# 34.3. `winreg` — Windows 注册表访问

这些函数将 Windows 注册表 API 暴露给 Python。为了确保即便程序员忽略了显式关闭句柄，该句柄依然能够正确关闭，它使用了一个 handle 对象 而不是整数来作为注册表句柄。

在 3.3 版更改: 该模块中的几个函数被用于引发 `WindowsError`，该异常现在是 `OSError` 的别名。

## 34.3.1. 函数

该模块提供了下列函数：

`winreg.``CloseKey`(hkey)

  关闭之前打开的注册表键。参数 hkey 指之前打开的键。

  注解

  如果没有使用该方法关闭 hkey (或者通过 `hkey.Close()`)，在对象 hkey 被 Python 销毁时会将其关闭。

`winreg.``ConnectRegistry`(computer_name, key)

  建立到另一台计算上上的预定义注册表句柄的连接，并返回一个 handle 对象.

  computer_name 是远程计算机的名称，以 `r"\\computername"` 的形式。如果是 `None` ，将会使用本地计算机。

  key 是所连接到的预定义句柄。

  返回值是所开打键的句柄。如果函数失败，则引发一个 `OSError` 异常。

  在 3.3 版更改: 参考 上文。

`winreg.``CreateKey`(key, sub_key)

  创建或打开特定的键，返回一个 handle 对象。

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  sub_key 是用于命名该方法所打开或创建的键的字符串。

  如果 key 是预定义键之一，sub_key 可能会是 `None`。该情况下，返回的句柄就是传入函数的句柄。

  如果键已经存在，则该函数打开已经存在的该键。

  返回值是所开打键的句柄。如果函数失败，则引发一个 `OSError` 异常。

  在 3.3 版更改: 参考 上文。

`winreg.``CreateKeyEx`(key, sub_key, reserved=0, access=KEY_WRITE)

  创建或打开特定的键，返回一个 handle 对象。

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  sub_key 是用于命名该方法所打开或创建的键的字符串。

  reserved 是一个保留的证书，必须是零。默认值为零。

  access 为一个整数，用于给键的预期安全访问指定访问掩码。默认值为 `KEY_WRITE`。 参阅 Access Rights 了解其它允许值。

  如果 key 是预定义键之一，sub_key 可能会是 `None`。该情况下，返回的句柄就是传入函数的句柄。

  如果键已经存在，则该函数打开已经存在的该键。

  返回值是所开打键的句柄。如果函数失败，则引发一个 `OSError` 异常。

  3.2 新版功能.

  在 3.3 版更改: 参考 上文。

`winreg.``DeleteKey`(key, sub_key)

  删除指定的键。

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  sub_key 这个字符串必须是由 key 参数所指定键的一个子项。该值项不可以是 `None`，同时键也不可以有子项。

  该方法不能删除带有子项的键。

  如果方法成功，则整个键，包括其所有值项都会被移除。如果方法失败，则引发一个 `OSError` 异常。

  在 3.3 版更改: 参考 上文。

`winreg.``DeleteKeyEx`(key, sub_key, access=KEY_WOW64_64KEY, reserved=0)

  删除指定的键。

  注解

  函数 `DeleteKeyEx()` 通过 RegDeleteKeyEx 这个 Windows API 函数实现，该函数为 Windows 的64位版本专属。 参阅 RegDeleteKeyEx 文档。

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  sub_key 这个字符串必须是由 key 参数所指定键的一个子项。该值项不可以是 `None`，同时键也不可以有子项。

  reserved 是一个保留的证书，必须是零。默认值为零。

  access 为一个整数，用于给键的预期安全访问指定访问掩码。默认值为常量 `_WOW64_64KEY` 。参阅 Access Rights 了解其它允许值。

  该方法不能删除带有子项的键。

  如果方法成功，则整个键，包括其所有值项都会被移除。如果方法失败，则引发一个 `OSError` 异常。

  在不支持的 Windows 版本之上，将会引发 `NotImplementedError` 异常。

  3.2 新版功能.

