[英]Execute a command line binary with Node.js
我正在將 CLI 庫從 Ruby 移植到 Node.js。 在我的代碼中,我會在必要時執行幾個第三方二進制文件。 我不確定如何最好地在 Node.js 中實現這一點。
這是我在 Ruby 中調用 PrinceXML 將文件轉換為 PDF 的示例:
cmd = system("prince -v builds/pdf/book.html -o builds/pdf/book.pdf")
Node 中的等效代碼是什么?
對於更新版本的 Node.js (v8.1.4),事件和調用與舊版本相似或相同,但鼓勵使用標准的更新語言功能。 例子:
對於緩沖的、非流格式的輸出(您一次獲得所有內容),請使用child_process.exec
:
const { exec } = require('child_process');
exec('cat *.js bad_file | wc -l', (err, stdout, stderr) => {
if (err) {
// node couldn't execute the command
return;
}
// the *entire* stdout and stderr (buffered)
console.log(`stdout: ${stdout}`);
console.log(`stderr: ${stderr}`);
});
您還可以將它與 Promise 一起使用:
const util = require('util');
const exec = util.promisify(require('child_process').exec);
async function ls() {
const { stdout, stderr } = await exec('ls');
console.log('stdout:', stdout);
console.log('stderr:', stderr);
}
ls();
如果您希望以塊的形式逐漸接收數據(作為流輸出),請使用child_process.spawn
:
const { spawn } = require('child_process');
const child = spawn('ls', ['-lh', '/usr']);
// use child.stdout.setEncoding('utf8'); if you want text chunks
child.stdout.on('data', (chunk) => {
// data from standard output is here as buffers
});
// since these are streams, you can pipe them elsewhere
child.stderr.pipe(dest);
child.on('close', (code) => {
console.log(`child process exited with code ${code}`);
});
這兩個函數都有一個同步對應物。 child_process.execSync
的示例:
const { execSync } = require('child_process');
// stderr is sent to stderr of parent process
// you can set options.stdio if you want it to go elsewhere
let stdout = execSync('ls');
const { spawnSync} = require('child_process');
const child = spawnSync('ls', ['-lh', '/usr']);
console.log('error', child.error);
console.log('stdout ', child.stdout);
console.log('stderr ', child.stderr);
注意:以下代碼仍然有效,但主要針對 ES5 及之前版本的用戶。
使用 Node.js 生成子進程的模塊在文檔(v5.0.0) 中有詳細記錄。 要執行命令並將其完整輸出作為緩沖區獲取,請使用child_process.exec
:
var exec = require('child_process').exec;
var cmd = 'prince -v builds/pdf/book.html -o builds/pdf/book.pdf';
exec(cmd, function(error, stdout, stderr) {
// command output is in stdout
});
如果您需要child_process.spawn
使用處理進程 I/O,例如當您需要大量輸出時,請使用child_process.spawn
:
var spawn = require('child_process').spawn;
var child = spawn('prince', [
'-v', 'builds/pdf/book.html',
'-o', 'builds/pdf/book.pdf'
]);
child.stdout.on('data', function(chunk) {
// output will be here in chunks
});
// or if you want to send output elsewhere
child.stdout.pipe(dest);
如果您正在執行文件而不是命令,您可能需要使用child_process.execFile
,其參數幾乎與spawn
相同,但有第四個回調參數,如exec
用於檢索輸出緩沖區。 這可能看起來有點像這樣:
var execFile = require('child_process').execFile;
execFile(file, args, options, function(error, stdout, stderr) {
// command output is in stdout
});
從v0.11.12 開始,Node 現在支持同步spawn
和exec
。 上面描述的所有方法都是異步的,並且有一個同步對應的方法。 可以在此處找到它們的文檔。 雖然它們對腳本很有用,但請注意,與用於異步生成子進程的方法不同,同步方法不返回ChildProcess
的實例。
v15.8.0
、LTS v14.15.4
和v12.20.1
--- 2021 年 2 月異步方法(Unix):
'use strict';
const { spawn } = require( 'child_process' );
const ls = spawn( 'ls', [ '-lh', '/usr' ] );
ls.stdout.on( 'data', ( data ) => {
console.log( `stdout: ${ data }` );
} );
ls.stderr.on( 'data', ( data ) => {
console.log( `stderr: ${ data }` );
} );
ls.on( 'close', ( code ) => {
console.log( `child process exited with code ${ code }` );
} );
異步方法(Windows):
'use strict';
const { spawn } = require( 'child_process' );
// NOTE: Windows Users, this command appears to be differ for a few users.
