Node.js VM模块
Executing JavaScript
Class: vm.Script
new vm.Script(code, options)
script.runInContext(contextifiedSandbox[, options])
script.runInNewContext([sandbox][, options])
script.runInThisContext([options])
vm.createContext([sandbox])
vm.isContext(sandbox)
vm.runInContext(code, contextifiedSandbox[, options])
vm.runInDebugContext(code)
vm.runInNewContext(code[, sandbox][, options])
vm.runInThisContext(code[, options])
Example: Running an HTTP Server within a VM
What does it mean to “contextify” an object?
Executing JavaScript
执行JavaScript
The vm module provides APIs for compiling and running code within V8 Virtual Machine contexts. It can be accessed using:
vm模块在V8虚拟机上下文中提供了编译和运行代码的API。它可以通过如下方式访问：
const vm = require('vm')
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JavaScript code can be compiled and run immediately or compiled, saved, and run later.
JavaScript代码可以被编译然后立即运行，或者编译，保存，并且之后运行。
Class: vm.Script
Added in:
Instances of the vm.Script class contain precompiled scripts that can be executed in specific sandboxes (or “contexts”).
vm.Script类的实例包含的预编译脚本可以在沙箱中被执行（或者上下文环境中）。
new vm.Script(code, options)
Added in: v0.3.1
code
options
filename
lineOffset
columnOffset
displayErrors
timeout
cachedData
produceCachedData
code
options 选项
filename
lineOffset
columnOffset
displayErrors
timeout
cachedData
produceCachedData
Creating a new vm.Script object compiles code but does not run it. The compiled vm.Script can be run later multiple times. It is important to note that the code is not bound to any global object; rather, it is bound before each run, just for that run.
创建一个新的vm.Script对象编译代码但是并不运行。编译的vm.Script之后可以被多次运行。必须注意的是该代码并没有绑定到任何的全局对象；相反的它们只在每次运行前被绑定到那次的运行环境上。
script.runInContext(contextifiedSandbox[, options])
Added in: v0.3.1
contextifiedSandbox
options
filename
lineOffset
columnOffset
displayErrors
timeout
breakOnSigint: if true, the execution will be terminated when SIGINT (Ctrl+C) is received. Existing handlers for the event that have been attached via process.on(“SIGINT”) will be disabled during script execution, but will continue to work after that. If execution is terminated, an Error will be thrown.
contextifiedSandbox
options
filename
lineOffset
columnOffset
displayErrors
timeout
breakOnSigint: 如果为真，当接收到（Ctrl+C）时，执行会被中断。在脚本执行期间，连接到process.on(“SIGINT”)上存在的事件处理程序将会被禁用，但是在这之后脚本会继续工作。如果执行被中断了，就会抛出一个错误。
Runs the compiled code contained by the vm.Script object within the given contextifiedSandbox and returns the result. Running code does not have access to local scope.
The following example compiles code that increments a global variable, sets the value of another global variable, then execute the code multiple times. The globals are contained in the sandbox object.
运行编译后的在给定的沙箱上下文中被vm.Script对象包含的代码，然后返回其结果。运行的代码无法获取本地变量。
下面的例子编译代码，增加一个全局变量，设置其它全局变量的值，然后多次执行该代码。全局变量被包含在一个沙盒对象中。
const util = require('util'); const vm = require('vm'); const sandbox = { animal: 'cat', count: 2 }; const script = new vm.Script('count += 1; name= "kitty"'); const context = new vm.createContext(sandbox); for(var i = 0; i < 10; i++) { script.runInContext(context); } console.log(util.inspect(sandbox)); //输出 { animal: 'cat', count: 12, name: 'kitty' }
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script.runInNewContext([sandbox][, options])
Added in: v0.3.1
sandbox
options
filename
lineOffset
columnOffset
displayErrors
timeout
sandbox
options
filename
lineOffset
columnOffset
displayErrors
timeout
First contextifies the given sandbox, runs the compiled code contained by the vm.Script object within the created sandbox, and returns the result. Running code does not have access to local scope.
The following example compiles code that sets a global variable, then executes the code multiple times in different contexts. The globals are set on and contained within each individual sandbox.
首先将给定的沙盘上下文化，在创建的沙盘中运行被vm.Script对象编译好的代码，然后返回其结果。运行的代码无法访问本地范围的对象。
下面的例子编译代码，然后设置一个全局变量，然后在不同的上下文中多次执行该代码。全局变量被设置并包含在每一个单独的沙盘中。
const util = require('util'); const vm = require('vm'); const script = new vm.Script('globalVar = "set"'); const sandboxes = [{}, {}, {}]; sandboxes.forEach((sandbox) => { script.runInNewContext(sandbox); }); console.log(util.inspect(sandboxes)); //输出 [{ globalVar: 'set' }, { globalVar: 'set' }, { globalVar: 'set' }]
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script.runInThisContext([options])
Added in: v0.3.1
- options
- filename
- lineOffset
- columnOffset
- displayErrors
- timeout
options
filename
lineOffset
columnOffset
displayErrors
timeout
Runs the compiled code contained by the vm.Script within the context of the current global object. Running code does not have access to local scope, but does have access to the current global object.
The following example compiles code that increments a global variable then executes that code multiple times:
运行被vm.Script包含的含有当前全局对象上下文的编译好的代码。运行的代码不能访问本地变量，但是可以访问当前的全局对象。
下面的例子编译增加一个全局变量的代码，然后多次执行那个代码。
const vm = require('vm'); //是否有加global都是全局变量 global.globalVar = 0; myVar = 0; const script = new vm.Script('globalVar += 1; myVar += 1', {filename: 'myfile.vm'}); for(var i = 0; i < 1000; i++) { script.runInThisContext(); } console.log(globalVar); // 1000 console.log(myVar); // 1000
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vm.createContext([sandbox])
Added in: v0.3.1
sandbox
If given a sandbox object, the vm.createContext() method will prepare that sandbox so that it can be used in calls to vm.runInContext() or script.runInContext(). Inside such scripts, the sandbox object will be the global object, retaining all of its existing properties but also having the built-in objects and functions any standard global object has. Outside of scripts run by the vm module, sandbox will remain unchanged.
If sandbox is omitted (or passed explicitly as undefined), a new, empty contextified sandbox object will be returned.
The vm.createContext() method is primarily useful for creating a single sandbox that can be used to run multiple scripts. For instance, if emulating a web browser, the method can be used to create a single sandbox representing a window’s global object, then run all