  在 3.3 版更改: 参考 上文。

`winreg.``DeleteValue`(key, value)

  从某个注册键中删除一个命名值项。

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  value 为标识所要删除值项的字符串。

`winreg.``EnumKey`(key, index)

  列举某个已经打开注册表键的子项，并返回一个字符串。

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  index 为一个整数，用于标识所获取键的索引。

  每次调用该函数都会获取一个子项的名字。通常它会被反复调用，直到引发 `OSError` 异常，这说明已经没有更多的可用值了。

  在 3.3 版更改: 参考 上文。

`winreg.``EnumValue`(key, index)

  列举某个已经打开注册表键的值项，并返回一个元组。

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  index 为一个整数，用于标识要获取值项的索引。

  每次调用该函数都会获取一个子项的名字。通常它会被反复调用，直到引发 `OSError` 异常，这说明已经没有更多的可用值了。

  结果为3元素的元组。

  索引 | 含义
  --- | ---
  `0` | 用于标识值项名称的字符串。
  `1` | 保存值项数据的对象，其类型取决于背后的注册表类型。
  `2` | 标识值项数据类型的整数。（请查阅 `SetValueEx()` 文档中的表格）

  在 3.3 版更改: 参考 上文。

`winreg.``ExpandEnvironmentStrings`(str)

  Expands environment variable placeholders `%NAME%` in strings like `REG_EXPAND_SZ`:

      >>> ExpandEnvironmentStrings('%windir%')
      'C:\\Windows'

`winreg.``FlushKey`(key)

  将某个键的所有属性写入注册表。

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  It is not necessary to call `FlushKey()` to change a key. Registry changes are flushed to disk by the registry using its lazy flusher. Registry changes are also flushed to disk at system shutdown. Unlike `CloseKey()`, the `FlushKey()` method returns only when all the data has been written to the registry. An application should only call `FlushKey()` if it requires absolute certainty that registry changes are on disk.

  注解

  If you don’t know whether a `FlushKey()` call is required, it probably isn’t.

`winreg.``LoadKey`(key, sub_key, file_name)

  Creates a subkey under the specified key and stores registration information from a specified file into that subkey.

  key is a handle returned by `ConnectRegistry()` or one of the constants `HKEY_USERS` or `HKEY_LOCAL_MACHINE`.

  sub_key is a string that identifies the subkey to load.

  file_name is the name of the file to load registry data from. This file must have been created with the `SaveKey()` function. Under the file allocation table (FAT) file system, the filename may not have an extension.

  A call to `LoadKey()` fails if the calling process does not have the `SE_RESTORE_PRIVILEGE` privilege. Note that privileges are different from permissions – see the RegLoadKey documentation for more details.

  If key is a handle returned by `ConnectRegistry()`, then the path specified in file_name is relative to the remote computer.

`winreg.``OpenKey`(key, sub_key, reserved=0, access=KEY_READ)
`winreg.``OpenKeyEx`(key, sub_key, reserved=0, access=KEY_READ)

  Opens the specified key, returning a handle object.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  sub_key is a string that identifies the sub_key to open.

  reserved is a reserved integer, and must be zero. The default is zero.

  access is an integer that specifies an access mask that describes the desired security access for the key. Default is `KEY_READ`. See Access Rights for other allowed values.

  The result is a new handle to the specified key.

  If the function fails, `OSError` is raised.

  在 3.2 版更改: Allow the use of named arguments.

  在 3.3 版更改: 参考 上文。

`winreg.``QueryInfoKey`(key)

  Returns information about a key, as a tuple.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  结果为3元素的元组。

  索引 | 含义
  --- | ---
  `0` | An integer giving the number of sub keys this key has.
  `1` | An integer giving the number of values this key has.
  `2` | An integer giving when the key was last modified (if available) as 100’s of nanoseconds since Jan 1, 1601.

`winreg.``QueryValue`(key, sub_key)

  Retrieves the unnamed value for a key, as a string.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  sub_key is a string that holds the name of the subkey with which the value is associated. If this parameter is `None` or empty, the function retrieves the value set by the `SetValue()` method for the key identified by key.

  Values in the registry have name, type, and data components. This method retrieves the data for a key’s first value that has a NULL name. But the underlying API call doesn’t return the type, so always use `QueryValueEx()` if possible.

`winreg.``QueryValueEx`(key, value_name)

  Retrieves the type and data for a specified value name associated with an open registry key.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  value_name is a string indicating the value to query.

  The result is a tuple of 2 items:

  索引 | 含义
  --- | ---
  `0` | The value of the registry item.
  `1` | An integer giving the registry type for this value (see table in docs for `SetValueEx()`)

`winreg.``SaveKey`(key, file_name)

  Saves the specified key, and all its subkeys to the specified file.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  file_name is the name of the file to save registry data to. This file cannot already exist. If this filename includes an extension, it cannot be used on file allocation table (FAT) file systems by the `LoadKey()` method.