// You can think of this as using Node to execute things in your Command Prompt.
// If `cmd` works there, it should work here.
// If you have an issue, try `dir`:
// const dir = spawn( 'dir', [ '.' ] );
const dir = spawn( 'cmd', [ '/c', 'dir' ] );
dir.stdout.on( 'data', ( data ) => console.log( `stdout: ${ data }` ) );
dir.stderr.on( 'data', ( data ) => console.log( `stderr: ${ data }` ) );
dir.on( 'close', ( code ) => console.log( `child process exited with code ${code}` ) );
同步:
'use strict';
const { spawnSync } = require( 'child_process' );
const ls = spawnSync( 'ls', [ '-lh', '/usr' ] );
console.log( `stderr: ${ ls.stderr.toString() }` );
console.log( `stdout: ${ ls.stdout.toString() }` );
您正在尋找child_process.exec
這是示例:
const exec = require('child_process').exec;
const child = exec('cat *.js bad_file | wc -l',
(error, stdout, stderr) => {
console.log(`stdout: ${stdout}`);
console.log(`stderr: ${stderr}`);
if (error !== null) {
console.log(`exec error: ${error}`);
}
});
const exec = require("child_process").exec
exec("ls", (error, stdout, stderr) => {
//do whatever here
})
如果您想要與最佳答案非常相似但也是同步的東西,那么這將起作用。
var execSync = require('child_process').execSync;
var cmd = "echo 'hello world'";
var options = {
encoding: 'utf8'
};
console.log(execSync(cmd, options));
現在您可以使用 shelljs(來自節點 v4),如下所示:
var shell = require('shelljs');
shell.echo('hello world');
shell.exec('node --version');
安裝
npm install shelljs
我剛剛寫了一個 Cli 助手來輕松處理 Unix/windows。
Javascript:
define(["require", "exports"], function (require, exports) {
/**
* Helper to use the Command Line Interface (CLI) easily with both Windows and Unix environments.
* Requires underscore or lodash as global through "_".
*/
var Cli = (function () {
function Cli() {}
/**
* Execute a CLI command.
* Manage Windows and Unix environment and try to execute the command on both env if fails.
* Order: Windows -> Unix.
*
* @param command Command to execute. ('grunt')
* @param args Args of the command. ('watch')
* @param callback Success.
* @param callbackErrorWindows Failure on Windows env.
* @param callbackErrorUnix Failure on Unix env.
*/
Cli.execute = function (command, args, callback, callbackErrorWindows, callbackErrorUnix) {
if (typeof args === "undefined") {
args = [];
}
Cli.windows(command, args, callback, function () {
callbackErrorWindows();
try {
Cli.unix(command, args, callback, callbackErrorUnix);
} catch (e) {
console.log('------------- Failed to perform the command: "' + command + '" on all environments. -------------');
}
});
};
/**
* Execute a command on Windows environment.
*
* @param command Command to execute. ('grunt')
* @param args Args of the command. ('watch')
* @param callback Success callback.
* @param callbackError Failure callback.
*/
Cli.windows = function (command, args, callback, callbackError) {
if (typeof args === "undefined") {
args = [];
}
try {
Cli._execute(process.env.comspec, _.union(['/c', command], args));
callback(command, args, 'Windows');
} catch (e) {
callbackError(command, args, 'Windows');
}
};
/**
* Execute a command on Unix environment.
*
* @param command Command to execute. ('grunt')
* @param args Args of the command. ('watch')
* @param callback Success callback.
* @param callbackError Failure callback.
*/
Cli.unix = function (command, args, callback, callbackError) {
if (typeof args === "undefined") {
args = [];
}
try {
Cli._execute(command, args);
callback(command, args, 'Unix');
} catch (e) {
callbackError(command, args, 'Unix');
}
};
/**
* Execute a command no matters what's the environment.
*
* @param command Command to execute. ('grunt')
* @param args Args of the command. ('watch')
* @private
*/
Cli._execute = function (command, args) {
var spawn = require('child_process').spawn;
var childProcess = spawn(command, args);
childProcess.stdout.on("data", function (data) {
console.log(data.toString());
});
childProcess.stderr.on("data", function (data) {
console.error(data.toString());
});
};
return Cli;
})();
exports.Cli = Cli;
});
打字稿原始源文件:
/**
* Helper to use the Command Line Interface (CLI) easily with both Windows and Unix environments.
* Requires underscore or lodash as global through "_".
*/
export class Cli {
/**
* Execute a CLI command.
* Manage Windows and Unix environment and try to execute the command on both env if fails.
