Fluid.Core 2.10.0

dotnet add package Fluid.Core --version 2.10.0
NuGet\Install-Package Fluid.Core -Version 2.10.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="Fluid.Core" Version="2.10.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add Fluid.Core --version 2.10.0
#r "nuget: Fluid.Core, 2.10.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install Fluid.Core as a Cake Addin
#addin nuget:?package=Fluid.Core&version=2.10.0

// Install Fluid.Core as a Cake Tool
#tool nuget:?package=Fluid.Core&version=2.10.0

<p align="center"><img width=25% src="https://github.com/sebastienros/fluid/raw/main/Assets/logo-vertical.png"></p>

NuGet MIT MyGet

Basic Overview

Fluid is an open-source .NET template engine based on the Liquid template language. It's a secure template language that is also very accessible for non-programmer audiences.

The following content is based on the 2.0.0-beta version, which is the recommended version even though some of its API might vary significantly. To see the corresponding content for v1.0 use this version

<br>

Tutorials

Deane Barker wrote a very comprehensive tutorial on how to write Liquid templates with Fluid. For a high-level overview, read The Four Levels of Fluid Development describing different stages of usages of Fluid.

<br>

Features

  • Very fast Liquid parser and renderer (no-regexp), with few allocations. See benchmarks.
  • Secure templates by allow-listing all the available properties in the template. User templates can't break your application.
  • Supports async filters. Templates can execute database queries more efficiently under load.
  • Customize filters and tag with your own. Even with complex grammar constructs. See Customizing tags and blocks
  • Parses templates in a concrete syntax tree that lets you cache, analyze and alter the templates before they are rendered.
  • Register any .NET types and properties, or define custom handlers to intercept when a named variable is accessed.

<br>

Contents

<br>

Source
<ul id="products">
  {% for product in products %}
    <li>
      <h2>{{product.name}}</h2>
      Only {{product.price | price }}

      {{product.description | prettyprint | paragraph }}
    </li>
  {% endfor %}
</ul>
Result
<ul id="products">
    <li>
      <h2>Apple</h2>
      $329

      Flat-out fun.
    </li>
    <li>
      <h2>Orange</h2>
      $25

      Colorful. 
    </li>
    <li>
      <h2>Banana</h2>
      $99

      Peel it.
    </li>
</ul>

Notice

  • The <li> tags are at the same index as in the template, even though the {% for } tag had some leading spaces
  • The <ul> and <li> tags are on contiguous lines even though the {% for } is taking a full line.

<br>

Using Fluid in your project

You can directly reference the Nuget package.

Hello World

Source
var parser = new FluidParser();

var model = new { Firstname = "Bill", Lastname = "Gates" };
var source = "Hello {{ Firstname }} {{ Lastname }}";

if (parser.TryParse(source, out var template, out var error))
{   
    var context = new TemplateContext(model);

    Console.WriteLine(template.Render(context));
}
else
{
    Console.WriteLine($"Error: {error}");
}
Result

Hello Bill Gates

Thread-safety

A FluidParser instance is thread-safe, and should be shared by the whole application. A common pattern is declare the parser in a local static variable:

    private static readonly FluidParser _parser = new FluidParser();

A IFluidTemplate instance is thread-safe and can be cached and reused by multiple threads concurrently.

A TemplateContext instance is not thread-safe and an instance should be created every time an IFluidTemplate instance is used.

<br>

Adding custom filters

Filters can be async or not. They are defined as a delegate that accepts an input, a set of arguments and the current context of the rendering process.

Here is the downcase filter as defined in Fluid.

Source
public static ValueTask<FluidValue> Downcase(FluidValue input, FilterArguments arguments, TemplateContext context)
{
    return new StringValue(input.ToStringValue().ToLower());
}
Registration

Filters are registered in an instance of TemplateOptions. This options object can be reused every time a template is rendered.

var options = new TemplateOptions();
options.Filters.AddFilter('downcase', Downcase);

var context = new TemplateContext(options);

<br>

Allow-listing object members

Liquid is a secure template language which will only allow a predefined set of members to be accessed, and where model members can't be changed. Property are added to the TemplateOptions.MemberAccessStrategy property. This options object can be reused every time a template is rendered.

Alternatively, the MemberAccessStrategy can be assigned an instance of UnsafeMemberAccessStrategy which will allow any property to be accessed.

Allow-listing a specific type

This will allow any public field or property to be read from a template.

var options = new TemplateOptions();
options.MemberAccessStrategy.Register<Person>();

Note: When passing a model with new TemplateContext(model) the type of the model object is automatically registered. This behavior can be disable by calling new TemplateContext(model, false)

Allow-listing specific members

This will only allow the specific fields or properties to be read from a template.

var options = new TemplateOptions();
options.MemberAccessStrategy.Register<Person>("Firstname", "Lastname");

Intercepting a type access

This will provide a method to intercept when a member is accessed and either return a custom value or prevent it.

