Line breaks of long URLs in biblatex bibliography?

Question

I have some long URLs which doesn't contain special "line break characters" like "-" or "/". How can I automatically break these URLs?

\documentclass{scrreprt}

\usepackage[ngerman]{babel}                    
\usepackage[latin1]{inputenc}                
\usepackage[T1]{fontenc}
\usepackage[backend=biber]{biblatex}
\usepackage{url}
\usepackage{dingbat}  % for \carriagereturn symbol
\makeatletter
\g@addto@macro{\UrlBreaks}{\UrlOrds}
\g@addto@macro{\UrlBreaks}{%
\do\/\do\d%
}
\makeatother

\begin{filecontents}{bachelorarbeit_lit.bib}
@ONLINE{java96,
    author = {{Joe Black}},
    title = {Foobar 1.0},
    year = {1996},
    month = {1},
    url = {http://www.aaa.bb.cccc.dh/uploads/dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd.pdf},
    urldate = {2011-03-02},
    sortname = {Sun},
    keywords = {www}
}
\end{filecontents}

\bibliography{bachelorarbeit_lit}

\begin{document}
Test \cite{java96}
\printbibliography
\end{document}

edit

I don't know why but it still doesn't work. Is there an option to automatically break long URLs. I don't care where the break is but it should be done automatically. Even if I manually specify the "breaking character" it doesn't work (as the example shows).

Answer 1

Hacking \UrlBreaks is not needed for \url inside the bibliography of biblatex. Package biblatex uses \biburlsetup and has already added lots of characters. The breaking at some character classes is controlled by counters. From the documentation of biblatex, "4.10.3 User-definable Lengths and Counters":

biburlnumpenalty: If this counter is set to a value greater than zero, biblatex will permit linebreaks after numbers in all strings formatted with the \url command from the url package. This will affect URLs and DOIs in the bibliography. The breakpoints will be penalized by the value of this counter. If URLs and/or DOIs in the bibliography run into the margin, try setting this counter to a value greater than zero but less than 10000 (you normally want to use a high value like 9000). Setting the counter to zero disables this feature. This is the default setting.

biburlucpenalty: Similar to biburlnumpenalty, except that it will add a breakpoint after all uppercase letters.

biburllcpenalty: Similar to biburlnumpenalty, except that it will add a breakpoint after all lowercase letters.

An example:

\RequirePackage{filecontents}
\begin{filecontents}{bachelorarbeit_lit.bib}
@ONLINE{java96,
    author = {{Joe Black}},
    title = {Foobar 1.0},
    year = {1996},
    month = {1},
    url = {http://www.aaa.bb.cccc.dh/uploads/dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd.pdf},
    urldate = {2011-03-02},
    sortname = {Sun},
    keywords = {www}
}
\end{filecontents}

\documentclass{scrreprt}

\usepackage[ngerman]{babel}                    
\usepackage[latin1]{inputenc}                
\usepackage[T1]{fontenc}

\usepackage[backend=biber]{biblatex}
\usepackage{url}

%%% --- The following two lines are what needs to be added --- %%%
\setcounter{biburllcpenalty}{7000}
\setcounter{biburlucpenalty}{8000}

\bibliography{bachelorarbeit_lit}

\begin{document}
Test \cite{java96}
\printbibliography
\end{document}

Answer 2

There is another way (SHORTER) of doing that: just put the entry below before the \begin{document}:

\usepackage{url}
\def\UrlBreaks{\do\/\do-}

This allows to have your customized (or required!) bibliography style (e.g. \bibliographystyle{IEEEtran}) unchanged.

Answer 3

For some reason the accepted answer did not work for me (maybe old package versions, which I can't update by myself here at work). Anyway, since I use LuaLaTeX to compile my document, here another solution (found at https://yingtongli.me/blog/2016/01/08/breaking-urls-anywhere-in-lualatex-even.html):

Create a document betterurl.lua with following content:

function betterurl(text)
  label = text:gsub(".", "%1\\allowbreak{}")

  label = label:gsub("~", "\\textasciitilde")
  label = label:gsub("&", "\\&")
  label = label:gsub("/", "/")
  label = label:gsub("-", "-")

  url = text

  tex.print("\\href{" .. url .. "}{" .. label .. "}")

end

and add

\RequirePackage{luacode}
  \luaexec{require("path/to/betterurl")}
  \renewcommand{\url}[1]{\luadirect{
    betterurl(\luastringN{#1})
  }}

to your preamble. Note that you do not need to add the file extension .lua.

This is the result:

Answer 4

All this didn't work for me.
My solution works, but it's not pretty - kind of a last resort (visually it fits, but it isn't automatic).

Be aware that I used the bibtex format, which could be the problem too.

You can directly define the url inside your references.bib (or however you named it).
You might have something like this:

@misc{a_very_consice_key,
  title = {A very nice title},
  urldate = {2023-11-19},
  howpublished = {https://www.example.com/aaaaaaaaa/bbbbbbbbb/ccccccccc/ddddddddd},
}

Do this:

@misc{a_very_consice_key,
  title = {A very nice title},
  urldate = {2023-11-19},
  howpublished = {\url{https://www.example.com/aaaaaaaaa/bbbbbbbbb/ccccccccc/ddddddddd}},
}

this already works ... but might add \texttt{} formatting that doesn't fit the rest of your literature (for me it didn't fit), so I added a few things.

in your packages.tex (or whereever you define your packages):

\usepackage{hyperref}  % <- I had that 
\usepackage{xurl}      % <- I added that 

It works without it too (changes the breakpoints a little - maybe you need it)

Now we define a new command (I have it in my definitions.tex)

\newcommand{\normalurl}[1]{%
    \begingroup
    \let\UrlFont\relax
    \urlstyle{same} % use current font style
    \url{#1}%
    \endgroup
}

...and use our new \normalurl command instead of the \url command inside of our .bib file:

@misc{a_very_consice_key,
  title = {A very nice title},
  urldate = {2023-11-19},
  howpublished = {\normalurl{https://www.example.com/aaaaaaaaa/bbbbbbbbb/ccccccccc/ddddddddd}},
}

---

I don't understand why this is a problem at all. Maybe someone with more experience can create a function from this that doesn't break \url and just automatically fixes the urls inside the bibliography?

Can't really have random dashes (-) in URLs. Especially if the biber package adds \hrefs after the fact.