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1"""
2Anything related to Extensible Metadata Platform (XMP) metadata.
4https://en.wikipedia.org/wiki/Extensible_Metadata_Platform
5"""
7import datetime
8import decimal
9import re
10from collections.abc import Iterator
11from string import hexdigits
12from typing import (
13 Any,
14 Callable,
15 Optional,
16 TypeVar,
17 Union,
18 cast,
19)
20from xml.dom.expatbuilder import ExpatBuilderNS
21from xml.dom.minidom import Document
22from xml.dom.minidom import Element as XmlElement
23from xml.dom.xmlbuilder import Options
24from xml.parsers.expat import ExpatError, XMLParserType
26from ._protocols import XmpInformationProtocol
27from ._utils import StreamType, deprecate_with_replacement, deprecation_no_replacement
28from .errors import LimitReachedError, PdfReadError, XmpDocumentError
29from .generic import ContentStream, PdfObject
31XMP_MAX_INPUT_LENGTH = 5_000_000
32XMP_MAX_ELEMENT_COUNT = 100_000
34RDF_NAMESPACE = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
35DC_NAMESPACE = "http://purl.org/dc/elements/1.1/"
36XMP_NAMESPACE = "http://ns.adobe.com/xap/1.0/"
37PDF_NAMESPACE = "http://ns.adobe.com/pdf/1.3/"
38XMPMM_NAMESPACE = "http://ns.adobe.com/xap/1.0/mm/"
40# What is the PDFX namespace, you might ask?
41# It's documented here: https://github.com/adobe/xmp-docs/raw/master/XMPSpecifications/XMPSpecificationPart3.pdf
42# This namespace is used to place "custom metadata"
43# properties, which are arbitrary metadata properties with no semantic or
44# documented meaning.
45#
46# Elements in the namespace are key/value-style storage,
47# where the element name is the key and the content is the value. The keys
48# are transformed into valid XML identifiers by substituting an invalid
49# identifier character with \u2182 followed by the unicode hex ID of the
50# original character. A key like "my car" is therefore "my\u21820020car".
51#
52# \u2182 is the unicode character \u{ROMAN NUMERAL TEN THOUSAND}
53#
54# The pdfx namespace should be avoided.
55# A custom data schema and sensical XML elements could be used instead, as is
56# suggested by Adobe's own documentation on XMP under "Extensibility of
57# Schemas".
58PDFX_NAMESPACE = "http://ns.adobe.com/pdfx/1.3/"
60# PDF/A
61PDFAID_NAMESPACE = "http://www.aiim.org/pdfa/ns/id/"
63# Internal mapping of namespace URI → prefix
64_NAMESPACE_PREFIX_MAP = {
65 DC_NAMESPACE: "dc",
66 XMP_NAMESPACE: "xmp",
67 PDF_NAMESPACE: "pdf",
68 XMPMM_NAMESPACE: "xmpMM",
69 PDFAID_NAMESPACE: "pdfaid",
70 PDFX_NAMESPACE: "pdfx",
71}
73iso8601 = re.compile(
74 """
75 (?P<year>[0-9]{4})
76 (-
77 (?P<month>[0-9]{2})
78 (-
79 (?P<day>[0-9]+)
80 (T
81 (?P<hour>[0-9]{2}):
82 (?P<minute>[0-9]{2})
83 (:(?P<second>[0-9]{2}(.[0-9]+)?))?
84 (?P<tzd>Z|[-+][0-9]{2}:[0-9]{2})
85 )?
86 )?
87 )?
