TemplR

Serializable, Type-safe Payload Enrichment for .NET

TemplR is a .NET library designed to facilitate API payload and event payload templating. It allows developers to define strongly typed, serializable templates where certain properties can be replaced with variables. This enables dynamic payload generation while maintaining type safety.

Installing TemplR

TemplR can be installed from NuGet:

Install-Package TemplR

or using the .NET CLI:

dotnet add package TemplR

Code Generation vs. Runtime Reflection

TemplR supports two different approaches for creating templates:

1. TemplR.Generator (Code Generation, Recommended)

   • Uses source generators to create strongly typed proxies at compile-time.
   • Requires [Template] attributes on partial classes.
   • Provides better performance since no reflection is needed at runtime.

2. From.Expression (Runtime Reflection, Alternative Approach)

   • Allows defining templates dynamically using expressions.
   • Uses reflection at runtime to infer variable replacements.
   • Useful if you want to avoid additional compilation steps.

If you don't mind using code generation, the [Template] approach is generally easier to use than From.Expression.

Using Code Generation

TemplR can auto-generate proxies from your existing data objects, allowing properties to be replaced by strongly typed variables. To create a proxy from an existing record or class, you first need to install TemplR's code generator library:

Install-Package TemplR.Generator

Next, define a new proxy by creating a partial class decorated with the [Template] attribute:

[Template(typeof(Person))] public partial class PersonTemplate {}

The TemplateAttribute takes a single argument equal to the type being proxied. After defining this, you can create a new PersonTemplate instance with properties that support variable substitution:

var person = new PersonTemplate { Name = "Santa Claus", Age = From.Variable("yearsSinceFirstChristmas"), IsImaginary = From.Variable() };