Stream SCADA Help

1. Overview

Page Scripts is a powerful feature in the Stream platform that allows you to execute JavaScript code at the page level. This functionality provides comprehensive control over dashboard behavior, enabling custom logic, data processing, and interactive features that go beyond individual component capabilities.

This feature is particularly effective for:

• Page Initialization: Set up page-specific data and configurations when the page loads
• Real-time Processing: Execute continuous monitoring and data processing tasks
• User Interactions: Handle complex user interactions and workflows
• Data Integration: Connect to external APIs and process data from multiple sources
• Custom Logic: Implement business rules and custom algorithms
• Page Lifecycle Management: Handle page opening, closing, and cleanup operations

Key Features

• Multiple Script Types: OnLoad, OnOpen, OnClose, and Loop scripts
• Asynchronous Execution: Non-blocking script execution with proper resource management
• Stream Integration: Full access to Stream built-in functions and platform APIs
• Resource Management: Automatic cleanup of intervals, timeouts, and event listeners
• Debug Support: Comprehensive debugging and error logging capabilities
• Security Sandbox: Safe execution environment with code sanitization
• Page State Management: Access to page state and lifecycle information

📚 View Stream Built-in Functions Documentation

2. Configuration Steps

2.1 Basic Configuration

Basic Configuration tab showing page name and enable/disable settings for Page Scripts.

The Basic Configuration tab controls the fundamental settings for Page Scripts.

Page Name Matching: The Page Name must exactly match the name of the dashboard page where you want the scripts to execute. This ensures scripts run on the correct page.

2.2 Script Types

The Script Types tab allows you to configure different types of scripts for various page lifecycle events.

Script Execution Order: Scripts execute in the following order: OnLoad → OnOpen → Loop (repeatedly) → OnClose. Each script type serves a specific purpose in the page lifecycle.

// Example OnLoad Script console.log('Page loaded: ' + Stream.System.GetCurrentPage()); Stream.UI.ShowNotification('Dashboard initialized', 'success'); // Example OnOpen Script const currentUser = Stream.System.GetCurrentUser(); console.log('Page opened by: ' + currentUser); // Example OnClose Script console.log('Page closing, cleaning up resources'); Stream.UI.ShowNotification('Page closed', 'info'); // Example Loop Script const temperature = Stream.Tag.GetValueNum('Temperature.Value'); if (temperature > 80) { Stream.UI.ShowNotification('High temperature warning!', 'warning'); }

2.3 Execution Settings

The Execution Settings tab controls how scripts are executed and managed.

Performance Considerations: Set appropriate loop intervals to balance responsiveness with performance. Avoid intervals less than 100ms to prevent excessive CPU usage.

3. Stream Built-in Functions

Page Scripts provide full access to the Stream Built-in Functions library, enabling comprehensive platform integration. All functions are available through the Stream object:

Tag Operations

Read and write tag values, check tag existence, and manage data connections.

Navigation

Navigate between dashboards, refresh pages, and open external URLs.

UI Functions

Show notifications, confirmations, prompts, and other user interface elements.

Utilities

Format numbers, dates, perform math operations, and manage timing functions.

System Info

Get current user, page name, and page state information.

📚 View Complete Stream Functions Documentation

4. Security Features

⚠️ Security Notice: Page Scripts include comprehensive security features to protect your dashboard from malicious code. All user input is sanitized and executed in a controlled environment.

Code Sanitization

The Page Scripts system automatically sanitizes all JavaScript code to prevent:

• Script Injection: Removes dangerous script patterns and event handlers
• XSS Attacks: Sanitizes code to prevent cross-site scripting
• Resource Access: Prevents unauthorized access to system resources
• Infinite Loops: Implements execution time limits to prevent runaway scripts

Execution Sandbox

Scripts run in a sandboxed environment with:

• Resource Tracking: Automatic cleanup of all created resources
• Time Limits: Maximum execution time to prevent hanging
• Error Handling: Graceful error handling and logging
• Access Controls: Restricted access to dangerous global objects

Page State Management

Each page maintains its own execution context with:

• Isolated Execution: Scripts don't interfere with other pages
• State Tracking: Monitor page load status and uptime
• Resource Isolation: Resources are tracked per page
• Cleanup on Close: Automatic cleanup when page is closed

5. Troubleshooting

Common Issues and Solutions