English
资源说明：PicaReader provides classes for reading Pica+ records encoded in PicaXML and PicaPlain.
#+TITLE: PicaReader -- Classes for reading Pica+ records
#+AUTHOR: David Maus
#+EMAIL: maus@hab.de
[](https://travis-ci.org/dmj/PicaReader)
* About
PicaReader provides classes for reading Pica+ records encoded in PicaXML and PicaPlain.
PicaReader is copyright (c) 2012-2017 by Herzog August Bibliothek Wolfenbüttel and released under the
terms of the GNU General Public License v3.
* Installation
You can install PicaReader via Composer.
#+BEGIN_EXAMPLE
composer require hab/picareader
#+END_EXAMPLE
* Usage
All readers adhere to the same interface. You open the reader with a string of input data by calling
=Reader::open()= and can call =Reader::read()= to read the next record in the input data. If the
input does not contain (anymore) records =Reader::read()= returns =FALSE=. Otherwise it returns
either a record object created with PicaRecord's =Record::factory()= function.
#+BEGIN_SRC php
$reader = new \HAB\Pica\Reader\PicaXmlReader()
$reader->open(file_get_contents('http://unapi.gbv.de?id=opac-de-23:ppn:635012286&format=picaxml'));
$record = $reader->read();
$reader->close();
#+END_SRC
To filter out records or fields you can attach a filter to the reader via =Reader::setFilter()=. A
filter is any valid PHP callback that takes an associative array representing the record as argument
and returns a possibly modified array or =FALSE= if the entire record should be skipped.
The array representation of a record is defined as follows:
#+BEGIN_EXAMPLE
RECORD := array('fields' => array(FIELD, …))
FIELD := array('tag' => TAG, 'occurrence' => OCCURRENCE, 'subfields' => array(SUBFIELD, …))
SUBFIELD := array('code' => CODE, 'value' => VALUE)
#+END_EXAMPLE
Where =TAG=, =OCCURRENCE=, =CODE=, and =VALUE= are the respective properties of a Pica+ field or
subfield.
For example, if your source delivers malformed PicaXML records like so:
#+BEGIN_SRC xml
0001:14-09-10
…
#+END_SRC
You can attach a filter function to remove these fields with an invalid tag:
#+BEGIN_SRC php
$reader = new PicaXmlReader();
$reader->setFilter(function (array $r) {
return array('fields' => array_filter($r['fields'],
function (array $f) {
return isset($f['tag']) && \HAB\Pica\Record\Field::isValidFieldTag($f['tag']);
}));
});
$record = $reader->read(…);
$reader->close();
#+END_SRC
* Acknowledgements
Large parts of this package would not have been possible without studying the source of
[[http://search.cpan.org/dist/PICA-Record/][Pica::Record]], an open source Perl library for handling Pica+ records by Jakob Voß, and the practical
knowledge of our library's catalogers.
* Footnotes
本源码包内暂不包含可直接显示的源代码文件，请下载源码包。
