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GraphQL API with Python

This is an API built for the purpose of studying the GraphQL technology and its integration with Python and the Flask framework. The library Graphene was used to build it.


Summary

  1. What is the API?
  2. How to run the project
  3. API Docs
    1. User
    2. Post
    3. Queries
      1. getAllPosts
      2. getAllUsers
      3. getPost
      4. getUser
    4. Mutations
      1. CreatePost
      2. UpdatePost
      3. DeletePost
      4. CreateUser
      5. UpdateUser
      6. DeleteUser

What is the API?

This API has two main models: Users and Posts. So, basically the goal here is to create a CRUD for them. It will also be possible to link a post to a user (its creator, in this case).

How to run the project

Go into your work directory and clone this repository:

$ git clone [email protected]:vitumenezes/flask-with-graphql.git

Now you will need to create a virtual environment to correctly run the projet.

There are differents ways to do it, here we will use the standard python lib called venv.

The virtualenv will be created in a folder. And where, leave it? I suggest creating it with a "." in front of the name, for example: .venv. And create it inside the project folder, so we know that that virtual environment belongs to the project itself. It's just a pattern and there are several, use whichever you prefer.

Enter the folder:

$ cd flask-with-graphql

Create the virtual environment:

$ python -m venv .venv

Use Python 3 versions to run this project. You can manage them with Pyenv ;)

Now, activate it:

$ source .venv/bin/activate

After that, you will now see the active prefix on your terminal:

(.venv) user@hostname$

This means that the virtualenv is active. Make shure it is always active while using the project for development purposes.

Now, install the depedencies on requirements.txt: Enter a python interpreter of your choice and import the SQLAlchemy instance from the main.py file

Before running the project, we first need to create the tables in our sqlite database. Enter a python interpreter of your choice and import the SQLAlchemy (called db) instance from the main.py file.

(.venv) $ python

...

>>> from main import db
>>> db.create_all()

Now, run it:

(.venv) $ python main.py runserver

Access http://127.0.0.1:5000/graphql to see the interface to write and test graphql queries.

API Docs

As stated earlier, there are two base models in the API.

User

Represents the User template to be saved in the database.

Fields:

uuid: ID!
The User identifier. Autofilled

username: String
The User username. Must be unique

password: String
The User password

posts: [PostType]
The User's posts

Post

Represents the Post template to be saved in the database.

Fields:

uuid: ID!
The Posti identifier. Autofilled

title: String
The Post title

body: String
The Post body (content)

authorId: Int
The Post creator identifier

author: UserType
The user who created the post itself


The API offers Create, Update and Delete mutations for User and Post, that is, 6 mutations in total. There are also queries to fetch one or all rows from each model's database table (User and Post).

Queries

getAllPosts

{
  getAllPosts {
    uuid
    title
    body
    authorId
    author
  }
}

Returns all posts from the database.

PARAMS:
not needed

FIELDS:
All fields from Post
The field author has all fields of User.

Example of usage:

{
  getAllPosts {
    title
    body
    authorId
  }
}


Example of return:

{
  "data": {
    "getAllPosts": [
      {
        "title": "Some title",
        "body": "content",
        "authorId": 2
      },
      {
        "title": "Title",
        "body": "Some Body",
        "authorId": 7
      },
      {
        "title": "title",
        "body": "body",
        "authorId": 2
      },
      {
        "title": "Nice Title",
        "body": "Cooooteeeennnnt",
        "authorId": 4
      }
    ]
  }
}

getAllUsers

{
  getAllUsers {
    uuid
    username
    password
    posts
  }
}

Returns all users from the database.

PARAMS:
not needed

FIELDS:
All fields from User
The field posts has all fields of Post.

Example of usage:

{
  getAllPosts {
    username
    posts {
      title
    }
  }
}

Example of return:

{
  "data": {
    "getAllUsers": [
      {
        "username": "edu",
        "posts": [
          {
            "title": "Some title"
          },
          {
            "title": "title"
          }
        ]
      },
      {
        "username": "luiz",
        "posts": []
      },
      {
        "username": "lupa",
        "posts": [
          {
            "title": "Nice Title"
          },
          {
            "title": "mvmwdivotu"
          }
        ]
      }
    ]
  } 
}

getPost

Returns data from a single user.