88 """,
89 re.VERBOSE,
90)
93K = TypeVar("K")
95# Minimal XMP template
96_MINIMAL_XMP = f"""<?xpacket begin="\ufeff" id="W5M0MpCehiHzreSzNTczkc9d"?>
97<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="pypdf">
98 <rdf:RDF xmlns:rdf="{RDF_NAMESPACE}">
99 <rdf:Description rdf:about=""
100 xmlns:dc="{DC_NAMESPACE}"
101 xmlns:xmp="{XMP_NAMESPACE}"
102 xmlns:pdf="{PDF_NAMESPACE}"
103 xmlns:xmpMM="{XMPMM_NAMESPACE}"
104 xmlns:pdfaid="{PDFAID_NAMESPACE}"
105 xmlns:pdfx="{PDFX_NAMESPACE}">
106 </rdf:Description>
107 </rdf:RDF>
108</x:xmpmeta>
109<?xpacket end="r"?>"""
112def _identity(value: K) -> K:
113 return value
116def _converter_date(value: str) -> datetime.datetime:
117 matches = iso8601.match(value)
118 if matches is None:
119 raise ValueError(f"Invalid date format: {value}")
120 year = int(matches.group("year"))
121 month = int(matches.group("month") or "1")
122 day = int(matches.group("day") or "1")
123 hour = int(matches.group("hour") or "0")
124 minute = int(matches.group("minute") or "0")
125 second = decimal.Decimal(matches.group("second") or "0")
126 seconds_dec = second.to_integral(decimal.ROUND_FLOOR)
127 milliseconds_dec = (second - seconds_dec) * 1_000_000
129 seconds = int(seconds_dec)
130 milliseconds = int(milliseconds_dec)
132 tzd = matches.group("tzd") or "Z"
133 dt = datetime.datetime(year, month, day, hour, minute, seconds, milliseconds)
134 if tzd != "Z":
135 tzd_hours, tzd_minutes = (int(x) for x in tzd.split(":"))
136 tzd_hours *= -1
137 if tzd_hours < 0:
138 tzd_minutes *= -1
139 dt = dt + datetime.timedelta(hours=tzd_hours, minutes=tzd_minutes)
140 return dt
143def _format_datetime_utc(value: datetime.datetime) -> str:
144 """Format a datetime as UTC with trailing 'Z'.
146 - If the input is timezone-aware, convert to UTC first.
147 - If naive, assume UTC.
148 """
149 if value.tzinfo is not None and value.utcoffset() is not None:
150 value = value.astimezone(datetime.timezone.utc)
152 value = value.replace(tzinfo=None)
153 return value.strftime("%Y-%m-%dT%H:%M:%S.%fZ")
156def _generic_get(
157 element: XmlElement, self: "XmpInformation", list_type: str, converter: Callable[[Any], Any] = _identity
158) -> Optional[list[str]]:
159 containers = element.getElementsByTagNameNS(RDF_NAMESPACE, list_type)
160 retval: list[Any] = []
161 if len(containers):
162 for container in containers:
163 for item in container.getElementsByTagNameNS(RDF_NAMESPACE, "li"):
164 value = self._get_text(item)
165 value = converter(value)
166 retval.append(value)
167 return retval
168 return None
171class _XmpBuilder(ExpatBuilderNS):
172 """
173 Custom XML parser denying all entity declarations.
175 This is a stripped down and typed version inspired by what *defusedxml* does.
177 Why do we need this? The default limits of *libexpat* used by Python only block exponential entity expansion,
178 but not cases like quadratic entity expansion which can still cause quite some memory usage.
179 """
181 def __init__(self, options: Optional[Options] = None) -> None:
182 super().__init__(options=options)
183 self._element_count = 0
185 def custom_entity_declaration_handler(
186 self,
187 entity_name: str,
188 is_parameter_entity: bool,
189 value: Optional[str],
190 base: Optional[str],
191 system_id: str,
192 public_id: Optional[str],
193 notation_name: Optional[str],
194 ) -> None:
195 raise ExpatError(f"Forbidden entities: {entity_name!r}")
197 def start_element_handler(self, name: str, attributes: list[str]) -> None:
198 self._element_count += 1
199 if self._element_count > XMP_MAX_ELEMENT_COUNT:
200 raise LimitReachedError(f"XMP metadata exceeds limit of {XMP_MAX_ELEMENT_COUNT} elements.")
