Building JSON APIs

Building a complete REST API involves handling different HTTP methods, request data, and returning appropriate status codes. This chapter creates a CRUD API for blog posts.

GET – Retrieve All Posts

@app.route('/api/posts', methods=['GET'])
def get_posts():
    posts = Post.query.all()
    return jsonify([{'id': p.id, 'title': p.title, 'content': p.content} for p in posts])

GET – Single Post by ID

@app.route('/api/posts/', methods=['GET'])
def get_post(post_id):
    post = Post.query.get_or_404(post_id)
    return jsonify({'id': post.id, 'title': post.title, 'content': post.content})

POST – Create New Post

@app.route('/api/posts', methods=['POST'])
def create_post():
    data = request.get_json()
    new_post = Post(title=data['title'], content=data['content'], author_id=current_user.id)
    db.session.add(new_post)
    db.session.commit()
    return jsonify({'message': 'Post created'}), 201

PUT – Update Post

@app.route('/api/posts/', methods=['PUT'])
def update_post(post_id):
    post = Post.query.get_or_404(post_id)
    data = request.get_json()
    post.title = data.get('title', post.title)
    post.content = data.get('content', post.content)
    db.session.commit()
    return jsonify({'message': 'Post updated'})

DELETE – Remove Post

@app.route('/api/posts/', methods=['DELETE'])
def delete_post(post_id):
    post = Post.query.get_or_404(post_id)
    db.session.delete(post)
    db.session.commit()
    return jsonify({'message': 'Post deleted'})

Two Minute Drill

Use `request.get_json()` to parse JSON request body.
Return status codes: 200 OK, 201 Created, 404 Not Found.
Use `get_or_404()` for cleaner error handling.
Test API with Postman or curl.

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Building JSON APIs

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