User: {{ user.name }}
``` Route-specific processors: - Have access to path parameters via `request.path_params` - Only execute when their route pattern matches the current request - Can be mixed with global processors in the same list - Use Starlette's existing `Route` class - no new abstractions ## Template Response Use TemplateResponse to render templates in route handlers: ``` from starlette.applications import Starlette from starlette.middleware import Middleware from starlette.routing import Route from starlette.requests import Request from jinja2 import PackageLoader from starlette_templates.responses import TemplateResponse from starlette_templates.middleware import JinjaEnvMiddleware async def homepage(request: Request) -> TemplateResponse: return TemplateResponse( "home.html", context={"title": "Welcome", "items": [1, 2, 3]} ) app = Starlette( routes=[ Route("/", homepage), ], middleware=[ # Required for template autodiscovery Middleware( JinjaMiddleware, template_loaders=[PackageLoader("myapp", "templates")], ) ] ) ``` ### Context Variables TemplateResponse automatically includes: - `request` - The Starlette `Request` object - All context variables from context processors - Any additional context passed to `TemplateResponse` ## Template Context All templates have access to: ### Request Object ```Current path: {{ request.url.path }}
Host: {{ request.url.hostname }}
Method: {{ request.method }}
User agent: {{ request.headers.get('user-agent') }}
``` ### URL Helpers #### url_for Generate URLs for named routes: ``` Profile ``` #### url Generate URLs for mounted apps: ``` ``` #### absurl Generate absolute URLs: ``` ``` ### JSON Serialization Safely embed Python data in templates with `jsonify`: ``` ``` This properly escapes and serializes Python objects to JSON. ## Custom Filters and Globals Add custom Jinja2 filters and globals through JinjaMiddleware: ``` from starlette.applications import Starlette from starlette.middleware import Middleware from jinja2 import Environment, PackageLoader from starlette_templates.middleware import JinjaMiddleware def setup_jinja_env(env: Environment): # Add custom filter env.filters['uppercase'] = lambda x: x.upper() # Add custom global env.globals['site_name'] = "My Site" app = Starlette( middleware=[ Middleware( JinjaMiddleware, template_loaders=[PackageLoader("myapp", "templates")], # Custom setup function environment_setup=setup_jinja_env, ) ] ) ``` Then use in templates: ``` {{ "hello" | uppercase }} {{ site_name }} ``` ## Template Loaders Configure template loading with [Jinja2 loaders](https://jinja.palletsprojects.com/en/stable/api/#loaders): ### PackageLoader Load templates from a Python package: ``` from starlette.applications import Starlette from starlette.middleware import Middleware from jinja2 import PackageLoader from starlette_templates.middleware import JinjaMiddleware app = Starlette( middleware=[ Middleware( JinjaMiddleware, template_loaders=[ PackageLoader("myapp", "templates"), ] ) ] ) ``` ### FileSystemLoader Load templates from filesystem directories: ``` from starlette.applications import Starlette from starlette.middleware import Middleware from jinja2 import FileSystemLoader from starlette_templates.middleware import JinjaMiddleware app = Starlette( middleware=[ Middleware( JinjaMiddleware, template_loaders=[ FileSystemLoader("custom/templates"), ] ) ] ) ``` ### Multiple Loaders Use multiple loaders with fallback priority: ``` from starlette.applications import Starlette from starlette.middleware import Middleware from jinja2 import PackageLoader, FileSystemLoader from starlette_templates.middleware import JinjaMiddleware app = Starlette( middleware=[ Middleware( JinjaMiddleware, template_loaders=[ PackageLoader("myapp", "templates"), # Check here first FileSystemLoader("custom/templates"), # Then here ], include_default_loader=True, # Then built-in templates ) ] ) ``` ## Error Pages Create custom error pages by adding templates to your template directory: ### 404.html ```{{ error_message }}
Go Home ``` ### 500.html ```{{ error_message }}
{% if structured_errors %}{{ error_message }}
``` ## Template Inheritance Use Jinja2's template inheritance for consistent layouts: ### base.html ```Welcome to our site!
{% endblock %} ``` ## Including Templates Include reusable template fragments: ``` {% include "partials/navigation.html" %} {% include "partials/alert.html" with context %} ``` ## Macros Define reusable template functions with macros: ``` {% macro render_field(field) %}Thank you, {{ form.name }}!
We'll contact you at {{ form.email }}
{{ form.get_error_banner_text() }}
{{ error_message }}
{% if structured_errors %}{{ traceback }}
{{ error_message }}
Need help? Contact us at {{ support_email }}
Request ID: {{ request_id }}
Check service status: {{ status_page_url }}