NB: If the model implements IDictionary or any similar generic dictionary types the dictionary access has priority over the custom accessors.

This example demonstrates how to intercept calls to a Person and always return the same property.

var model = new Person { Name = "Bill" };

var options = new TemplateOptions();
options.MemberAccessStrategy.Register<Person, object>((obj, name) => obj.Name);

Customizing object accessors

To provide advanced customization for specific types, it is recommended to use value converters and a custom FluidValue implementation by inheriting from ObjectValueBase.

The following example show how to provide a custom transformation for any Person object:

private class PersonValue : ObjectValueBase
{
    public PersonValue(Person value) : base(value)
    {
    }

    public override ValueTask<FluidValue> GetIndexAsync(FluidValue index, TemplateContext context)
    {
        return Create(((Person)Value).Firstname + "!!!" + index.ToStringValue(), context.Options);
    }
}

This custom type can be used with a converter such that any time a Person is used, it is wrapped as a PersonValue.

var options = new TemplateOptions();
options.ValueConverters.Add(o => o is Person p ? new PersonValue(p) : null);

It can also be used to replace custom member access by customizing GetValueAsync, or do custom conversions to standard Fluid types.

Inheritance

All the members of the class hierarchy are registered. Besides, all inherited classes will be correctly evaluated when a base class is registered and a member of the base class is accessed.

<br>

Object members casing

By default, the properties of a registered object are case sensitive and registered as they are in their source code. For instance, the property FirstName would be access using the {{ p.FirstName }} tag.

However it can be necessary to register these properties with different cases, like Camel case (firstName), or Snake case (first_name).

The following example configures the templates to use Camel casing.

var options = new TemplateOptions();
options.MemberAccessStrategy.MemberNameStrategy = MemberNameStrategies.CamelCase;

Execution limits

Limiting templates recursion

When invoking {% include 'sub-template' %} statements it is possible that some templates create an infinite recursion that could block the server. To prevent this the TemplateOptions class defines a default MaxRecursion = 100 that prevents templates from being have a depth greater than 100.

Limiting templates execution

Template can inadvertently create infinite loop that could block the server by running indefinitely. To prevent this the TemplateOptions class defines a default MaxSteps. By default this value is not set.

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Converting CLR types

Whenever an object is manipulated in a template it is converted to a specific FluidValue instance that provides a dynamic type system somehow similar to the one in JavaScript.

In Liquid they can be Number, String, Boolean, Array, Dictionary, or Object. Fluid will automatically convert the CLR types to the corresponding Liquid ones, and also provides specialized ones.

To be able to customize this conversion you can add value converters.

Adding a value converter

When the conversion logic is not directly inferred from the type of an object, a value converter can be used.

Value converters can return:

  • null to indicate that the value couldn't be converted
  • a FluidValue instance to stop any further conversion and use this value
  • another object instance to continue the conversion using custom and internal type mappings

The following example shows how to convert any instance implementing an interface to a custom string value:

var options = new TemplateOptions();

options.ValueConverters.Add((value) => value is IUser user ? user.Name : null);

Note: Type mapping are defined globally for the application.

<br>

Encoding

By default Fluid doesn't encode the output. Encoders can be specified when calling Render() or RenderAsync() on the template.

HTML encoding

To render a template with HTML encoding use the System.Text.Encodings.Web.HtmlEncoder.Default instance.

This encoder is used by default for the MVC View engine.

Disabling encoding contextually

When an encoder is defined you can use a special raw filter or {% raw %} ... {% endraw %} tag to prevent a value from being encoded, for instance if you know that the content is HTML and is safe.

Source
{% assign html = '<em>This is some html</em>' %}

Encoded: {{ html }}
Not encoded: {{ html | raw }
Result
&lt;em%gt;This is some html&lt;/em%gt;
<em>This is some html</em>

Captured blocks are not double-encoded

When using capture blocks, the inner content is flagged as pre-encoded and won't be double-encoded if used in a {{ }} tag.

Source
{% capture breaktag %}<br />{% endcapture %}

{{ breaktag }}
Result
<br />

<br>

Localization

By default templates are rendered using an invariant culture so that the results are consistent across systems. This is important for instance when rendering dates, times and numbers.

However it is possible to define a specific culture to use when rendering a template using the TemplateContext.CultureInfo property.

Source
var options = new TemplateOptions();
options.CultureInfo = new CultureInfo("en-US");
var context = new TemplateContext(options);
var result = template.Render(context);
{{ 1234.56 }}
{{ "now" | date: "%v" }}
Result
1234.56
Tuesday, August 1, 2017

<br>

Time zones

System time zone

TemplateOptions and TemplateContext provides a property to define a default time zone to use when parsing date and times. The default value is the current system's time zone. Setting a custom one can also prevent different environments (data centers) from generating different results.

