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Validators

sqlalchemy_file.validators.Validator

Interface that must be implemented by file validators.

File validators get executed before a file is stored on the database using one of the supported fields. Can be used to add additional data to file object or change it.

process(file, attr_key) abstractmethod

Should be overridden in inherited class.

Parameters:

Name Type Description Default
file File

File object

 required
attr_key str

current SQLAlchemy column key. Can be passed to ValidationError

 required

sqlalchemy_file.validators.SizeValidator

Bases: Validator

Validate file maximum size.

Attributes:

Name Type Description
max_size

The size of the underlying file must be below this file size in order to be valid. The size of the file can be given in one of the following formats:

Suffix Unit Name Value Example
(none) byte 1 byte 4096
k kilobyte 1,000 bytes 200k
M megabyte 1,000,000 bytes 2M
Ki kibibyte 1,024 bytes 32Ki
Mi mebibyte 1,048,576 bytes 8Mi

For more information, view Wikipedia: Binary prefix
Example 
class Attachment(Base):
    __tablename__ = "attachment"

    id = Column(Integer, autoincrement=True, primary_key=True)
    name = Column(String(50), unique=True)
    content = Column(FileField(validators=[SizeValidator(max_size="2M")]))

Raises:

Type Description
SizeValidationError

When file size is greater than max_size

sqlalchemy_file.validators.ContentTypeValidator

Bases: Validator

Validate file mimetype Attributes: allowed_content_types: If set, file content_type must be one of the provided list.

Example 
class Attachment(Base):
    __tablename__ = "attachment"

    id = Column(Integer, autoincrement=True, primary_key=True)
    name = Column(String(50), unique=True)
    content = Column(
        FileField(validators=[ContentTypeValidator(["text/plain", "text/csv"])])
    )

Raises:

Type Description
ContentTypeValidationError

When file content_type not in allowed_content_types

sqlalchemy_file.validators.ImageValidator

Bases: ContentTypeValidator

Default Validator for ImageField.

Attributes:

Name Type Description
min_wh

Minimum allowed dimension (w, h).
max_wh

Maximum allowed dimension (w, h).
allowed_content_types

An iterable whose items are allowed content types. Default is image/*
min_aspect_ratio

Minimum allowed image aspect ratio.
max_aspect_ratio

Maximum allowed image aspect ratio.
Example 
class Book(Base):
    __tablename__ = "book"

    id = Column(Integer, autoincrement=True, primary_key=True)
    title = Column(String(100), unique=True)
    cover = Column(
        ImageField(
            image_validator=ImageValidator(
                allowed_content_types=["image/x-icon", "image/tiff", "image/jpeg"],
                min_wh=(200, 200),
                max_wh=(400, 400),
                min_aspect_ratio=1,
                max_aspect_ratio=16/9,
            )
        )
    )

Raises:

Type Description
ContentTypeValidationError

When file content_type not in allowed_content_types
InvalidImageError

When file is not a valid image
DimensionValidationError

When image width and height constraints fail.

Will add width and height properties to the file object