Thoughts on Tech

My API Server

This project is to produce a simple API server I can run locally with persistence because frankly the ones offered online are useless for serious testing and learning. This was done and run on LMDE and I was using HTTPie as my API client.

• Create a project folder. I called it myapiproject. IT doesn't lend itself to poetry.
• Open a terminal inside that folder (you could also do this from your IDE).
• Create a virtual environment: python -m venv venv — this will create a folder called venv inside your project folder.venv contains its own Python interpreter, its own site packages, and its own pip. Essentially it's a contained, isolated mini-Python.
• Activate the virtual environment (this is the only step that differs across platforms). On Linux: source venv/bin/activate; on Windows CMD: venv\Scripts\activate.bat. When successfully activated, your prompt will be preceded by venv.
• Inside your project folder, install FastAPI: pip install fastapi — this installs FastAPI, but only into that project environment. This is the point. You can have multiple projects and they won't interfere with each other.
• Create your main.py file inside your project folder. Mine looks like the following:

  
  import json
  from pathlib import Path
  
  DATA_FILE = Path(__file__).parent / "todos.json"
  
  def load_data():
      if DATA_FILE.exists():
          with open(DATA_FILE, "r") as f:
              return json.load(f)
      return {}
  
  def save_data(data):
      with open(DATA_FILE, "w") as f:
          json.dump(data, f, indent=4)
  
  from fastapi import FastAPI, HTTPException
  from pydantic import BaseModel
  
  app = FastAPI()
  
  class Todo(BaseModel):
      id: int
      title: str
      completed: bool = False
  
  # Load persisted todos
  todos = load_data()
  
  @app.get("/")
  def read_root():
      return {"message": "Your API is running"}
  
  @app.post("/todos")
  def create_todo(todo: Todo):
      key = str(todo.id)
      if key in todos:
          raise HTTPException(status_code=400, detail="ID already exists")
      todos[key] = todo.dict()
      save_data(todos)
      return todos[key]
  
  @app.get("/todos")
  def list_todos():
      return list(todos.values())
  
  @app.get("/todos/{todo_id}")
  def get_todo(todo_id: int):
      key = str(todo_id)
      if key not in todos:
          raise HTTPException(status_code=404, detail="Todo not found")
      return todos[key]
  
  @app.patch("/todos/{todo_id}")
  def update_todo(todo_id: int, data: dict):
      key = str(todo_id)
      if key not in todos:
          raise HTTPException(status_code=404, detail="Todo not found")
      updated = {**todos[key], **data}
      todos[key] = updated
      save_data(todos)
      return updated
  
  @app.delete("/todos/{todo_id}")
  def delete_todo(todo_id: int):
      key = str(todo_id)
      if key not in todos:
          raise HTTPException(status_code=404, detail="Todo not found")
      del todos[key]
      save_data(todos)
      return {"status": "deleted"}
      
  

With this done, shut everything down and, for the sake of clarity, start from scratch. This is all in a terminal. So: