Help to extend openapi-core request

[techntools]

This is my revised version for implementing OpenAPI protocol:

from typing import Optional

from blacksheep.messages import Request

from openapi_core.datatypes import RequestParameters
from werkzeug.datastructures import Headers


class BlackSheepOpenAPIRequest:
    def __init__(self, request: Request):
        if not isinstance(request, Request):
            raise TypeError(f"'request' argument is not type of {Request}")

        self.request = request

        headers = []
        for h, v in self.request.headers.items():
            headers.append((h.decode(), v.decode()))

        self.parameters = RequestParameters(
            query=self.request.query,

            # Headers does convert header values from byte to str but it is
            # deprecated
            header=Headers(headers),

            cookie=self.request.cookies,
        )

    @property
    def host_url(self) -> str:
        return self.request.host

    @property
    def path(self) -> str:
        return self.request.path

    @property
    def method(self) -> str:
        return self.request.method.lower()

    @property
    def body(self) -> Optional[str]:
        # blacksheep.Request.text() or blacksheep.Request.read() must be awaited
        # before unmarshalling or validating request. It makes the request body
        # available on content object.
        content = self.request.content
        if content and content.body:
            return content.body.decode()

        return None

    @property
    def mimetype(self) -> str:
        content_type = self.request.content_type()
        if content_type:
            return content_type.decode().split(';')[0]

        return ''

Please help me with following two:

1. How to read request body synchronously ? Check the comments above

2. How to solve decode() error ? I am testing with Postman. No issue for text
   files. But for images, pdf, etc. following error is raised.

UnicodeDecodeError: 'utf-8' codec can't decode byte 0x89 in position 383: invalid start byte