williamhaw / friends-management

Friend Management API

Prerequisites

• Oracle Java 8 installed and JAVA_HOME set or java executable in PATH

Running the App

On Windows

./gradlew.bat run in root of project directory

On Linux

./gradlew run in root of project directory

App Details

Server will start running at http://localhost:8080 with default configuration.

API endpoints are at http://localhost:8080/api/v1/*

Configuration

Configuration is perform with a Java properties file specified within the run task in build.gradle. Default configuration is at config/config.ini

Documentation

Endpoints, requests, responses are documented using Swagger here (default server port is 8080)

Technical Choices

• Embedded Jetty for server and servlets
• JSON-Simple for (de)serialisation of JSON request and responses
• MongoDB for persistence
• Gradle for dependency management and scripting

Design Considerations of System

1. Separation of concerns between Actions and request/reponse mechanisms

• JSON parsing and response properties setting encapsulated in FriendManagementServlet
• Action routing and extraction of action arguments in ActionHandler
• Action logic encapsulated in XAction classes e.g. (AddFriendAction)

2. Ablility to switch out persistence implementations for easy testing

• Instantiation of persistence handler through reflection
• HashMapUserPersistence for testing

3. Easy basic configuration of route to Action objects

• Added PropertiesHelper to parse config for routes and Actions enum

JSON response proposals

1. Create friend connection

• If any email address doesn't exist as a user
  • return {"notUser" : [email1, email2]}

2. Retrieve friend list

• If requested email address doesn't exist as a user
  • return {"notUser" : [email]}

3. Get common friends

• If either email adress doesn't exist as a user
  • return {"notUser" : [email1, email2]}
• If the two email addresses are the same
  • return {"sameUser": true, "friends":[...]}

4. Subscribe to updates

• If target doesnt exist as a user
  • return {"notUser" : [target_email]}
• If requestor doesn't exist as a user
  • return {"notUser" : [requestor_email]}

5. Block updates

• If target doesnt exist as a user
  • return {"notUser" : [target_email]}
• If requestor doesn't exist as a user
  • return {"notUser" : [requestor_email]}
• If requestor is already friends with target but blocks target
  • return {"isFriend": true}

6. Retrieve recipients

• If @ mentioned email is not a user
  • return {"notUser" : [email1, email2, ...]}
• If recipient is already friends with sender but blocks sender
  • return {"recipient": recipientEmail, "isFriend": true}
• If recipient is already subscribed to sender but blocks sender
  • return {"recipient": recipientEmail, "isSubscribed": true}

Current implementation does not check whether user exists unless it checks the friend list, blocked list or list of subscribers.