Node.js v20.18.0 文档

生成单个可执行准备 blob#

¥Generating single executable preparation blobs

可以使用将用于构建单个可执行文件的 Node.js 二进制文件的 --experimental-sea-config 标志生成注入到应用中的单个可执行文件准备 blob。它采用 JSON 格式的配置文件路径。如果传递给它的路径不是绝对路径，Node.js 将使用相对于当前工作目录的路径。

¥Single executable preparation blobs that are injected into the application can be generated using the --experimental-sea-config flag of the Node.js binary that will be used to build the single executable. It takes a path to a configuration file in JSON format. If the path passed to it isn't absolute, Node.js will use the path relative to the current working directory.

该配置当前读取以下顶层字段：

¥The configuration currently reads the following top-level fields:

{
  "main": "/path/to/bundled/script.js",
  "output": "/path/to/write/the/generated/blob.blob",
  "disableExperimentalSEAWarning": true, // Default: false
  "useSnapshot": false,  // Default: false
  "useCodeCache": true, // Default: false
  "assets": {  // Optional
    "a.dat": "/path/to/a.dat",
    "b.txt": "/path/to/b.txt"
  }
} 拷贝

如果路径不是绝对路径，Node.js 将使用相对于当前工作目录的路径。用于生成 blob 的 Node.js 二进制文件的版本必须与将注入 blob 的版本相同。

¥If the paths are not absolute, Node.js will use the path relative to the current working directory. The version of the Node.js binary used to produce the blob must be the same as the one to which the blob will be injected.

注意：生成跨平台 SEA 时（例如，在 darwin-arm64 上为 linux-x64 生成 SEA），必须将 useCodeCache 和 useSnapshot 设置为 false，以避免生成不兼容的可执行文件。由于代码缓存和快照只能在编译它们的同一平台上加载，因此在尝试加载在不同平台上构建的代码缓存或快照时，生成的可执行文件可能会在启动时崩溃。

¥Note: When generating cross-platform SEAs (e.g., generating a SEA for linux-x64 on darwin-arm64), useCodeCache and useSnapshot must be set to false to avoid generating incompatible executables. Since code cache and snapshots can only be loaded on the same platform where they are compiled, the generated executable might crash on startup when trying to load code cache or snapshots built on a different platform.

资源#

¥Assets

用户可以通过将键路径字典添加到配置中作为 assets 字段来包含资源。在构建时，Node.js 将从指定路径读取资源并将它们打包到准备 blob 中。在生成的可执行文件中，用户可以使用 sea.getAsset() 和 sea.getAssetAsBlob() API 检索资源。

¥Users can include assets by adding a key-path dictionary to the configuration as the assets field. At build time, Node.js would read the assets from the specified paths and bundle them into the preparation blob. In the generated executable, users can retrieve the assets using the sea.getAsset() and sea.getAssetAsBlob() APIs.

{
  "main": "/path/to/bundled/script.js",
  "output": "/path/to/write/the/generated/blob.blob",
  "assets": {
    "a.jpg": "/path/to/a.jpg",
    "b.txt": "/path/to/b.txt"
  }
} 拷贝

单一可执行应用可以按如下方式访问资源：

¥The single-executable application can access the assets as follows:

const { getAsset, getAssetAsBlob, getRawAsset } = require('node:sea');
// Returns a copy of the data in an ArrayBuffer.
const image = getAsset('a.jpg');
// Returns a string decoded from the asset as UTF8.
const text = getAsset('b.txt', 'utf8');
// Returns a Blob containing the asset.
const blob = getAssetAsBlob('a.jpg');
// Returns an ArrayBuffer containing the raw asset without copying.
const raw = getRawAsset('a.jpg'); 拷贝

有关更多信息，请参阅 sea.getAsset()、sea.getAssetAsBlob() 和 sea.getRawAsset() API 的文档。

¥See documentation of the sea.getAsset(), sea.getAssetAsBlob() and sea.getRawAsset() APIs for more information.

启动快照支持#

¥Startup snapshot support

useSnapshot 字段可用于启用启动快照支持。在这种情况下，启动最终可执行文件时将不会出现 main 脚本。相反，它将在构建计算机上生成单个可执行应用准备 blob 时运行。然后，生成的准备 blob 将包含捕获由 main 脚本初始化的状态的快照。注入准备 blob 的最终可执行文件将在运行时反序列化快照。

¥The useSnapshot field can be used to enable startup snapshot support. In this case the main script would not be when the final executable is launched. Instead, it would be run when the single executable application preparation blob is generated on the building machine. The generated preparation blob would then include a snapshot capturing the states initialized by the main script. The final executable with the preparation blob injected would deserialize the snapshot at run time.

