Subscription Service

Welcome to the Subscription Service repository! This guide will help you set up the project environment and complete the assigned tasks related to implementing subscription functionalities.

Table of Contents

• Prerequisites
• Setup Instructions
• Assignment
  • Part 1: Implement list_subscriptions
  • Part 2: Add Email Filter

Prerequisites

Before you begin, ensure you have the following installed on your system:

1. Rust (version 1.60 or later)

   • Installation: Rust Official Website

2. Cargo (comes bundled with Rust)

   • Verification: Run cargo --version in your terminal.

3. SQLite (version 3.0 or later)

   • Installation:
     • Ubuntu/Debian:

       sudo apt update
       sudo apt install sqlite3 libsqlite3-dev

     • macOS (using Homebrew):

       brew install sqlite3

     • Windows: Download the precompiled binaries from the SQLite Download Page and follow the installation instructions.

4. Git (for cloning the repository)

   • Installation: Git Official Website

Setup Instructions

1. Clone the Repository

Start by cloning the repository to your local machine:

git clone https://github.com/your-username/subscription-service.git
cd subscription-service

2. Start the Server

With the dependencies installed and the database initialized, you can now start the gRPC server:

cargo run

You should see logs indicating that the server has started and is listening on the specified port.

Assignment

Your task involves enhancing the Subscription Service by implementing and extending the list_subscriptions functionality.

Part 1: Implement list_subscriptions

Objective: Finish implementing the list_subscriptions function to retrieve all subscriptions from the database and test it using Postman.

Steps:

1. Locate the Function:

   • Open the file src/handlers/api.rs
   • Find the list_subscriptions function, which is currently unimplemented (todo!())

2. Implement Database Retrieval:

   • Use the appropriate database queries to fetch all email entries from the subscriptions table
   • Populate the ListSubscriptionsResponse with the retrieved emails

3. Test Using Postman:

   • Setup Postman for gRPC
   • Create a new request
   • Set the request type to gRPC
   • Enter the server address (e.g., localhost:50051)
   • Invoke ListSubscriptions
   • Send the request and verify that all subscriptions are returned correctly

Deliverables:

• A working list_subscriptions function that retrieves and returns all subscribed emails
• Confirmation of functionality through successful Postman tests

Part 2: Add Email Filter

Objective: Enhance the list_subscriptions functionality by adding the ability to filter subscriptions based on a provided email substring.

Steps:

1. Update the Proto File:

   • Open the .proto file defining the ListSubscriptionsRequest
   • Add an optional filter field to allow clients to specify a substring for filtering emails

2. Regenerate Rust Code:

   • After modifying the proto file, regenerate the Rust code using tonic-build or your preferred method

3. Modify the list_subscriptions Function:

   • Update the function to accept the filter parameter
   • Adjust the database query to include a condition that filters emails containing the specified substring

4. Test the Filter:

   • Using Postman:
     • Modify the ListSubscriptions request to include a filter value
     • Send the request and verify that only emails containing the specified substring are returned
   • Edge Cases:
     • Test with filters that match multiple, single, or no emails to ensure robustness

Deliverables:

• An updated ListSubscriptionsRequest that includes an optional filter field
• Enhanced list_subscriptions function capable of filtering results based on the provided email substring
• Successful tests demonstrating the filtering functionality