Publish and Subscribe Model
MQTT uses the Publish/Subscribe method to send messages to their clients. The design pattern Publish/Subscribe is also known as Pub/Sub. The design involves a message broken that is MQTT in this case. MQTT broker passes messages from the publisher to the subscribers.
Subscribers can join a channel by signing up to receive messages (events) that have been published by the host (publisher). By subscribing to specific topics, they can filter out messages they don't require.
To interact with the broker, publishers and clients, send a Connect message. With this method, the broker can also send messages even if the publisher's connection is down or the client isn't online when a message is published. All newly connected subscribers receive the message from the broker when it has been stored. When the publisher experiences connection problems, a Will message is sent.
MQTT Topics
The term "topic" in MQTT defines a UTF-8 string that the broker uses to filter messages for each connected client. One or more topic levels make up the topic. A forward slash separates each topic level. MQTT topics are lighter as compared to a message queue. For e.g., See the below image.
Will Message
A Will message is sent to the relevant subscriber when the client disconnects. Will Messages will be sent when:
🌞 The server faces an I/O error or a network problem.
🌞 During a specific heartbeat period, if the client loses contact.
🌞 Before sending offline packets, the client disconnects from the network.
🌞 Before receiving the offline packet, the server cuts off the network connection.
MQTT Testing
In this section, we will learn about Testing in MQTT using Ready API.
MQTT Functional Testing
You can build a functional test using the MQTT-related test steps to examine the broker's performance. The three steps of functional testing using MQTT are listed below.
⭐ Publish: Publish creates an MQTT connection and publishes the message given in the attributes of the test step.
⭐ Receive: In Receive MQTT Message, it waits for the first message to be posted to an MQTT subject after subscribing to one.
⭐ Drop: Drop MQTT Message simulates the publisher's eventual disconnect from the server. This can happen either naturally by sending a Disconnect message or suddenly.
MQTT Load Testing
Performance Testing or Load Testing helps you verify that your service can deal with a large number of users.
Movie Ticketing Service
Let's take an example for better clarity. A movie ticketing service must be able to handle a steady flow of clients as well as sudden spikes of activities happening when tickets go on sale.
Load Tests are usually created after functional tests. The functional tests typically show the action of one user. But a Load Test simulates many users performing the same action in parallel.
Legacy MQTT Connections
There is an Individual connection option for legacy connections in the Connection drop-down menu. The new connection management model is mutable by the user. Use the Convert Connection button to convert this transfer.
Follow the below steps to view Legacy MQTT Connection Configuration:
Step 1: Open a service that already runs and makes use of the Manage MQTT assertions. Open the MAS Messaging service, for instance.
Step 2: Now, search for the "broker" option.
Step 3: Click to open the assertion properties.
Step 4: Click on the Legacy tab.
Step 5: To create a new connection, manually copy this data or choose Cancel.
Frequently Asked Questions
What is the difference between ready API and Postman?
Since Postman is created to work with each API endpoint, it is nearly hard to manage and monitor testing over time. Since each test case is built for ReadyAPI, tests may include a variety of endpoints, resources, or data sets.
Which is the best tool for API automation?
Testim is the tool that is most often used for API testing. The effective API testing tool Testim makes designing and running automated tests for your API simple. Some best tools for API automation are Postman, Soap UI, Karate DSL, JMeter, and Apigee.
What are API tools?
An API is a group of software procedures and functions. It provides access to the execution of other software apps. In API testing, you make calls to the API, receive output, and record the system's response using the software.
Conclusion
We have discussed the topic of the Internet of Things in Ready API. We have learned MQTT Protocol, Publish & Subscribe Model, Will Message, MQTT Testing, and Legacy MQTT Connections.
We hope this blog has helped you enhance your knowledge of the Internet of Things in Ready API. If you want to learn more, check out our similar articles on:
⚡ What is Ready API?
⚡ Installing Ready API.
⚡ Test Result in Ready API.
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