  If key represents a key on a remote computer, the path described by file_name is relative to the remote computer. The caller of this method must possess the `SeBackupPrivilege` security privilege. Note that privileges are different than permissions – see the Conflicts Between User Rights and Permissions documentation for more details.

  This function passes NULL for security_attributes to the API.

`winreg.``SetValue`(key, sub_key, type, value)

  Associates a value with a specified key.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  sub_key is a string that names the subkey with which the value is associated.

  type is an integer that specifies the type of the data. Currently this must be `REG_SZ`, meaning only strings are supported. Use the `SetValueEx()` function for support for other data types.

  value is a string that specifies the new value.

  If the key specified by the sub_key parameter does not exist, the SetValue function creates it.

  Value lengths are limited by available memory. Long values (more than 2048 bytes) should be stored as files with the filenames stored in the configuration registry. This helps the registry perform efficiently.

  The key identified by the key parameter must have been opened with `KEY_SET_VALUE` access.

`winreg.``SetValueEx`(key, value_name, reserved, type, value)

  Stores data in the value field of an open registry key.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  value_name is a string that names the subkey with which the value is associated.

  reserved can be anything – zero is always passed to the API.

  type is an integer that specifies the type of the data. See Value Types for the available types.

  value is a string that specifies the new value.

  This method can also set additional value and type information for the specified key. The key identified by the key parameter must have been opened with `KEY_SET_VALUE` access.

  To open the key, use the `CreateKey()` or `OpenKey()` methods.

  Value lengths are limited by available memory. Long values (more than 2048 bytes) should be stored as files with the filenames stored in the configuration registry. This helps the registry perform efficiently.

`winreg.``DisableReflectionKey`(key)

  Disables registry reflection for 32-bit processes running on a 64-bit operating system.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  Will generally raise `NotImplemented` if executed on a 32-bit operating system.

  If the key is not on the reflection list, the function succeeds but has no effect. Disabling reflection for a key does not affect reflection of any subkeys.

`winreg.``EnableReflectionKey`(key)

  Restores registry reflection for the specified disabled key.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  Will generally raise `NotImplemented` if executed on a 32-bit operating system.

  Restoring reflection for a key does not affect reflection of any subkeys.

`winreg.``QueryReflectionKey`(key)

  Determines the reflection state for the specified key.

  key 为某个已经打开的键，或者预定义的 HKEY_* 常量 之一。

  Returns `True` if reflection is disabled.

  Will generally raise `NotImplemented` if executed on a 32-bit operating system.

## 34.3.2. 常量

The following constants are defined for use in many `_winreg` functions.

### 34.3.2.1. HKEY_* Constants

`winreg.``HKEY_CLASSES_ROOT`

  Registry entries subordinate to this key define types (or classes) of documents and the properties associated with those types. Shell and COM applications use the information stored under this key.

`winreg.``HKEY_CURRENT_USER`

  Registry entries subordinate to this key define the preferences of the current user. These preferences include the settings of environment variables, data about program groups, colors, printers, network connections, and application preferences.

`winreg.``HKEY_LOCAL_MACHINE`

  Registry entries subordinate to this key define the physical state of the computer, including data about the bus type, system memory, and installed hardware and software.

`winreg.``HKEY_USERS`

  Registry entries subordinate to this key define the default user configuration for new users on the local computer and the user configuration for the current user.

`winreg.``HKEY_PERFORMANCE_DATA`

  Registry entries subordinate to this key allow you to access performance data. The data is not actually stored in the registry; the registry functions cause the system to collect the data from its source.

`winreg.``HKEY_CURRENT_CONFIG`

  Contains information about the current hardware profile of the local computer system.

`winreg.``HKEY_DYN_DATA`

  This key is not used in versions of Windows after 98.

### 34.3.2.2. Access Rights

For more information, see Registry Key Security and Access.

`winreg.``KEY_ALL_ACCESS`

  Combines the STANDARD_RIGHTS_REQUIRED, `KEY_QUERY_VALUE`, `KEY_SET_VALUE`, `KEY_CREATE_SUB_KEY`, `KEY_ENUMERATE_SUB_KEYS`, `KEY_NOTIFY`, and `KEY_CREATE_LINK` access rights.

`winreg.``KEY_WRITE`

  Combines the STANDARD_RIGHTS_WRITE, `KEY_SET_VALUE`, and `KEY_CREATE_SUB_KEY` access rights.

