Importer projects url wrongly to file field

[karliwalti]

The bib importer has currently two issues that prevent efficient import

I refer here in general to the biblatex documentation: http://ftp.fau.de/ctan/macros/latex/contrib/biblatex/doc/biblatex.pdf

1) the url field is projected to the file field file_url which does not match common nomenclature, it should be the field 'file' (local link to PDF) that should project to file_url . see also http://ftp.fau.de/ctan/macros/latex/contrib/biblatex/doc/biblatex.pdf url was originally used for an online resource, in combination with a access date urldate and should be therefore projected to web_url and urldate to web_url_date respectively https://github.com/in2code-de/publications/blob/e54dbd4455e7baf6f3f6c732598998f2c4192ed6/Classes/Import/Importer/BibImporter.php#L24

2) the url field can contain multiple urls as when used for electronic publishing information many sources can be available. this is the case for all bib versions that do not use the eprintoption : http://ftp.fau.de/ctan/macros/latex/contrib/biblatex/doc/biblatex.pdf (3.14.7) . Therefore, url should be parsed for , and and the first entry projected to web_url, and if more entries the second to web_url2 . All others should likely be ignored in this application