当 useSnapshot 为 true 时，主脚本必须调用 v8.startupSnapshot.setDeserializeMainFunction() API 来配置用户启动最终可执行文件时需要运行的代码。

¥When useSnapshot is true, the main script must invoke the v8.startupSnapshot.setDeserializeMainFunction() API to configure code that needs to be run when the final executable is launched by the users.

应用在单个可执行应用中使用快照的典型模式是：

¥The typical pattern for an application to use snapshot in a single executable application is:

1. 在构建时，在构建机器上，运行主脚本以将堆初始化为准备接受用户输入的状态。该脚本还应该使用 v8.startupSnapshot.setDeserializeMainFunction() 配置一个 main 函数。该函数将被编译并序列化到快照中，但不会在构建时调用。

   ¥At build time, on the building machine, the main script is run to initialize the heap to a state that's ready to take user input. The script should also configure a main function with v8.startupSnapshot.setDeserializeMainFunction(). This function will be compiled and serialized into the snapshot, but not invoked at build time.

2. 在运行时，主函数将在用户计算机上的反序列化堆之上运行，以处理用户输入并生成输出。

   ¥At run time, the main function will be run on top of the deserialized heap on the user machine to process user input and generate output.

当用于为单个可执行应用构建快照时，启动快照脚本的一般约束也适用于主脚本，并且主脚本可以使用 v8.startupSnapshot API 来适应这些约束。参见 有关 Node.js 中启动快照支持的文档。

¥The general constraints of the startup snapshot scripts also apply to the main script when it's used to build snapshot for the single executable application, and the main script can use the v8.startupSnapshot API to adapt to these constraints. See documentation about startup snapshot support in Node.js.

V8 代码缓存支持#

¥V8 code cache support

当配置中将 useCodeCache 设置为 true 时，在生成单个可执行准备 blob 期间，Node.js 将编译 main 脚本以生成 V8 代码缓存。生成的代码缓存将成为准备 blob 的一部分，并注入到最终的可执行文件中。当单个可执行应用启动时，Node.js 不会从头开始编译 main 脚本，而是使用代码缓存来加速编译，然后执行脚本，这将提高启动性能。

¥When useCodeCache is set to true in the configuration, during the generation of the single executable preparation blob, Node.js will compile the main script to generate the V8 code cache. The generated code cache would be part of the preparation blob and get injected into the final executable. When the single executable application is launched, instead of compiling the main script from scratch, Node.js would use the code cache to speed up the compilation, then execute the script, which would improve the startup performance.

注意：当 useCodeCache 为 true 时，import() 不起作用。

¥Note: import() does not work when useCodeCache is true.

在注入的主脚本中#

¥In the injected main script

单个可执行应用 API#

¥Single-executable application API

node:sea 内置允许通过嵌入到可执行文件中的 JavaScript 主脚本与单个可执行应用进行交互。

¥The node:sea builtin allows interaction with the single-executable application from the JavaScript main script embedded into the executable.

sea.isSea()#

• 返回：<boolean> 该脚本是否在单个可执行应用内运行。

  ¥Returns: <boolean> Whether this script is running inside a single-executable application.

sea.getAsset(key[, encoding])#

此方法可用于检索配置为在构建时打包到单个可执行应用中的资源。当找不到匹配的资源时会抛出错误。

¥This method can be used to retrieve the assets configured to be bundled into the single-executable application at build time. An error is thrown when no matching asset can be found.

• key <string> 单一可执行应用配置中的 assets 字段指定的字典中资源的键。

  ¥key <string> the key for the asset in the dictionary specified by the assets field in the single-executable application configuration.

• encoding <string> 如果指定，资源将被解码为字符串。接受 TextDecoder 支持的任何编码。如果未指定，则将返回包含资源副本的 ArrayBuffer。

  ¥encoding <string> If specified, the asset will be decoded as a string. Any encoding supported by the TextDecoder is accepted. If unspecified, an ArrayBuffer containing a copy of the asset would be returned instead.

• 返回：<string> | <ArrayBuffer>

  ¥Returns: <string> | <ArrayBuffer>

sea.getAssetAsBlob(key[, options])#

与 sea.getAsset() 类似，但以 Blob 形式返回结果。当找不到匹配的资源时会抛出错误。

¥Similar to sea.getAsset(), but returns the result in a Blob. An error is thrown when no matching asset can be found.

• key <string> 单一可执行应用配置中的 assets 字段指定的字典中资源的键。

  ¥key <string> the key for the asset in the dictionary specified by the assets field in the single-executable application configuration.

• options <Object>

  • type <string> blob 的可选 MIME 类型。

    ¥type <string> An optional mime type for the blob.

• 返回：<Blob>

  ¥Returns: <Blob>

sea.getRawAsset(key)#

此方法可用于检索配置为在构建时打包到单个可执行应用中的资源。当找不到匹配的资源时会抛出错误。

¥This method can be used to retrieve the assets configured to be bundled into the single-executable application at build time. An error is thrown when no matching asset can be found.

