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ProcessLinksMiddleware

Middleware to remove the application root path from incoming requests and update links in responses.

ProcessLinksMiddleware dataclass

Bases: JsonResponseMiddleware

Middleware to update links in responses, removing the upstream_url path and adding the root_path if it exists.

Parameters:

Name Type Description Default
app Callable[list, Awaitable[None]]
required
upstream_url str
required
root_path str | None
None
json_content_type_expr str
'application/(geo\\+)?json'
Source code in src/stac_auth_proxy/middleware/ProcessLinksMiddleware.py 
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@dataclass
class ProcessLinksMiddleware(JsonResponseMiddleware):
    """
    Middleware to update links in responses, removing the upstream_url path and adding
    the root_path if it exists.
    """

    app: ASGIApp
    upstream_url: str
    root_path: Optional[str] = None

    json_content_type_expr: str = r"application/(geo\+)?json"

    def should_transform_response(self, request: Request, scope: Scope) -> bool:
        """Only transform responses with JSON content type."""
        return bool(
            re.match(
                self.json_content_type_expr,
                Headers(scope=scope).get("content-type", ""),
            )
        )

    def transform_json(self, data: dict[str, Any], request: Request) -> dict[str, Any]:
        """Update links in the response to include root_path."""
        for link in get_links(data):
            href = link.get("href")
            if not href:
                continue

            try:
                parsed_link = urlparse(href)

                # Ignore links that are not for this proxy
                if parsed_link.netloc != request.headers.get("host"):
                    continue

                # Remove the upstream_url path from the link if it exists
                parsed_upstream_url = urlparse(self.upstream_url)
                if parsed_upstream_url.path != "/" and parsed_link.path.startswith(
                    parsed_upstream_url.path
                ):
                    parsed_link = parsed_link._replace(
                        path=parsed_link.path[len(parsed_upstream_url.path) :]
                    )

                # Add the root_path to the link if it exists
                if self.root_path:
                    parsed_link = parsed_link._replace(
                        path=f"{self.root_path}{parsed_link.path}"
                    )

                link["href"] = urlunparse(parsed_link)
            except Exception as e:
                logger.error(
                    "Failed to parse link href %r, (ignoring): %s", href, str(e)
                )

        return data

should_transform_response(request: Request, scope: Scope) -> bool

Only transform responses with JSON content type.

Source code in src/stac_auth_proxy/middleware/ProcessLinksMiddleware.py 
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def should_transform_response(self, request: Request, scope: Scope) -> bool:
    """Only transform responses with JSON content type."""
    return bool(
        re.match(
            self.json_content_type_expr,
            Headers(scope=scope).get("content-type", ""),
        )
    )

transform_json(data: dict[str, Any], request: Request) -> dict[str, Any]

Update links in the response to include root_path.

Source code in src/stac_auth_proxy/middleware/ProcessLinksMiddleware.py 
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def transform_json(self, data: dict[str, Any], request: Request) -> dict[str, Any]:
    """Update links in the response to include root_path."""
    for link in get_links(data):
        href = link.get("href")
        if not href:
            continue

        try:
            parsed_link = urlparse(href)

            # Ignore links that are not for this proxy
            if parsed_link.netloc != request.headers.get("host"):
                continue

            # Remove the upstream_url path from the link if it exists
            parsed_upstream_url = urlparse(self.upstream_url)
            if parsed_upstream_url.path != "/" and parsed_link.path.startswith(
                parsed_upstream_url.path
            ):
                parsed_link = parsed_link._replace(
                    path=parsed_link.path[len(parsed_upstream_url.path) :]
                )

            # Add the root_path to the link if it exists
            if self.root_path:
                parsed_link = parsed_link._replace(
                    path=f"{self.root_path}{parsed_link.path}"
                )

            link["href"] = urlunparse(parsed_link)
        except Exception as e:
            logger.error(
                "Failed to parse link href %r, (ignoring): %s", href, str(e)
            )

    return data