pyhanko.sign.diff_analysis.rules_api module

Module defining common API types for use by rules and policies.

In principle, these aren’t relevant to the high-level validation API.

class pyhanko.sign.diff_analysis.rules_api.QualifiedWhitelistRule

Bases: object

Abstract base class for a whitelisting rule that outputs references together with the modification level at which they’re cleared.

This is intended for use by complicated whitelisting rules that need to differentiate between multiple levels.

apply_qualified(old: HistoricalResolver, new: HistoricalResolver) → Iterable[Tuple[ModificationLevel, ReferenceUpdate]]

Apply the rule to the changes between two revisions.

Parameters:

• old – The older, base revision.

• new – The newer revision to be vetted.

class pyhanko.sign.diff_analysis.rules_api.WhitelistRule

Bases: object

Abstract base class for a whitelisting rule that simply outputs cleared references without specifying a modification level.

These rules are more flexible than rules of type QualifiedWhitelistRule, since the modification level can be specified separately (see WhitelistRule.as_qualified()).

apply(old: HistoricalResolver, new: HistoricalResolver) → Iterable[ReferenceUpdate]

Apply the rule to the changes between two revisions.

Parameters:

• old – The older, base revision.

• new – The newer revision to be vetted.

as_qualified(level: ModificationLevel) → QualifiedWhitelistRule

Construct a new QualifiedWhitelistRule that whitelists the object references from this rule at the level specified.

Parameters:

level – The modification level at which the output of this rule should be cleared.

Returns:

A QualifiedWhitelistRule backed by this rule.

class pyhanko.sign.diff_analysis.rules_api.ReferenceUpdate(updated_ref: pyhanko.pdf_utils.generic.Reference, context_checked: Union[pyhanko.sign.diff_analysis.rules_api.Context, NoneType] = None)

Bases: object

updated_ref: Reference

Reference that was (potentially) updated.

context_checked: Optional[Context] = None

classmethod curry_ref(**kwargs)

property approval_type: ApprovalType

class pyhanko.sign.diff_analysis.rules_api.Context

Bases: object

classmethod from_absolute(pdf_handler: PdfHandler, absolute_path: RawPdfPath) → AbsoluteContext

classmethod relative_to(start: Union[DictionaryObject, ArrayObject], path: Union[RawPdfPath, int, str]) → RelativeContext

descend(path: Union[RawPdfPath, int, str]) → Context

class pyhanko.sign.diff_analysis.rules_api.RelativeContext(anchor: pyhanko.pdf_utils.generic.Dereferenceable, relative_path: pyhanko.pdf_utils.reader.RawPdfPath)

Bases: Context

anchor: Dereferenceable

Reference to the container object. In comparisons, this should be the reference tied to the older revision.

relative_path: RawPdfPath

Path to the object from the container.

descend(path: Union[RawPdfPath, int, str]) → RelativeContext

class pyhanko.sign.diff_analysis.rules_api.AbsoluteContext(path: pyhanko.pdf_utils.reader.RawPdfPath, pdf_handler: pyhanko.pdf_utils.rw_common.PdfHandler = None)

Bases: Context

path: RawPdfPath

Absolute path from the trailer.

pdf_handler: PdfHandler = None

The PDF handler to which this context is tied.

property relative_view: RelativeContext

descend(path: Union[RawPdfPath, int, str]) → AbsoluteContext