  • When dates and times are parsed and don't specify a time zone, the configured one is assumed.
  • When a time zone is provided in the source string, the resulting date time uses it.

Note: The date filter conforms to the Ruby date and time formats https://ruby-doc.org/core-3.0.0/Time.html#method-i-strftime. To use the .NET standard date formats, use the format_date filter.

Source
var context = new TemplateContext { TimeZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time") } ;
var result = template.Render(context);
{{ '1970-01-01 00:00:00' | date: '%c' }}
Result
Wed Dec 31 19:00:00 -08:00 1969

Converting time zones

Dates and times can be converted to specific time zones using the time_zone: <iana> filter.

Example
var context = new TemplateContext();
context.SetValue("published", DateTime.UtcNow);
{{ published | time_zone: 'America/New_York' | date: '%+' }}
Result
Tue Aug  1 17:04:36 -05:00 2017

<br>

Customizing tags and blocks

Fluid's grammar can be modified to accept any new tags and blocks with any custom parameters. The parser is based on Parlot which makes it completely extensible.

Unlike blocks, tags don't have a closing element (e.g., cycle, increment). A closing element will match the name of the opening tag with and end suffix, like endfor. Blocks are useful when manipulating a section of a a template as a set of statements.

Fluid provides helper method to register common tags and blocks. All tags and block always start with an identifier that is the tag name.

Each custom tag needs to provide a delegate that is evaluated when the tag is matched. Each delegate will be able to use these properties:

  • writer, a TextWriter instance that is used to render some text.
  • encode, a TextEncoder instance, like HtmlEncoder, or NullEncoder. It's defined by the caller of the template.
  • context, a TemplateContext instance.

Registering a custom tag

  • Empty: Tag with no parameter, like {% renderbody %}
  • Identifier: Tag taking an identifier as parameter, like {% increment my_variable %}
  • Expression: Tag taking an expression as parameter, like {% layout 'home' | append: '.liquid' %}

Here are some examples:

Source
parser.RegisterIdentifierTag("hello", (identifier, writer, encoder, context) =>
{
    writer.Write("Hello ");
    writer.Write(identifier);
});
{% hello you %}
Result
Hello you

Registering a custom block

Blocks are created the same way as tags, and the lambda expression can then access the list of statements inside the block.

Source

parser.RegisterExpressionBlock("repeat", async (value, statements, writer, encoder, context) =>
{
    var fluidValue = await value.EvaluateAsync(context);

    for (var i = 0; i < fluidValue.ToNumberValue(); i++)
    {
        await statements.RenderStatementsAsync(writer, encoder, context);
    }

    return Completion.Normal;
});
{% repeat 1 | plus: 2 %}Hi! {% endrepeat %}
Result
Hi! Hi! Hi!

Custom parsers

If identifier, empty and expression parsers are not sufficient, the methods RegisterParserBlock and RegisterParserTag accept any custom parser construct. These can be the standard ones defined in the FluidParser class, like Primary, or any other composition of them.

For instance, RegisterParseTag(Primary.AndSkip(Comma).And(Primary), ...) will expect two Primary elements separated by a comma. The delegate will then be invoked with a ValueTuple<Expression, Expression> representing the two Primary expressions.

Registering a custom operator

Operator are used to compare values, like > or contains. Custom operators can be defined if special comparisons need to be provided.

Source

The following example creates a custom xor operator that will evaluate to true if only one of the left and right expressions is true when converted to booleans.

XorBinaryExpression.cs

using Fluid.Ast;
using Fluid.Values;
using System.Threading.Tasks;

namespace Fluid.Tests.Extensibility
{
    public class XorBinaryExpression : BinaryExpression
    {
        public XorBinaryExpression(Expression left, Expression right) : base(left, right)
        {
        }

        public override async ValueTask<FluidValue> EvaluateAsync(TemplateContext context)
        {
            var leftValue = await Left.EvaluateAsync(context);
            var rightValue = await Right.EvaluateAsync(context);

            return BooleanValue.Create(leftValue.ToBooleanValue() ^ rightValue.ToBooleanValue());
        }
    }
}

Parser configuration

parser.RegisteredOperators["xor"] = (a, b) => new XorBinaryExpression(a, b);

Usage

{% if true xor false %}Hello{% endif %}
Result
Hello

Accessing the concrete syntax tree

The syntax tree is accessible by casting the template to its concrete FluidTemplate type and using the Statements property.

Source
var template = (FluidTemplate)iTemplate;
var statements = template.Statements;

<br>

ASP.NET MVC View Engine

The package Fluid.MvcViewEngine provides a convenient way to use Liquid as a replacement or in combination of Razor in ASP.NET MVC.

