modosaic.services.extension

modosaic.services.extension

ExtensionService

Helpers for image extensions and filesystem-safe path fragments.

infer_extension_from_bytes staticmethod

infer_extension_from_bytes(data)

Infer a known image extension from encoded bytes.

Parameters:

Name	Type	Description	Default
data	bytes	Encoded image bytes.	required

Returns:

Type	Description
str | None	.png, .jpg, or None when the signature is unknown.

Source code in modosaic/services/extension.py

@staticmethod
def infer_extension_from_bytes(data: bytes) -> str | None:
    """Infer a known image extension from encoded bytes.

    Args:
        data: Encoded image bytes.

    Returns:
        `.png`, `.jpg`, or `None` when the signature is unknown.
    """
    if data.startswith(PNG_BYTES):
        return PNG_EXTENSION
    if data.startswith(JPG_BYTES):
        return JPG_EXTENSION
    return None

normalize_extension staticmethod

normalize_extension(extension, fallback='.bin')

Normalize a file extension.

Parameters:

Name	Type	Description	Default
extension	str | None	Optional extension with or without a leading dot.	required
fallback	str	Extension returned when extension is empty.	'.bin'

Returns:

Type	Description
str	Extension with a leading dot.

Source code in modosaic/services/extension.py

@staticmethod
def normalize_extension(extension: str | None, fallback: str = ".bin") -> str:
    """Normalize a file extension.

    Args:
        extension: Optional extension with or without a leading dot.
        fallback: Extension returned when `extension` is empty.

    Returns:
        Extension with a leading dot.
    """
    if not extension:
        return fallback
    return extension if extension.startswith(".") else f".{extension}"

sanitize_fragment staticmethod

sanitize_fragment(value)

Convert arbitrary text into a safe filename fragment.

Parameters:

Name	Type	Description	Default
value	str	Text to sanitize.	required

Returns:

Type	Description
str	A non-empty fragment containing alphanumeric characters, dots,
str	dashes, and underscores only.

Source code in modosaic/services/extension.py

@staticmethod
def sanitize_fragment(value: str) -> str:
    """Convert arbitrary text into a safe filename fragment.

    Args:
        value: Text to sanitize.

    Returns:
        A non-empty fragment containing alphanumeric characters, dots,
        dashes, and underscores only.
    """
    safe = "".join(ch if ch.isalnum() or ch in {"-", "_", "."} else "_" for ch in value)
    return safe.strip("._") or "sample"