Class HeaderBlock

slack_sdk/models/blocks/blocks.py:542–579

class HeaderBlock(Block):
    type = "header"
    text_max_length = 150

    @property
    def attributes(self) -> Set[str]:  # type: ignore[override]
        return super().attributes.union({"text"})

    def __init__(
        self,
        *,
        block_id: Optional[str] = None,
        text: Optional[Union[str, dict, TextObject]] = None,
        **others: dict,
    ):
        """A header is a plain-text block that displays in a larger, bold font.
        https://docs.slack.dev/reference/block-kit/blocks/header-block

        Args:
            block_id: A string acting as a unique identifier for a block. If not specified, one will be generated.
                Maximum length for this field is 255 characters.
                block_id should be unique for each message and each iteration of a message.
                If a message is updated, use a new block_id.
            text (required): The text for the block, in the form of a plain_text text object.
                Maximum length for the text in this field is 150 characters.
        """
        super().__init__(type=self.type, block_id=block_id)
        show_unknown_key_warning(self, others)

        self.text = TextObject.parse(text, default_type=PlainTextObject.type)  # type: ignore[arg-type]

    @JsonValidator("text attribute must be specified")
    def _validate_text(self):
        return self.text is not None

    @JsonValidator(f"text attribute cannot exceed {text_max_length} characters")
    def _validate_alt_text_length(self):
        return self.text is None or len(self.text.text) <= self.text_max_length


class MarkdownBlock(Block):