Configuration

Registering the view engine
  1. Reference the Fluid.MvcViewEngine NuGet package
  2. Add a using statement on Fluid.MvcViewEngine
  3. Call AddFluid() in your Startup.cs.
Sample
using Fluid.MvcViewEngine;

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc().AddFluid();
    }
}
Registering view models

Because the Liquid language only accepts known members to be accessed, the View Model classes need to be registered in Fluid. Usually from a static constructor such that the code is run only once for the application.

View Model registration

View models are automatically registered and available as the root object in liquid templates. Custom model registrations can be added when calling AddFluid().

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc().AddFluid(o => o.TemplateOptions.Register<Person>());
    }
}

More way to register types and members can be found in the Allow-listing object members section.

Registering custom tags

When using the MVC View engine, custom tags can still be added to the parser. Refer to this section on how to create custom tags.

It is recommended to create a custom class inheriting from FluidViewParser, and to customize the tags in the constructor of this new class. This class can then be registered as the default parser for the MVC view engine.

using Fluid.Ast;
using Fluid.MvcViewEngine;

namespace Fluid.MvcSample
{
    public class CustomFluidViewParser : FluidViewParser
    {
        public CustomFluidViewParser()
        {
            RegisterEmptyTag("mytag", static async (s, w, e, c) =>
            {
                await w.WriteAsync("Hello from MyTag");

                return Completion.Normal;
            });
        }
    }
}
public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.Configure<MvcViewOptions>(options =>
        {
            options.Parser = new CustomFluidViewParser();
        });

        services.AddMvc().AddFluid();
    }
}

Layouts

Index.liquid
{% layout '_layout.liquid' %}

This is the home page

The {% layout [template] %} tag accepts one argument which can be any expression that return the relative location of a liquid template that will be used as the master template.

The layout tag is optional in a view. It can also be defined multiple times or conditionally.

From a layout template the {% renderbody %} tag is used to depict the location of the view's content inside the layout itself.

Layout.liquid
<html>
  <body>
    <div class="menu"></div>
    
    <div class="content">
      {% renderbody %}
    </div>
    
    <div class="footer"></div>
  </body>
</html>

Sections

Sections are defined in a layout as for views to render content in specific locations. For instance a view can render some content in a menu or a footer section.

Rendering content in a section
{% layout '_layout.liquid' %}

This is is the home page

{% section menu %}
  <a href="h#">This link goes in the menu</a>
{% endsection %}

{% section footer %}
  This text will go in the footer
{% endsection %}
Rendering the content of a section
<html>
  <body>
    <div class="menu">
      {% rendersection menu %}
    </div>
    
    <div class="content">
      {% renderbody %}
    </div>
    
    <div class="footer">
      {% rendersection footer %}
    </div>
  </body>
</html>

ViewStart files

Defining the layout template in each view might me cumbersome and make it difficult to change it globally. To prevent that it can be defined in a _ViewStart.liquid file.

When a view is rendered all _ViewStart.liquid files from its current and parent directories are executed before. This means multiple files can be defined to defined settings for a group of views.

_ViewStart.liquid
{% layout '_layout.liquid' %}
{% assign background = 'ffffff' }

You can also define other variables or render some content.

Custom views locations

It is possible to add custom file locations containing views by adding them to FluidMvcViewOptions.ViewsLocationFormats.

The default ones are:

  • Views/{1}/{0}.liquid
  • Views/Shared/{0}.liquid

Where {0} is the view name, and {1} is the controller name.

For partials, the list is defined in FluidMvcViewOptions.PartialsLocationFormats:

  • Views/{0}.liquid
  • Views/Partials/{0}.liquid
  • Views/Partials/{1}/{0}.liquid
  • Views/Shared/Partials/{0}.liquid

Layouts will be searched in the same locations as Views.

Execution

The content of a view is parsed once and kept in memory until the file or one of its dependencies changes. Once parsed, the tag are executed every time the view is called. To compare this with Razor, where views are first compiled then instantiated every time they are rendered. This means that on startup or when the view is changed, views with Fluid will run faster than those in Razor, unless you are using precompiled Razor views. In all cases Razor views will be faster on subsequent calls as they are compiled directly to C#.

This difference makes Fluid very adapted for rapid development cycles where the views can be deployed and updated frequently. And because the Liquid language is secure, developers give access to them with more confidence.

<br>

View Engine

The Fluid ASP.NET MVC View Engine is based on an MVC agnostic view engine provided in the Fluid.ViewEngine package. The same options and features are available, but without requiring ASP.NET MVC. This is useful to provide the same experience to build template using layouts and sections.

Usage

Use the class FluidViewRenderer : IFluidViewRender and FluidViewEngineOptions.