201 super().start_element_handler(name=name, attributes=attributes)
203 def install(self, parser: XMLParserType) -> None:
204 super().install(parser)
206 parser.EntityDeclHandler = self.custom_entity_declaration_handler
207 parser.StartElementHandler = self.start_element_handler
210class XmpInformation(XmpInformationProtocol, PdfObject):
211 """
212 An object that represents Extensible Metadata Platform (XMP) metadata.
213 Usually accessed by :py:attr:`xmp_metadata()<pypdf.PdfReader.xmp_metadata>`.
215 Raises:
216 PdfReadError: if XML is invalid
218 """
220 def __init__(self, stream: ContentStream) -> None:
221 self.stream = stream
222 try:
223 data = self.stream.get_data()
224 if (length := len(data)) > XMP_MAX_INPUT_LENGTH:
225 raise LimitReachedError(f"XMP stream size {length} exceeds limit of {XMP_MAX_INPUT_LENGTH}.")
226 doc_root: Document = _XmpBuilder().parseString(data)
227 except (AttributeError, ExpatError) as e:
228 raise PdfReadError(f"XML in XmpInformation was invalid: {e}")
229 rdf_roots = doc_root.getElementsByTagNameNS(RDF_NAMESPACE, "RDF")
230 if not rdf_roots:
231 raise PdfReadError(
232 "XML in XmpInformation was invalid: Missing rdf:RDF root element"
233 )
234 self.rdf_root: XmlElement = rdf_roots[0]
235 self.cache: dict[Any, Any] = {}
237 @classmethod
238 def create(cls) -> "XmpInformation":
239 """
240 Create a new XmpInformation object with minimal structure.
242 Returns:
243 A new XmpInformation instance with empty metadata fields.
244 """
245 stream = ContentStream(None, None)
246 stream.set_data(_MINIMAL_XMP.encode("utf-8"))
247 return cls(stream)
249 def write_to_stream(
250 self, stream: StreamType, encryption_key: Union[None, str, bytes] = None
251 ) -> None:
252 deprecate_with_replacement(
253 "XmpInformation.write_to_stream",
254 "PdfWriter.xmp_metadata",
255 "6.0.0"
256 )
257 if encryption_key is not None: # deprecated
258 deprecation_no_replacement(
259 "the encryption_key parameter of write_to_stream", "5.0.0"
260 )
261 self.stream.write_to_stream(stream)
263 def get_element(self, about_uri: str, namespace: str, name: str) -> Iterator[Any]:
264 for desc in self.rdf_root.getElementsByTagNameNS(RDF_NAMESPACE, "Description"):
265 if desc.getAttributeNS(RDF_NAMESPACE, "about") == about_uri:
266 attr = desc.getAttributeNodeNS(namespace, name)
267 if attr is not None:
268 yield attr
269 yield from desc.getElementsByTagNameNS(namespace, name)
271 def get_nodes_in_namespace(self, about_uri: str, namespace: str) -> Iterator[Any]:
272 for desc in self.rdf_root.getElementsByTagNameNS(RDF_NAMESPACE, "Description"):
273 if desc.getAttributeNS(RDF_NAMESPACE, "about") == about_uri:
274 for i in range(desc.attributes.length):
275 attr = desc.attributes.item(i)
276 if attr and attr.namespaceURI == namespace:
277 yield attr
278 for child in desc.childNodes:
279 if child.namespaceURI == namespace:
280 yield child
282 def _get_text(self, element: XmlElement) -> str:
283 text = ""
284 for child in element.childNodes:
285 if child.nodeType == child.TEXT_NODE:
286 text += child.data
287 return text
289 def _get_single_value(
290 self,
291 namespace: str,
292 name: str,
293 converter: Callable[[str], Any] = _identity,
294 ) -> Optional[Any]:
295 cached = self.cache.get(namespace, {}).get(name)
296 if cached:
297 return cached
298 value = None
299 for element in self.get_element("", namespace, name):
300 if element.nodeType == element.ATTRIBUTE_NODE:
301 value = element.nodeValue
302 else:
303 value = self._get_text(element)
304 break
305 if value is not None:
306 value = converter(value)
307 ns_cache = self.cache.setdefault(namespace, {})
308 ns_cache[name] = value
309 return value
311 def _getter_bag(self, namespace: str, name: str) -> Optional[list[str]]:
312 cached = self.cache.get(namespace, {}).get(name)
313 if cached:
314 return cast(list[str], cached)
315 retval: list[str] = []
316 for element in self.get_element("", namespace, name):
317 if (bags := _generic_get(element, self, list_type="Bag")) is not None:
318 retval.extend(bags)
319 else:
320 value = self._get_text(element)
321 retval.append(value)
322 ns_cache = self.cache.setdefault(namespace, {})
323 ns_cache[name] = retval
324 return retval
326 def _get_seq_values(
327 self,
328 namespace: str,
329 name: str,
330 converter: Callable[[Any], Any] = _identity,
331 ) -> Optional[list[Any]]:
332 cached = self.cache.get(namespace, {}).get(name)
333 if cached:
334 return cast(list[Any], cached)
335 retval: list[Any] = []
336 for element in self.get_element("", namespace, name):
337 if (seqs := _generic_get(element, self, list_type="Seq", converter=converter)) is not None:
338 retval.extend(seqs)
339 elif (bags := _generic_get(element, self, list_type="Bag")) is not None:
340 # See issue at https://github.com/py-pdf/pypdf/issues/3324
341 # Some applications violate the XMP metadata standard regarding `dc:creator` which should
342 # be an "ordered array" and thus a sequence, but use an unordered array (bag) instead.
