Suppress URL if DOI is present in biblatex-chicago

Question

This question is probably a home-run for people that are more into the workings of biblatex than me... Anyway, I want to achieve what has been solved here and here, but with using biblatex-chicago instead of biblatex. That means the URL should be suppressed whenever a DOI is present in the reference. Note: In the original questions it was the other way round.

The MWE of karlkoeller will not work as soon as I replace biblatex:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[backend=biber]{biblatex-chicago}

\addbibresource{\jobname.bib}

\renewbibmacro*{doi+eprint+url}{%
  \iftoggle{bbx:doi}
    {\iffieldundef{url}{\printfield{doi}}{}}
    {}%
  \newunit\newblock
  \iftoggle{bbx:eprint}
    {\usebibmacro{eprint}}
    {}%
  \newunit\newblock
  \iftoggle{bbx:url}
    {\usebibmacro{url+urldate}}
    {}}

\usepackage{filecontents}

\begin{filecontents}{\jobname.bib}
@article{kastenholz1,
  hyphenation = {american},
  author = {Kastenholz, M. A. and H{\"u}nenberger, Philippe H.},
  indextitle = {Computation of ionic solvation free energies},
  title = {Computation of methodology\hyphen independent ionic solvation free
    energies from molecular simulations},
  subtitle = {I. The electrostatic potential in molecular liquids},
  journaltitle = jchph,
  volume = {124},
  eid = {124106},
  date = {2006},
  url = {http://dx.doi.org/10.1063/1.2172593},
  urldate = {2006-10-01},
  doi = {10.1063/1.2172593},
}
@article{kastenholz2,
  hyphenation = {american},
  author = {Kastenholz, M. A. and H{\"u}nenberger, Philippe H.},
  indextitle = {Computation of ionic solvation free energies},
  title = {Computation of methodology\hyphen independent ionic solvation free
    energies from molecular simulations},
  subtitle = {I. The electrostatic potential in molecular liquids},
  journaltitle = jchph,
  volume = {124},
  eid = {124106},
  date = {2006},
  doi = {10.1063/1.2172593},
}
\end{filecontents}


\begin{document}
  \nocite{*}
  \printbibliography
\end{document}

Output:

Who can help, please?

Answer 1

Unless I misunderstand the question, wouldn't adding the option

\usepackage[doi=only]{biblatex-chicago}

or

\usepackage[url=false]{biblatex-chicago}

work (the latter would suppress all URLs)? See 4.4.2 in the biblatex-chicago documentation.

Answer 2

You can patch the two macros responsible for printing the doi and the url to clear the url field if there is a doi defined:

\usepackage{biblatex-chicago}
\usepackage{xpatch}

% patch macro used in bibliography
\xpretobibmacro{bib+doi+url}
  {\iffieldundef{doi}
     {}
     {\clearfield{url}}}
  {}{}

% patch macro used in notes
\xpretobibmacro{cite+doi+url}
  {\iffieldundef{doi}
     {}
     {\clearfield{url}}}
  {}{}