使用discord.py开发等级系统时遭遇JSONDecodeError错误求助

我为Discord机器人开发等级系统，参考了Stack Overflow上的基础实现方案，创建了level.json文件后运行代码，触发错误：
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

尝试多种修复方法均无效，附上代码求助：

@bot.event
async def on_message(message):
    if not message.author.bot:
        print('function load')
        with open('level.json','r') as f:
            users = json.load(f)
            print('file load')
        await update_data(users, message.author,message.guild)
        await add_experience(users, message.author, 4, message.guild)
        await level_up(users, message.author,message.channel, message.guild)

        with open('level.json','w') as f:
            json.dump(users, f)
    await bot.process_commands(message)

async def update_data(users, user,server):
    if not str(server.id) in users:
        users[str(server.id)] = {}
        if not str(user.id) in users[str(server.id)]:
            users[str(server.id)][str(user.id)] = {}
            users[str(server.id)][str(user.id)]['experience'] = 0
            users[str(server.id)][str(user.id)]['level'] = 1
    elif not str(user.id) in users[str(server.id)]:
            users[str(server.id)][str(user.id)] = {}
            users[str(server.id)][str(user.id)]['experience'] = 0
            users[str(server.id)][str(user.id)]['level'] = 1

async def add_experience(users, user, exp, server):
  users[str(user.guild.id)][str(user.id)]['experience'] += exp

async def level_up(users, user, channel, server):
  experience = users[str(user.guild.id)][str(user.id)]['experience']
  lvl_start = users[str(user.guild.id)][str(user.id)]['level']
  lvl_end = int(experience ** (1/4))
  if str(user.guild.id) != '757383943116030074':
    if lvl_start < lvl_end:
      await channel.send('{} has leveled up to Level {}'.format(user.mention, lvl_end))
      users[str(user.guild.id)][str(user.id)]['level'] = lvl_end

@bot.command(aliases = ['rank','lvl'])
async def level(ctx,member: discord.Member = None):
    if not member:
        user = ctx.message.author
        with open('level.json','r') as f:
            users = json.load(f)
        lvl = users[str(ctx.guild.id)][str(user.id)]['level']
        exp = users[str(ctx.guild.id)][str(user.id)]['experience']

        embed = discord.Embed(title = 'Level {}'.format(lvl), description = f"{exp} XP " ,color = discord.Color.green())
        embed.set_author(name = ctx.author, icon_url = ctx.author.avatar_url)
        await ctx.send(embed = embed)
    else:
      with open('level.json','r') as f:
          users = json.load(f)
      lvl = users[str(ctx.guild.id)][str(member.id)]['level']
      exp = users[str(ctx.guild.id)][str(member.id)]['experience']
      embed = discord.Embed(title = 'Level {}'.format(lvl), description = f"{exp} XP" ,color = discord.Color.green())
      embed.set_author(name = member, icon_url = member.avatar_url)

      await ctx.send(embed = embed)

问题原因及修复方案 #

1. 空JSON文件引发解码失败
   新创建的level.json是空白文件，json.load()无法解析空内容。两种解决方式：

   • 手动打开level.json，写入{}后保存；
   • 在代码中添加自动初始化逻辑，替换原读取文件的代码：

     import os
     import json
     
     def get_users():
         # 检查文件是否存在或为空
         if not os.path.exists('level.json') or os.path.getsize('level.json') == 0:
             with open('level.json', 'w') as f:
                 json.dump({}, f)  # 初始化空字典
         with open('level.json', 'r') as f:
             return json.load(f)
     

     之后在需要读取用户数据的地方，用users = get_users()替代原json.load(f)的代码块。

2. 变量名统一优化
   add_experience和level_up函数中使用user.guild.id，但update_data里用的是server.id，虽然逻辑一致，但建议统一变量名，比如都用guild代替server，避免后续维护混淆。

3. 升级曲线调整（可选）
   当前lvl_end = int(experience ** (1/4))的升级节奏过快，可根据需求修改公式，比如lvl_end = int((experience / 100) ** 0.5)，让等级提升更平缓。

4. 异常捕获增强
   在读取JSON时添加异常处理，避免因文件损坏导致机器人崩溃：

   def get_users():
       try:
           with open('level.json', 'r') as f:
               return json.load(f)
       except (json.JSONDecodeError, FileNotFoundError):
           # 文件损坏或不存在时初始化空字典
           with open('level.json', 'w') as f:
               json.dump({}, f)
           return {}
   

内容的提问来源于stack exchange，提问作者As2Bax