python的pyc文件详细理解

文章目录

1 什么是pyc文件

1.1 什么是pyc文件

1.2 pyc文件是怎么生成的，有什么好处

2 把python的py文件编译成pyc文件

2.1 使用python内置库py_compile把单个py文件编译成pyc文件

2.2 使用python内置库compileall把多个py文件编译成pyc文件

2.2.1 使用python -m compileall命令把多个py文件编译成pyc文件

2.2.2 使用compileall的API把多个py文件编译成pyc文件

3 使用uncomplye6工具把pyc文件反编译成py文件

3.1 使用uncomplye6工具安装

3.1.1 uncomplye6介绍

3.1.2 uncomplye6安装

3.2 使用uncomplye6工具把pyc反编译为py文件的具体使用

3.2.1 查看uncomplye6的参数

3.2.2 使用uncompyle6命令把pyc反编译成py文件

4 python编译的如何设置不生成pyc文件

1 什么是pyc文件

1.1 什么是pyc文件

1、pyc文件：是由Python文件经过编译后所生成的文件，它是一种字节码 byte code，因此我们直接查看就是乱码的，也对源码起到一定的保护作用，但是这种字节码byte code是可以反编译的，后面会介绍！

我们都知道计算机是不认识你在代码里写的那一行行字母的，计算机只认二进制，也只执行二进制文件，我们写的代码是需要编译器编译成二进制的。（参考）

对于Python来说你写的Python代码在执行python xxx.py时会由Python解析器翻译成PyCodeObject对象，俗称字节码(byte code)，然后交由Python虚拟机来执行字节码（PS：字节码才是可执行的）。

在这个过程中这些字节码都是在内存中的，众所周知Python的运行性能不如编译性语言(比如C语言，JAVA …)，所以Python在程序执行结束后会把字节码写入到硬盘中，保存为.pyc文件，目的是下一次再执行python xxx.py程序时，Python会先在目录下找xxx.pyc文件来执行，因为.pyc文件里保存的是字节码，所以就节省了Python解析器把xxx.py翻译成字节码的时间，所以就提高了性能。

总结就是.pyc文件是一个可执行的字节码文件，目的是节省Python解析器翻译时间，提高运行效率。其实性能只会提高那么一丢丢，大型项目.py文件很多的话，猿人学Python测试过节省的时间就多一点。

2、我们同样可以像执行py文件一样来执行pyc文件，例如：

python test.py

python test.pyc

注意：

必须保证编译成pyc文件的python解释器版本和现在执行的python解释器版本保持一致，否则会报错，如下我导入deepsocial.pyc文件中的模块是报错：ImportError: bad magic number in 'deepsocial': b'B\r\r\n'

from deepsocial import *

ImportError: bad magic number in 'deepsocial': b'B\r\r\n'

1.2 pyc文件是怎么生成的，有什么好处

从上面的介绍我们已经知道pyc的好处主要是：

由于pyc源码的不可见，因此可以起到保护代码安全性的作用，但也不是绝对的，因为pyc文件是可以被反编译

pyc文件可以提高代码的执行效率

pyc的内容与python的版本相关，不同版本编译的pyc文件不一样

2 把python的py文件编译成pyc文件

下面我测试的文件目录结构：

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project$ tree test/

test/

├── deepsocial.py

└── scripts

└── run.py

1 directory, 2 files

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project$

2.1 使用python内置库py_compile把单个py文件编译成pyc文件

1、使用py_compile把单个py文件编译成pyc文件

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/test$ ls

deepsocial.py scripts

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/test$ python

Python 3.6.12 |Anaconda, Inc.| (default, Sep 8 2020, 23:10:56)

[GCC 7.3.0] on linux

Type "help", "copyright", "credits" or "license" for more information.

>>> import py_compile

>>> py_compile.compile("./deepsocial.py")

'./__pycache__/deepsocial.cpython-36.pyc'

>>>

生成文件如下：

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/test$ tree

.

├── deepsocial.py

├── __pycache__

│ └── deepsocial.cpython-36.pyc

└── scripts

└── run.py

2 directories, 3 files

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/test$

2.2 使用python内置库compileall把多个py文件编译成pyc文件

2.2.1 使用python -m compileall命令把多个py文件编译成pyc文件

1、首先来查看python -m compileall有哪些参数

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/test$ python -m compileall -h

usage: compileall.py [-h] [-l] [-r RECURSION] [-f] [-q] [-b] [-d DESTDIR]

[-x REGEXP] [-i FILE] [-j WORKERS]

[FILE|DIR [FILE|DIR ...]]

