Python 在应用程序之间发送画布数据

main.py

import socket

def start_server(host,port):
    s = socket.socket()
    s.bind((host,port))

    s.listen(1)
    c, addr = s.accept()
    print "Connection from: " + str(addr)
    while True:
        data = c.recv(1024)
        if not data:
            break
        print "from connected user: " + str(data)
        data = str(data).upper()
        print "sending: " + str(data)
        c.send(data)
    c.close()

if __name__ == '__main__':
    start_server()

上面是我的简单绘画应用程序代码（采用kivy Blueprints）

我的目标是在本地主机上的一个应用程序上启动服务器，然后其他应用程序连接到它。那些可以连接到它的人应该从他们连接到的服务器上获得画布更新。如何发送数据和更新画布。我已经在上面的代码中使用python的套接字库创建了一个服务器

---

我不想使用http请求/线程，而是使用套接字建立连接并使用async.io

我使用支持post的/canvas端点创建了一个QuickREST flask服务。我还创建了CanvasWidget类的lines成员，以保存如何重新创建数据并将其发送到服务器。我曾考虑过逐像素进行跟踪，但我认为跟踪线条创建更为优雅，如果需要，还可以支持撤销重做功能

方向

• 启动server.py
• 启动main.py
• 画点东西
• 按“s”键将当前画布发送到服务器
• 退出main.py应用程序
• 启动main.py应用程序
• 按“r”键接收服务器的当前状态

main.py

import socket

def start_server(host,port):
    s = socket.socket()
    s.bind((host,port))

    s.listen(1)
    c, addr = s.accept()
    print "Connection from: " + str(addr)
    while True:
        data = c.recv(1024)
        if not data:
            break
        print "from connected user: " + str(data)
        data = str(data).upper()
        print "sending: " + str(data)
        c.send(data)
    c.close()

if __name__ == '__main__':
    start_server()

---

让服务器发出（可能广播）JSON化的画布命令对象。每个命令都可以是上下文命令的索引以及参数数组：

{i:0，p:[]}

其中

i

是命令数组

var cmds=['beginPath'，…]

的索引，

p

是任何命令参数的数组。然后您可以使用

上下文。应用
在客户端上执行命令。非常感谢！！你能用按键代替键盘吗。使用Flask似乎有些过分，如果可能的话，我更喜欢python标准库。是的，您可以使用原始套接字进行客户机/服务器通信。您必须支持多个试图从同一套接字读取的客户端。这不是小事，我很懒，用flask创建了一个RESTful服务。我实现了你的方法，但它的可伸缩性不是很好。是否有任何解决方案使用，比如说烧瓶。所以，您不需要每次都发送请求。
from kivy.app import App
from kivy.base import EventLoop
from kivy.config import Config
from kivy.graphics import Color, Line
from kivy.uix.behaviors import ToggleButtonBehavior
from kivy.uix.togglebutton import ToggleButton
from kivy.uix.widget import Widget
from kivy.utils import get_color_from_hex
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.uix.popup import Popup
from kivy.clock import Clock
from kivy.network.urlrequest import UrlRequest
import flask

CURSOR = (
    '       @@@@             ',
    '       @--@             ',
    '       @--@             ',
    '       @--@             ',
    '       @--@             ',
    '       @@@@             ',
    '                        ',
    '@@@@@@ @@@@ @@@@@@      ',
    '@----@ @--@ @----@      ',
    '@----@ @--@ @----@      ',
    '@@@@@@ @@@@ @@@@@@      ',
    '                        ',
    '       @@@@             ',
    '       @--@             ',
    '       @--@             ',
    '       @--@             ',
    '       @--@             ',
    '       @@@@             ',
    '                        ',
    '                        ',
    '                        ',
    '                        ',
    '                        ',
    '                        ',
)
class Update_Location(Widget):
    pass

class CanvasWidget(Widget):
    line_width = 2
    lines = []

    def __init__(self, **kwargs):
        super(CanvasWidget, self).__init__(**kwargs)
        self._keyboard = Window.request_keyboard(self._keyboard_closed, self)
        self._keyboard.bind(on_key_down=self._on_keyboard_down)

    def _keyboard_closed(self):
        self._keyboard.unbind(on_key_down=self._on_keyboard_down)
        self._keyboard = None

