spongebob-characters-backend

This repository serves as a proof of concept for GraphQL. It also serves a little bit like a personal wiki to keep track of this. It was randomly chosen that Spongebob characters should serve as placeholders here.

Table of contents

How it works
.....How the data is structured
Example requests and responses
.....Known queries
.....Valid requests
..........First request
..........Same endpoint, different data - Second request
..........Search via ID
..........Concatenation of queries
.....Invalid requests

How it works

This API only serves one endpoint: POST request to /api/characters with

• 200 OK on success with respective data or
• 500 INTERNAL SERVER ERROR when provided with falsy input

The user has to provide an GraphQL body (plain text body if there is no support for GraphQL bodies) to the POST request.
The response will contain all the fields the body specified.

The characters are stored in the database structured like this:

{
  "id": "5f2aa6632332d8b438db53a5",
  "firstName": "Spongebob",
  "lastName": "Squarepants",
  "voicedBy": "Tom Kenny",
  "role": "Main character",
  "firstAppearance": "Season 1, Episode 1"
}

Note that id is of type String

Example requests and responses

The API knows following queries:

• allCharacters
• character(id: String)

This implies that all characters can be returned (with specified fields) or only one character if searched by id

Valid requests

Request:
POST to /api/characters with body:

{
  allCharacters {
    firstName
    lastName
  }
}

Response:
200 OK with body

{
  "allCharacters": [
    {
      "firstName": "Spongebob",
      "lastName": "Squarepants"
    },
    {
      "firstName": "Patrick",
      "lastName": "Star"
    }
  ]
}

The interesting part about GraphQL is that a second request with a different body to the same endpoint of /api/characters will return different data.

Request:
POST to /api/characters with body:

{
  allCharacters {
    id
    firstName
    role
  }
}

Response:
200 OK with body

{
  "allCharacters": [
    {
      "id": "5f2aa6632332d8b438db53a5",
      "firstName": "Spongebob",
      "role": "Main character"
    },
    {
      "id": "5f2aa6cd2332d8b438db53a6",
      "firstName": "Patrick",
      "role": "Side character"
    }
  ]
}

Lets search for a single character with the id of Spongebob. The request will look like this:

Request:
POST to /api/characters with body:

{
  character(id: "5f2aa6632332d8b438db53a5") {
    firstName
    lastName
    firstAppearance
  }
}

Response:
200 OK with body

{
  "character": {
    "firstName": "Spongebob",
    "lastName": "Squarepants",
    "firstAppearance": "Season 1 Episode 1"
  }
}

These queries can also be concatenated.

Request:
POST to /api/characters with body:

{
  allCharacters {
    id
    firstName
  }
  
  character(id: "5f2aa6632332d8b438db53a5") {
    firstName
    lastName
    firstAppearance
  }
}

Response:
200 OK with body

{
  "allCharacters": [
    {
      "id": "5f2aa6632332d8b438db53a5",
      "firstName": "Spongebob",
    },
    {
      "id": "5f2aa6cd2332d8b438db53a6",
      "firstName": "Patrick",
    }
  ],
  
  "character": {
    "firstName": "Spongebob",
    "lastName": "Squarepants",
    "firstAppearance": "Season 1 Episode 1"
  }
}

Invalid Requests

A POST request to /api/characters with a body that contains a filed which is not present in the database (henceforth cannot be mapped to the entity) will result in an 500 INTERNAL SERVER ERROR

{
  allCharacters {
    id
    firstName
    fieldThatDoesNotExist # this will trigger the 500 response
  }
}