Utilities to support installing Python libraries.

positional arguments:

FILE|DIR zero or more file and directory names to compile; if

no arguments given, defaults to the equivalent of -l

sys.path

optional arguments:

-h, --help show this help message and exit

-l don't recurse into subdirectories

-r RECURSION control the maximum recursion level. if `-l` and `-r`

options are specified, then `-r` takes precedence.

-f force rebuild even if timestamps are up to date

-q output only error messages; -qq will suppress the

error messages as well.

-b use legacy (pre-PEP3147) compiled file locations

-d DESTDIR directory to prepend to file paths for use in compile-

time tracebacks and in runtime tracebacks in cases

where the source file is unavailable

-x REGEXP skip files matching the regular expression; the regexp

is searched for in the full path of each file

considered for compilation

-i FILE add all the files and directories listed in FILE to

the list considered for compilation; if "-", names are

read from stdin

-j WORKERS, --workers WORKERS

Run compileall concurrently

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/test$

2、把单个py文件生成pyc文件，例如

python -m compileall deepsocial.py

3、递归的把当前目录下所有的py文件都生成对应的pyc文件

python -m compileall .

注意：

后面有一个点.， 表示当前目录！

2.2.2 使用compileall的API把多个py文件编译成pyc文件

如下，是通过调用compileall的API接口，递归的把指定目录下所有的py文件都生成对应的pyc文件！

>>> import compileall

>>> compileall.compile_dir("/home/shl/shl_res/5_new_project/test")

Listing '/home/shl/shl_res/5_new_project/test'...

Compiling '/home/shl/shl_res/5_new_project/test/deepsocial.py'...

Listing '/home/shl/shl_res/5_new_project/test/scripts'...

Compiling '/home/shl/shl_res/5_new_project/test/scripts/run.py'...

True

>>>

3 使用uncomplye6工具把pyc文件反编译成py文件

只有pyc文件可以运行程序，但是是不能获取程序源码的。同时如果python的版本和pyc版本使用的不同，那么程序会闪退。对pyc文件进行反编译需要用到python第三方库包uncompyle。

3.1 使用uncomplye6工具安装

3.1.1 uncomplye6介绍

1、uncomplye6介绍

uncomplye6继承了decompyle、uncompyle 和uncompyle2。uncompyle6可将python字节码转换回等效的python源代码，它接受python 1.3版到3.8版的字节码。

2、uncomplye6的github地址

uncomplye6 github地址：https://github.com/rocky/python-uncompyle6

3.1.2 uncomplye6安装

1、pip安装

pip install uncomplye6

2、从源码安装

git clone https://github.com.cnpmjs.org/rocky/python-uncompyle6.git

编译：

$cd python-uncompyle6

$pip install -e . # set up to run from source tree

# Or if you want to install instead

$python setup.py install # may need sudo

3.2 使用uncomplye6工具把pyc反编译为py文件的具体使用

3.2.1 查看uncomplye6的参数

1、安装好uncomplye6后，可以使用uncomplye6 -h从

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/DeepSOCIAL$ python -V

Python 3.6.12 :: Anaconda, Inc.

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/DeepSOCIAL$ uncompyle6 -V

uncompyle6 3.7.4

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/DeepSOCIAL$ uncompyle6 -h

Usage:

uncompyle6 [OPTIONS]... [ FILE | DIR]...

uncompyle6 [--help | -h | --V | --version]

Examples:

uncompyle6 foo.pyc bar.pyc # decompile foo.pyc, bar.pyc to stdout

uncompyle6 -o . foo.pyc bar.pyc # decompile to ./foo.pyc_dis and ./bar.pyc_dis

uncompyle6 -o /tmp /usr/lib/python1.5 # decompile whole library

Options:

-o output decompiled files to this path:

if multiple input files are decompiled, the common prefix

is stripped from these names and the remainder appended to

uncompyle6 -o /tmp bla/fasel.pyc bla/foo.pyc

-> /tmp/fasel.pyc_dis, /tmp/foo.pyc_dis

uncompyle6 -o /tmp bla/fasel.pyc bar/foo.pyc

-> /tmp/bla/fasel.pyc_dis, /tmp/bar/foo.pyc_dis

uncompyle6 -o /tmp /usr/lib/python1.5

-> /tmp/smtplib.pyc_dis ... /tmp/lib-tk/FixTk.pyc_dis

--compile | -c

attempts a decompilation after compiling

-d print timestamps

-p use number of processes

-r recurse directories looking for .pyc and .pyo files

--fragments use fragments deparser

--verify compare generated source with input byte-code

--verify-run compile generated source, run it and check exit code

--syntax-verify compile generated source

--linemaps generated line number correspondencies between byte-code

and generated source output

--encoding

use in generated source according to pep-0263

--help show this message

Debugging Options:

