### 13. 客户端Client的编程实现 主讲人：古月 ## 话题模型  服务模型（客户端/服务器） ## • 创建功能包 $ cd ~/catkin_ws/src $ catkin_create_pkg learning_service c564ba4d556568db04/p3_2.jpg) ## • 创建客户端代码（C++） #include #include int main(int argc, char** argv) // 发现/spawn服务后，创建一个服务客户端，连接名为/spawn的service ## // 初始化turtlesim::spawn的请求数据 response.name.c_str()); return 0; }; ## 如何实现一个客户端 turtle_spawn.cpp • 初始化ROS节点； • 创建一个Client实例； - 等待Server处理之后的应答结果。 • 发布服务请求数据; ## - 配置客户端代码编译规则 ## Declare a C++ executable ## With

Limitations 17 7 License 19 Python Module Index 21 websockets is a library for developing WebSocket servers and clients in Python. It implements RFC 6455 with a focus on correctness and simplicity Example Here’s a WebSocket server example. It reads a name from the client and sends a message. #!/usr/bin/env python import asyncio import websockets @asyncio.coroutine def hello(websocket, path): name name = yield from websocket.recv() print("{}".format(name)) greeting = "Hello {}!" yield from websocket.send(greeting) print("{}".format(greeting)) start_server =

Limitations 15 6 License 17 Python Module Index 19 websockets is a library for developing WebSocket servers and clients in Python. It implements RFC 6455 with a focus on correctness and simplicity Example Here’s a WebSocket server example. It reads a name from the client and sends a message. #!/usr/bin/env python import asyncio import websockets @asyncio.coroutine def hello(websocket, uri): name name = yield from websocket.recv() print("{}".format(name)) greeting = "Hello {}!".format(name) print("> {}".format(greeting)) websocket.send(greeting) start_server

Limitations ..... 3.6 Changelog ..... 3.7 License ..... Python Module Index websocket is a library for developing WebSocket servers and clients in Python. It implements RFC 6455 with focus on correctness Here’s a WebSocket server example. It reads a name from the client, sends a greeting, and closes the connection. #!/usr/bin/env python import asyncio import websockets async def hello(websocket, path): path): name = await websocket.recv() print("{}".format(name)) greeting = "Hello {}!".format(name) await websocket.send(greeting) print("> {}".format(greeting))

to a module, dictionary, or a list of modules and/or dicts. See UI modules for more details. • websocket_ping_interval: If set to a number, all websockets will be pinged every n seconds. This can help proxy servers which close idle connections, and it can detect if the websocket has failed without being properly closed. • websocket_ping_timeout: If the ping interval is set, and the server doesn’t receive receive a ‘pong’ in this many seconds, it will close the websocket. The default is three times the ping interval, with a minimum of 30 seconds. Ignored if the ping interval is not set. Authentication and

[https://en.wikipedia.org/wiki/Push_technology#Long_polling], WebSockets [https://en.wikipedia.org/wiki/WebSocket], and other applications that require a long-lived connection to each user. ## Quick links • Current — Escaping and string manipulation ☐ tornado.locale — Internationalization support ○ tornado.websocket — Bidirectional communication to the browser • HTTP servers and clients ☐ tornado.httpserver — [http://en.wikipedia.org/wiki/Push_technology#Long_polling], WebSockets [http://en.wikipedia.org/wiki/WebSocket], and other applications that require a long-lived connection to each user. Tornado can be roughly

[https://en.wikipedia.org/wiki/Push_technology#Long_polling], WebSockets [https://en.wikipedia.org/wiki/WebSocket], and other applications that require a long-lived connection to each user. ## Quick links • Current — Escaping and string manipulation ☐ tornado.locale — Internationalization support ○ tornado.websocket — Bidirectional communication to the browser • HTTP servers and clients ☐ tornado.httpserver — [http://en.wikipedia.org/wiki/Push_technology#Long_polling], WebSockets [http://en.wikipedia.org/wiki/WebSocket], and other applications that require a long-lived connection to each user. Tornado can be roughly

Changelog 20 3.7 License 23 Python Module Index 25 websockets is a library for developing WebSocket servers and clients in Python. It implements RFC 6455 with a focus on correctness and simplicity Here’s a WebSocket server example. It reads a name from the client, sends a greeting, and closes the connection. #!/usr/bin/env python import asyncio import websockets async def hello(websocket, path): path): name = await websocket.recv() print("{}".format(name)) greeting = "Hello {}!".format(name) await websocket.send(greeting) print("}>{}".format(greeting))