BlazorFrame 2.4.1

<h1> <div align="center" style="margin:0; padding:0;"> <img src="https://github.com/Tim-Maes/BlazorFrame/blob/master/assets/BlazorFrameLogo.png" alt="BlazorFrame Logo" width="600" /> </div> </h1>

A security-first Blazor iframe component with automatic resizing, cross-frame messaging, and comprehensive Content Security Policy integration.

Features

• Security-First Design - Built-in origin validation, message filtering, and sandbox isolation
• Content Security Policy - Comprehensive CSP integration with fluent configuration API
• Bidirectional Communication - Secure postMessage communication with validation for both directions
• Navigation Tracking - Capture iframe navigation events with URL and query parameters
• Sandbox Support - Multiple security levels from permissive to paranoid isolation
• Environment-Aware - Different configurations for development vs production
• Automatic Resizing - Smart height adjustment based on iframe content with configurable options
• Programmatic Reload - Refresh iframe content without recreating the entire component

Documentation

Complete Documentation

• Quick Start Guide
• Security Features
  • Configuration Validation
  • Sandbox
• Configuration Guide
  • Display options
  • Advanced options
  • Communication options
  • CSP configuration
  • Security options
• Real-world Examples
• API Reference
• Troubleshooting

🚀 Quick Start

Installation

dotnet add package BlazorFrame

Basic Usage

@using BlazorFrame


<BlazorFrame Src="https://example.com" />


<BlazorFrame @ref="iframeRef"
            Src="https://widget.example.com"
            EnableNavigationTracking="true"
            SecurityOptions="@securityOptions"
            OnValidatedMessage="HandleMessage"
            OnNavigation="HandleNavigation"
            OnSecurityViolation="HandleViolation" />

<button @onclick="SendDataToIframe">Send Data</button>

@code {
    private BlazorFrame? iframeRef;
    
    private readonly MessageSecurityOptions securityOptions = new MessageSecurityOptions()
        .ForProduction()        // Strict security settings
        .WithBasicSandbox()     // Enable iframe sandboxing
        .RequireHttps();        // Enforce HTTPS transport
        
    private Task HandleMessage(IframeMessage message)
    {
        Console.WriteLine($"Received message from {message.Origin}: {message.Data}");
        return Task.CompletedTask;
    }

    private Task HandleNavigation(NavigationEvent navigation)
    {
        Console.WriteLine($"Navigation to: {navigation.Url}");
        Console.WriteLine($"Query params: {string.Join(", ", navigation.QueryParameters)}");
        return Task.CompletedTask;
    }

    private Task HandleViolation(IframeMessage violation)
    {
        Console.WriteLine($"Security violation: {violation.ValidationError}");
        return Task.CompletedTask;
    }
    
    private async Task SendDataToIframe()
    {
        if (iframeRef != null)
        {
            await iframeRef.SendTypedMessageAsync("user-data", new { userId = 123, name = "John" });
        }
    }
}

Configuration Examples

// Development environment - relaxed security
var devOptions = new MessageSecurityOptions()
    .ForDevelopment()
    .WithPermissiveSandbox();

// Production environment - strict security
var prodOptions = new MessageSecurityOptions()
    .ForProduction()
    .WithStrictSandbox()
    .ValidateAndThrow();

// Payment widgets - maximum security
var paymentOptions = new MessageSecurityOptions()
    .ForPaymentWidget();

Auto-Resize Configuration

Control how the iframe automatically adjusts its height based on content:

<BlazorFrame Src="https://example.com"
            EnableAutoResize="true"
            ResizeOptions="@resizeOptions" />

@code {
    // Custom resize configuration
    private readonly ResizeOptions resizeOptions = new()
    {
        MinHeight = 200,
        MaxHeight = 2000,
        PollingInterval = 500,
        DebounceMs = 100,
        UseResizeObserver = true
    };
    
    // Or use built-in presets:
    // ResizeOptions.Default      - Balanced defaults
    // ResizeOptions.Performance  - Less frequent updates (better performance)
    // ResizeOptions.Responsive   - More frequent updates (smoother resizing)
}

Programmatic Reload

Refresh iframe content without recreating the entire component - useful for PDFs, dynamic content, or cache-busting:

<BlazorFrame @ref="iframeRef" Src="@pdfUrl" />

<button @onclick="RefreshContent">Refresh</button>
<button @onclick="LoadNewDocument">Load New Document</button>

@code {
    private BlazorFrame? iframeRef;
    private string pdfUrl = "https://example.com/document.pdf";
    
    // Reload the current content
    private async Task RefreshContent()
    {
        if (iframeRef != null)
        {
            await iframeRef.ReloadAsync();
        }
    }
    
    // Load a new URL with cache-busting
    private async Task LoadNewDocument()
    {
        if (iframeRef != null)
        {
            var cacheBustedUrl = $"https://example.com/document.pdf?v={DateTime.UtcNow.Ticks}";
            await iframeRef.ReloadAsync(cacheBustedUrl);
        }
    }
}

Content Security Policy

<BlazorFrame Src="https://widget.example.com"
            CspOptions="@cspOptions"
            OnCspHeaderGenerated="HandleCspGenerated" />

@code {
    private readonly CspOptions cspOptions = new CspOptions()
        .ForProduction()
        .AllowFrameSources("https://widget.example.com")
        .WithScriptNonce("secure-nonce-123");
        
    private Task HandleCspGenerated(CspHeader cspHeader)
    {
        // Apply CSP header to HTTP response
        // HttpContext.Response.Headers.Add(cspHeader.HeaderName, cspHeader.HeaderValue);
        return Task.CompletedTask;
    }
}

Security

Content Security Policy

Comprehensive CSP integration for defense-in-depth security:

• Automatic header generation - CSP headers built from iframe requirements
• Environment-aware policies - Different rules for development vs production
• Fluent configuration API - Easy-to-use builder pattern for CSP rules
• Violation monitoring - Real-time CSP violation reporting and analysis
• Nonce and hash support - Modern CSP techniques for script security

Message Validation

All iframe messages are automatically validated for:

• Origin verification - Ensures messages come from allowed domains
• Content validation - JSON structure and size limits
• Security filtering - Blocks malicious patterns and script injection
• Custom validation - Extensible validation pipeline

Sandbox Security Levels

API Reference

Component Parameters

Component Methods

Events

Demo

Interactive Demo - Try different security configurations live

Requirements

• .NET 8.0 or later
• Blazor Server or Blazor WebAssembly
• Modern browser with ES6 modules support

Browser Support

• Chrome 91+
• Firefox 90+
• Safari 15+
• Edge 91+

Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions
• NuGet: BlazorFrame Package

License

This project is licensed under the MIT License.

Built with ❤️ for the Blazor community