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Extract plain text from newspapers (extract_text 0.3.0)

Converts XML (in METS 1.8/ALTO 1.4, METS 1.3/ALTO 1.4, BLN or UKP format) publications to plaintext articles and generates minimal metadata. Downsampling can be used to convert only every Nth issue of each newspaper. One text file is output per article, each complemented by one XML metadata file.

Quality assurance is performed to check for:

  • Unexpected directories.
  • Unexpected files.
  • Malformed XML.
  • Empty files.
  • Files that otherwise do not expose content.

Installation

We recommend installation via Anaconda:

conda create -n py37alto python=3.7
  • Activate the environment:
conda activate py37alto
  • Install additional packages
pip install -r requirements.txt

Usage

extract_publications_text.py [-h] [-d [DOWNSAMPLE]]
                                    [-p [PROCESS_TYPE]]
                                    [-l [LOG_FILE]]
                                    [-n [NUM_CORES]]
                                    xml_in_dir txt_out_dir

Converts XML publications to plaintext articles

positional arguments:
  xml_in_dir            Input directory with XML publications
  txt_out_dir           Output directory for plaintext articles

optional arguments:
  -h, --help            show this help message and exit
  -d [DOWNSAMPLE], --downsample [DOWNSAMPLE]
                        Downsample. Default 1
  -l [LOG_FILE], --log-file [LOG_FILE]
                        Log file. Default out.log
  -p [PROCESS_TYPE], --process-type [PROCESS_TYPE]
                        Process type.
                        One of: single,serial,multi,spark
                        Default: multi
  -n [NUM_CORES], --num-cores [NUM_CORES]
                        Number of cores (Spark only). Default 1")

xml_in_dir is expected to hold XML for multiple publications, in the following structure:

xml_in_dir
|-- publication
|   |-- year
|   |   |-- issue
|   |   |   |-- xml_content
|   |-- year
|-- publication

However, if -p|--process-type single is provided then xml_in_dir is expected to hold XML for a single publication, in the following structure:

xml_in_dir
|-- year
|   |-- issue
|   |   |-- xml_content
|-- year

txt_out_dir is created with an analogous structure to xml_in_dir.

PROCESS_TYPE can be one of:

  • single: Process single publication.
  • serial: Process publications serially.
  • multi: Process publications using multiprocessing (default).
  • spark: Process publications using Spark.

DOWNSAMPLE must be a positive integer, default 1.

The following XSLT files need to be in an extract_text.xslts module:

  • extract_text_mets18.xslt: METS 1.8 XSL file.
  • extract_text_mets13.xslt: METS 1.3 XSL file.
  • extract_text_bln.xslt: BLN XSL file.
  • extract_text_ukp.xslt: UKP XSL file.

Process publications

Assume ~/BNA exists and matches the structure above.

Extract text from every publication:

./extract_publications_text.py ~/BNA txt

Extract text from every 100th issue of every publication:

./extract_publications_text.py ~/BNA txt -d 100

Process a single publication

Extract text from every issue of a single publication:

./extract_publications_text.py -p single ~/BNA/0000151 txt

Extract text from every 100th issue of a single publication:

./extract_publications_text.py -p single ~/BNA/0000151 txt -d 100

Configure logging

By default, logs are put in out.log.

To specify an alternative location for logs, use the -l flag e.g.

./extract_publications_text.py -l mylog.txt ~/BNA txt -d 100 2> err.log

Process publications via Spark

Information on running on spark.

XML metadata

Metadata about extract_text.py itself is inserted into the XML metadata files. The current values, including version, are defined in extract_text_common.xslt.

The following metadata for the following dataset types are not output, due to it not being present in the XML for those datasets:

METS1.3/ALTO1.4:

  • /lwm/publication/location

BLN:

  • /lwm/process/namespace
  • /lwm/publication/issue/item/item_type

UKP:

  • /lwm/process/software
  • /lwm/process/namespace
  • /lwm/publication/title
  • /lwm/publication/location

Update version

To update the version number:

  1. Edit README.md:
# Extract plain text from newspapers (extract_text 0.3.0)
  1. Edit setup.py:
version="0.3.0",
  1. Exit extract_text/xslts/extract_text_common.xslt:
<xsl:param name="version">0.3.0</xsl:param>

Future work

  • Export more metadata from alto, probably by parsing mets first.
  • Check and ensure that articles that span multiple pages are pulled into a single article file.
  • Smarter handling of articles spanning multiple pages.