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"""Provides low-level, write-only API to serialized (OPC) package.
OPC stands for Open Packaging Convention. This is e, essentially an implementation of
OpcPackage.save().
"""
from __future__ import annotations
from typing import TYPE_CHECKING, Iterable
from docx.opc.constants import CONTENT_TYPE as CT
from docx.opc.oxml import CT_Types, serialize_part_xml
from docx.opc.packuri import CONTENT_TYPES_URI, PACKAGE_URI
from docx.opc.phys_pkg import PhysPkgWriter
from docx.opc.shared import CaseInsensitiveDict
from docx.opc.spec import default_content_types
if TYPE_CHECKING:
from docx.opc.part import Part
class PackageWriter:
"""Writes a zip-format OPC package to `pkg_file`, where `pkg_file` can be either a
path to a zip file (a string) or a file-like object.
Its single API method, :meth:`write`, is static, so this class is not intended to be
instantiated.
"""
@staticmethod
def write(pkg_file, pkg_rels, parts):
"""Write a physical package (.pptx file) to `pkg_file` containing `pkg_rels` and
`parts` and a content types stream based on the content types of the parts."""
phys_writer = PhysPkgWriter(pkg_file)
PackageWriter._write_content_types_stream(phys_writer, parts)
PackageWriter._write_pkg_rels(phys_writer, pkg_rels)
PackageWriter._write_parts(phys_writer, parts)
phys_writer.close()
@staticmethod
def _write_content_types_stream(phys_writer, parts):
"""Write ``[Content_Types].xml`` part to the physical package with an
appropriate content type lookup target for each part in `parts`."""
cti = _ContentTypesItem.from_parts(parts)
phys_writer.write(CONTENT_TYPES_URI, cti.blob)
@staticmethod
def _write_parts(phys_writer: PhysPkgWriter, parts: Iterable[Part]):
"""Write the blob of each part in `parts` to the package, along with a rels item
for its relationships if and only if it has any."""
for part in parts:
phys_writer.write(part.partname, part.blob)
if len(part.rels):
phys_writer.write(part.partname.rels_uri, part.rels.xml)
@staticmethod
def _write_pkg_rels(phys_writer, pkg_rels):
"""Write the XML rels item for `pkg_rels` ('/_rels/.rels') to the package."""
phys_writer.write(PACKAGE_URI.rels_uri, pkg_rels.xml)
class _ContentTypesItem:
"""Service class that composes a content types item ([Content_Types].xml) based on a
list of parts.
Not meant to be instantiated directly, its single interface method is xml_for(),
e.g. ``_ContentTypesItem.xml_for(parts)``.
"""
def __init__(self):
self._defaults = CaseInsensitiveDict()
self._overrides = {}
@property
def blob(self):
"""Return XML form of this content types item, suitable for storage as
``[Content_Types].xml`` in an OPC package."""
return serialize_part_xml(self._element)
@classmethod
def from_parts(cls, parts):
"""Return content types XML mapping each part in `parts` to the appropriate
content type and suitable for storage as ``[Content_Types].xml`` in an OPC
package."""
cti = cls()
cti._defaults["rels"] = CT.OPC_RELATIONSHIPS
cti._defaults["xml"] = CT.XML
for part in parts:
cti._add_content_type(part.partname, part.content_type)
return cti
def _add_content_type(self, partname, content_type):
"""Add a content type for the part with `partname` and `content_type`, using a
default or override as appropriate."""
ext = partname.ext
if (ext.lower(), content_type) in default_content_types:
self._defaults[ext] = content_type
else:
self._overrides[partname] = content_type
@property
def _element(self):
"""Return XML form of this content types item, suitable for storage as
``[Content_Types].xml`` in an OPC package.
Although the sequence of elements is not strictly significant, as an aid to
testing and readability Default elements are sorted by extension and Override
elements are sorted by partname.
"""
_types_elm = CT_Types.new()
for ext in sorted(self._defaults.keys()):
_types_elm.add_default(ext, self._defaults[ext])
for partname in sorted(self._overrides.keys()):
_types_elm.add_override(partname, self._overrides[partname])
return _types_elm
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