--asm | -a include byte-code (disables --verify)

--grammar | -g show matching grammar

--tree={before|after}

-t {before|after} include syntax before (or after) tree transformation

(disables --verify)

--tree++ | -T add template rules to --tree=before when possible

Extensions of generated files:

'.pyc_dis' '.pyo_dis' successfully decompiled (and verified if --verify)

+ '_unverified' successfully decompile but --verify failed

+ '_failed' decompile failed (contact author for enhancement)

(yolov4) shl@zhihui-mint:~/shl_res/5_new_project/DeepSOCIAL$

3.2.2 使用uncompyle6命令把pyc反编译成py文件

1、首先我们可以去下载一个pyc文件（我正式因为看不到它的源码，才去搞的这个）

wget https://github.com.cnpmjs.org/DrMahdiRezaei/DeepSOCIAL/blob/master/deepsocial.pyc

2、使用uncompyle6命令把pyc反编译成py文件

uncompyle6 deepsocial.pyc > deepsocial.py

或

uncompyle6 -o deepsocial.py deepsocial.pyc

输出的deepsocial.py文件开头会多一段这样的注释：

# uncompyle6 version 3.7.4

# Python bytecode 3.7 (3394)

# Decompiled from: Python 3.6.12 |Anaconda, Inc.| (default, Sep 8 2020, 23:10:56)

# [GCC 7.3.0]

# Embedded file name: deepsocial.py

# Compiled at: 2021-03-06 05:54:51

# Size of source mod 2**32: 14036 bytes

说明：

uncompyle6 version 3.7.4：uncompyle6工具的版本是3.7.4

Python bytecode 3.7：deepsocial.pyc字节码byte code文件是使用python3.7生成的，因此要执行pyc文件，必须要python的版本也是3.7版本才可以！

Decompiled from: Python 3.6.12：我解码pyc使用的是python版本是3.6.12

3、将当前文件夹中所有的 pyc 文件反编译成后缀名为.pyc_dis 的源文件

uncompile -o . *.pyc

4 python编译的如何设置不生成pyc文件

pyc文件一般是在使用import导入另一个模块的时候会生成，python3会把生成的pyc文件存储在__pycache__目录下。

那如何让python编译的时候不生成pyc文件呢，有如下几种方法：

方法一：使用-B参数 即

python -B test.py

可以使用python -h查看参数的含义：

(base) shl@zhihui-mint:~$ python -h

usage: python [option] ... [-c cmd | -m mod | file | -] [arg] ...

Options and arguments (and corresponding environment variables):

-b : issue warnings about str(bytes_instance), str(bytearray_instance)

and comparing bytes/bytearray with str. (-bb: issue errors)

-B : don't write .pyc files on import; also PYTHONDONTWRITEBYTECODE=x

-c cmd : program passed in as string (terminates option list)

-d : debug output from parser; also PYTHONDEBUG=x

-E : ignore PYTHON* environment variables (such as PYTHONPATH)

-h : print this help message and exit (also --help)

-i : inspect interactively after running script; forces a prompt even

if stdin does not appear to be a terminal; also PYTHONINSPECT=x

-I : isolate Python from the user's environment (implies -E and -s)

-m mod : run library module as a script (terminates option list)

-O : remove assert and __debug__-dependent statements; add .opt-1 before

.pyc extension; also PYTHONOPTIMIZE=x

-OO : do -O changes and also discard docstrings; add .opt-2 before

.pyc extension

-q : don't print version and copyright messages on interactive startup

-s : don't add user site directory to sys.path; also PYTHONNOUSERSITE

-S : don't imply 'import site' on initialization

-u : force the stdout and stderr streams to be unbuffered;

this option has no effect on stdin; also PYTHONUNBUFFERED=x

-v : verbose (trace import statements); also PYTHONVERBOSE=x

can be supplied multiple times to increase verbosity

-V : print the Python version number and exit (also --version)

when given twice, print more information about the build

-W arg : warning control; arg is action:message:category:module:lineno

also PYTHONWARNINGS=arg

-x : skip first line of source, allowing use of non-Unix forms of #!cmd

方法二：设置环境变量

export PYTHONDONTWRITEBYTECODE=1

方法三：在导入的地方设置如下

import sys

sys.dont_write_bytecode = True

参考：https://www.yuanrenxue.com/tricks/what-is-pyc-file.html # 对pyc文件解释比较清楚

参考：https://www.php.cn/python-tutorials-416352.html # 把py文件生成pyc文件