## 内嵌python,有手就行
今天我们通过将`yt-dlp`封装成一个exe来学习如何将`python`内嵌到你的应用程序
### 下载源码
我们下载`yt-dlp`的源码
~~~
git clone https://github.com/yt-dlp/yt-dlp.git
~~~

我们先查看源码的入口文件\_\_main\_\_.py

**\_\_main\_\_.py**

~~~python
#!/usr/bin/env python3

# Execute with
# $ python -m yt_dlp

import sys

if __package__ is None and not getattr(sys, ‘frozen’, False):
# direct call of __main__.py
import os.path
path = os.path.realpath(os.path.abspath(__file__))
sys.path.insert(0, os.path.dirname(os.path.dirname(path)))

import yt_dlp

if __name__ == ‘__main__’:
yt_dlp.main()

~~~

很明显我们要调用其功能的话，只需要导入`yt-dlp`，并调用 `main`函数即可

### 前期准备

c++调用python的原理大概是将python当做一个c++库来调用，那么我需要哪些组件呢，这里以python3.7.4为例

– 准备bin目录

进入python安装目录，我们将除了`Lib`、`include`、`libs`文件夹的所有文件都复制到你项目文件夹的`sdk/win/bin`文件夹中

将python安装目录`Lib`文件夹除了site-packages文件夹的所有文件进行zip压缩，命名为python37.zip,放到项目文件夹的`sdk/win/bin/Lib`

进入`yt-dlp`文件夹,使用python3.7.4[创建并进入虚拟环境](https://www.cnblogs.com/xiao-apple36/p/12810941.html) `venv`,使用`pip install -r requirements.txt`安装`yt-dlp`所需的第三方库，将`venv\Lib\site-packages`文件夹复制到项目文件夹的`sdk/win/bin`

最后将`yt_dlp`目录复制到项目文件夹的`sdk/win/bin`

– 准备头文件目录

将python安装目录`include`文件夹内的所有文件复制到项目文件夹的`sdk/include/python`，并将`pyconfig.h`的部分代码注释掉

~~~c++
#ifdef _DEBUG
#define Py_DEBUG
#endif
~~~
同时将：`pragma comment(lib,”python37_d.lib”)`修改为:`pragma comment(lib,”python37.lib”)`

– 准备库目录

将python安装目录libs文件夹内的`python3.lib`、`python37.lib`复制到项目文件夹的`sdk/win/lib`

### 构建项目

我这里使用`cmake`构建项目

~~~cmake
cmake_minimum_required(VERSION 3.0.0 FATAL_ERROR)

project(cYt-dlp)

if(NOT CMAKE_BUILD_TYPE)
set(CMAKE_BUILD_TYPE “Debug”)
endif()

# 设置c++17
if(MSVC)
set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} /std:c++17”)
else() # gcc clang
set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -std=c++17”)
endif(MSVC)

if(MSVC)
set(PLATFORM win)
set(LINK_LIBRARY_DIR lib)
set(LINK_LIBRARY python37 python3)
endif()

add_executable(cYt-dlp main.cpp)

#添加头文件目录
target_include_directories(cYt-dlp PUBLIC ${CMAKE_SOURCE_DIR}/sdk/include)

# 添加库目录
target_link_directories(cYt-dlp PUBLIC ${CMAKE_SOURCE_DIR}/sdk/${PLATFORM}/${LINK_LIBRARY_DIR})

# 链接动态库
target_link_libraries(cYt-dlp PUBLIC ${LINK_LIBRARY})

if(MSVC)
# 后处理脚本，将sdk bin目录复制到生成文件夹
add_custom_command(
TARGET cYt-dlp POST_BUILD
COMMAND xcopy “\”${CMAKE_SOURCE_DIR}/sdk/win/bin\”” “$(Outdir)” /E /Y
)

# 设置vs调试目录
set_target_properties(cYt-dlp PROPERTIES VS_DEBUGGER_WORKING_DIRECTORY “$(OutDir)”)
endif()
~~~

