from flask import Flask, request, jsonify

app = Flask(__name__)

# 假設(shè)我們有一個(gè)數(shù)據(jù)庫(kù)查詢(xún)函數(shù)
def query_db(query, args=(), one=False):
    # 這里應(yīng)該是執(zhí)行數(shù)據(jù)庫(kù)查詢(xún)的代碼，比如使用 pymysql 或者 sqlalchemy
    # 這里只是為了示例，不提供具體實(shí)現(xiàn)
    pass

# 分頁(yè)查詢(xún)的API
@app.route('/users', methods=['GET'])
def get_users():
    # 設(shè)置默認(rèn)每頁(yè)數(shù)量和最大數(shù)量
    default_page_size = 10
    max_page_size = 100
    
    # 從請(qǐng)求中獲取 last_seen_id 和每頁(yè)數(shù)量參數(shù)
    last_seen_id = request.args.get('last_seen_id', None)
    page_size = int(request.args.get('page_size', default_page_size))
    
    # 限制page_size不能超過(guò)最大限制
    if page_size > max_page_size:
        page_size = max_page_size
    
    # 創(chuàng)建查詢(xún)，使用 last_seen_id 定位下一頁(yè)數(shù)據(jù)
    if last_seen_id:
        query = "SELECT * FROM users WHERE id > %s ORDER BY id ASC LIMIT %s"
        args = (last_seen_id, page_size)
    else:
        # 如果沒(méi)有提供 last_seen_id，就返回第一頁(yè)數(shù)據(jù)
        query = "SELECT * FROM users ORDER BY id ASC LIMIT %s"
        args = (page_size,)
    
    # 執(zhí)行查詢(xún)
    users = query_db(query, args)
    
    # 將查詢(xún)結(jié)果轉(zhuǎn)換為字典列表
    # 假設(shè)每個(gè) user 是一個(gè)元組(id, name)
    users_list = [{'id': user[0], 'name': user[1]} for user in users]
    last_seen_id = users[-1][0] if users else None
    
    # 返回JSON響應(yīng)
    return jsonify({
        'users': users_list,
        'last_seen_id': last_seen_id
    })

# 啟動(dòng)Flask應(yīng)用
if __name__ == '__main__':
    app.run(debug=True)