`winreg.``KEY_READ`

  Combines the STANDARD_RIGHTS_READ, `KEY_QUERY_VALUE`, `KEY_ENUMERATE_SUB_KEYS`, and `KEY_NOTIFY` values.

`winreg.``KEY_EXECUTE`

  Equivalent to `KEY_READ`.

`winreg.``KEY_QUERY_VALUE`

  Required to query the values of a registry key.

`winreg.``KEY_SET_VALUE`

  Required to create, delete, or set a registry value.

`winreg.``KEY_CREATE_SUB_KEY`

  Required to create a subkey of a registry key.

`winreg.``KEY_ENUMERATE_SUB_KEYS`

  Required to enumerate the subkeys of a registry key.

`winreg.``KEY_NOTIFY`

  Required to request change notifications for a registry key or for subkeys of a registry key.

`winreg.``KEY_CREATE_LINK`

  Reserved for system use.

#### 34.3.2.2.1. 64-bit Specific

For more information, see Accessing an Alternate Registry View.

`winreg.``KEY_WOW64_64KEY`

  Indicates that an application on 64-bit Windows should operate on the 64-bit registry view.

`winreg.``KEY_WOW64_32KEY`

  Indicates that an application on 64-bit Windows should operate on the 32-bit registry view.

### 34.3.2.3. Value Types

For more information, see Registry Value Types.

`winreg.``REG_BINARY`

  Binary data in any form.

`winreg.``REG_DWORD`

  32-bit number.

`winreg.``REG_DWORD_LITTLE_ENDIAN`

  A 32-bit number in little-endian format. Equivalent to `REG_DWORD`.

`winreg.``REG_DWORD_BIG_ENDIAN`

  A 32-bit number in big-endian format.

`winreg.``REG_EXPAND_SZ`

  Null-terminated string containing references to environment variables (`%PATH%`).

`winreg.``REG_LINK`

  A Unicode symbolic link.

`winreg.``REG_MULTI_SZ`

  A sequence of null-terminated strings, terminated by two null characters. (Python handles this termination automatically.)

`winreg.``REG_NONE`

  No defined value type.

`winreg.``REG_QWORD`

  A 64-bit number.

  3.6 新版功能.

`winreg.``REG_QWORD_LITTLE_ENDIAN`

  A 64-bit number in little-endian format. Equivalent to `REG_QWORD`.

  3.6 新版功能.

`winreg.``REG_RESOURCE_LIST`

  A device-driver resource list.

`winreg.``REG_FULL_RESOURCE_DESCRIPTOR`

  A hardware setting.

`winreg.``REG_RESOURCE_REQUIREMENTS_LIST`

  A hardware resource list.

`winreg.``REG_SZ`

  A null-terminated string.

## 34.3.3. Registry Handle Objects

This object wraps a Windows HKEY object, automatically closing it when the object is destroyed. To guarantee cleanup, you can call either the `Close()` method on the object, or the `CloseKey()` function.

All registry functions in this module return one of these objects.

All registry functions in this module which accept a handle object also accept an integer, however, use of the handle object is encouraged.

Handle objects provide semantics for `__bool__()` – thus

    if handle:
        print("Yes")

will print `Yes` if the handle is currently valid (has not been closed or detached).

The object also support comparison semantics, so handle objects will compare true if they both reference the same underlying Windows handle value.

Handle objects can be converted to an integer (e.g., using the built-in `int()` function), in which case the underlying Windows handle value is returned. You can also use the `Detach()` method to return the integer handle, and also disconnect the Windows handle from the handle object.

`PyHKEY.``Close`()

  Closes the underlying Windows handle.

  If the handle is already closed, no error is raised.

`PyHKEY.``Detach`()

  Detaches the Windows handle from the handle object.

  The result is an integer that holds the value of the handle before it is detached. If the handle is already detached or closed, this will return zero.

  After calling this function, the handle is effectively invalidated, but the handle is not closed. You would call this function when you need the underlying Win32 handle to exist beyond the lifetime of the handle object.

`PyHKEY.``__enter__`()
`PyHKEY.``__exit__`(*exc_info)

  The HKEY object implements `__enter__()` and `__exit__()` and thus supports the context protocol for the `with` statement:

      with OpenKey(HKEY_LOCAL_MACHINE, "foo") as key:
          ...  # work with key

  will automatically close key when control leaves the `with` block.