apacite: how to suppress url if doi is avalable?

Question

I am using apacite package for my BibTex file, but according to my writing style, it's not required for url to be listed in the bibliography if doi is available. Is there any way I can forced apacite to suppress url in bibliography and display only the doi?

Answer 1

We can use the specific format of \bibitem produced by the apacite.bst style.

\documentclass{article}

\usepackage{filecontents}
\usepackage{apacite}
\usepackage{etoolbox}

\begin{filecontents}{\jobname.bib}
@article{aa,
  title = "DOI and URL",
  author = "Author, Author",
  year = 2000,
  journal = "Apacite Examples",
  url = "http://www.example.com/1",
  doi = "123/123"
  }
@article{bb,
  title = "Only URL",
  author = "Author, Author",
  year = 2001,
  journal = "Apacite Examples",
  url = "http://www.example.com/2"
  }
@article{cc,
  title = "No DOI no URL",
  author = "Author, Author",
  year = 2002,
  journal = "Apacite Examples" 
  }
@article{dd,
  title = "Only DOI",
  author = "Author. Author",
  year = 2004,
  journal = "Apacite Examples",
  doi = "123/124"
  }
\end{filecontents}


\newtoggle{bibdoi}
\newtoggle{biburl}
\makeatletter
\newsavebox{\bib@url}
\newsavebox{\bib@doi}

\undef{\APACrefURL}
\undef{\endAPACrefURL}
\undef{\APACrefDOI}
\undef{\endAPACrefDOI}

\newenvironment{APACrefURL}
  {\global\toggletrue{biburl}\lrbox\bib@url}
  {\endlrbox}

\newenvironment{APACrefDOI}
  {\global\toggletrue{bibdoi}\lrbox\bib@doi}
  {\endlrbox}


\newcommand{\printinfo}{
  \iftoggle{bibdoi}{\usebox{\bib@doi}}{\usebox{\bib@url}}
  \togglefalse{bibdoi}
}

\AtBeginEnvironment{thebibliography}{
\pretocmd{\PrintBackRefs}{%
  \iftoggle{bibdoi}
    {\iftoggle{biburl}{\unskip\unskip}{}Doi: \usebox{\bib@doi}}
    {\iftoggle{biburl}{Retrieved from \usebox{\bib@url}}}{}
  \togglefalse{bibdoi}\togglefalse{biburl}%
}{}{}}
\makeatother

\begin{document}

\cite{aa}
\cite{bb}
\cite{cc}
\cite{dd}


\bibliographystyle{apacite}
\bibliography{\jobname}

\end{document}

apacite uses APACrefURL and APACrefDOI environments to wrap \url and doi. Thus we can use lrbox to store such pieces of text and set toggle to identify whether they are present or not. Then, apacite inserts \PrintBackRefs at the end of each bibitem thus we can use it to hook into it the commands to print the url and doi. In this hook we do the reasoning to determine which ones has to be printed (and undo spaces).