如何设置代码转换

Question

我遵循transcrypt提供的入门部分，创建了一个名为hello的文件夹，然后创建了两个文件hello.py、hello.html

我的目标是在客户端运行一个函数，并将结果输出到网页

hello.py

from datetime import datetime
import time
import random

def FUN():
    for i in range(random.randrange(1, 9)):
        time.sleep(random.randrange(10 , 30 ))
        print (f"Current time {datetime.now()} , Number {i}")

hello.html

<script type="module">import * as hello from './__target__/hello.js'; window.hello = hello;</script>
    <p>
    <div id = "FUN">...</div>
    <button onclick="hello.FUN()">Do code</button>

使用python3 -m http.server启动服务器并浏览到hello.html

当我按下do code按钮时，什么也得不到

[08/May/2021 04:30:16] "GET /hello.html HTTP/1.1" 200 -
127.0.0.1 - - [08/May/2021 04:30:17] code 404, message File not found
127.0.0.1 - - [08/May/2021 04:30:17] "GET /__target__/hello.js HTTP/1.1" 404 -
127.0.0.1 - - [08/May/2021 04:30:17] code 404, message File not found
127.0.0.1 - - [08/May/2021 04:30:17] "GET /favicon.ico HTTP/1.1" 404 -

我使用命令pip3 install transcrypt安装了代码转换

但是当我运行这个命令时，python -m transcrypt -b -m -n hello.py

它中止，并显示以下输出

Saving target code in: /home/kali/n3w/__target__/org.transcrypt.__runtime__.js
Saving target code in: /home/kali/n3w/__target__/re.translate.js
Saving target code in: /home/kali/n3w/__target__/re.js
Saving target code in: /home/kali/n3w/__target__/warnings.js

Error while compiling (offending file last):
        File '/home/kali/n3w/hello.py', line 1, at import of:
        File '/home/kali/.local/lib/python3.9/site-packages/wget.py', line 562, at import of:
        File '/usr/lib/python3.9/optparse.py', line 90, at import of:
        File '/usr/lib/python3.9/gettext.py', line 718, at import of:
        File '/usr/lib/python3.9/locale.py', line 658, at import of:
        File '_bootlocale', line 8, namely:

        Import error, can't find any of:
                /home/kali/n3w/locale.py
                /home/kali/n3w/locale.js
                /home/kali/.local/lib/python3.9/site-packages/transcrypt/modules/locale.py
                /home/kali/.local/lib/python3.9/site-packages/transcrypt/modules/locale.js
                /home/kali/n3w/locale.py
                /home/kali/n3w/locale.js
                /home/kali/n3w/_bootlocale.py
                /home/kali/n3w/_bootlocale.js
                /home/kali/.local/lib/python3.9/site-packages/transcrypt/modules/_bootlocale.py
                /home/kali/.local/lib/python3.9/site-packages/transcrypt/modules/_bootlocale.js
                /home/kali/n3w/_bootlocale.py
                /home/kali/n3w/_bootlocale.js
                /home/kali/n3w/_locale.py
                /home/kali/n3w/_locale.js
                /home/kali/.local/lib/python3.9/site-packages/transcrypt/modules/_locale.py
                /home/kali/.local/lib/python3.9/site-packages/transcrypt/modules/_locale.js
                /home/kali/n3w/_locale.py
                /home/kali/n3w/_locale.js
                /usr/lib/python3.9/_locale.py
                /usr/lib/python3.9/_locale.js
                /usr/lib/python3.9/lib-dynload/_locale.py
                /usr/lib/python3.9/lib-dynload/_locale.js
                /home/kali/.local/lib/python3.9/site-packages/_locale.py
                /home/kali/.local/lib/python3.9/site-packages/_locale.js
                /home/kali/testing_0505/npm_socket/batavia/_locale.py
                /home/kali/testing_0505/npm_socket/batavia/_locale.js
                /usr/local/lib/python3.9/dist-packages/_locale.py
                /usr/local/lib/python3.9/dist-packages/_locale.js
                /usr/lib/python3/dist-packages/_locale.py
                /usr/lib/python3/dist-packages/_locale.js
                /usr/lib/python3.9/dist-packages/_locale.py
                /usr/lib/python3.9/dist-packages/_locale.js

Transcrypt站点有如何设置小演示的步骤，但没有详细说明每个命令的作用

Answer 1

Transcrypt目前适用于Python 3.7。一个新版本正在制作中，但可能还需要一段时间。致以亲切的问候雅克·德·胡奇

Answer 2

这里有一些信息，也许会有帮助。

• 你的系统也安装了Python3.9，当你输入' Python‘时，它会优先选择。

要使用3.7版本，您可能必须键入'python3.7‘或类似的内容，这取决于您使用的操作系统。要在键入'python‘时查看它使用的是哪个版本，您可以使用：

python --版本

要查看python的位置(您可能也可以在那里找到3.7版本)，请使用以下命令：

python #在哪里取决于您的操作系统

• 使用python virtual env将您从不必要的问题中解救出来。

例如:使用内置的' venv‘模块:在你的项目文件夹中:python3.7python venv package_dir #上面创建了一个名为package_dir的目录，#本地项目python包可以放到这个目录中。#然后'activate'，之后你可以在package_dir中使用' python‘#来引用python的版本，#和'pip’来引用pip3等: source package_dir/bin/activate #现在将在package_dir中安装代码转换，而不是全局。pip安装转加密

• Transcrypt不包含太多标准库，您可以在这些情况下使用js。This SO question权衡了各种python-in-browser选项的利弊。

例如，我注意到random.randrange isn't implemented，但randint是。有关兴趣，请参阅CPython source code中的randrange，这暗示了为什么它不在代码转换中。randint(a，b)与randrange(a，b+ 1)相同。

看看Transcrypt的时间实现，睡眠被排除在外，因为在当时，在浏览器中处理它需要一个循环(阻塞)。

因此，假设你想使用a non-blocking js version of sleep，因为它的性能和占用空间很小，并且决定使用randint来满足你的需求，并且你想使用randint，下面是你想要的样子：

from datetime import datetime
import random

# Add a js function that can be called by your python code.
__pragma__ ('js', '{}', '''
// Will not block main thread.
function async_sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms * 1000));
}
''')

# We're using async / await to avoid blocking the main thread.
async def FUN():
    for i in range(random.randint(1, 9 - 1)):
        await async_sleep(random.randint(10 , 30 - 1))
        current_time = f"Current time {datetime.now()} , Number {i}"
        # To output to the DOM, use js DOM functions.
        document.getElementById('FUN').innerHTML += current_time + '<br>'

作为比较，休眠的线程阻塞版本可能如下所示。

from datetime import datetime
import random

__pragma__ ('js', '{}', '''
// Bad, will block main thread.
function blocking_sleep(sec) {
    var unixtime_ms = new Date().getTime();
    while(new Date().getTime() < unixtime_ms + sec * 1000) {}
}
''')

def FUN():
    for i in range(random.randint(1, 9 - 1)):
        blocking_sleep(random.randint(10 , 30 - 1))
        current_time = f"Current time {datetime.now()} , Number {i}"
        # print() outputs to the dev console.
        print (current_time)
        document.getElementById('FUN').innerHTML += current_time + '<br>'