    def _on_keyboard_down(self, keyboard, keycode, text, modifiers):
        if keycode[1] == 's':
            print 'send'
            json = flask.json.dumps(self.lines)
            req = UrlRequest('http://127.0.0.1:5000/canvas', req_body=json)
        elif keycode[1] == 'r':
            print 'receive'
            req = UrlRequest('http://127.0.0.1:5000/canvas', self.load_state)

    def on_touch_down(self, touch):
        if Widget.on_touch_down(self, touch):
           return

        with self.canvas:
            touch.ud['current_line'] = Line(
                points=(touch.x, touch.y),
                width=self.line_width)
            self.lines.append({'points':[touch.x,touch.y], 'width':self.line_width})

    def on_touch_move(self, touch):
        if 'current_line' in touch.ud:
            touch.ud['current_line'].points += (touch.x, touch.y)
            self.lines[-1]['points'].append(touch.x)
            self.lines[-1]['points'].append(touch.y)

    def set_color(self, new_color):
        self.last_color = new_color
        self.canvas.add(Color(*new_color))

    def set_line_width(self, line_width='Normal'):
        self.line_width = {
            'Thin': 1, 'Normal': 2, 'Thick': 4
        }[line_width]

    def clear_canvas(self):
        saved = self.children[:]
        self.clear_widgets()
        self.canvas.clear()
        for widget in saved:
            self.add_widget(widget)
        self.set_color(self.last_color)

    def load_state(self, req, results):
        print 'load_state req', repr(req)
        print 'load_state results', repr(results)
        #needs some validation here
        self.clear_canvas()
        with self.canvas:
            for line in results:
                Line(points=line['points'], width=line['width'])
        self.line = results 

    def start_server(self):
        host = '127.0.0.1'
        port = 5000
        notification_text="Server started on host: "+host+" and port: "+str(port)
        server_start=Popup(title='Notification',content=Label(text=notification_text),size_hint=(.75,.75),auto_dismiss=True)
        server_start.open()
        Clock.schedule_interval(server_start.dismiss, 3)


class PaintApp(App):
    def build(self):
        EventLoop.ensure_window()
        if EventLoop.window.__class__.__name__.endswith('Pygame'):
            try:
                from pygame import mouse

                a, b = pygame_compile_cursor()
                mouse.set_cursor((24, 24), (9, 9), a, b)
            except:
                pass
        #boxlayout
        self.layout = BoxLayout(orientation='vertical')

        self.canvas_widget = CanvasWidget()
        self.canvas_widget.set_color(
            get_color_from_hex('#2980b9'))
        self.layout.add_widget(self.canvas_widget)
        #self.layout.add_widget(Label(text="Started Server : False , Connected to Server : False",color=(1,1,1),size_hint=(1, .1)))
        return self.layout
        #return self.canvas_widget


class RadioButton(ToggleButton):
    def _do_press(self):
        if self.state == 'normal':
            ToggleButtonBehavior._do_press(self)


def pygame_compile_cursor(black='@', white='-'):
    aa, bb = [], []
    a = b = 0
    i = 8
    for s in CURSOR:
        for c in s:
            a <<= 1
            b <<= 1
            i -= 1
            if c == black:
                a |= 1
                b |= 1
            elif c == white:
                b |= 1

            if not i:
                aa.append(a)
                bb.append(b)
                a = b = 0
                i = 8

    return tuple(aa), tuple(bb)

if __name__ == '__main__':
    Config.set('graphics', 'width', '960')
    Config.set('graphics', 'height', '540')  # 16:9
    # Config.set('graphics', 'resizable', '0')
    # Config.set('input', 'mouse', 'mouse,disable_multitouch')

    from kivy.core.window import Window
    Window.clearcolor = get_color_from_hex('#ffffff')

    PaintApp().run()

from flask import Flask, jsonify, request, json
app = Flask(__name__)

data = []

@app.route('/canvas', methods = ['GET', 'POST'])
def canvas():
    global data
    if request.method == 'GET':
        tmp = jsonify({})
        tmp.set_data(json.dumps(data))
        return tmp

    if request.method == 'POST':
        data = json.loads(request.data)
        tmp = jsonify({})
        tmp.set_data(json.dumps(data))
        return tmp


if __name__ == '__main__':
    app.run(debug=True)