Scriban Engine — Sandboxing, Global Contexts & Includes

This page covers the Scriban template engine configuration, including global contexts that inject ambient data, sandboxing constraints that keep rendering safe, template includes for partial reuse, and a full template example.

Global contexts

Global contexts inject ambient data into every template under a named variable. Three are registered by default when using Granit.Templating.Scriban:

Namespace	Variable	Example output
now	{{ now.date }}	27/02/2026
now	{{ now.datetime }}	27/02/2026 14:35
now	{{ now.iso }}	2026-02-27T14:35:00+00:00
now	{{ now.year }}	2026
now	{{ now.month }}	02
now	{{ now.time }}	14:35
context	{{ context.culture }}	fr-BE
context	{{ context.culture_name }}	francais (Belgique)
context	{{ context.tenant_id }}	3fa85f64-... or empty
context	{{ context.tenant_name }}	Acme Corp or empty
app	{{ app.name }}	Guava Admin
app	{{ app.base_url }}	https://app.example.com
app	{{ app.support_email }}	[email protected]
app	{{ app.logo_url }}	https://cdn.example.com/logo.png

The app.* context is bound to the Granit:Templating:App configuration section:

{
  "Granit": {
    "Templating": {
      "App": {
        "Name": "Guava Admin",
        "BaseUrl": "https://app.example.com",
        "SupportEmail": "[email protected]",
        "LogoUrl": "https://cdn.example.com/logo.png"
      }
    }
  }
}

Caution

User identity is intentionally not exposed in global contexts. Avoid injecting PII into ITemplateGlobalContext implementations — pass PII through TData instead.

Custom global context

public sealed class AcmeBrandingContext : ITemplateGlobalContext
{
    public string ContextName => "brand";

    public object Resolve() => new
    {
        logo_url = "https://cdn.acme.com/logo.svg",
        primary_color = "#1A73E8",
    };
}

// Registration
services.AddSingleton<ITemplateGlobalContext, AcmeBrandingContext>();

Template usage: {{ brand.logo_url }}, {{ brand.primary_color }}.

Scriban sandboxing

The Scriban engine runs in strict sandboxed mode with explicit resource limits:

• EnableRelaxedMemberAccess = false — no access to .NET internals
• No I/O, reflection, or network access from templates
• LoopLimit = 500 — prevents CPU exhaustion from nested loops
• RecursiveLimit = 50 — prevents stack overflow from recursive includes
• MemberFilter blocks regex builtins — prevents ReDoS attacks (CWE-1333) via user-controlled regex patterns
• Snake_case property mapping — PatientName becomes {{ model.patient_name }}
• Bounded template cache — parsed Template objects are cached by RevisionId with a maximum of 1 000 entries (evicts oldest on overflow)
• CancellationToken propagation — long-running templates can be cancelled
• Content size limit — template body is capped at 1 MB via SaveTemplateRequestValidator
• MIME type allowlist — only text/html and text/plain are accepted

Template includes

Templates can include other templates via {{ include 'template_name' }}. Included templates are resolved through the standard ITemplateResolver chain with culture fallback.

{{ include 'Partial.EmailHeader' }}
<p>Dear {{ model.patient_name }}, your appointment is confirmed.</p>
{{ include 'Partial.EmailFooter' }}

Include support is provided by GranitTemplateLoader, which bridges Scriban’s ITemplateLoader to Granit’s resolver chain. It is registered automatically by AddGranitTemplatingWithScriban().

Async-only

GranitTemplateLoader.Load() (sync) throws NotSupportedException. Always use Template.RenderAsync — the async path calls LoadAsync which properly awaits scoped resolvers (e.g. database-backed templates). This prevents thread starvation under load.

Scriban template example

A discharge letter template stored in the EF Core store or as an embedded resource:

<h1>Discharge Summary</h1>
<p>Date: {{ now.date }}</p>
<p>Dear {{ model.patient_name }},</p>
<p>
  You were admitted on {{ model.admission_date }} and discharged on
  {{ model.discharge_date }} from the {{ model.ward_name }} ward.
</p>
<h2>Diagnosis</h2>
<p>{{ model.primary_diagnosis }}</p>
<h2>Follow-up Instructions</h2>
<ul>
  {{ for instruction in model.follow_up_instructions }}
  <li>{{ instruction }}</li>
  {{ end }}
</ul>
<p style="font-size: 0.8em; color: #666;">
  Culture: {{ context.culture }} | Generated: {{ now.datetime }}
</p>