Whitespace control

Liquid follows strict rules with regards to whitespace support. By default all spaces and new lines are preserved from the template. The Liquid syntax and some Fluid options allow to customize this behavior.

Hyphens

For example:

{%  assign name = "Bill" %}
{{ name }}

There is a new line after the assign tag which will be preserved.

Outputs:


Bill

Tags and values can use hyphens to strip whitespace.

Example:

{%  assign name = "Bill" -%}
{{ name }}

Outputs:

Bill

The -%} strips the whitespace from the right side of the assign tag.

Template Options

Fluid provides the TemplateOptions.Trimming property that can be set with predefined preferences for when whitespace should be stripped automatically, even if hyphens are not present in tags and output values.

Greedy Mode

When greedy model is disabled in TemplateOptions.Greedy, only the spaces before the first new line are stripped. Greedy mode is enabled by default since this is the standard behavior of the Liquid language.

<br>

Custom filters

Some non-standard filters are provided by default

format_date

Formats date and times using standard .NET date and time formats. It uses the current culture of the system.

Input

"now" | format_date: "G"

Output

6/15/2009 1:45:30 PM

Documentation: https://docs.microsoft.com/en-us/dotnet/standard/base-types/standard-date-and-time-format-strings

format_number

Formats numbers using standard .NET number formats.

Input

123 | format_number: "N"

Output

123.00

Documentation: https://docs.microsoft.com/en-us/dotnet/standard/base-types/standard-numeric-format-strings

format_string

Formats custom string using standard .NET format strings.

Input

"hello {0} {1:C}" | format_string: "world" 123

Output

hello world $123.00

Documentation: https://docs.microsoft.com/en-us/dotnet/api/system.string.format

<br>

Functions

Fluid provides optional support for functions, which is not part of the standard Liquid templating language. As such it is not enabled by default.

Enabling functions

When instantiating a FluidParser set the FluidParserOptions.AllowFunction property to true.

var parser = new FluidParser(new FluidParserOptions { AllowFunctions = true });

When functions are used while the feature is not enabled, a parse error will be returned.

Declaring local functions with the macro tag

macro allows you to define reusable chunks of content invoke with local function.

{% macro field(name, value='', type='text') %}
<div class="field">
  <input type="{{ type }}" name="{{ name }}"
         value="{{ value }}" />
</div>
{% endmacro %}

Now field is available as a local property of the template and can be invoked as a function.

{{ field('user') }}
{{ field('pass', type='password') }}

Macros need to be defined before they are used as they are discovered as the template is executed.

Importing functions from external templates

Macros defined in an external template must be imported before they can be invoked.

{% from 'forms' import field %}

{{ field('user') }}
{{ field('pass', type='password') }}

Extensibility

Functions are FluidValue instances implementing the InvokeAsync method. It allows any template to be provided custom function values as part of the model, the TemplateContext or globally with options.

A FunctionValue type is also available to provide out of the box functions. It takes a delegate that returns a ValueTask<FluidValue> as the result.

var lowercase = new FunctionValue((args, context) => 
{
  var firstArg = args.At(0).ToStringValue();
  var lower = firstArg.ToLowerCase();
  return new ValueTask<FluidValue>(new StringValue(lower));
});

var context = new TemplateContext();
context.SetValue("tolower", lowercase);

var parser = new FluidParser(new FluidParserOptions { AllowFunctions = true });
parser.TryParse("{{ tolower('HELLO') }}", out var template, out var error);
template.Render(context);

<br>

Visiting and altering a template

Fluid provides a Visitor pattern allowing you to analyze what a template is made of, but also altering it. This can be used for instance to check if a specific identifier is used, replace some filters by another one, or remove any expression that might not be authorized.

Visiting a template

The Fluid.Ast.AstVisitor class can be used to create a custom visitor.

Here is an example of a visitor class which records if an identifier is accessed anywhere in a template:

  public class IdentifierIsAccessedVisitor : AstVisitor
  {
      private readonly string _identifier;

      public IdentifierIsAccessedVisitor(string identifier)
      {
          _identifier = identifier;
      }

      public bool IsAccessed { get; private set; }

      public override IFluidTemplate VisitTemplate(IFluidTemplate template)
      {
          // Initialize the result each time a template is visited with the same visitor instance

          IsAccessed = false;
          return base.VisitTemplate(template);
      }

      protected override Expression VisitMemberExpression(MemberExpression memberExpression)
      {
          var firstSegment = memberExpression.Segments.FirstOrDefault() as IdentifierSegment;

          if (firstSegment != null)
          {
              IsAccessed |= firstSegment.Identifier == _identifier;
          }

          return base.VisitMemberExpression(memberExpression);
      }
  }

And its usage:

var template = new FluidParser().Parse("{{ a.b | plus: 1}}");

var visitor = new IdentifierIsAccessedVisitor("a");
visitor.VisitTemplate(template);

Console.WriteLine(visitor.IsAccessed); // writes True

Rewriting a template

The Fluid.Ast.AstRewriter class can be used to create a custom rewriter.

