Web Quiz Engine

(a JetBrains Academy Project)

A multi-user web service with Spring-Boot for creating and solving quizzes.

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About

A multi-user web service for creating and solving quizzes using REST API, an embedded database, security, and other technologies.

Description

Create a new quiz

To create a new quiz, the client needs to send a JSON as the request's body via POST to /api/quizzes. The JSON should contain the four fields:

• title: a string, required;
• text: a string, required;
• options: an array of strings, required, should contain at least 2 items;
• answer: an array of indexes of correct options, optional, since all options can be wrong.

Here is a new JSON quiz as an example:

{
  "title": "Coffee drinks",
  "text": "Select only coffee drinks.",
  "options": ["Americano","Tea","Cappuccino","Sprite"],
  "answer": [0,2]
}

The answer equals [0,2] corresponds to the first and the third item from the options array ("Americano" and "Cappuccino").

The server response is a JSON with four fields: id, title, text and options. Here is an example:

{
  "id": 1,
  "title": "Coffee drinks",
  "text": "Select only coffee drinks.",
  "options": ["Americano","Tea","Cappuccino","Sprite"]
}

The id field is a generated unique integer identifier for the quiz.

If the request JSON does not contain title or text, or they are empty strings (""), then the server responds with the 400 (Bad request) status code. If the number of options in the quiz is less than 2, the server returns the same status code.

Get a quiz by id

To get a quiz by id, the client sends the GET request to /api/quizzes/{id}.

Here is a response example:

{
  "id": 1,
  "title": "The Java Logo",
  "text": "What is depicted on the Java logo?",
  "options": ["Robot","Tea leaf","Cup of coffee","Bug"]
}

If the specified quiz does not exist, the server returns the 404 (Not found) status code.

Get all quizzes (with paging)

To get all existing quizzes in the service, the client sends the GET request to /api/quizzes.

The API returns only 10 quizzes at once and supports the ability to specify which portion of quizzes is needed.

The response contains a JSON with quizzes (inside content) and some additional metadata:

{
  "totalPages":1,
  "totalElements":3,
  "last":true,
  "first":true,
  "sort":{ },
  "number":0,
  "numberOfElements":3,
  "size":10,
  "empty":false,
  "pageable": { },
  "content":[
    {"id":102,"title":"Test 1","text":"Text 1","options":["a","b","c"]},
    {"id":103,"title":"Test 2","text":"Text 2","options":["a", "b", "c", "d"]},
    {"id":202,"title":"The Java Logo","text":"What is depicted on the Java logo?",
     "options":["Robot","Tea leaf","Cup of coffee","Bug"]}
  ]
}

The API supports the navigation through pages by passing the page parameter ( /api/quizzes?page=1). The first page is 0 since pages start from zero.

If there are no quizzes, the service returns an empty JSON array: [].

If the user is authorized, the status code is 200 (OK); otherwise, it's 401 (Unauthorized).

Solving a quiz

To solve a quiz, the client sends the POST request to /api/quizzes/{id}/solve with a JSON that contains the indexes of all chosen options as the answer. This looks like a regular JSON object with key "answer" and value as the array: {"answer": [0,2]}. Indexes start from zero.

It is also possible to send an empty array [] since some quizzes may not have correct options.

The service returns a JSON with two fields: success (true or false) and feedback (just a string). There are three possible responses:

• If the passed answer is correct:

{"success":true,"feedback":"Congratulations, you're right!"}

• If the answer is incorrect:

{"success":false,"feedback":"Wrong answer! Please, try again."}

• If the specified quiz does not exist, the server returns the 404 (Not found) status code.

Delete a quiz

A user can delete their quiz by sending the DELETE request to /api/quizzes/{id}.

If the operation was successful, the service returns the 204 (No content) status code without any content.

If the specified quiz does not exist, the server returns 404 (Not found). If the specified user is not the author of this quiz, the response is the 403 (Forbidden) status code.

Get all completions of quizzes (with paging)

For getting all completions of quizzes for a specified user, send the GET request to /api/quizzes/completed together with the user auth data. All the completions is sorted from the most recent to the oldest.

A response is separated by pages since the service may return a lot of data. It contains a JSON with quizzes (inside content) and some additional metadata.

Here is a response example:

{
  "totalPages":1,
  "totalElements":5,
  "last":true,
  "first":true,
  "empty":false,
  "content":[
    {"id":103,"completedAt":"2019-10-29T21:13:53.779542"},
    {"id":102,"completedAt":"2019-10-29T21:13:52.324993"},
    {"id":101,"completedAt":"2019-10-29T18:59:58.387267"},
    {"id":101,"completedAt":"2019-10-29T18:59:55.303268"},
    {"id":202,"completedAt":"2019-10-29T18:59:54.033801"}
  ]
}

Since it is allowed to solve a quiz multiple times, the response may contain duplicate quizzes, but with the different completion date.

If there are no quizzes, content is empty []. If the user is authorized, the status code is 200 (OK); otherwise, it's 401 (Unauthorized).