课程 11：通过 Flask API 提供 Redis 数据

# populate_redis_for_api.py
import redis

try:
    r = redis.Redis(host='localhost', port=6379, db=0, decode_responses=True)
    r.ping() # 检查连接

    # 词频统计示例数据 (可以来自课程 9 或类似)
    word_counts_data = {'spark': 15, 'flask': 10, 'redis': 20, 'api': 12, 'python': 25}
    # 如果您的 redis-py 版本较旧或直接使用字典，可以使用 HMSET
    # 对于 redis-py 4.x 及更高版本, HMSET 已弃用, 请使用带 mapping 参数的 HSET
    if hasattr(r, 'hmset'):
         r.hmset('api_word_counts', word_counts_data)
    else:
        r.hset('api_word_counts', mapping=word_counts_data)
    
    print("已在 Redis 中填充 'api_word_counts' 哈希。") # "Populated 'api_word_counts' hash in Redis."

    # 用户数据示例
    r.set('user:profile:1', '{"name": "Alice Smith", "email": "alice@example.com"}')
    r.set('user:profile:2', '{"name": "Bob Johnson", "email": "bob@example.com"}')
    print("已在 Redis 中填充用户个人资料示例。") # "Populated sample user profiles in Redis."

    print("示例数据填充成功。") # "Sample data populated successfully."

except redis.exceptions.ConnectionError as e:
    print(f"无法连接到 Redis 以填充数据: {e}") # "Could not connect to Redis to populate data:"
except Exception as e:
    print(f"Redis 数据填充期间发生错误: {e}") # "An error occurred during Redis population:"

from flask import Flask, jsonify
import redis
import json # 用于解析用户个人资料字符串

app = Flask(__name__)

# 初始化 Redis 连接
try:
    redis_client = redis.Redis(host='localhost', port=6379, db=0, decode_responses=True)
    redis_client.ping()
    print("Flask 应用：成功连接到 Redis！") # "Flask App: Successfully connected to Redis!"
except redis.exceptions.ConnectionError as e:
    print(f"Flask 应用：无法连接到 Redis: {e}") # "Flask App: Could not connect to Redis:"
    redis_client = None # 允许应用运行，但依赖 Redis 的路由将优雅地失败

# --- API 端点 ---

@app.route('/')
def home():
    return "欢迎！此 API 提供来自 Redis 的数据。请尝试 /api/wordcounts 或 /api/user/profile/1" # "Welcome! This API serves data from Redis. Try /api/wordcounts or /api/user/profile/1"

@app.route('/api/wordcounts', methods=['GET'])
def get_all_word_counts():
    if not redis_client:
        return jsonify({"error": "Redis 连接不可用"}), 500 # "Redis connection not available"
    
    word_counts = redis_client.hgetall('api_word_counts')
    if word_counts:
        # 将计数值从字符串转换为整数以便正确的 JSON 格式
        word_counts_int = {word: int(count) for word, count in word_counts.items()}
        return jsonify(word_counts_int)
    else:
        return jsonify({"message": "未找到词频统计或键 'api_word_counts' 不存在。"}), 404 # "No word counts found or key 'api_word_counts' does not exist."

@app.route('/api/wordcount/<word>', methods=['GET'])
def get_specific_word_count(word):
    if not redis_client:
        return jsonify({"error": "Redis 连接不可用"}), 500 # "Redis connection not available"
        
    count = redis_client.hget('api_word_counts', word.lower()) # 假设单词以小写形式存储
    if count is not None:
        return jsonify({word: int(count)})
    else:
        return jsonify({"error": f"未找到单词 '{word}'。"}), 404 # "Word '{word}' not found."

@app.route('/api/user/profile/<user_id>', methods=['GET'])
def get_user_profile(user_id):
    if not redis_client:
        return jsonify({"error": "Redis 连接不可用"}), 500 # "Redis connection not available"
        
    profile_json_str = redis_client.get(f'user:profile:{user_id}')
    if profile_json_str:
        try:
            profile_data = json.loads(profile_json_str) # 解析来自 Redis 的 JSON 字符串
            return jsonify(profile_data)
        except json.JSONDecodeError:
            return jsonify({"error": "从 Redis 解码用户个人资料数据失败。"}), 500 # "Failed to decode user profile data from Redis."
    else:
        return jsonify({"error": f"未找到 ID 为 '{user_id}' 的用户个人资料。"}), 404 # "User profile for ID '{user_id}' not found."

if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0', port=5000)