Cloud Variables

Cloud variables in Bilup provide shared data storage and enable real-time collaboration between users. Bilup uses a cloud server compatible with Scratch’s protocol.

Understanding Cloud Variables

What Are Cloud Variables?

Cloud variables are special variables that:

• Sync: Share data between different users in real time
• Global: Accessible to all active instances of your project
• Server-backed: Stored on a cloud server while users are connected

Limitations

• Numbers only: Cloud variables only hold numbers
• Length limit: Up to 100,000 characters
• Buffering: Updates may be batched and reordered; sending over ~10 per second is redundant

Creating Cloud Variables

In Bilup Editor

Basic Creation

1. Go to Variables category in blocks palette
2. Click Make a Variable
3. Enter variable name
4. Check ☁ Cloud variable checkbox
5. Click OK

Naming Conventions

• Use descriptive names: ☁ high_score, ☁ player_data
• Avoid spaces: Use underscores instead
• Keep names short but meaningful
• Consider data type: ☁ json_data, ☁ user_count

Cloud Variable Blocks

Set Cloud Variable

set [☁ high_score v] to (1000)

Read Cloud Variable

say (☁ high_score) for (2) seconds

Change Cloud Variable

change [☁ user_count v] by (1)

Data Formats

Simple Values

Store simple text and numbers:

set [☁ high_score v] to (1000)
set [☁ player_name v] to [Alice]
set [☁ game_state v] to [playing]

Structured Data

Use delimiters for complex data:

// Comma-separated values
set [☁ player_stats v] to (join (username) (join [,] (join (score) (join [,] (level)))))

// JSON-like format
set [☁ game_data v] to [{"score":1000,"level":5,"lives":3}]

List Simulation

Simulate lists using cloud variables:

// Add item to list
set [☁ item_list v] to (join (☁ item_list) (join [|] (new_item)))

// Get item from list
set [item v] to (item (1) of (split (☁ item_list) by [|]))

Real-Time Features

Live Synchronization

Cloud variables update in real-time across all connected users:

// User counter system
when green flag clicked
change [☁ user_count v] by (1)

when I receive [user_left v]
change [☁ user_count v] by (-1)

Event Broadcasting

Create real-time events using cloud variables:

// Event trigger
when green flag clicked
forever
  if <(☁ global_event) = [start_game]> then
    broadcast [game_started v]
    set [☁ global_event v] to [none]
  end
end

// Event sender
when [space v] key pressed
set [☁ global_event v] to [start_game]

Advanced Patterns

Chat System

Implement a basic chat using cloud variables:

// Send message
when [enter v] key pressed
set [☁ chat_log v] to (join (☁ chat_log) (join [|] (join (username) (join [:] (message)))))

// Display messages
when green flag clicked
forever
  set [messages v] to (split (☁ chat_log) by [|])
  // Display logic here
end

Multiplayer State

Synchronize player positions:

// Update player position
when green flag clicked
forever
  set [☁ player_data v] to (join (username) (join [,] (join (x position) (join [,] (y position)))))
  wait (0.1) seconds
end

// Read other players
when green flag clicked
forever
  set [other_players v] to (split (☁ all_players) by [|])
  // Process other player data
end

Leaderboard System

Create persistent leaderboards:

// Submit score
when [game over v] received
if <(score) > (☁ high_score)> then
  set [☁ high_score v] to (score)
  set [☁ high_score_player v] to (username)
end

// Display leaderboard
when green flag clicked
forever
  say (join [High Score: ] (join (☁ high_score) (join [ by ] (☁ high_score_player)))) for (2) seconds
end

Server Configuration

Custom Cloud Host

Override the cloud server with a URL parameter:

https://editor.bilup.org/?cloud_host=wss://clouddata.turbowarp.org

Bilup uses wss:// by default. Insecure ws:// hosts may not work in HTTPS environments.

Best Practices

Data Management

Minimize Updates

• Batch multiple changes
• Only update when necessary
• Use local variables for temporary data

Structure Data Efficiently

// Good: Structured format
set [☁ player_data v] to [alice,100,5,active]

// Better: JSON-like format
set [☁ player_data v] to [{"name":"alice","score":100,"level":5,"status":"active"}]

Handle Large Data

// Split large data across variables
set [☁ data_part_1 v] to (letters (1) to (50000) of (large_data))
set [☁ data_part_2 v] to (letters (50001) to (100000) of (large_data))

Error Handling

Network Issues

// Check if cloud variables are working
if <(☁ test_variable) = []> then
  say [Cloud variables not available] for (2) seconds
else
  say [Cloud variables working] for (2) seconds
end

Data Validation

// Validate cloud data
if <(length of (☁ player_data)) > (0)> then
  // Process data
else
  // Use default values
end

Performance Optimization

Reduce Update Frequency

// Update every 5 seconds instead of continuously
when green flag clicked
forever
  // Update cloud variables
  wait (5) seconds
end

Use Local Caching

// Cache cloud data locally
set [cached_data v] to (☁ remote_data)
// Use cached_data for frequent reads

Troubleshooting

Common Issues

Variables Not Syncing

• Check internet connection
• Verify project is shared
• Ensure variable name starts with ☁
• Avoid very frequent updates

Data Loss

• Implement periodic backups
• Use multiple variables for redundancy
• Validate data before saving

Performance Problems

• Reduce update frequency
• Minimize data size
• Use efficient data structures

Debug Tools

Cloud Variable Monitor

// Monitor cloud variable changes
when green flag clicked
forever
  if <not <(☁ debug_var) = (last_value)>> then
    say (join [Changed: ] (☁ debug_var)) for (1) seconds
    set [last_value v] to (☁ debug_var)
  end
end

Connection Status

// Test cloud connectivity
set [☁ test_ping v] to (timer)
wait (1) seconds
if <(☁ test_ping) = (timer)> then
  say [Cloud variables offline] for (2) seconds
else
  say [Cloud variables online] for (2) seconds
end

Cloud variables unlock powerful collaborative and persistent features in Bilup. Use them to create multiplayer games, shared experiences, and data-driven projects that persist across sessions!