16 Apr 26 09:15 symlinkFile -> example_file.txt
示例 2: 此示例显示了 chown()和 lchown()在取消符号链接引用方面的比较。
// Node.js program to demonstrate the
// fs.lchown() method
// Import the filesystem module
const fs = require('fs');
let filepath = "example_file.txt";
let symlinkpath1 = "symlinkFile1";
let symlinkpath2 = "symlinkFile2";
// Create two symlinks to the file
fs.symlinkSync(filepath, symlinkpath1);
fs.symlinkSync(filepath, symlinkpath2);
// Use lchown() on the first symlink
// New owner is "geeksforgeeks" with user id 1200
// New group is "owner" with group id 1300
fs.lchown(symlinkpath1, 1200, 1300, (err) => {
if (err)
console.log(err);
else {
console.log("lchownSync: uid and gid set successfully");
}
});
// Use chown() on the second symlink
// New owner is "max" with user id 1100
// New group is "author" with group id 1202
fs.chown(symlinkpath1, 1100, 1202, (err) => {
if (err)
console.log(err);
else {
console.log("chownSync: uid and gid set successfully");
}
});
运行代码前:
xubuntu@xubuntu: ~/Desktop/fs-lchown$ ls -l
total 4
-rw-rw--w- 1 xubuntu xubuntu 6 Apr 26 09:15 example_file.txt
-rw-rw-r-- 1 xubuntu xubuntu 777 Apr 26 09:16 index.js
代码输出:
lchown: uid and gid set successfully
chown: uid and gid set successfully
运行代码后:
xubuntu@xubuntu: ~/Desktop/fs-lchown$ ls -l
total 4
-rw-rw--w- 1 max author 6 Apr 26 09:15 example_file.txt
-rw-rw-r-- 1 xubuntu xubuntu 777 Apr 26 09:16 index.js
lrwxrwxrwx 1 geeksforgeeks owner 16 Apr 26 09:15 symlinkFile1 -> example_file.txt
lrwxrwxrwx 1 root root 16 Apr 26 09:15 symlinkFile2 -> example_file.txt
参考:T2】https://nodejs . org/API/fs . html # fs _ fs _ lctown _ path _ uid _ GID _ callback
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