Automatic user registration in JSON database for Discord bot streak tracking system

[davidw]

I’m working on a streak tracking feature for my Discord bot using Python and discord.py. The bot should automatically create entries for new users when they run the streak command for the first time.

Here’s my current implementation:

import json
from datetime import datetime, timedelta

@bot.command()
async def checkin(ctx):
    with open("userdata.json", "r") as file:
        user_data = json.load(file)
    
    user_streak = user_data[f"{ctx.author.id}"]["streak_count"]
    previous_checkin = user_data[f"{ctx.author.id}"]["previous_timestamp"]
    last_activity = datetime.fromtimestamp(float(previous_checkin))
    current_time = datetime.now()
    time_diff = current_time - last_activity
    
    if time_diff < timedelta(hours=24):
        await ctx.send('Already checked in today! Wait 24 hours')
        return
    
    if time_diff > timedelta(hours=48):
        user_streak = 1
    else:
        user_streak += 1
    
    reward_amount = 50 + (user_streak * 3)
    user_data[f'{ctx.author.id}']["streak_count"] = user_streak
    user_data[f'{ctx.author.id}']["previous_timestamp"] = str(current_time.timestamp())
    
    with open("userdata.json", "w") as file:
        json.dump(user_data, file, indent=4)
    
    result_embed = discord.Embed(title="Check-in Reward", color=0x00ff00)
    result_embed.add_field(name="Reward", value=f"{reward_amount} coins")
    result_embed.set_footer(text=f"Current streak: {user_streak} days")
    
    await ctx.send(embed=result_embed)

The problem is that new users aren’t automatically added to the JSON file. When someone uses the command for the first time, it crashes because their ID doesn’t exist in the database yet. I need help implementing automatic user registration that creates a new entry with default values when a user runs the command for the first time.

[Jack81]

Your problem is trying to access dictionary keys that don’t exist yet. I’ve hit this same issue tons of times with my bots. Just wrap your user data access in try-except blocks or use dictionary methods that handle missing keys.

Don’t directly access user_data[f"{ctx.author.id}"] - use .get() with default values instead. Way cleaner than a bunch of if statements and no more KeyError exceptions. Replace your data retrieval with:

user_info = user_data.get(f"{ctx.author.id}", {
    "streak_count": 0,
    "previous_timestamp": "0"
})
user_streak = user_info["streak_count"]
previous_checkin = user_info["previous_timestamp"]

This creates the default structure for new users automatically. Watch out for the edge case where previous_timestamp is “0” - you’ll get datetime conversion errors. Everything else should work fine with this change.

[Ryan_Innovative]

The Problem:

Your Discord bot crashes when a new user tries to use the checkin command because their user ID is not yet present in your userdata.json file. The current code attempts to access data for a non-existent user, resulting in a KeyError.

Understanding the “Why” (The Root Cause):

The KeyError arises because your code directly accesses the user_data dictionary using the user ID as a key. If the key (the user ID) doesn’t exist, Python raises a KeyError. Your program doesn’t handle this case gracefully, leading to a crash. The fundamental issue is the missing error handling for the scenario where a new user is encountered. The solution should ensure that a new user entry is automatically created if one isn’t found before attempting to access the user’s data.

Step-by-Step Guide:

1. Safely Access User Data with get(): The most efficient and Pythonic solution is to use the get() method of dictionaries. get() allows you to specify a default value to return if the key is not found, preventing the KeyError.

   Replace this part of your code:

   user_streak = user_data[f"{ctx.author.id}"]["streak_count"]
   previous_checkin = user_data[f"{ctx.author.id}"]["previous_timestamp"]
   

   With this:

   user_info = user_data.get(str(ctx.author.id), {"streak_count": 0, "previous_timestamp": "0"})
   user_streak = user_info["streak_count"]
   previous_checkin = user_info["previous_timestamp"]
   

   This modification automatically creates a default entry for new users with a streak_count of 0 and a previous_timestamp of “0”. The rest of your code can continue to function without modification because the default values will trigger the correct behavior for a new user’s first check-in.

2. Handle the “0” Timestamp Edge Case: Note that using "0" as a placeholder for previous_timestamp requires a minor adjustment in how you process previous_checkin. Your original code assumes previous_checkin will always be a valid timestamp, so it should be modified to account for the case where it is “0”.

   Modify this section:

   last_activity = datetime.fromtimestamp(float(previous_checkin))
   

   To include a check:

   if previous_checkin == "0":
       last_activity = datetime.min  # Or any suitable default datetime
   else:
       last_activity = datetime.fromtimestamp(float(previous_checkin))
   

3. (Optional) Improve Data Handling: For better code readability and maintainability, consider defining a User class or using a more structured data format (like a list of dictionaries).

Common Pitfalls & What to Check Next:

• Data Consistency: Ensure the data types in your userdata.json file are consistent. Incorrect data types (e.g., strings where integers are expected) can lead to further errors.
• Error Handling: Although get() prevents KeyError, consider adding more general try...except blocks around file I/O operations to handle potential issues like file not found errors.
• Large Data Sets: If you anticipate a very large number of users, consider using a more robust database solution (like SQLite or a cloud-based database) instead of a JSON file. JSON files can become slow and cumbersome for very large datasets.

Still running into issues? Share your (sanitized) config files, the exact command you ran, and any other relevant details. The community is here to help!

[jess_brown]

wrap your whole code in a try-except block. when you get a KeyError, just create the user entry right there and set streak to 1 since it’s their first check-in. way simpler than checking if the user exists first