343 # This seems to stem from the fact that the original Dublin Core specification does indeed
344 # use bags or direct values, while PDFs are expected to follow the XMP standard and ignore
345 # the plain Dublin Core variant. For this reason, add a fallback here to deal with such
346 # issues accordingly.
347 retval.extend(bags)
348 else:
349 value = converter(self._get_text(element))
350 retval.append(value)
351 ns_cache = self.cache.setdefault(namespace, {})
352 ns_cache[name] = retval
353 return retval
355 def _get_langalt_values(self, namespace: str, name: str) -> Optional[dict[Any, Any]]:
356 cached = self.cache.get(namespace, {}).get(name)
357 if cached:
358 return cast(dict[Any, Any], cached)
359 retval: dict[Any, Any] = {}
360 for element in self.get_element("", namespace, name):
361 alts = element.getElementsByTagNameNS(RDF_NAMESPACE, "Alt")
362 if len(alts):
363 for alt in alts:
364 for item in alt.getElementsByTagNameNS(RDF_NAMESPACE, "li"):
365 value = self._get_text(item)
366 retval[item.getAttribute("xml:lang")] = value
367 else:
368 retval["x-default"] = self._get_text(element)
369 ns_cache = self.cache.setdefault(namespace, {})
370 ns_cache[name] = retval
371 return retval
373 @property
374 def dc_contributor(self) -> Optional[list[str]]:
375 """Contributors to the resource (other than the authors)."""
376 return self._getter_bag(DC_NAMESPACE, "contributor")
378 @dc_contributor.setter
379 def dc_contributor(self, values: Optional[list[str]]) -> None:
380 self._set_bag_values(DC_NAMESPACE, "contributor", values)
382 @property
383 def dc_coverage(self) -> Optional[str]:
384 """Text describing the extent or scope of the resource."""
385 return self._get_single_value(DC_NAMESPACE, "coverage")
387 @dc_coverage.setter
388 def dc_coverage(self, value: Optional[str]) -> None:
389 self._set_single_value(DC_NAMESPACE, "coverage", value)
391 @property
392 def dc_creator(self) -> Optional[list[str]]:
393 """A sorted array of names of the authors of the resource, listed in order of precedence."""
394 return self._get_seq_values(DC_NAMESPACE, "creator")
396 @dc_creator.setter
397 def dc_creator(self, values: Optional[list[str]]) -> None:
398 self._set_seq_values(DC_NAMESPACE, "creator", values)
400 @property
401 def dc_date(self) -> Optional[list[datetime.datetime]]:
402 """A sorted array of dates of significance to the resource. The dates and times are in UTC."""
