Manually URL linebreak with Biblatex

Question

First I should say that I don't have much experience with LaTeX.

I'm using BibLaTeX and Biber.

My Problem: I have a (justified) bibliography with long URL's containing long words. BibLaTeX makes a linebreak at a place with a slash. But I want to make that linebreak in the following word.

In the minimal example: I want to do the linebreak at: Markt-beobachtung.

The aim is that in the second line there aren't that big spaces between the letters, words, slashes. And that the second line doesn't start with //.

I'm trying to do this for 3 hours now, so I really appreciate your help.

Here is the .tex file.

\documentclass[oneside]{scrbook}
\usepackage[backend=biber,style=alphabetic]{biblatex}
\usepackage[ngerman]{babel}
\bibliography{test_bib.bib}

\begin{document}
\cite{bundesnetzagentur}
\printbibliography
\end{document}

And that's the test_bib.bib:

@ONLINE{bundesnetzagentur,
author = {Bundesnetzagentur},
title = {Teilnehmerentwicklung im Mobilfunk},
year = {2012},
url = {http://www.bundesnetzagentur.de/DE/Sachgebiete/Telekommunikation/Marktbeobachtung/Mobilfunkteilnehmer/Mobilfunkteilnehmer_node.html },
hyphenation=ngerman
}

Answer 1

The package biblatex loads the package url. The list of characters that allow line-breaks is given by \UrlBreaks and \UrlBigBreaks, which have the format \do\c for each character c. For more information read the documentation.

The default setting of \UrlBreaks is

\def\UrlBreaks{\do\.\do\@\do\\\do\/\do\!\do\_\do\|\do\;\do\>\do\]%
  \do\)\do\,\do\?\do\'\do+\do\=\do\#}%
\def\UrlBigBreaks{\do\:\do@url@hyp}%

To allow more break points you can add

\g@addto@macro{\UrlBreaks}{\UrlOrds}

for ordinary symbols and you can do

\g@addto@macro{\UrlBreaks}{%
  \do\/\do\a\do\b\do\c\do\d\do\e\do\f%
  \do\g\do\h\do\i\do\j\do\k\do\l\do\m%
  \do\n\do\o\do\p\do\q\do\r\do\s\do\t%
  \do\u\do\v\do\w\do\x\do\y\do\z%
  \do\A\do\B\do\C\do\D\do\E\do\F\do\G%
  \do\H\do\I\do\J\do\K\do\L\do\M\do\N%
  \do\O\do\P\do\Q\do\R\do\S\do\T\do\U%
  \do\V\do\W\do\X\do\Y\do\Z}

for breakpoints after letters.

In the same way you can setup the command \UrlNoBreaks to define symbols/letters where no linebreaks are allowed. The default setting is:

\def\UrlNoBreaks{\do\(\do\[\do\{\do\<}%

---

The commands using the special symbol @. So you need \makeatletter/\makeatother. Please refer the question What do \makeatletter and \makeatother do? for more information.

Answer 2

It's not great, but if you want to do it manually, then you can do it manually:

@online{bundesnetzagentur,
author = {Bundesnetzagentur},
title = {Teilnehmerentwicklung im Mobilfunk},
year = "2012",
addendum = "\texttt{\href{http://www.bundesnetzagentur.de/DE/Sachgebiete/Telekommunikation/Marktbeobachtung/Mobilfunkteilnehmer/Mobilfunkteilnehmer_node.html}{http://www.bundesnetzagentur.de/DE/Sachgebiete/Telekommunikation/Markt\\beobachtung/Mobilfunkteilnehmer/Mobilfunkteilnehmer\_node.html}}",
hyphenation=ngerman
}

Note that:

1. It requires loading hyperref package in the preamble of the document.
2. In the text part of href, _ needs to be replaced by \_ to avoid errors.

If you don't necessarily want a hyperlink, you can remove \href and the first group in curly brackets, and then you don't need to load the hyperref package.

Something similar can be done with doi addresses too, for example:

addendum = "doi:\href{https://doi.org/10.1023/B:MOON.0000031922.78588.6d}{10.1023/B:MOON.0000031922.785\\88.6d}"