biblatex: make title hyperlink to DOIs, URL or ISBN
One possibility is to extend Herbert's bibmacro to several nested conditions. (The following example contains only placeholder links for the ISBN/ISSN fields because I don't know how this links must be formatted.)
With regard to your further issues:
I'm not sure if the
urlfield allows to specify several URLs separated by white spaces; if it does, I don't know how to retain only the first URL.Herbert's code actually first covers all entry types, then specifies a special title format (quotes instead of emphasis) for articles.
\documentclass{article}
\usepackage[doi=false,url=false,isbn=false]{biblatex}
\usepackage[colorlinks]{hyperref}
\newbibmacro{string+doiurlisbn}[1]{%
\iffieldundef{doi}{%
\iffieldundef{url}{%
\iffieldundef{isbn}{%
\iffieldundef{issn}{%
#1%
}{%
\href{http://books.google.com/books?vid=ISSN\thefield{issn}}{#1}%
}%
}{%
\href{http://books.google.com/books?vid=ISBN\thefield{isbn}}{#1}%
}%
}{%
\href{\thefield{url}}{#1}%
}%
}{%
\href{http://dx.doi.org/\thefield{doi}}{#1}%
}%
}
\DeclareFieldFormat{title}{\usebibmacro{string+doiurlisbn}{\mkbibemph{#1}}}
\DeclareFieldFormat[article,incollection]{title}%
{\usebibmacro{string+doiurlisbn}{\mkbibquote{#1}}}
\begin{filecontents}{\jobname.bib}
@article{A01,
author = {Author, A.},
year = {2001},
title = {Alpha},
doi = {doi},
url = {url},
issn = {isbn-issn},
}
@book{B02,
author = {Buthor, B.},
year = {2002},
title = {Bravo},
url = {http://tex.stackexchange.com/},
isbn = {isbn-issn},
}
@incollection{C03,
author = {Cuthor, C.},
year = {2003},
title = {Charlie},
isbn = {9780521867016},
}
@misc{D04,
author = {Duthor, D.},
year = {2004},
title = {Delta},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\nocite{*}
\begin{document}
\printbibliography
\end{document}
Another approach is to define a new format that adds links. This can be used in any bibliography macro that applies the title format. In standard styles there are only two of these macros: title and periodical. You can revert to the original style with \DeclareFieldAlias{<new format name>}{default}.
The url field is intended to hold only one URL, so we need to devise a way to access the first URL. One option is to have biber to drop the extra URLs by adapting this previous answer. The code below demonstrates an alternative that accesses bibliographic data like the internal biblatex formatting commands.
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{csquotes}
\usepackage[american]{babel}
\usepackage[style=verbose,url=false,doi=false,isbn=false]{biblatex}
\usepackage[colorlinks]{hyperref}
% Define new format that applies a hypertext reference
\DeclareFieldFormat{linked}{%
\ifboolexpr{ test {\ifhyperref} and not test {\ifentrytype{online}} }
{\iffieldundef{doi}
{\iffieldundef{url}
{\iffieldundef{isbn}
{\iffieldundef{issn}
{#1}
{\href{\worldcatsearch\thefield{issn}}{#1}}}
{\href{\worldcatsearch\thefield{isbn}}{#1}}}
{\href{\thefieldfirstword{url}}{#1}}}
{\href{http://dx.doi.org/\thefield{doi}}{#1}}}
{#1}}
% URL prefix for WorldCat query
\def\worldcatsearch{http://www.worldcat.org/search?qt=worldcat_org_all&q=}
% Define new command that returns the first word of a given field
\makeatletter
\def\thefieldfirstword#1{%
\expandafter\expandafter
\expandafter\firstword
\expandafter\expandafter
\expandafter{\csname abx@field@#1\endcsname}}
\def\firstword#1{\firstword@i#1 \@nil}
\def\firstword@i#1 #2\@nil{#1}
\makeatother
% Redefine url format to print only first URL, omit URL prefix
\DeclareFieldFormat{url}{\url{\firstword{#1}}}
\renewbibmacro*{title}{% Based on generic definition from biblatex.def
\ifboolexpr{ test {\iffieldundef{title}} and test {\iffieldundef{subtitle}} }
{}
{\printtext[title]{\printtext[linked]{%
\printfield[titlecase]{title}%
\setunit{\subtitlepunct}%
\printfield[titlecase]{subtitle}}}%
\newunit}%
\printfield{titleaddon}}
\renewbibmacro*{periodical}{% Based on generic definition from biblatex.def
\iffieldundef{title}
{}
{\printtext[title]{\printtext[linked]{%
\printfield[titlecase]{title}%
\setunit{\subtitlepunct}%
\printfield[titlecase]{subtitle}}}}}
\begin{filecontents}{\jobname.bib}
@Online{ctanmirror,
label = {CTAN},
title = {CTAN Mirror},
date = {2006},
url = {http://mirror.ctan.org http://www.ctan.org},
urldate = {2006-10-01}}
@Periodical{jcg,
title = {Computers and Graphics},
issuetitle = {Semantic {3D} Media and Content},
volume = {35},
number = {4},
year = {2011},
issn = {0097-8493}}
@Manual{cmso,
label = {CMS Online},
title = {The Chicago Manual of Style Online},
edition = {16},
publisher = {University of Chicago},
date = {2010},
url = {http://www.chicagomanualofstyle.org http://www.chicagomanualofstyle.org/16/contents.html},
isbn = {0-226-10403-6}}
@Article{sarfraz,
author = {M. Sarfraz and M. F. A. Razzak},
title = {An algorithm for automatic capturing of the font outlines},
journal = {Computers and Graphics},
volume = {26},
number = {5},
pages = {795--804},
year = {2002},
issn = {0097-8493},
doi = {10.1016/S0097-8493(02)00134-6}}
\end{filecontents}
% Don't link titles in citations
\AtEveryCite{\DeclareFieldAlias{linked}{default}}
\addbibresource{\jobname.bib}
\addbibresource{biblatex-examples.bib}
\begin{document}
\null\vfill
Filler text.\footcite{gonzalez,companion,cmso}
Filler text.\footcite{sarfraz,ctan,ctanmirror,jcg}
\printbibliography
\end{document}
Instead of redefining bibliography macros, the new format can be applied in the title format definition.
\DeclareFieldFormat{title}{\printtext[linked]{\mkbibemph{#1}}}
\DeclareFieldFormat
[article,inbook,incollection,inproceedings,patent,thesis,unpublished]
{title}{\mkbibquote{\printtext[linked]{#1}\isdot}}
\DeclareFieldFormat[suppbook,suppcollection,suppperiodical]{title}
{\printtext[linked]{#1}}