Passed
Pull Request — master (#663)
by Konstantin
02:07
created

ocrd.processor.base.Processor.show_help()   A

Complexity

Conditions 1

Size

Total Lines 2
Code Lines 2

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
eloc 2
dl 0
loc 2
rs 10
c 0
b 0
f 0
cc 1
nop 1
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"""
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Processor base class and helper functions
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"""
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__all__ = [
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    'Processor',
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    'generate_processor_help',
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    'run_cli',
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    'run_processor'
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]
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from os import makedirs
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from os.path import exists, isdir, join
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from shutil import copyfileobj
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import json
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import os
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import re
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import sys
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import requests
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from ocrd_utils import (
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    VERSION as OCRD_VERSION,
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    MIMETYPE_PAGE,
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    getLogger,
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    initLogging,
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    list_resource_candidates,
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    list_all_resources,
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)
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from ocrd_validators import ParameterValidator
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from ocrd_models.ocrd_page import MetadataItemType, LabelType, LabelsType
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from ..resource_manager import OcrdResourceManager
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# XXX imports must remain for backwards-compatibilty
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from .helpers import run_cli, run_processor, generate_processor_help # pylint: disable=unused-import
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class Processor():
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    """
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    A processor is an OCR-D compliant command-line-interface for executing
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    a single workflow step on the workspace (represented by local METS). It
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    reads input files for all or requested physical pages of the input fileGrp(s),
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    and writes output files for them into the output fileGrp(s). It may take 
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    a number of optional or mandatory parameters.
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    """
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    def __init__(
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            self,
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            workspace,
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            ocrd_tool=None,
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            parameter=None,
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            # TODO OCR-D/core#274
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            # input_file_grp=None,
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            # output_file_grp=None,
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            input_file_grp="INPUT",
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            output_file_grp="OUTPUT",
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            page_id=None,
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            show_resource=None,
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            list_resources=False,
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            show_help=False,
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            show_version=False,
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            dump_json=False,
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            version=None
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    ):
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        if parameter is None:
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            parameter = {}
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        if dump_json:
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            print(json.dumps(ocrd_tool, indent=True))
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            return
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        if list_resources:
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            for res in list_all_resources(ocrd_tool['executable']):
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                print(res)
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            return
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        if show_resource:
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            res_fname = list_resource_candidates(ocrd_tool['executable'], show_resource, is_file=True)
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            if not res_fname:
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                initLogging()
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                logger = getLogger('ocrd.%s.__init__' % ocrd_tool['executable'])
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                logger.error("Failed to resolve %s for processort %s" % (show_resource, ocrd_tool['executable']))
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            else:
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                with open(res_fname[0], 'rb') as f:
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                    copyfileobj(f, sys.stdout.buffer)
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            return
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        self.ocrd_tool = ocrd_tool
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        if show_help:
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            self.show_help()
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            return
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        self.version = version
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        if show_version:
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            self.show_version()
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            return
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        self.workspace = workspace
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        # FIXME HACK would be better to use pushd_popd(self.workspace.directory)
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        # but there is no way to do that in process here since it's an
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        # overridden method. chdir is almost always an anti-pattern.
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        if self.workspace:
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            os.chdir(self.workspace.directory)
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        self.input_file_grp = input_file_grp
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        self.output_file_grp = output_file_grp
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        self.page_id = None if page_id == [] or page_id is None else page_id
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        parameterValidator = ParameterValidator(ocrd_tool)
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        report = parameterValidator.validate(parameter)
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        if not report.is_valid:
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            raise Exception("Invalid parameters %s" % report.errors)
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        self.parameter = parameter
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    def show_help(self):
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        print(generate_processor_help(self.ocrd_tool, processor_instance=self))
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    def show_version(self):
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        print("Version %s, ocrd/core %s" % (self.version, OCRD_VERSION))
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    def verify(self):
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        """
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        Verify that the input fulfills the processor's requirements.
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        """
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        return True
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    def process(self):
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        """
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        Process the workspace
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        """
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        raise Exception("Must be implemented")
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    def add_metadata(self, pcgts):
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        """
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        Adds PAGE-XML MetadataItem describing the processing step
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        """
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        pcgts.get_Metadata().add_MetadataItem(
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                MetadataItemType(type_="processingStep",
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                    name=self.ocrd_tool['steps'][0],
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                    value=self.ocrd_tool['executable'],
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                    Labels=[LabelsType(
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                        externalModel="ocrd-tool",
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                        externalId="parameters",
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                        Label=[LabelType(type_=name,
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                                         value=self.parameter[name])
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                               for name in self.parameter.keys()]),
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                            LabelsType(
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                        externalModel="ocrd-tool",
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                        externalId="version",
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                        Label=[LabelType(type_=self.ocrd_tool['executable'],
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                                         value=self.version),
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                               LabelType(type_='ocrd/core',
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                                         value=OCRD_VERSION)])
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                    ]))
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    def resolve_resource(self, val):
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        """
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        Resolve a resource name to an absolute file path with the algorithm in
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        https://ocr-d.de/en/spec/ocrd_tool#file-parameters
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        Args:
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            val (string): resource value to resolve
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        """
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        if exists(val):
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            return val
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        executable = self.ocrd_tool['executable']
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        ret = [cand for cand in list_resource_candidates(executable, val) if exists(cand)]
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        if ret:
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            return ret[0]
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        raise FileNotFoundError("Could not find resource '%s' for executable '%s'. Try 'ocrd resmgr download %s %s' to download this resource." %
