## ROS入门 21讲 ### 11. 订阅者Subscriber的编程实现 主讲人：古月 ## 话题模型  话题模型（发布/订阅） ## • 创建订阅者代码（C++） * 该例程将订阅/turtle1/pose话题，消息类型turtlesim::Pose*/ 初始化ROS节点 ros::init(argc, argv, "pose_subscriber"); // 创建节点句柄 ros::NodeHandle n; // 创建一个Subscriber，订阅名为/turtle1/pose的topic，注册回调函数poseCallback ros::Subscriber pose_sub = n.subscribe("/turtle1/pose" /pose", 10, poseCallback); // 循环等待回调函数 ros::spin(); return 0; pose_subscriber.cpp ## 如何实现一个订阅者 • 初始化ROS节点； • 订阅需要的话题; - 循环等待话题消息，接收到消息后进入回调函数； - 在回调函数中完成消息处理。 ## - 配置订阅者代码编译规则 ## Declare

订阅者动态注册 type subscriber chan interface{} type topicFunc func(v interface{}) bool type Publisher struct { m sync.RWMutex buffer int timeout time.Duration subscribers map[subscriber]topicFunc go p.sendTopic(sub, topic, v, wg) // 消息推送到订阅者的chan } func (p *Publisher) sendTopic(sub subscriber, topic topicFunc, v interface{}...) { select { case sub <- v:

Using a handler • Creating a handler • Testing Guzzle Clients • Mock Subscriber • History Subscriber • Mock Adapter • Test Web Server • FAQ • Why should I use Guzzle the client. Log Subscriber [https://github.com/guzzle/log-subscriber] Logs HTTP requests and responses sent over the wire using customizable log message templates. OAuth Subscriber [https://github. com/guzzle/oauth-subscriber] Signs requests using OAuth 1.0. Cache Subscriber [https://github.com/guzzle/cache-subscriber] Implements a private transparent proxy cache that caches HTTP responses. Retry

containing cookies to send in the request and start a new cookie session. • Set to a GuzzleHttp\Subscriber\CookieJar\CookieJarInterface object to use an existing cookie jar. #### 1.2.6 Redirects Guzzle GuzzleHttp\Event\SubscriberInterface. Types array Default None use GuzzleHttp\Subscriber\History; use GuzzleHttp\Subscriber\Mock; use GuzzleHttp\Message\Response; $history = new History(); $mock = new and event subscribers to all requests created by the client. Important: Every event listener or subscriber added to a client will be added to every request created by the client. use GuzzleHttp\Client;

Observable(function subscribe(subscriber) { subscriber.next("My First Observable"); }); We have created an observable and added a message "My First Observable" using subscriber.next method available Observable } from 'rxjs'; var observer = Observable.create(function subscribe(subscriber) { subscriber.next("My First Observable"); }); ## Subscribe Observable You can subscribe to import { Observable } from 'rxjs'; var observer = new Observable(function subscribe(subscriber) { subscriber.next("My First Observable"); }); observer.subscribe(x => console.log(x));

ng_list(userID id) { subscriber_list.remove( lookup_user(id).email ); } ## Composing functions void unsubscribe_from_mailing_list(userID id) { subscriber_list.remove( lookup_user(id) ling_list(UserID id) { std::optional user = lookup_user(id); if (user) { subscriber_list.remove(user->email); } } ## Composing optional functions void unsubscribe_ ling_list(UserID id) { std::optional user = lookup_user(id); if (user) { subscriber_list.remove(user->email); } } ## Composition chain: UserID -> User or nothing ->

ros::init(argc, argv, "person_subscriber"); // 创建节点句柄 ros::NodeHandle n; // 创建一个Subscriber，订阅名为/person_info的topic，注册回调函数personInfoCallback ros::Subscriber person_info_sub = n.subscribe("/person_info" ages_cpp) add_executable(person_subscriber src/person_subscriber.cpp) target_link_libraries(person_subscriber ${catkin_LIBRARYES}) add_dependencies(person_subscriber ${PROJECT_NAME}_generate_messages_cpp) ~/catkin_ws $ catkin_make $ source devel/setup.bash $ roscore $ rosrun learning_topic person_subscriber $ rosrun learning_topic person_publisher ## - 创建发布者和订阅者代码（Python） ### person_publisher.py #

gRPC and protocol buffers. • duo-subscriber - instrumentation for collecting logging and tracing data from a process and exposing it over the wire format. duo-subscriber crate in this repository contains contains an implementation of the instrumentation-side API as a tracing-subscriber Layer, for projects using Tokio and tracing. • duo-ui - the web UI for duo. Currently, we just use the jaeger-ui for tracing https://127.0.0.1:3000 at your local browser to wait application report data. ## Application duo-subscriber = "0.1" 

topic as a topic subscriber. [[amop]] topicName = "PrivateTopic" privateKey = "conf/amop/consumer_private_key.p12" # Your private key that →used to subscriber verification private topic message sender →or subscriber. # Usually, the public key and private key is generated by subscriber. # Message sender receive public key from topic subscriber then make configuration. # But But, please do not config as both the message sender and the subscriber of one →private topic, or you may send the message to yourself. （下页继续） # Configure a private topic as a topic message sender. #

[Image](/uploads/documents/8/c/f/6/8cf6a2ee9e212c6a8409afd0a26b9bd4/p36_2.jpg) Processor1 Processor2 Subscriber Request N data items Subscription Push stream of N data items ## 接口定义 3 public final class static interface Publisher { public void subscribe(Subscriber subscriber); } 10 public static interface Subscriber { public void onSubscribe(Subscription subscription); n); public void cancel(); } 20 public static interface Processor extends Subscriber, Publisher { 23 } 26 } ## Reactor - 两个基本概念：Flux 和 Mono。 Flux：包含