Module

middleware.inject

HTML injection middleware.

Injects a snippet (e.g. a<script> tag) into every text/html response before a configurable target string (default:</body>).

Useful for live-reload scripts, analytics, debug toolbars, or any markup that should appear on every page without modifying templates.

4Classes

Classes

HTMLInject 2 ▼
Middleware that injects HTML content into text/html responses. Only affects ``Response`` objects w…

Middleware that injects HTML content into text/html responses.

Only affectsResponse objects whose content_typecontains text/html. StreamingResponse and SSEResponseare passed through unchanged (seeAlpineInjectfor streaming HTML).

When full_page_only isTrue, the snippet is injected only when the before target string is found in the response body. WhenFalse(the default), the snippet is appended at the end if the target string is absent.

Usage::

app.add_middleware(HTMLInject(
    '<script src="/__reload.js"></script>',
    before="</body>",
))

Methods

Internal Methods 2 ▼
__init__ 4 ▼
def __init__(self, snippet: str, *, before: str = '</body>', full_page_only: bool = False, skip_htmx: bool = False) -> None
Parameters
Name Type Description
snippet —
before — Default:'</body>'
full_page_only — Default:False
skip_htmx — Default:False
__call__ 2 AnyResponse ▼
Inject the snippet into HTML responses.
async
async def __call__(self, request: Request, next: Next) -> AnyResponse
Parameters
Name Type Description
request —
next —
Returns
AnyResponse
StreamingHTMLInject 2 ▼
HTMLInject variant that also rewrites full-page StreamingResponse HTML.

HTMLInject variant that also rewrites full-page StreamingResponse HTML.

Methods

Internal Methods 2 ▼
__init__ 5 ▼
def __init__(self, snippet: str, *, before: str = '</body>', full_page_only: bool = False, dedup_marker: str | None = None, skip_htmx: bool = False) -> None
Parameters
Name Type Description
snippet —
before — Default:'</body>'
full_page_only — Default:False
dedup_marker — Default:None
skip_htmx — Default:False
__call__ 2 AnyResponse ▼
async
async def __call__(self, request: Request, next: Next) -> AnyResponse
Parameters
Name Type Description
request —
next —
Returns
AnyResponse
AlpineInject 1 ▼
HTMLInject that skips when Alpine is already present in the page. Checks for ``data-chirp="alpine"…

HTMLInject that skips when Alpine is already present in the page.

Checks fordata-chirp="alpine"in the response body before injecting. This prevents double-loading when the document already includes Alpine from another source.

ForStreamingResponse (e.g. Suspense), the same snippet is inserted before the first</body>using a bounded buffer so</body>may be split across chunks.

Methods

Internal Methods 1 ▼
__call__ 2 AnyResponse ▼
async
async def __call__(self, request: Request, next: Next) -> AnyResponse
Parameters
Name Type Description
request —
next —
Returns
AnyResponse
ViewTransitionCssDebugWarning 1 ▼
Log when the response body uses View Transition CSS but VT injection is off. Only runs in debug bu…

Log when the response body uses View Transition CSS but VT injection is off.

Only runs in debug builds (seecompiler._collect_builtin_middleware). Helps catchview-transition-name / @view-transitionin templates while AppConfig.view_transitions is False, which disables HTMX global VT.

Methods

Internal Methods 1 ▼
__call__ 2 AnyResponse ▼
async
async def __call__(self, request: Request, next: Next) -> AnyResponse
Parameters
Name Type Description
request —
next —
Returns
AnyResponse