403 return self._get_seq_values(DC_NAMESPACE, "date", _converter_date)
405 @dc_date.setter
406 def dc_date(self, values: Optional[list[Union[str, datetime.datetime]]]) -> None:
407 if values is None:
408 self._set_seq_values(DC_NAMESPACE, "date", None)
409 else:
410 date_strings = []
411 for value in values:
412 if isinstance(value, datetime.datetime):
413 date_strings.append(_format_datetime_utc(value))
414 else:
415 date_strings.append(str(value))
416 self._set_seq_values(DC_NAMESPACE, "date", date_strings)
418 @property
419 def dc_description(self) -> Optional[dict[str, str]]:
420 """A language-keyed dictionary of textual descriptions of the content of the resource."""
421 return self._get_langalt_values(DC_NAMESPACE, "description")
423 @dc_description.setter
424 def dc_description(self, values: Optional[dict[str, str]]) -> None:
425 self._set_langalt_values(DC_NAMESPACE, "description", values)
427 @property
428 def dc_format(self) -> Optional[str]:
429 """The mime-type of the resource."""
430 return self._get_single_value(DC_NAMESPACE, "format")
432 @dc_format.setter
433 def dc_format(self, value: Optional[str]) -> None:
434 self._set_single_value(DC_NAMESPACE, "format", value)
436 @property
437 def dc_identifier(self) -> Optional[str]:
438 """Unique identifier of the resource."""
439 return self._get_single_value(DC_NAMESPACE, "identifier")
441 @dc_identifier.setter
442 def dc_identifier(self, value: Optional[str]) -> None:
443 self._set_single_value(DC_NAMESPACE, "identifier", value)
445 @property
446 def dc_language(self) -> Optional[list[str]]:
447 """An unordered array specifying the languages used in the resource."""
448 return self._getter_bag(DC_NAMESPACE, "language")
450 @dc_language.setter
451 def dc_language(self, values: Optional[list[str]]) -> None:
452 self._set_bag_values(DC_NAMESPACE, "language", values)
454 @property
455 def dc_publisher(self) -> Optional[list[str]]:
456 """An unordered array of publisher names."""
457 return self._getter_bag(DC_NAMESPACE, "publisher")
459 @dc_publisher.setter
460 def dc_publisher(self, values: Optional[list[str]]) -> None:
461 self._set_bag_values(DC_NAMESPACE, "publisher", values)
463 @property
464 def dc_relation(self) -> Optional[list[str]]:
465 """An unordered array of text descriptions of relationships to other documents."""
466 return self._getter_bag(DC_NAMESPACE, "relation")
468 @dc_relation.setter
469 def dc_relation(self, values: Optional[list[str]]) -> None:
470 self._set_bag_values(DC_NAMESPACE, "relation", values)
472 @property
473 def dc_rights(self) -> Optional[dict[str, str]]:
474 """A language-keyed dictionary of textual descriptions of the rights the user has to this resource."""
475 return self._get_langalt_values(DC_NAMESPACE, "rights")
477 @dc_rights.setter
478 def dc_rights(self, values: Optional[dict[str, str]]) -> None:
479 self._set_langalt_values(DC_NAMESPACE, "rights", values)
481 @property
482 def dc_source(self) -> Optional[str]:
483 """Unique identifier of the work from which this resource was derived."""
484 return self._get_single_value(DC_NAMESPACE, "source")
486 @dc_source.setter
487 def dc_source(self, value: Optional[str]) -> None:
488 self._set_single_value(DC_NAMESPACE, "source", value)
490 @property
491 def dc_subject(self) -> Optional[list[str]]:
492 """An unordered array of descriptive phrases or keywords that specify the topic of the content."""
493 return self._getter_bag(DC_NAMESPACE, "subject")
495 @dc_subject.setter
496 def dc_subject(self, values: Optional[list[str]]) -> None:
497 self._set_bag_values(DC_NAMESPACE, "subject", values)
499 @property
500 def dc_title(self) -> Optional[dict[str, str]]:
501 """A language-keyed dictionary of the title of the resource."""
502 return self._get_langalt_values(DC_NAMESPACE, "title")
504 @dc_title.setter
505 def dc_title(self, values: Optional[dict[str, str]]) -> None:
506 self._set_langalt_values(DC_NAMESPACE, "title", values)
508 @property
509 def dc_type(self) -> Optional[list[str]]:
510 """An unordered array of textual descriptions of the document type."""
