Backend - Trivia API

Backend API for the Trivia quiz game.

NB: The frontend implementation can be found at Trivia API Frontend

Setting up the Backend

Install Dependencies

1. Python 3.8

2. PIP Dependencies install the required dependencies by navigating to the /backend directory and running:

pip install -r requirements.txt

Key Pip Dependencies

• Flask is a lightweight backend microservices framework. Flask is required to handle requests and responses.

• SQLAlchemy is the Python SQL toolkit and ORM we'll use to handle the lightweight SQL database. You'll primarily work in app.pyand can reference models.py.

• Flask-CORS is the extension we'll use to handle cross-origin requests from our frontend server.

Set up the Database

With Postgres running, create a trivia database:

createdb -U postgres trivia

Populate the database using the trivia.psql file provided. From the backend folder in terminal run:

psql -U postgres trivia < trivia.psql

Run the Server

To run the server, execute:

flask --app flaskr --debug run --reload 

Documentation

Tip 1: Objects returned by endpoints will have a success boolean property with a value of true or false to indicate whether the operation was successful or failed respectively.

Tip 2: Text in angle brackets <> are placeholders. You will need to replace them with real values

GET '/questions?page=<page_number>'

• For returning a paginated list of questions. The page number is passed as url parameter.
• Request Parameters: page: int argument for specifying the page number
• Returns: List of questions, total number of questions, current category, and categories

{
  "categories": [
    {
      "id": 1,
      "type": "Science"
    },
    {
      "id": 2,
      "type": "Art"
    },
    {
      "id": 3,
      "type": "Geography"
    },
    {
      "id": 4,
      "type": "History"
    },
    {
      "id": 5,
      "type": "Entertainment"
    },
    {
      "id": 6,
      "type": "Sports"
    }
  ],
  "current_category": null,
  "questions": [
    {
      "answer": "Maya Angelou",
      "category": 4,
      "difficulty": 2,
      "id": 5,
      "question": "Whose autobiography is entitled 'I Know Why the Caged Bird Sings'?"
    },
    {
      "answer": "Muhammad Ali",
      "category": 4,
      "difficulty": 1,
      "id": 9,
      "question": "What boxer's original name is Cassius Clay?"
    },
    {
      "answer": "Apollo 13",
      "category": 5,
      "difficulty": 4,
      "id": 2,
      "question": "What movie earned Tom Hanks his third straight Oscar nomination, in 1996?"
    },
    {
      "answer": "Tom Cruise",
      "category": 5,
      "difficulty": 4,
      "id": 4,
      "question": "What actor did author Anne Rice first denounce, then praise in the role of her beloved Lestat?"
    },
    {
      "answer": "Brazil",
      "category": 6,
      "difficulty": 3,
      "id": 10,
      "question": "Which is the only team to play in every soccer World Cup tournament?"
    },
    {
      "answer": "George Washington Carver",
      "category": 4,
      "difficulty": 2,
      "id": 12,
      "question": "Who invented Peanut Butter?"
    },
    {
      "answer": "Lake Victoria",
      "category": 3,
      "difficulty": 2,
      "id": 13,
      "question": "What is the largest lake in Africa?"
    },
    {
      "answer": "The Palace of Versailles",
      "category": 3,
      "difficulty": 3,
      "id": 14,
      "question": "In which royal palace would you find the Hall of Mirrors?"
    },
    {
      "answer": "Agra",
      "category": 3,
      "difficulty": 2,
      "id": 15,
      "question": "The Taj Mahal is located in which Indian city?"
    },
    {
      "answer": "Escher",
      "category": 2,
      "difficulty": 1,
      "id": 16,
      "question": "Which Dutch graphic artist\u2013initials M C was a creator of optical illusions?"
    }
  ],
  "success": true,
  "total_questions": 16
}

GET '/categories'

• Fetches categories as array of objects.
• Request Parameters: None
• Returns: An object with categories as an array of category objects. Each category object has two keys: id and type, representing the category's unique id and name respectively.

{
  "categories": [
    {
      "id": 1,
      "type": "Science"
    },
    {
      "id": 2,
      "type": "Art"
    },
    {
      "id": 3,
      "type": "Geography"
    },
    {
      "id": 4,
      "type": "History"
    },
    {
      "id": 5,
      "type": "Entertainment"
    },
    {
      "id": 6,
      "type": "Sports"
    }
  ],
  "success": true
}

DELETE '/questions/<question_id>'

• Deletes a question whose id is question_id.
• Request Argument: question_id: int
• Returns: An object with the id of the deleted question on success.

{
  "deleted": 5,
  "success": true
}

POST '/questions

• Posts a new question
• Request Payload: an object with the question, answer, category, and difficulty

{
    "question":"What is the tallest mountain on earth?",
    "answer":"Mt Everest",
    "category": 2,
    "difficulty": 1
}

• Returns: An object with the new question on success

{
  "question": {
    "answer": "Mt Everest",
    "category": 2,
    "difficulty": 1,
    "id": 25,
    "question": "What is the tallest mountain on earth?"
  },
  "success": true
}

GET '/categories/<category_id>/questions?page=<page_number>

• Fetch questions based on category specified by category_id. Page number may optionally be specified via page url parameter.
• Request Parameters: category_id: int: to specify category id and optional page: int parameter for page number
• Returns all questions from category specified by category_id, current category and the total number of questions

{
  "current_category": 1,
  "questions": [
    {
      "answer": "The Liver",
      "category": 1,
      "difficulty": 4,
      "id": 20,
      "question": "What is the heaviest organ in the human body?"
    },
    {
      "answer": "Alexander Fleming",
      "category": 1,
      "difficulty": 3,
      "id": 21,
      "question": "Who discovered penicillin?"
    },
    {
      "answer": "Blood",
      "category": 1,
      "difficulty": 4,
      "id": 22,
      "question": "Hematology is a branch of medicine involving the study of what?"
    }
  ],
  "success": true,
  "total_questions": 3
}

POST '/questions

• Endpoint to get questions based on a search term. It returns any questions for whom the search term is a substring.
• Request Payload: An object with property search_term to specify the search keyword.

{
  "search_term": "<searchTerm>"
}

• Returns: An object with an array of the matched questions, current category, and total number of questions on success

{
  "current_category": null,
  "questions": [],
  "success": true,
  "total_questions": 0
}

POST '/quizzes'

• This endpoint takes a category and ids of previous questions and returns random questions within the given category. Question returned will be different from previous questions.
• Request Payload: An object with the current category id, and an array of ids of previous questions.

{
  "previous_questions": ["<question_id1>", "<question_id2>"],
  "quiz_category": "<category_id>"
}

• Returns a question

{
  "question": {
    "answer": "The Liver",
    "category": 1,
    "difficulty": 4,
    "id": 20,
    "question": "What is the heaviest organ in the human body?"
  },
  "success": true
}