### 编写代码

– 设置Home路径

~~~c++
/**
设置python37.dll的所在路径
**/
void Py_SetPythonHome(const wchar_t *home)
~~~

~~~c++
wstring wStrExeDir;
wchar_t wszExeName[MAX_PATH] = { 0, };

::GetModuleFileNameW(NULL, wszExeName, MAX_PATH);
wStrExeDir = wszExeName;
wStrExeDir = wStrExeDir.substr(0, wStrExeDir.find_last_of(L”\\”));

//设置Home路径
Py_SetPythonHome(wStrExeDir.c_str());
~~~

这里设置exe所在目录即可

+ 初始化

~~~c++
Py_Initialize();
~~~

+ 传递命令行参数

~~~c++
PyObject* sys = PyImport_ImportModule(“sys”);
PyObject* arglist = PyList_New(argc);
for (int i = 0; i < argc; i++) {
PyObject* arg = PyUnicode_DecodeFSDefault(argv[i]);
PyList_SetItem(arglist, i, arg);
}
PyObject_SetAttrString(sys, “argv”, arglist);
Py_DECREF(arglist);
Py_DECREF(sys);
~~~
这里是写死的，不用讲解

+ 调用目标函数

~~~c++
/*
导入模块，相当于python语法里的import 语句
*/
PyObject* PyImport_ImportModule(const char *name)
~~~

~~~c++
/**
获取对象属性
**/
PyObject* PyObject_GetAttrString(PyObject *o, const char *attr_name)
~~~
~~~c++
/*
调用Python函数
*/
PyObject* PyObject_CallObject(PyObject *callable, PyObject *args)
~~~
~~~c++
char* result;
PyObject* pModule = PyImport_ImportModule(“yt_dlp”);
if (pModule == NULL) {
PyErr_Print();
cout << “module not found” << endl;
return -1;
}

PyObject* pFunc = PyObject_GetAttrString(pModule, “main”);
if (!pFunc || !PyCallable_Check(pFunc)) {
PyErr_Print();
cout << “not found function init” << endl; return -1; } PyObject* pReturn = PyObject_CallObject(pFunc, NULL); PyErr_Print(); ~~~ + 释放资源 ~~~c++ Py_Finalize(); ~~~ > 可以查看[官方文档](https://docs.python.org/zh-tw/3.7/extending/embedding.html?highlight=pyobject_getattrstring)

最后完整代码如下

`main.cpp`

~~~c++
#include
#include
#include <python/Python.h>

using namespace std;

int main(int argc,char ** argv) {

wstring wStrExeDir;
wchar_t wszExeName[MAX_PATH] = { 0, };

::GetModuleFileNameW(NULL, wszExeName, MAX_PATH);
wStrExeDir = wszExeName;
wStrExeDir = wStrExeDir.substr(0, wStrExeDir.find_last_of(L”\\”));

//设置Home路径
Py_SetPythonHome(wStrExeDir.c_str());

//初始化
Py_Initialize();

//传递命令行参数
PyObject* sys = PyImport_ImportModule(“sys”);
PyObject* arglist = PyList_New(argc);
for (int i = 0; i < argc; i++) {
PyObject* arg = PyUnicode_DecodeFSDefault(argv[i]);
PyList_SetItem(arglist, i, arg);
}
PyObject_SetAttrString(sys, “argv”, arglist);
Py_DECREF(arglist);
Py_DECREF(sys);

//调用目标函数
char* result;
PyObject* pModule = PyImport_ImportModule(“yt_dlp”);
if (pModule == NULL) {
PyErr_Print();
cout << “module not found” << endl;
return -1;
}

PyObject* pFunc = PyObject_GetAttrString(pModule, “main”);
if (!pFunc || !PyCallable_Check(pFunc)) {
PyErr_Print();
cout << “not found function init” << endl;
return -1;
}

PyObject* pReturn = PyObject_CallObject(pFunc, NULL);
PyErr_Print();

//释放资源
Py_Finalize();

return 0;
}
~~~