511 return self._getter_bag(DC_NAMESPACE, "type")
513 @dc_type.setter
514 def dc_type(self, values: Optional[list[str]]) -> None:
515 self._set_bag_values(DC_NAMESPACE, "type", values)
517 @property
518 def pdf_keywords(self) -> Optional[str]:
519 """An unformatted text string representing document keywords."""
520 return self._get_single_value(PDF_NAMESPACE, "Keywords")
522 @pdf_keywords.setter
523 def pdf_keywords(self, value: Optional[str]) -> None:
524 self._set_single_value(PDF_NAMESPACE, "Keywords", value)
526 @property
527 def pdf_pdfversion(self) -> Optional[str]:
528 """The PDF file version, for example 1.0 or 1.3."""
529 return self._get_single_value(PDF_NAMESPACE, "PDFVersion")
531 @pdf_pdfversion.setter
532 def pdf_pdfversion(self, value: Optional[str]) -> None:
533 self._set_single_value(PDF_NAMESPACE, "PDFVersion", value)
535 @property
536 def pdf_producer(self) -> Optional[str]:
537 """The name of the tool that saved the document as a PDF."""
538 return self._get_single_value(PDF_NAMESPACE, "Producer")
540 @pdf_producer.setter
541 def pdf_producer(self, value: Optional[str]) -> None:
542 self._set_single_value(PDF_NAMESPACE, "Producer", value)
544 @property
545 def xmp_create_date(self) -> Optional[datetime.datetime]:
546 """The date and time the resource was originally created. Returned as a UTC datetime object."""
547 return self._get_single_value(XMP_NAMESPACE, "CreateDate", _converter_date)
549 @xmp_create_date.setter
550 def xmp_create_date(self, value: Optional[datetime.datetime]) -> None:
551 if value:
552 date_str = _format_datetime_utc(value)
553 self._set_single_value(XMP_NAMESPACE, "CreateDate", date_str)
554 else:
555 self._set_single_value(XMP_NAMESPACE, "CreateDate", None)
557 @property
558 def xmp_modify_date(self) -> Optional[datetime.datetime]:
559 """The date and time the resource was last modified. Returned as a UTC datetime object."""
560 return self._get_single_value(XMP_NAMESPACE, "ModifyDate", _converter_date)
562 @xmp_modify_date.setter
563 def xmp_modify_date(self, value: Optional[datetime.datetime]) -> None:
564 if value:
565 date_str = _format_datetime_utc(value)
566 self._set_single_value(XMP_NAMESPACE, "ModifyDate", date_str)
567 else:
568 self._set_single_value(XMP_NAMESPACE, "ModifyDate", None)
570 @property
571 def xmp_metadata_date(self) -> Optional[datetime.datetime]:
572 """The date and time that any metadata for this resource was last changed. Returned as a UTC datetime object."""
573 return self._get_single_value(XMP_NAMESPACE, "MetadataDate", _converter_date)
575 @xmp_metadata_date.setter
576 def xmp_metadata_date(self, value: Optional[datetime.datetime]) -> None:
577 if value:
578 date_str = _format_datetime_utc(value)
579 self._set_single_value(XMP_NAMESPACE, "MetadataDate", date_str)
580 else:
581 self._set_single_value(XMP_NAMESPACE, "MetadataDate", None)
583 @property
584 def xmp_creator_tool(self) -> Optional[str]:
585 """The name of the first known tool used to create the resource."""
586 return self._get_single_value(XMP_NAMESPACE, "CreatorTool")
588 @xmp_creator_tool.setter
589 def xmp_creator_tool(self, value: Optional[str]) -> None:
590 self._set_single_value(XMP_NAMESPACE, "CreatorTool", value)
592 @property
593 def xmpmm_document_id(self) -> Optional[str]:
594 """The common identifier for all versions and renditions of this resource."""
595 return self._get_single_value(XMPMM_NAMESPACE, "DocumentID")
597 @xmpmm_document_id.setter
598 def xmpmm_document_id(self, value: Optional[str]) -> None:
599 self._set_single_value(XMPMM_NAMESPACE, "DocumentID", value)
601 @property
602 def xmpmm_instance_id(self) -> Optional[str]:
603 """An identifier for a specific incarnation of a document, updated each time a file is saved."""
