What is server-side Pub/Sub Messaging?

Pub/Sub (Publish/Subscribe) is a messaging model used to facilitate data transmission and communication, especially in distributed systems. Essentially, the model has two key roles: publisher and subscriber.

With Hardal, you can operate this system in a fully server-side and first-party mode.

Hardal pub-sub

How Does Pub/Sub Work?

Publisher: Publishers produce messages and publish them to specific topics. Publishers do not know who receives the message.
Subscriber: Subscribers subscribe to the topics they are interested in. They receive messages only from the topics they are subscribed to. A subscriber can subscribe to one or more topics.
Message Broker: A message broker mediates between publishers and subscribers. Publishers send messages to brokers, and brokers deliver these messages to the appropriate subscribers. - Think of this as Hardal in this case.

Why Do Companies Need Pub/Sub?

You can direct event-based analytics data from end-user applications or server data from your system (this could be your company's CRM or another first-party data source) to Pub/Sub. You can later process this data with stream processing tools such as DataFlow and use it in databases.

Examples of these databases include BigQuery and Cloud Storage.

In summary, Pub/Sub allows you to collect events from multiple clients simultaneously.

Thus, using the Pub/Sub model server-side can provide the following advantages:

1. Real-Time Data Processing

With Pub/Sub, user actions on the site (adding items to cart, making purchases, product reviews, etc.) can be collected in real-time. This enables instant opportunities such as notifications and marketing campaigns. For example:

Instant Campaigns: If many users add a particular item to their cart, a short-term discount on that product can be launched.
Personalized Recommendations: You can offer better product suggestions to customers using real-time data.

2. Scalability

E-commerce sites often experience high traffic, especially during sales or special events. Pub/Sub can manage events from thousands or even millions of users simultaneously, ensuring your system is not overloaded. This allows:

Stability Under High Traffic: During busy periods, data transfer continues smoothly without degrading system performance.
Expandable System: As your customer base grows, you can easily scale your infrastructure.

3. Asynchronous Operations

Operations such as order processing, payment, or product inquiries can be handled asynchronously, reducing wait times for customers and enabling background tasks to continue smoothly:

Fast User Experience: Customers don’t need to wait while their order is processed in the background.
Smooth Processes: Tasks like order processing, invoicing, or stock updates can occur in sequence and without disruption.

4. Preventing Data Loss

With Pub/Sub, incoming data is queued and saved before being processed, preventing data loss in the event of server outages or errors. This is crucial for critical e-commerce events such as purchases or payment information:

Data Security: Users’ purchase history, payment details, or product orders are not lost.
Fault Tolerance: Even if your server goes down temporarily, the system resumes processing the data where it left off once it recovers.

5. Segmentation and Targeting

By analyzing the user interaction data collected via Pub/Sub, you can create customer segments, enabling more targeted marketing campaigns and personalized experiences:

Personalized Emails: For example, you can send reminder emails to users who left items in their cart.
Dynamic Ads: Create product campaigns and ads tailored to different customer segments.

How to Use?

You can use the Hardal Custom Endpoint API with two request methods.

POST

/pubsub

Request Format

Parameter	Type	Required	Description
messages	`Message[]`	Yes	List of messages to be sent
pubsub	`"gcp"`	Yes	Pub/Sub cloud provider, such as AWS, GCP, etc.
Extra Parameters	`string`	No	Additional query parameters are treated as attributes

Message Type

Field	Type	Description
value	`string`	The content of the message
attributes	`{"key": "value"}`	Additional attributes related to the message
messageId	`string`	The unique ID of the message
publishTime	`DateTime String`	The time the message was sent (ISO 8601)

Example POST Request

curl -X POST https://s2s.yourcustomdomain.com/pubsub \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR-HARDAL-SUPER-SECRET-TOKEN" \
  -d '{    
    "messages": [
      {
        "value": "Test",
        "attributes": {
          "language": "English",
          "greeting": "formal"
        },
        "messageId": "c1d7e88a-4e35-4e8e-9a0f-8c9fbd9d1123",
        "publishTime": "2024-09-09T12:30:45.123Z"
      }
    ],
    "pubsub": "gcp"
  }'

GET