184. API Development

Snippet 1: Basic REST API with Flask

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from flask import Flask, jsonify

app = Flask(__name__)

@app.route('/api/hello', methods=['GET'])
def hello_world():
    return jsonify({"message": "Hello, World!"})

if __name__ == '__main__':
    app.run(debug=True)

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Snippet 2: Basic REST API with FastAPI

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from fastapi import FastAPI

app = FastAPI()

@app.get("/api/hello")
def hello_world():
    return {"message": "Hello, World!"}

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Snippet 3: CRUD Operations in Flask

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from flask import Flask, request, jsonify

app = Flask(__name__)
data = []

@app.route('/items', methods=['GET'])
def get_items():
    return jsonify(data)

@app.route('/items', methods=['POST'])
def create_item():
    item = request.json
    data.append(item)
    return jsonify({"message": "Item added", "item": item}), 201

@app.route('/items/<int:item_id>', methods=['PUT'])
def update_item(item_id):
    item = request.json
    data[item_id] = item
    return jsonify({"message": "Item updated", "item": item})

@app.route('/items/<int:item_id>', methods=['DELETE'])
def delete_item(item_id):
    deleted_item = data.pop(item_id)
    return jsonify({"message": "Item deleted", "item": deleted_item})

if __name__ == '__main__':
    app.run(debug=True)

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Snippet 4: CRUD Operations in FastAPI

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from fastapi import FastAPI, HTTPException

app = FastAPI()
data = []

@app.get("/items")
def get_items():
    return data

@app.post("/items", status_code=201)
def create_item(item: dict):
    data.append(item)
    return {"message": "Item added", "item": item}

@app.put("/items/{item_id}")
def update_item(item_id: int, item: dict):
    if item_id >= len(data):
        raise HTTPException(status_code=404, detail="Item not found")
    data[item_id] = item
    return {"message": "Item updated", "item": item}

@app.delete("/items/{item_id}")
def delete_item(item_id: int):
    if item_id >= len(data):
        raise HTTPException(status_code=404, detail="Item not found")
    deleted_item = data.pop(item_id)
    return {"message": "Item deleted", "item": deleted_item}

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Snippet 5: Path Parameters in Flask

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from flask import Flask

app = Flask(__name__)

@app.route('/users/<username>', methods=['GET'])
def get_user(username):
    return {"message": f"User: {username}"}

if __name__ == '__main__':
    app.run(debug=True)

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Snippet 6: Path Parameters in FastAPI

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from fastapi import FastAPI

app = FastAPI()

@app.get("/users/{username}")
def get_user(username: str):
    return {"message": f"User: {username}"}

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Snippet 7: Query Parameters in Flask

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from flask import Flask, request

app = Flask(__name__)

@app.route('/search', methods=['GET'])
def search():
    query = request.args.get('q', 'default query')
    return {"message": f"Search results for: {query}"}

if __name__ == '__main__':
    app.run(debug=True)

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Snippet 8: Query Parameters in FastAPI

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from fastapi import FastAPI

app = FastAPI()

@app.get("/search")
def search(q: str = "default query"):
    return {"message": f"Search results for: {q}"}

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Snippet 9: Middleware in FastAPI

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from fastapi import FastAPI, Request

app = FastAPI()

@app.middleware("http")
async def add_custom_header(request: Request, call_next):
    response = await call_next(request)
    response.headers["X-Custom-Header"] = "CustomValue"
    return response

@app.get("/")
def home():
    return {"message": "Hello with custom header"}

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Snippet 10: Using Flask-RESTful for Cleaner APIs

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from flask import Flask
from flask_restful import Api, Resource

app = Flask(__name__)
api = Api(app)

class HelloWorld(Resource):
    def get(self):
        return {"message": "Hello, World!"}

api.add_resource(HelloWorld, "/")

if __name__ == '__main__':
    app.run(debug=True)

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