ASTTemplateParser 2.0.3

AST Template Parser

A high-performance, security-hardened template parser for .NET with HTML-like syntax. Works on .NET Standard 2.0, .NET Framework 4.8, .NET 6.0, and .NET 8.0.

✨ Features

• 🚀 High Performance - 90,000+ renders/second with compiled property accessors.
• 🔒 Enterprise Security - Built-in XSS protection, loop limits, and property whitelisting.
• 🧩 Component System - Reusable <Element>, <Block>, <Data>, and <Nav> components.
• 📐 Layout System - Master page layouts with sections and slots.
• 🔄 Auto Cache - AST and component files automatically reload when modified.
• 🎯 Indexer Support - Access arrays and dictionaries: {{ items[0] }} (v2.0.1+).
• 🧪 Template Filters - Transform data with pipes: {{ Name | uppercase }} (v2.0.3+).
• 🔁 Template Fragments - <Define> and <Render> for inline recursion and menus.
• 🌐 Global Variables - Set static variables once for all engine instances.
• 🌍 Cross-Platform - Fully compatible with Windows, Linux, and macOS.

📦 Installation

NuGet Package Manager:

Install-Package ASTTemplateParser

.NET CLI:

dotnet add package ASTTemplateParser

🚀 Quick Start (5 Minutes)

Step 1: Create the Engine

using ASTTemplateParser;
var engine = new TemplateEngine();

Step 2: Set Your Data

engine.SetVariable("UserName", "Antigravity");
engine.SetVariable("Products", new List<object> {
    new { Name = "Laptop", Price = 999.99 },
    new { Name = "Mouse", Price = 29.99 }
});

Step 3: Write Template & Render

<h1>Welcome, {{UserName}}!</h1>
<ul>
    <ForEach var="p" in="Products">
        <li>{{p.Name}} - {{p.Price | currency:"en-US"}}</li>
    </ForEach>
</ul>

string html = engine.Render(template);

📖 Template Syntax Guide

1. Variables & Accessors

Supports simple variables, nested properties, and indexers.

{{Name}}                      
{{User.Address.City}}         
{{Items[0].Title}}            
{{Meta["version"]}}           

2. Template Filters (NEW in v2.0.3)

Transform data using the pipe (|) syntax.

Custom Filters:

TemplateEngine.RegisterFilter("shout", (val, args) => val?.ToString() + "!!!");

3. Conditionals (If/Else)

<If condition="IsLoggedIn">
    <p>Welcome back!</p>
<ElseIf condition="Role == 'admin'">
    <p>Admin Dashboard</p>
<Else>
    <p>Please log in</p>
</If>

4. Loops (ForEach)

<ForEach var="item" in="Items">
    <li>{{item.Name}}</li>
</ForEach>

5. Components & Tags

Instead of generic includes, use type-specific tags for auto-path resolution:

🔒 Security Configuration

The parser is hardened by default, but you can customize it:

var security = new SecurityConfig {
    MaxLoopIterations = 500,        // DoS protection
    MaxRecursionDepth = 5,          // StackOverflow protection
    HtmlEncodeOutput = true,        // XSS protection
    BlockedPropertyNames = new HashSet<string> { "Password", "Secret" }
};
var engine = new TemplateEngine(security);

📊 Performance Metrics

Tested on .NET 8.0 / Intel i7 / Windows 11.

🧪 Global & Local Callbacks

Global Variables

Perfect for site-wide settings like SiteName or CopyrightYear.

TemplateEngine.SetGlobalVariable("Year", 2026);

OnBeforeIncludeRender

Fires before each component renders. Use it to inject dynamic data based on component name.

engine.OnBeforeIncludeRender((info, eng) => {
    var data = Database.Fetch(info.Name);
    eng.SetVariable("item", data);
});

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.