PARAMS:
post_id: The Post ID

FIELDS:
All fields from Post
The field author has all User fields.

Example of usage:

{
  getUser(userId: 2) {
    username
    posts {
      title
    }
  }
}

Example of return:

{
  "data": {
    "getPost": {
      "title": "Title",
      "body": "Some Body"
    }
  }
}

getUser

Returns data from a single user.

PARAMS:
user_id: The User ID

FIELDS:
All fields from User
The field posts has all Post fields.

Example of usage:

{
  getUser(userId: 2) {
    username
    posts {
      title
    }
  }
}

Example of return:

{
"data": {
  "getUser": {
    "username": "edu",
      "posts": [
        {
          "title": "Some title"
        },
        {
          "title": "title"
        }
      ]
    }
  }
}

Mutations

CreatePost

Creates a new Post.

PARAMS:
title: The Post title
body: The Post content
username: The username of the user who created the post

FIELDS:
ok: True or False. Informs if the request went well
message: A message stating the status of the request
post: The post created. Has all Post fields

Example of usage:

mutation {
  CreatePost (title: "Some Title", body: "Some content", username: "edu") {
    ok
    message
    post {
      uuid
    }
  }
}

Example of return:

{
  "data": {
    "CreatePost": {
      "ok": true,
      "message": "Post criado",
      "post": {
        "uuid": "10"
      }
    }
  }
}

UpdatePost

Updates an existing Post.

PARAMS:
postId: The Post identifier. Required
title: The new Post title. Not required
body: The new Post body. Not required

FIELDS:
ok: True or False. Informs if the request went well
message: A message stating the status of the request
post: The post updated. Has all Post fields

Example of usage:

mutation {
  UpdatePost (postId: 3, title: "Some new Title", body: "Some new content") {
    ok
    message
    post {
      uuid
      title
      body
    }
  }
}

Example of return:

{
  "data": {
    "UpdatePost": {
      "ok": true,
      "message": "Post atualizado",
      "post": {
        "uuid": "3",
        "title": "Some new Title",
        "body": "Some new content"
      }
    }
  }
}

DeletePost

Deletes an existing Post.

PARAMS:
postId: The Post identifier. Required

FIELDS:
ok: True or False. Informs if the request went well
message: A message stating the status of the request

Example of usage:

mutation {
  DeletePost (postId: 3) {
    ok
    message
  }
}

Example of return:

{
  "data": {
    "DeletePost": {
      "ok": true,
      "message": "Post removido com sucesso."
    }
  }
}

CreateUser

Creates a new User.

PARAMS:
username: The User username
password: The User password

FIELDS:
ok: True or False. Informs if the request went well
message: A message stating the status of the request
post: The Post created. Has all Post fields

Example of usage:

mutation {
  CreatePost (username: "joe", password: "strongpassword") {
    ok
    message
    user {
      uuid
      username
    }
  }
}

Example of return:

{
  "data": {
    "CreateUser": {
      "ok": true,
      "message": "Criado com sucesso",
      "user": {
        "uuid": "8",
        "username": "joe"
      }
    }
  }
}

UpdateUser

Updates an existing User.

PARAMS:
postId: The User identifier. Required
username: The new User username. Not required
password: The new User password. Not required

FIELDS:
ok: True or False. Informs if the request went well
message: A message stating the status of the request
post: The User updated. Has all User fields

Example of usage:

mutation {
  UpdateUser (userId: 3, username: "joh doe", password: "newstrongpassword") {
    ok
    message
    user {
      uuid
      username
      password
    }
  }
}

Example of return:

{
  "data": {
    "UpdateUser": {
      "ok": true,
      "message": "Usuário atualizado",
      "user": {
        "uuid": "3",
        "username": "joh doe",
        "password": "newstrongpassword"
      }
    }
  }
}

DeleteUser

Deletes an existing User.

PARAMS:
postId: The User identifier. Required

FIELDS:
ok: True or False. Informs if the request went well
message: A message stating the status of the request

Example of usage:

mutation {
  DeleteUser (userId: 3) {
    ok
    message
  }
}

Example of return:

{
  "data": {
    "DeleteUser": {
      "ok": true,
      "message": "Usuário removido com sucesso."
    }
  }
}

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