GraphQL API PoC

Proof of Concept (PoC) showcasing both FastAPI for REST and Strawberry for GraphQL. This example demonstrates how you can implement both approaches in a single project.

REST vs. GraphQL

Feature/Aspect	REST	GraphQL
Endpoints	Multiple endpoints	Single endpoint that takes dynamic parameters
Data Structure Control	Controlled by the backend	Controlled by the frontend
Server Type	Stateless servers with structured access to resources	Stateless servers with flexible controlled access to resources
Data Format Control	Frontend has no control over the structure or format	Frontend specifies the data structure and format it needs
API Changes	New or modified APIs needed when data requirements change, leading to longer production times	No need for API changes for different data requirements, leading to faster iterations
Request Structure	Multiple requests for different resources	Single request in the body with a query specifying all data requirements
Backend Workload	Requires more backend development to adapt to changing data needs	Reduces backend workload by leaving data structure control to the frontend
Iteration Speed	Slower due to backend dependency on API changes	Faster iteration and quicker feedback for the business
Schema

Prerequisites

• Ensure you have Python 3.11 or higher installed.

Download and Install

1. Clone the repository:

   https://github.com/dpedwards/python-graphql-fastapi.git

2. Change into the project directory:

   cd python-graphql-fastapi

3. Create and activate a virtual environment:

   python -m venv venv

   source venv/bin/activate

   On Windows, use

   venv\Scripts\activate

4. Install dependencies:

   pip install -r requirements.txt

Start the API server (FastAPI & GraphQL) with Docker or Uvicorn

Docker

Build:

docker compose up

Rebuild (optional):

docker compose down

docker compose up --build

Clean (optional):

docker system prune -a --volumes

Uvicorn

Run the API server with the following command:

uvicorn main:app --reload

FastAPI

Access the FastAPI Swagger Playground

Visit http://localhost:8000/docs in your browser to access the Swagger documentation and explore available API endpoints.

GraphQL API

Access the GraphQL GraphiQL Playground

Visit http://localhost:8000/graphql in your browser to access the GraphQL Playground.

Examples of GraphQL Queries

Get Resource Data

query MyQuery {
  getHeaders {
    active
    buyerId
    headerId
    name
    salesRepId
    lines {
      creationDate
      headerId
      itemId
      lineId
      marketId
      name
      items {
        description
        itemId
        name
      }
      markets {
        location
        marketId
        name
      }
    }
    salesRep {
      resourceId
      salesRepId
      resource {
        name
        resourceId
      }
    }
    buyers {
      buyerId
      name
    }
  }
}

Resposnse:

{
  "data": {
    "getHeaders": [
      {
        "active": "Y",
        "buyerId": 1003,
        "headerId": 1,
        "name": "Header Name 1",
        "salesRepId": 102,
        "lines": {
          "creationDate": "2023-01-01",
          "headerId": 1,
          "itemId": 701,
          "lineId": 55001,
          "marketId": 2201,
          "name": "Line Name 1",
          "items": {
            "description": "gold",
            "itemId": 701,
            "name": "gold"
          },
          "markets": {
            "location": "Europe",
            "marketId": 2201,
            "name": "NotSo Wet Market"
          }
        },
        "salesRep": {
          "resourceId": 12,
          "salesRepId": 102,
          "resource": {
            "name": "Jaba Maba",
            "resourceId": 12
          }
        },
        "buyers": {
          "buyerId": 1003,
          "name": "Simon Sims"
        }
      },
      {
        "active": "Y",
        "buyerId": 1002,
        "headerId": 2,
        "name": "Header Name 2",
        "salesRepId": 105,
        "lines": {
          "creationDate": "2022-01-05",
          "headerId": 2,
          "itemId": 701,
          "lineId": 55003,
          "marketId": 2203,
          "name": "Line Name 3",
          "items": {
            "description": "gold",
            "itemId": 701,
            "name": "gold"
          },
          "markets": {
            "location": "Africa",
            "marketId": 2203,
            "name": "Rainy Days Market"
          }
        },
        "salesRep": {
          "resourceId": 15,
          "salesRepId": 105,
          "resource": {
            "name": "Viper Song",
            "resourceId": 15
          }
        },
        "buyers": {
          "buyerId": 1002,
          "name": "Bobby DropTable"
        }
      },
    ]
  }
}

Mutation:

mutation MyMutation {
  updateHeader(header: {name: "Mutation Update", headerId: 6, salesRepId: 1, buyerId: 2, active: "yes"}) {
    name
    salesRepId
    buyerId
    active
  }
}

Result:

{
  "data": {
    "updateHeader": {
      "name": "Mutation Update",
      "salesRepId": 1,
      "buyerId": 2,
      "active": "yes"
    }
  }
}

Insert:

mutation MyMutation {
  createHeader(
    header: {headerId: 7, name: "TEST", buyerId: 1002, active: "Y", salesRepId: 105}
  ) {
    name
    salesRepId
    buyerId
    active
  }
}

Result:

{
  "data": {
    "createHeader": {
      "name": "TEST",
      "salesRepId": 105,
      "buyerId": 1002,
      "active": "Y"
    }
  }
}