与 sea.getAsset() 或 sea.getAssetAsBlob() 不同，此方法不返回副本。相反，它返回打包在可执行文件内的原始资源。

¥Unlike sea.getAsset() or sea.getAssetAsBlob(), this method does not return a copy. Instead, it returns the raw asset bundled inside the executable.

目前，用户应避免写入返回的数组缓冲区。如果注入的部分未标记为可写或未正确对齐，则写入返回的数组缓冲区可能会导致崩溃。

¥For now, users should avoid writing to the returned array buffer. If the injected section is not marked as writable or not aligned properly, writes to the returned array buffer is likely to result in a crash.

• key <string> 单一可执行应用配置中的 assets 字段指定的字典中资源的键。

  ¥key <string> the key for the asset in the dictionary specified by the assets field in the single-executable application configuration.

• 返回：<string> | <ArrayBuffer>

  ¥Returns: <string> | <ArrayBuffer>

注入的主脚本中的 require(id) 不是基于文件的#

¥require(id) in the injected main script is not file based

注入的主脚本中的 require() 与未注入的模块可用的 require() 不同。除 require.main 外，它也不具有非注入 require() 所具有的任何属性。它只能用于加载内置模块。尝试加载只能在文件系统中找到的模块将引发错误。

¥require() in the injected main script is not the same as the require() available to modules that are not injected. It also does not have any of the properties that non-injected require() has except require.main. It can only be used to load built-in modules. Attempting to load a module that can only be found in the file system will throw an error.

用户可以将他们的应用打包到一个独立的 JavaScript 文件中以注入可执行文件，而不是依赖于基于 require() 的文件。这也确保了更具确定性的依赖图。

¥Instead of relying on a file based require(), users can bundle their application into a standalone JavaScript file to inject into the executable. This also ensures a more deterministic dependency graph.

但是，如果仍然需要基于 require() 的文件，也可以实现：

¥However, if a file based require() is still needed, that can also be achieved:

const { createRequire } = require('node:module');
require = createRequire(__filename); 拷贝

注入主脚本中的 __filename 和 module.filename#

¥__filename and module.filename in the injected main script

注入的主脚本中的 __filename 和 module.filename 的值等于 process.execPath。

¥The values of __filename and module.filename in the injected main script are equal to process.execPath.

注入的主脚本中的 __dirname#

¥__dirname in the injected main script

注入的主脚本中 __dirname 的值等于 process.execPath 的目录名。

¥The value of __dirname in the injected main script is equal to the directory name of process.execPath.

注意事项#

¥Notes

单个可执行应用创建过程#

¥Single executable application creation process

旨在创建单个可执行 Node.js 应用的工具必须将使用 --experimental-sea-config" 准备的 blob 的内容注入到：

¥A tool aiming to create a single executable Node.js application must inject the contents of the blob prepared with --experimental-sea-config" into:

• 如果 node 二进制文件是 PE 文件，则名为 NODE_SEA_BLOB 的资源

  ¥a resource named NODE_SEA_BLOB if the node binary is a PE file

• 如果 node 二进制文件是 Mach-O 文件，则 NODE_SEA 段中名为 NODE_SEA_BLOB 的部分

  ¥a section named NODE_SEA_BLOB in the NODE_SEA segment if the node binary is a Mach-O file

• 如果 node 二进制文件是 ELF 文件，则名为 NODE_SEA_BLOB 的注释

  ¥a note named NODE_SEA_BLOB if the node binary is an ELF file

在二进制文件中搜索 NODE_SEA_FUSE_fce680ab2cc467b6e072b8b5df1996b2:0 fuse 字符串并将最后一个字符翻转为 1 以指示已注入资源。

¥Search the binary for the NODE_SEA_FUSE_fce680ab2cc467b6e072b8b5df1996b2:0 fuse string and flip the last character to 1 to indicate that a resource has been injected.

平台支持#

¥Platform support

仅在以下平台上的 CI 上定期测试单一可执行支持：

¥Single-executable support is tested regularly on CI only on the following platforms:

• Windows

• macOS

• Linux（除 Alpine 外的所有发行版 由 Node.js 支持 和除 s390x 外的所有架构 由 Node.js 支持）

  ¥Linux (all distributions supported by Node.js except Alpine and all architectures supported by Node.js except s390x)

这是由于缺乏更好的工具来生成可用于在其他平台上测试此功能的单一可执行文件。

¥This is due to a lack of better tools to generate single-executables that can be used to test this feature on other platforms.

欢迎对其他资源注入工具/工作流程提出建议。请在 https://github.com/nodejs/single-executable/discussions 开始讨论以帮助我们记录它们。

¥Suggestions for other resource injection tools/workflows are welcomed. Please start a discussion at https://github.com/nodejs/single-executable/discussions to help us document them.