Method parse_headers

aiohttp/http_parser.py:174–250

(
        self, lines: list[bytes]
    )

        self._lax = lax

    def parse_headers(
        self, lines: list[bytes]
    ) -> tuple["CIMultiDictProxy[str]", RawHeaders]:
        headers: CIMultiDict[str] = CIMultiDict()
        # note: "raw" does not mean inclusion of OWS before/after the field value
        raw_headers = []

        lines_idx = 0
        line = lines[lines_idx]
        line_count = len(lines)

        while line:
            # Parse initial header name : value pair.
            try:
                bname, bvalue = line.split(b":", 1)
            except ValueError:
                raise InvalidHeader(line) from None

            if len(bname) == 0:
                raise InvalidHeader(bname)

            # https://www.rfc-editor.org/rfc/rfc9112.html#section-5.1-2
            if {bname[0], bname[-1]} & {32, 9}:  # {" ", "\t"}
                raise InvalidHeader(line)

            bvalue = bvalue.lstrip(b" \t")
            name = bname.decode("utf-8", "surrogateescape")
            if not TOKENRE.fullmatch(name):
                raise InvalidHeader(bname)

            # next line
            lines_idx += 1
            line = lines[lines_idx]

            # consume continuation lines
            continuation = self._lax and line and line[0] in (32, 9)  # (' ', '\t')

            # Deprecated: https://www.rfc-editor.org/rfc/rfc9112.html#name-obsolete-line-folding
            if continuation:
                header_length = len(bvalue)
                bvalue_lst = [bvalue]
                while continuation:
                    header_length += len(line)
                    if header_length > self.max_field_size:
                        header_line = bname + b": " + b"".join(bvalue_lst)
                        raise LineTooLong(
                            header_line[:100] + b"...", self.max_field_size
                        )
                    bvalue_lst.append(line)

                    # next line
                    lines_idx += 1
                    if lines_idx < line_count:
                        line = lines[lines_idx]
                        if line:
                            continuation = line[0] in (32, 9)  # (' ', '\t')
                    else:
                        line = b""