Code Challenge

Solution to the code challange as part of the recruiting process for HSBC by Milena Sapunova.

Requires: java 8, maven

Technologies used: java 8, maven, Spring Boot, mockito, checkstyle

Run application: mvn spring-boot:run

Base url: http://localhost:8080

Description

A simple social networking application, similar to Twitter, exposed through a web API.

Supported scenarios:

Posting

A user should be able to post a 140 character message.

To add a message to user's wall: POST /user/{username}

{
   "message": "Your message here."
}

Note:

• If the message is empty or contains more than 140 characters a 400 Bad Request error is returned.
• If no user exists with given {username}, user is created and the post is added to their wall.

Wall

A user should be able to see a list of the messages they've posted, in reverse chronological order.

To see all messages posted by user: GET /user/{username}

The output:

[
    {
        "postedOn": "26-09-2018 07:09:54",
        "author": "alice",
        "message": "My second message here"
    },
    {
        "postedOn": "26-09-2018 07:09:50",
        "author": "alice",
        "message": "My first message here"
    }
]

Following

A user should be able to follow another user. Following does not have to be reciprocal: Alice can follow Bob without Bob having to follow Alice.

To follow another user: POST /user/{username}/follow

{
    "username" : "bob"
}

Note:

• If user tries to follow himself a 400 Bad Request error is returned.

Timeline

A user should be able to see a list of the messages posted by all the people they follow, in reverse chronological order.

To see user's timeline: GET /user/{username}/timeline

[
    {
        "postedOn": "26-09-2018 03:06:12",
        "author": "bob",
        "message": "Bob's second message here."
    },
    {
        "postedOn": "26-09-2018 03:05:40",
        "author": "bob",
        "message": "Bob's first message here."
    }
]

Example

1. Alice posts few messages: POST /user/alice

   {
      "message": "Alice's message here."
   }

   {
      "message": "Alice's second message here."
   }

2. Alice wants to see her wall: GET /user/alice

   [
       {
           "postedOn": "26-09-2018 10:42:38",
           "author": "alice",
           "message": "Alice's second message here."
       },
       {
           "postedOn": "26-09-2018 10:42:31",
           "author": "alice",
           "message": "Alice's message here."
       }
   ]

3. Bob posts a message: POST /user/bob

   {
      "message": "Bob has a message."
   }

4. Megan posts a message: POST /user/megan

   {
      "message": "Megan's post."
   }

5. Megan follows Alice and Bob: POST /user/megan/follow

   {
       "username" : "alice"
   }

   {
       "username" : "bob"
   }

6. Megan wants to see her timeline: GET /user/megan/timeline

   [
       {
           "postedOn": "26-09-2018 10:43:33",
           "author": "bob",
           "message": "Bob has a message."
       },
       {
           "postedOn": "26-09-2018 10:42:38",
           "author": "alice",
           "message": "Alice's second message here."
       },
       {
           "postedOn": "26-09-2018 10:42:31",
           "author": "alice",
           "message": "Alice's message here."
       }
   ]