Here is an example of a visitor class which replaces any plus filter with a minus one:

  public class ReplacePlusFiltersVisitor : AstRewriter
  {
      protected override Expression VisitFilterExpression(FilterExpression filterExpression)
      {
          if (filterExpression.Name == "plus")
          {
              return new FilterExpression(filterExpression.Input, "minus", filterExpression.Parameters);
          }

          return filterExpression;
      }
  }

And its usage:


var template = new FluidParser().Parse("{{ 1 | plus: 2 }}");

var visitor = new ReplacePlusFiltersVisitor();
var changed = visitor.VisitTemplate(template);

var result = changed.Render();

Console.WriteLine(result); // writes -1

Performance

Caching

Some performance boost can be gained in your application if you decide to cache the parsed templates before they are rendered. Even though parsing is memory-safe as it won't induce any compilation (meaning all the memory can be collected if you decide to parse a lot of templates), you can skip the parsing step by storing and reusing the FluidTemplate instance.

These object are thread-safe as long as each call to Render() uses a dedicated TemplateContext instance.

Benchmarks

A benchmark application is provided in the source code to compare Fluid, Scriban, DotLiquid, Liquid.NET and Handlebars.NET. Run it locally to analyze the time it takes to execute specific templates.

Results

Fluid is faster and allocates less memory than all other well-known .NET Liquid parsers. For parsing, Fluid is 19% faster than the second, Scriban, allocating nearly 3 times less memory. For rendering, Fluid is 26% faster than the second, Handlebars, 5 times faster than Scriban, but allocates half the memory. Compared to DotLiquid, Fluid renders 11 times faster, and allocates 35 times less memory.

BenchmarkDotNet v0.13.12, Windows 11 (10.0.22631.3007/23H2/2023Update/SunValley3)
12th Gen Intel Core i7-1260P, 1 CPU, 16 logical and 12 physical cores
.NET SDK 8.0.101
  [Host]     : .NET 8.0.1 (8.0.123.58001), X64 RyuJIT AVX2
  DefaultJob : .NET 8.0.1 (8.0.123.58001), X64 RyuJIT AVX2


| Method             | Mean          | Error       | StdDev      | Ratio  | RatioSD | Gen0      | Gen1     | Gen2    | Allocated   | Alloc Ratio |
|------------------- |--------------:|------------:|------------:|-------:|--------:|----------:|---------:|--------:|------------:|------------:|
| Fluid_Parse        |      2.807 us |   0.0106 us |   0.0088 us |   1.00 |    0.00 |    0.2899 |        - |       - |     2.68 KB |        1.00 |
| Scriban_Parse      |      3.343 us |   0.0548 us |   0.0486 us |   1.19 |    0.02 |    0.7744 |   0.0267 |       - |     7.14 KB |        2.67 |
| DotLiquid_Parse    |      6.413 us |   0.1190 us |   0.1323 us |   2.29 |    0.04 |    1.7395 |        - |       - |    16.21 KB |        6.05 |
| LiquidNet_Parse    |     25.812 us |   0.4131 us |   0.3662 us |   9.20 |    0.12 |    6.7444 |   0.6104 |       - |    62.04 KB |       23.15 |
| Handlebars_Parse   |  2,387.174 us |  32.5388 us |  28.8448 us | 851.62 |    9.06 |   15.6250 |   7.8125 |       - |   156.89 KB |       58.55 |
|                    |               |             |             |        |         |           |          |         |             |             |
| Fluid_ParseBig     |     16.306 us |   0.0856 us |   0.0669 us |   1.00 |    0.00 |    1.2512 |   0.0305 |       - |    11.61 KB |        1.00 |
| Scriban_ParseBig   |     18.582 us |   0.3524 us |   0.3297 us |   1.14 |    0.02 |    3.4790 |   0.4883 |       - |    32.07 KB |        2.76 |
| DotLiquid_ParseBig |     27.384 us |   0.4307 us |   0.3818 us |   1.68 |    0.02 |   10.2539 |   0.4883 |       - |    94.36 KB |        8.13 |
| LiquidNet_ParseBig | 11,744.957 us | 185.4959 us | 144.8230 us | 720.29 |    9.27 | 3093.7500 |  15.6250 |       - | 28543.38 KB |    2,458.65 |
|                    |               |             |             |        |         |           |          |         |             |             |
| Fluid_Render       |    127.090 us |   1.3743 us |   1.2182 us |   1.00 |    0.00 |   10.2539 |   0.4883 |       - |    95.86 KB |        1.00 |
| Scriban_Render     |    619.533 us |   5.3542 us |   4.4710 us |   4.88 |    0.06 |   68.3594 |  68.3594 | 68.3594 |   498.43 KB |        5.20 |
| DotLiquid_Render   |  1,414.229 us |  14.7840 us |  13.8290 us |  11.12 |    0.16 |  351.5625 | 132.8125 | 23.4375 |  3367.98 KB |       35.13 |
| LiquidNet_Render   |    829.018 us |  14.3937 us |  13.4639 us |   6.53 |    0.16 |  339.8438 | 160.1563 |       - |  3130.77 KB |       32.66 |
| Handlebars_Render  |    160.397 us |   2.3408 us |   2.1896 us |   1.26 |    0.02 |   20.9961 |   3.4180 |       - |   194.92 KB |        2.03 |