604 return self._get_single_value(XMPMM_NAMESPACE, "InstanceID")
606 @xmpmm_instance_id.setter
607 def xmpmm_instance_id(self, value: Optional[str]) -> None:
608 self._set_single_value(XMPMM_NAMESPACE, "InstanceID", value)
610 @property
611 def pdfaid_part(self) -> Optional[str]:
612 """The part of the PDF/A standard that the document conforms to (e.g., 1, 2, 3)."""
613 return self._get_single_value(PDFAID_NAMESPACE, "part")
615 @pdfaid_part.setter
616 def pdfaid_part(self, value: Optional[str]) -> None:
617 self._set_single_value(PDFAID_NAMESPACE, "part", value)
619 @property
620 def pdfaid_conformance(self) -> Optional[str]:
621 """The conformance level within the PDF/A standard (e.g., 'A', 'B', 'U')."""
622 return self._get_single_value(PDFAID_NAMESPACE, "conformance")
624 @pdfaid_conformance.setter
625 def pdfaid_conformance(self, value: Optional[str]) -> None:
626 self._set_single_value(PDFAID_NAMESPACE, "conformance", value)
628 @property
629 def custom_properties(self) -> dict[Any, Any]:
630 """
631 Retrieve custom metadata properties defined in the undocumented pdfx
632 metadata schema.
634 Returns:
635 A dictionary of key/value items for custom metadata properties.
637 """
638 if not hasattr(self, "_custom_properties"):
639 self._custom_properties = {}
640 for node in self.get_nodes_in_namespace("", PDFX_NAMESPACE):
641 key = node.localName
642 start = 0
643 while True:
644 # see documentation about PDFX_NAMESPACE earlier in file
645 idx = key.find("\u2182", start)
646 if idx == -1:
647 break
648 hex_id = key[idx + 1 : idx + 5]
649 if len(hex_id) != 4 or not all(c in hexdigits for c in hex_id):
650 # Not a well-formed escape; leave the marker untouched
651 # and continue past it instead of crashing.
652 start = idx + 1
653 continue
654 key = key[:idx] + chr(int(hex_id, base=16)) + key[idx + 5 :]
655 start = idx + 1
656 if node.nodeType == node.ATTRIBUTE_NODE:
657 value = node.nodeValue
658 else:
659 value = self._get_text(node)
660 self._custom_properties[key] = value
661 return self._custom_properties
663 def _get_or_create_description(self, about_uri: str = "") -> XmlElement:
664 """Get or create an rdf:Description element with the given about URI."""
665 for desc in self.rdf_root.getElementsByTagNameNS(RDF_NAMESPACE, "Description"):
666 if desc.getAttributeNS(RDF_NAMESPACE, "about") == about_uri:
667 return desc
669 doc = self.rdf_root.ownerDocument
670 if doc is None:
671 raise XmpDocumentError("XMP Document is None")
672 desc = doc.createElementNS(RDF_NAMESPACE, "rdf:Description")
673 desc.setAttributeNS(RDF_NAMESPACE, "rdf:about", about_uri)
674 self.rdf_root.appendChild(desc)
675 return desc
677 def _clear_cache_entry(self, namespace: str, name: str) -> None:
678 """Remove a cached value for a given namespace/name if present."""
679 ns_cache = self.cache.get(namespace)
680 if ns_cache and name in ns_cache:
681 del ns_cache[name]
683 def _set_single_value(self, namespace: str, name: str, value: Optional[str]) -> None:
684 """Set or remove a single metadata value."""
685 self._clear_cache_entry(namespace, name)
686 desc = self._get_or_create_description()
688 existing_elements = list(desc.getElementsByTagNameNS(namespace, name))
689 for elem in existing_elements:
690 desc.removeChild(elem)
692 if existing_attr := desc.getAttributeNodeNS(namespace, name):
693 desc.removeAttributeNode(existing_attr)
695 if value is not None:
696 doc = self.rdf_root.ownerDocument
697 if doc is None:
698 raise XmpDocumentError("XMP Document is None")
699 prefix = self._get_namespace_prefix(namespace)
700 elem = doc.createElementNS(namespace, f"{prefix}:{name}")
701 text_node = doc.createTextNode(str(value))
702 elem.appendChild(text_node)
703 desc.appendChild(elem)
705 self._update_stream()
707 def _set_bag_values(self, namespace: str, name: str, values: Optional[list[str]]) -> None:
708 """Set or remove bag values (unordered array)."""
