diff options
Diffstat (limited to 'webmentions_ssg/tasks/receiver.py')
| -rw-r--r-- | webmentions_ssg/tasks/receiver.py | 155 |
1 files changed, 105 insertions, 50 deletions
diff --git a/webmentions_ssg/tasks/receiver.py b/webmentions_ssg/tasks/receiver.py index 39def73..4aba3d8 100644 --- a/webmentions_ssg/tasks/receiver.py +++ b/webmentions_ssg/tasks/receiver.py @@ -47,7 +47,17 @@ HTML_URL_ATTRIBUTES = { def html_mentions_target(body: bytes, source_url: str, target_url: str) -> bool: - """Check valid HTML URL attributes for the exact target URL.""" + """ + Check whether an HTML document mentions the target URL. + + URL references are resolved against the document's ``base`` element when + present, or against the source URL otherwise. + + :param body: HTML document body. + :param source_url: URL from which the document was retrieved. + :param target_url: Exact URL to look for. + :return: Whether a supported HTML URL attribute references the target URL. + """ document = BeautifulSoup(body, "html.parser") base_url = source_url @@ -59,12 +69,7 @@ def html_mentions_target(body: bytes, source_url: str, target_url: str) -> bool: for attribute, selectors in HTML_URL_ATTRIBUTES.items(): selector = ", ".join( - [ - "{selector}[{attribute}]".format( - selector=selector_string, attribute=attribute - ) - for selector_string in selectors - ] + [f"{selector_string}[{attribute}]" for selector_string in selectors] ) for element in document.select(selector): @@ -78,12 +83,25 @@ def html_mentions_target(body: bytes, source_url: str, target_url: str) -> bool: def text_mentions_target(body: str, target_url: str) -> bool: - """Check whether plain text contains the exact target IRI.""" + """ + Check whether plain text contains the exact target IRI. + + :param body: Plain-text document body. + :param target_url: Exact IRI to look for. + :return: Whether the target IRI occurs in the document. + """ return any(match.group() == target_url for match in IRI_PATTERN.finditer(body)) def ensure_public_request(request: httpx.Request) -> None: - """Prevent requests to non-public network addresses.""" + """ + Ensure that an HTTP request targets a public network address. + + :param request: HTTP request to validate. + :raises VerificationError: If the URL has no hostname or resolves to a + non-public address. + :raises TemporaryFetchError: If the hostname cannot be resolved. + """ try: if not is_public_url(str(request.url)): raise VerificationError("Source resolves to a non-public address") @@ -94,56 +112,83 @@ def ensure_public_request(request: httpx.Request) -> None: def fetch_source(source_url: str) -> tuple[httpx.Response, bytes]: - """Fetch a source with limits on redirects, time, and response size.""" + """ + Fetch a webmention source document. - with httpx.Client( - headers={ - "Accept": "text/html, application/xhtml+xml;q=0.9, text/plain;q=0.8", - "User-Agent": f"{APP_NAME}/{VERSION} ReceivedWebmention", - }, - timeout=httpx.Timeout( - current_app.config.get("WEBMENTIONS_SSG_REQUEST_TIMEOUT", 5.0) - ), - follow_redirects=True, - max_redirects=current_app.config.get("WEBMENTIONS_SSG_MAX_REDIRECTS", 20), - trust_env=False, - event_hooks={"request": [ensure_public_request]}, - ) as client: - with client.stream("GET", source_url) as response: - match response.status_code: - case 200: - pass - case 410: - raise SourceGoneError("Source returned HTTP 410") - case status: - if status in {408, 425, 429} or 500 <= status <= 599: - raise TemporaryFetchError(f"Source returned HTTP {status}") - else: - raise VerificationError(f"Source returned HTTP {status}") + The request follows redirects while enforcing the configured timeout, + redirect limit, and maximum response size. - max_source_bytes = current_app.config.get( - "WEBMENTIONS_SSG_MAX_SOURCE_BYTES", 1_000_000 - ) + :param source_url: URL of the source document. + :return: HTTP response and response body. + :raises SourceGoneError: If the source returns HTTP 410. + :raises TemporaryFetchError: If the source returns a temporary HTTP error. + :raises VerificationError: If the source returns another unsuccessful HTTP + status or exceeds the configured maximum response size. + """ - if (content_length := response.headers.get("Content-Length")) is not None: - try: - if int(content_length) > max_source_bytes: - raise VerificationError("Source document is too large") - except ValueError: - pass + with ( + httpx.Client( + headers={ + "Accept": "text/html, application/xhtml+xml;q=0.9, text/plain;q=0.8", + "User-Agent": f"{APP_NAME}/{VERSION} ReceivedWebmention", + }, + timeout=httpx.Timeout( + current_app.config.get("WEBMENTIONS_SSG_REQUEST_TIMEOUT", 5.0) + ), + follow_redirects=True, + max_redirects=current_app.config.get("WEBMENTIONS_SSG_MAX_REDIRECTS", 20), + trust_env=False, + event_hooks={"request": [ensure_public_request]}, + ) as client, + client.stream("GET", source_url) as response, + ): + match response.status_code: + case 200: + pass + case 410: + raise SourceGoneError("Source returned HTTP 410") + case status: + if status in {408, 425, 429} or 500 <= status <= 599: + raise TemporaryFetchError(f"Source returned HTTP {status}") + else: + raise VerificationError(f"Source returned HTTP {status}") - body = bytearray() - for chunk in response.iter_bytes(chunk_size=64 * 1024): - body.extend(chunk) + max_source_bytes = current_app.config.get( + "WEBMENTIONS_SSG_MAX_SOURCE_BYTES", 1_000_000 + ) - if len(body) > max_source_bytes: + if (content_length := response.headers.get("Content-Length")) is not None: + try: + if int(content_length) > max_source_bytes: raise VerificationError("Source document is too large") + except ValueError: + pass + + body = bytearray() + for chunk in response.iter_bytes(chunk_size=64 * 1024): + body.extend(chunk) - return response, bytes(body) + if len(body) > max_source_bytes: + raise VerificationError("Source document is too large") + + return response, bytes(body) def source_mentions_target(source_url: str, target_url: str) -> bool: - """Fetch the source and verify it according to its media type.""" + """ + Fetch a source and check whether it mentions the target URL. + + HTML and XHTML sources are inspected for supported URL attributes, while + plain-text sources are searched for the exact target IRI. + + :param source_url: URL of the source document. + :param target_url: Exact target URL to look for. + :return: Whether the source mentions the target URL. + :raises VerificationError: If the source has an unsupported or missing + content type. + :raises SourceGoneError: If the source explicitly reports that it is gone. + :raises TemporaryFetchError: If fetching the source fails temporarily. + """ response, body = fetch_source(source_url) @@ -170,7 +215,17 @@ def source_mentions_target(source_url: str, target_url: str) -> bool: @huey.task(retries=2, retry_delay=50) def verify_webmention(webmention_uuid: uuid.UUID) -> None: - """Verify a ReceivedWebmention and store the result.""" + """ + Verify a received webmention and store its verification status. + + Temporary fetch failures are stored before being re-raised so that Huey can + retry the task. + + :param webmention_uuid: Identifier of the received webmention to verify. + :raises TemporaryFetchError: If fetching the source fails temporarily. + :raises httpx.RequestError: If an HTTP request error occurs while fetching + the source. + """ webmention = db.session.get(ReceivedWebmention, webmention_uuid) |