* Order: Windows -> Unix.
*
* @param command Command to execute. ('grunt')
* @param args Args of the command. ('watch')
* @param callback Success.
* @param callbackErrorWindows Failure on Windows env.
* @param callbackErrorUnix Failure on Unix env.
*/
public static execute(command: string, args: string[] = [], callback ? : any, callbackErrorWindows ? : any, callbackErrorUnix ? : any) {
Cli.windows(command, args, callback, function () {
callbackErrorWindows();
try {
Cli.unix(command, args, callback, callbackErrorUnix);
} catch (e) {
console.log('------------- Failed to perform the command: "' + command + '" on all environments. -------------');
}
});
}
/**
* Execute a command on Windows environment.
*
* @param command Command to execute. ('grunt')
* @param args Args of the command. ('watch')
* @param callback Success callback.
* @param callbackError Failure callback.
*/
public static windows(command: string, args: string[] = [], callback ? : any, callbackError ? : any) {
try {
Cli._execute(process.env.comspec, _.union(['/c', command], args));
callback(command, args, 'Windows');
} catch (e) {
callbackError(command, args, 'Windows');
}
}
/**
* Execute a command on Unix environment.
*
* @param command Command to execute. ('grunt')
* @param args Args of the command. ('watch')
* @param callback Success callback.
* @param callbackError Failure callback.
*/
public static unix(command: string, args: string[] = [], callback ? : any, callbackError ? : any) {
try {
Cli._execute(command, args);
callback(command, args, 'Unix');
} catch (e) {
callbackError(command, args, 'Unix');
}
}
/**
* Execute a command no matters what's the environment.
*
* @param command Command to execute. ('grunt')
* @param args Args of the command. ('watch')
* @private
*/
private static _execute(command, args) {
var spawn = require('child_process').spawn;
var childProcess = spawn(command, args);
childProcess.stdout.on("data", function (data) {
console.log(data.toString());
});
childProcess.stderr.on("data", function (data) {
console.error(data.toString());
});
}
}
Example of use:
Cli.execute(Grunt._command, args, function (command, args, env) {
console.log('Grunt has been automatically executed. (' + env + ')');
}, function (command, args, env) {
console.error('------------- Windows "' + command + '" command failed, trying Unix... ---------------');
}, function (command, args, env) {
console.error('------------- Unix "' + command + '" command failed too. ---------------');
});
使用這個輕量級的npm
包: system-commands
看看這里。
像這樣導入:
const system = require('system-commands')
運行這樣的命令:
system('ls').then(output => {
console.log(output)
}).catch(error => {
console.error(error)
})
如果您不介意依賴並希望使用 Promise,則child-process-promise
可以工作:
安裝
npm install child-process-promise --save
exec 用法
var exec = require('child-process-promise').exec;
exec('echo hello')
.then(function (result) {
var stdout = result.stdout;
var stderr = result.stderr;
console.log('stdout: ', stdout);
console.log('stderr: ', stderr);
})
.catch(function (err) {
console.error('ERROR: ', err);
});
生成使用
var spawn = require('child-process-promise').spawn;
var promise = spawn('echo', ['hello']);
var childProcess = promise.childProcess;
console.log('[spawn] childProcess.pid: ', childProcess.pid);
childProcess.stdout.on('data', function (data) {
console.log('[spawn] stdout: ', data.toString());
});
childProcess.stderr.on('data', function (data) {
console.log('[spawn] stderr: ', data.toString());
});
promise.then(function () {
console.log('[spawn] done!');
})
.catch(function (err) {
console.error('[spawn] ERROR: ', err);
});
@hexacyanide 的回答幾乎是完整的。 在Windows命令prince
可能是prince.exe
, prince.cmd
, prince.bat
或者只是prince
(我不知道的寶石捆綁的方式,但NPM箱都配有SH腳本,批處理腳本- npm
和npm.cmd
)。 如果您想編寫可在 Unix 和 Windows 上運行的可移植腳本,您必須生成正確的可執行文件。
這是一個簡單但便攜的 spawn 函數:
function spawn(cmd, args, opt) {
var isWindows = /win/.test(process.platform);
if ( isWindows ) {
if ( !args ) args = [];
args.unshift(cmd);
args.unshift('/c');
cmd = process.env.comspec;
}
return child_process.spawn(cmd, args, opt);
}
var cmd = spawn("prince", ["-v", "builds/pdf/book.html", "-o", "builds/pdf/book.pdf"])
// Use these props to get execution results:
// cmd.stdin;
// cmd.stdout;
// cmd.stderr;
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