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                (val, executable, executable, val))
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    def list_all_resources(self):
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        """
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        List all resources found in the filesystem
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        """
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        return list_all_resources(self.ocrd_tool['executable'])
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    @property
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    def input_files(self):
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        """
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        List the input files (for single input file groups).
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        For each physical page:
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        - If there is a single PAGE-XML for the page, take it (and forget about all
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          other files for that page)
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        - Else if there is a single image file, take it (and forget about all other
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          files for that page)
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        - Otherwise raise an error (complaining that only PAGE-XML warrants
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          having multiple images for a single page)
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        (https://github.com/cisocrgroup/ocrd_cis/pull/57#issuecomment-656336593)
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        """
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        if not self.input_file_grp:
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            raise ValueError("Processor is missing input fileGrp")
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        ret = self.zip_input_files(mimetype=None, on_error='abort')
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        if not ret:
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            return []
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        assert len(ret[0]) == 1, 'Use zip_input_files() instead of input_files when processing multiple input fileGrps'
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        return [tuples[0] for tuples in ret]
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    def zip_input_files(self, require_first=True, mimetype=None, on_error='skip'):
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        """
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        List tuples of input files (for multiple input file groups).
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        Processors that expect/need multiple input file groups,
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        cannot use ``input_files``. They must align (zip) input files
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        across pages. This includes the case where not all pages
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        are equally present in all file groups. It also requires
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        making a consistent selection if there are multiple files
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        per page.
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        Following the OCR-D functional model, this function tries to
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        find a single PAGE file per page, or fall back to a single
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        image file per page. In either case, multiple matches per page
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        are an error (see error handling below).
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        This default behaviour can be changed by using a fixed MIME
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        type filter via ``mimetype``. But still, multiple matching
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        files per page are an error.
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        Single-page multiple-file errors are handled according to
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        ``on_error``:
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        - if ``skip``, then the page for the respective fileGrp will be
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          silently skipped (as if there was no match at all)
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        - if ``first``, then the first matching file for the page will be
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          silently selected (as if the first was the only match)
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        - if ``last``, then the last matching file for the page will be
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          silently selected (as if the last was the only match)
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        - if ``abort``, then an exception will be raised.
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        Multiple matches for PAGE-XML will always raise an exception.
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        Args:
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             require_first (bool): If true, then skip a page entirely
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             whenever it is not available in the first input fileGrp.
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             mimetype (str): If not None, filter by the specified MIME
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             type (literal or regex prefixed by ``//``.
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             Otherwise prefer PAGE or image.
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        """
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        if not self.input_file_grp:
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            raise ValueError("Processor is missing input fileGrp")
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        LOG = getLogger('ocrd.processor.base')
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        ifgs = self.input_file_grp.split(",")
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        # Iterating over all files repeatedly may seem inefficient at first sight,
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        # but the unnecessary OcrdFile instantiations for posterior fileGrp filtering
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        # can actually be much more costly than traversing the ltree.
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        # This might depend on the number of pages vs number of fileGrps.
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        pages = dict()
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        for i, ifg in enumerate(ifgs):
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            for file_ in sorted(self.workspace.mets.find_all_files(
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                    pageId=self.page_id, fileGrp=ifg, mimetype=mimetype),
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                                # sort by MIME type so PAGE comes before images
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                                key=lambda file_: file_.mimetype):
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                if not file_.pageId:
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                    continue
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                ift = pages.setdefault(file_.pageId, [None]*len(ifgs))
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                if ift[i]:
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                    LOG.debug("another file %s for page %s in input file group %s", file_.ID, file_.pageId, ifg)
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                    # fileGrp has multiple files for this page ID
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                    if mimetype:
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                        # filter was active, this must not happen
255 View Code Duplication
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                            ift[i] = None
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                        elif on_error == 'first':
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                            pass # keep first match
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                        elif on_error == 'last':
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                            ift[i] = file_
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                        elif on_error == 'abort':
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                            raise ValueError(
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                                "Multiple '%s' matches for page '%s' in fileGrp '%s'." % (
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                                    mimetype, file_.pageId, ifg))
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                        else:
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                            raise Exception("Unknown 'on_error' strategy '%s'" % on_error)
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                    elif (ift[i].mimetype == MIMETYPE_PAGE and
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                          file_.mimetype != MIMETYPE_PAGE):
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                        pass # keep PAGE match
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                    elif (ift[i].mimetype == MIMETYPE_PAGE and
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                          file_.mimetype == MIMETYPE_PAGE):
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                            raise ValueError(
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                                "Multiple PAGE-XML matches for page '%s' in fileGrp '%s'." % (
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                                    file_.pageId, ifg))
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                    else:
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                        # filter was inactive but no PAGE is in control, this must not happen
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278
                            ift[i] = None
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                        elif on_error == 'first':
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                            pass # keep first match
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                        elif on_error == 'last':
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                            ift[i] = file_
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                        elif on_error == 'abort':
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                            raise ValueError(
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                                "No PAGE-XML for page '%s' in fileGrp '%s' but multiple matches." % (
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                                    file_.pageId, ifg))
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                        else:
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                            raise Exception("Unknown 'on_error' strategy '%s'" % on_error)
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                else:
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                    LOG.debug("adding file %s for page %s to input file group %s", file_.ID, file_.pageId, ifg)
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                    ift[i] = file_
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        ifts = list()
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        for page, ifiles in pages.items():
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            for i, ifg in enumerate(ifgs):
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                if not ifiles[i]:
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                    # other fallback options?
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                    LOG.error('found no page %s in file group %s',
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                              page, ifg)
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            if ifiles[0] or not require_first:
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                ifts.append(tuple(ifiles))
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        return ifts
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