Tested on January 31, 2024 with

  • Scriban 5.9.1
  • DotLiquid 2.2.692
  • Liquid.NET 0.10.0
  • Handlebars.Net 2.1.4
Legend
  • Parse: Parses a simple HTML template containing filters and properties
  • ParseBig: Parses a Blog Post template.
  • Render: Renders a simple HTML template containing filters and properties, with 500 products.

Used by

Fluid is known to be used in the following projects:

  • Orchard Core CMS Open Source .NET modular framework and CMS
  • MaltReport OpenDocument/OfficeOpenXML powered reporting engine for .NET and Mono
  • Elsa Workflows .NET Workflows Library
  • FluentEmail All in one email sender for .NET
  • NJsonSchema Library to read, generate and validate JSON Schema draft v4+ schemas
  • NSwag Swagger/OpenAPI 2.0 and 3.0 toolchain for .NET
  • Optimizely An enterprise .NET CMS
  • Rock Relationship Management System
  • TemplateTo Powerful Template Based Document Generation

Please file an issue to be listed here.

Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 is compatible.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 is compatible.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 is compatible.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 is compatible. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (61)

Showing the top 5 NuGet packages that depend on Fluid.Core:

Package Downloads
NJsonSchema.CodeGeneration

JSON Schema reader, generator and validator for .NET

Elsa.Scripting.Liquid

Elsa is a set of workflow libraries and tools that enable lean and mean workflowing capabilities in any .NET Core application. This package provides a Liquid expression evaluator based on Fluid.

OrchardCore.Liquid.Abstractions The ID prefix of this package has been reserved for one of the owners of this package by NuGet.org.

Orchard Core Framework is an application framework for building modular, multi-tenant applications on ASP.NET Core. Abstractions for liquid syntax.

Hona

Hona, a rapidly development framework for api & pc & desktop & mobile & android & harmony & ios terminals. Experience: https://dev.honastar.com Remark: Limited money, low server bandwidth, please understand if page loads slowly.

BotSharp.Core

Open source LLM application framework to build scalable, flexible and robust AI system.

GitHub repositories (17)

Showing the top 5 popular GitHub repositories that depend on Fluid.Core:

