目录

前言1 使用方法1.1 安装 Pywebio1.2 输出内容1.3 输入内容

2 示例程序2.1 BMI 计算器2.2 Markdown 编辑器2.3 聊天室2.4 五子棋

前言

前两天正在逛 Github，偶然看到一个很有意思的项目：PyWebIo。

这是一个 Python 第三方库，可以只用 Python 语言写出一个网页，而且支持 Flask，Django，Tornado 等 web 框架。

甚至，它可以支持数据可视化图表的绘制，还提供了一行函数渲染 Markdown 文本。

那么话不多说，正片开始——

仓库地址：https://github.com/pywebio/PyWebIO

1 使用方法

1.1 安装 Pywebio

打开 CMD，在里面输入以下代码：

<code>pip install pywebio

如果速度太慢，建议使用国内镜像：

pip install -i https://pypi.tuna.tsinghua.edu.cn/simple pywebio

1.2 输出内容

put_text() 输出文字put_table() 输出表格put_markdown() 输出 markdown 内容put_file() 输出文件下载链接put_image() 输出图片put_button() 输出按钮

请看示例程序：

from pywebio.output import *

def main():

# 文本输出

put_text("Hello world!")

# 表格输出

put_table([

['商品', '价格'],

['苹果', '5.5'],

['香蕉', '7'],

])

# Markdown输出

put_markdown('~~删除线~~')

# 文件输出

put_file('hello_word.txt', b'hello word!')

if __name__ == '__main__':

main()

1.3 输入内容

<code>input() 和 python 一样的函数欸

from pywebio.input import *

def main():

name = input("请输入你的名字：")

if __name__ == '__main__':

main()

2 示例程序

这些都是官方给出的实例，代码都不到 100 行！

官方项目地址：https://pywebio-demos.pywebio.online/

2.1 BMI 计算器

<code>from pywebio.input import input, FLOAT

from pywebio.output import put_text

def bmi():

height = input("Your Height(cm)：", type=FLOAT)

weight = input("Your Weight(kg)：", type=FLOAT)

BMI = weight / (height / 100) ** 2

top_status = [(14.9, 'Severely underweight'), (18.4, 'Underweight'),

(22.9, 'Normal'), (27.5, 'Overweight'),

(40.0, 'Moderately obese'), (float('inf'), 'Severely obese')]

for top, status in top_status:

if BMI <= top:

put_text('Your BMI: %.1f, category: %s' % (BMI, status))

break

if __name__ == '__main__':

bmi()

2.2 Markdown 编辑器

<code>from pywebio import start_server

from pywebio.output import *

from pywebio.pin import *

from pywebio.session import set_env, download

def main():

"""Markdown Previewer"""

set_env(output_animation=False)

put_markdown("""# Markdown Live Preview

The online markdown editor with live preview. The source code of this application is [here](https://github.com/wang0618/PyWebIO/blob/dev/demos/markdown_previewer.py).

## Write your Markdown

""")

put_textarea('md_text', rows=18, code={ 'mode': 'markdown'})

put_buttons(['Download content'], lambda _: download('saved.md', pin.md_text.encode('utf8')), small=True)

put_markdown('## Preview')

while True:

change_detail = pin_wait_change('md_text')

with use_scope('md', clear=True):

put_markdown(change_detail['value'], sanitize=False)

if __name__ == '__main__':

start_server(main, port=8080, debug=True)

2.3 聊天室

<code>import asyncio

from pywebio import start_server

from pywebio.input import *

from pywebio.output import *

from pywebio.session import defer_call, info as session_info, run_async

MAX_MESSAGES_CNT = 10 ** 4

chat_msgs = [] # The chat message history. The item is (name, message content)

online_users = set()

def t(eng, chinese):

"""return English or Chinese text according to the user's browser language"""

return chinese if 'zh' in session_info.user_language else eng

async def refresh_msg(my_name):

"""send new message to current session"""

global chat_msgs

last_idx = len(chat_msgs)

while True:

await asyncio.sleep(0.5)

for m in chat_msgs[last_idx:]:

if m[0] != my_name: # only refresh message that not sent by current user

put_markdown('`%s`: %s' % m, sanitize=True, scope='msg-box')code>

# remove expired message

if len(chat_msgs) > MAX_MESSAGES_CNT:

chat_msgs = chat_msgs[len(chat_msgs) // 2:]

last_idx = len(chat_msgs)

async def main():

"""PyWebIO chat room

You can chat with everyone currently online.

"""

global chat_msgs

put_markdown(t("## PyWebIO chat room\nWelcome to the chat room, you can chat with all the people currently online. You can open this page in multiple tabs of your browser to simulate a multi-user environment. This application uses less than 90 lines of code, the source code is [here](https://github.com/wang0618/PyWebIO/blob/dev/demos/chat_room.py)", "## PyWebIO聊天室\n欢迎来到聊天室，你可以和当前所有在线的人聊天。你可以在浏览器的多个标签页中打开本页面来测试聊天效果。本应用使用不到90行代码实现，源代码[链接](https://github.com/wang0618/PyWebIO/blob/dev/demos/chat_room.py)"))

put_scrollable(put_scope('msg-box'), height=300, keep_bottom=True)

nickname = await input(t("Your nickname", "请输入你的昵称"), required=True, validate=lambda n: t('This name is already been used', '昵称已被使用') if n in online_users or n == '📢' else None)

online_users.add(nickname)

chat_msgs.append(('📢', '`%s` joins the room. %s users currently online' % (nickname, len(online_users))))

put_markdown('`📢`: `%s` join the room. %s users currently online' % (nickname, len(online_users)), sanitize=True, scope='msg-box')code>

@defer_call

def on_close():

online_users.remove(nickname)

chat_msgs.append(('📢', '`%s` leaves the room. %s users currently online' % (nickname, len(online_users))))

refresh_task = run_async(refresh_msg(nickname))

while True:

data = await input_group(t('Send message', '发送消息'), [

input(name='msg', help_text=t('Message content supports inline Markdown syntax', '消息内容支持行内Markdown语法')),code>

actions(name='cmd', buttons=[t('Send', '发送'), t('Multiline Input', '多行输入'), { 'label': t('Exit', '退出'), 'type': 'cancel'}])code>

], validate=lambda d: ('msg', 'Message content cannot be empty') if d['cmd'] == t('Send', '发送') and not d['msg'] else None)

if data is None:

break

if data['cmd'] == t('Multiline Input', '多行输入'):

data['msg'] = '\n' + await textarea('Message content', help_text=t('Message content supports Markdown syntax', '消息内容支持Markdown语法'))

put_markdown('`%s`: %s' % (nickname, data['msg']), sanitize=True, scope='msg-box')code>

chat_msgs.append((nickname, data['msg']))

refresh_task.close()

toast("You have left the chat room")

if __name__ == '__main__':

start_server(main, debug=True)

2.4 五子棋