709 self._clear_cache_entry(namespace, name)
710 desc = self._get_or_create_description()
712 existing_elements = list(desc.getElementsByTagNameNS(namespace, name))
713 for elem in existing_elements:
714 desc.removeChild(elem)
716 if values:
717 doc = self.rdf_root.ownerDocument
718 if doc is None:
719 raise XmpDocumentError("XMP Document is None")
720 prefix = self._get_namespace_prefix(namespace)
721 elem = doc.createElementNS(namespace, f"{prefix}:{name}")
722 bag = doc.createElementNS(RDF_NAMESPACE, "rdf:Bag")
724 for value in values:
725 li = doc.createElementNS(RDF_NAMESPACE, "rdf:li")
726 text_node = doc.createTextNode(str(value))
727 li.appendChild(text_node)
728 bag.appendChild(li)
730 elem.appendChild(bag)
731 desc.appendChild(elem)
733 self._update_stream()
735 def _set_seq_values(self, namespace: str, name: str, values: Optional[list[str]]) -> None:
736 """Set or remove sequence values (ordered array)."""
737 self._clear_cache_entry(namespace, name)
738 desc = self._get_or_create_description()
740 existing_elements = list(desc.getElementsByTagNameNS(namespace, name))
741 for elem in existing_elements:
742 desc.removeChild(elem)
744 if values:
745 doc = self.rdf_root.ownerDocument
746 if doc is None:
747 raise XmpDocumentError("XMP Document is None")
748 prefix = self._get_namespace_prefix(namespace)
749 elem = doc.createElementNS(namespace, f"{prefix}:{name}")
750 seq = doc.createElementNS(RDF_NAMESPACE, "rdf:Seq")
752 for value in values:
753 li = doc.createElementNS(RDF_NAMESPACE, "rdf:li")
754 text_node = doc.createTextNode(str(value))
755 li.appendChild(text_node)
756 seq.appendChild(li)
758 elem.appendChild(seq)
759 desc.appendChild(elem)
761 self._update_stream()
763 def _set_langalt_values(self, namespace: str, name: str, values: Optional[dict[str, str]]) -> None:
764 """Set or remove language alternative values."""
765 self._clear_cache_entry(namespace, name)
766 desc = self._get_or_create_description()
768 existing_elements = list(desc.getElementsByTagNameNS(namespace, name))
769 for elem in existing_elements:
770 desc.removeChild(elem)
772 if values:
773 doc = self.rdf_root.ownerDocument
774 if doc is None:
775 raise XmpDocumentError("XMP Document is None")
776 prefix = self._get_namespace_prefix(namespace)
777 elem = doc.createElementNS(namespace, f"{prefix}:{name}")
778 alt = doc.createElementNS(RDF_NAMESPACE, "rdf:Alt")
780 for lang, value in values.items():
781 li = doc.createElementNS(RDF_NAMESPACE, "rdf:li")
782 li.setAttribute("xml:lang", lang)
783 text_node = doc.createTextNode(str(value))
784 li.appendChild(text_node)
785 alt.appendChild(li)
787 elem.appendChild(alt)
788 desc.appendChild(elem)
790 self._update_stream()
792 def _get_namespace_prefix(self, namespace: str) -> str:
793 """Get the appropriate namespace prefix for a given namespace URI."""
794 return _NAMESPACE_PREFIX_MAP.get(namespace, "unknown")
796 def _update_stream(self) -> None:
797 """Update the stream with the current XML content."""
798 doc = self.rdf_root.ownerDocument
799 if doc is None:
800 raise XmpDocumentError("XMP Document is None")
802 xml_data = doc.toxml(encoding="utf-8")
803 self.stream.set_data(xml_data)