Repository Stars
OrchardCMS/OrchardCore
Orchard Core is an open-source modular and multi-tenant application framework built with ASP.NET Core, and a content management system (CMS) built on top of that framework.
elsa-workflows/elsa-core
A .NET workflows library
BililiveRecorder/BililiveRecorder
录播姬 | mikufans 生放送录制
scriban/scriban
A fast, powerful, safe and lightweight scripting language and engine for .NET
lukencode/FluentEmail
All in one email sender for .NET. Supports popular senders (SendGrid, MailGun, etc) and Razor templates.
Version Downloads Last updated
2.10.0 53,257 5/17/2024
2.9.0 60,069 4/23/2024
2.8.0 69,864 4/4/2024
2.7.0 84,932 3/18/2024
2.6.0 18,903 3/11/2024
2.5.0 1,287,350 9/28/2023
2.4.0 871,604 3/1/2023
2.3.1 351,594 12/17/2022
2.3.0 35,346 11/30/2022
2.2.16 381,748 9/21/2022
2.2.15 3,672,109 4/12/2022
2.2.14 2,628,026 1/13/2022
2.2.13 6,220 1/8/2022
2.2.12 1,455 1/7/2022
2.2.11 1,301 1/7/2022
2.2.10 1,709 1/7/2022
2.2.9 2,087 1/5/2022
2.2.8 1,002,618 12/9/2021
2.2.7 94,226 12/2/2021
2.2.6 2,529 12/1/2021
2.2.5 4,982 11/27/2021
2.2.4 10,956 11/25/2021
2.2.3 4,633 11/22/2021
2.2.2 2,400 11/20/2021
2.2.1 2,159 11/20/2021
2.2.0 19,693 11/2/2021
2.1.4 146,476 10/26/2021
2.1.3 15,311 10/19/2021
2.1.2 6,393 10/16/2021
2.1.1 1,709 10/15/2021
2.1.0 74,529 10/12/2021
2.0.13 397,735 5/29/2021
2.0.12 7,971 5/25/2021
2.0.11 94,539 5/20/2021
2.0.10 28,308 5/8/2021
2.0.9 12,072 5/4/2021
2.0.8 2,642 5/3/2021
2.0.7 7,964 4/23/2021
2.0.6 8,931 4/21/2021
2.0.5 12,508 4/14/2021
2.0.4 1,459 4/14/2021
2.0.3 5,426 4/10/2021
2.0.2 10,105 4/9/2021
2.0.1 11,233 4/6/2021
2.0.0-beta-1014 2,587 4/2/2021
2.0.0-beta-1013 2,196 3/29/2021
2.0.0-beta-1012 1,723 3/27/2021
2.0.0-beta-1011 1,026 3/25/2021
2.0.0-beta-1010 10,926 3/15/2021
2.0.0-beta-1009 2,957 3/12/2021
2.0.0-beta-1008 1,389 3/9/2021
2.0.0-beta-1007 4,794 2/28/2021
2.0.0-beta-1006 1,092 2/25/2021
2.0.0-beta-1005 1,072 2/25/2021
2.0.0-beta-1004 1,642 2/10/2021
2.0.0-beta-1003 3,425 1/25/2021
2.0.0-beta-1002 1,081 1/22/2021
2.0.0-beta-1001 317,776 1/19/2021
1.0.0 620,846 1/18/2021
1.0.0-beta-9722 60,342 12/4/2020
1.0.0-beta-9693 325,467 9/21/2020
1.0.0-beta-9681 17,088 8/6/2020
1.0.0-beta-9678 3,867 7/21/2020
1.0.0-beta-9672 14,299 6/22/2020
1.0.0-beta-9663 3,580 6/8/2020
1.0.0-beta-9660 4,267 6/8/2020
1.0.0-beta-9651 163,396 5/21/2020
1.0.0-beta-9637 58,250 3/2/2020
1.0.0-beta-9634 11,614 1/15/2020
1.0.0-beta-9626 9,914 1/8/2020
1.0.0-beta-9624 2,919 12/28/2019
1.0.0-beta-9621 1,262 12/28/2019
1.0.0-beta-9619 1,337 12/28/2019
1.0.0-beta-9617 1,388 12/24/2019
1.0.0-beta-9614 1,388 12/24/2019
1.0.0-beta-9608 68,129 10/30/2019
1.0.0-beta-9605 199,903 10/10/2019
1.0.0-beta-9599 90,216 9/20/2019
1.0.0-beta-9588 10,347 8/28/2019
1.0.0-beta-9586 2,154 8/22/2019
1.0.0-beta-9578 6,958 8/15/2019
1.0.0-beta-9571 106,174 4/2/2019
1.0.0-beta-9560 3,293 3/22/2019
1.0.0-beta-9558 1,549 3/21/2019
1.0.0-beta-9554 2,550 3/14/2019
1.0.0-beta-9545 32,674 3/5/2019
1.0.0-beta-9542 1,428 3/3/2019
1.0.0-beta-9519 17,617 2/4/2019
1.0.0-beta-9513 4,757 1/22/2019
1.0.0-beta-9507 1,648 1/21/2019
1.0.0-beta-9504 1,916 1/17/2019
1.0.0-beta-9501 1,453 1/17/2019
1.0.0-beta-9480 27,348 12/4/2018
1.0.0-beta-9463 4,496 11/15/2018
1.0.0-beta-9446 18,749 6/22/2018
1.0.0-beta-9442 56,721 6/22/2018
1.0.0-beta-9422 66,727 1/22/2018
1.0.0-beta-9415 2,215 1/16/2018
1.0.0-beta-9399 96,257 11/5/2017
1.0.0-beta-9398 1,685 11/5/2017
1.0.0-beta-9389 2,032 11/2/2017
1.0.0-beta-9334 2,349 8/30/2017
1.0.0-beta-9333 1,725 8/30/2017
1.0.0-beta-9327 14,378 8/15/2017
1.0.0-beta-9325 1,689 8/13/2017
1.0.0-beta-9308 1,801 8/10/2017
1.0.0-beta-9300 2,510 8/2/2017
1.0.0-beta-93 1,765 7/31/2017
1.0.0-beta-84 1,973 6/30/2017
1.0.0-beta-67 1,982 6/20/2017
1.0.0-beta-47 1,629 6/16/2017
1.0.0-beta-32 6,159 6/15/2017
1.0.0-beta-30 1,638 6/15/2017
1.0.0-beta-21 1,594 6/14/2017
1.0.0-beta-20 1,610 6/14/2017
1.0.0-beta-18 1,603 6/14/2017
1.0.0-beta-107 1,718 8/2/2017
0.1.0-alpha-11 1,643 6/13/2017