How to add externally stored link text into a hyperlink?

Question

I have a bunch of links which are individually stored in text files. I would like to create a LaTeX document in which those files are accessed using relative paths and the link included into the final PDF. The reason is that later in the future I might want to change the links in the files and the generated PDF should update accordingly.

This is what I have tried:

\usepackage{verbatim}
\href{\verbatiminput{./links/1.txt}}

but I get the error:

TeX capacity exceeded, sorry [input stack size=5000].

Here is a minimum working example:

Create File: 1.txt

1.1. Input https://www.youtube.com/

1.2. Close file

Latex Code without pulling from text file

% !TeX program = lualatex
\documentclass{article}%
\usepackage{graphicx}


\usepackage{hyperref}% for the links
\usepackage{verbatim}% for the input

\begin{document}%
\href{https://www.youtube.com}{\includegraphics[width=\linewidth]{example-image}}

\end{document}%

works great !

now with pulling from text file

% !TeX program = lualatex
\documentclass{article}%
\usepackage{graphicx}


\usepackage{hyperref}% for the links
\usepackage{verbatim}% for the input

\begin{document}%
\href{\include{1.txt}}{\includegraphics[width=\linewidth]{example-image}}

\end{document}%

I get the errors:

line 10: Argument of @include has an extra }. \href{\include{1.txt}}

line 10: Paragraph ended before @include was complete.

\href{\include{1.txt}} line 10: Paragraph ended before \href@ was

complete. \href{\include{1.txt}} line 10: Extra }, or forgotten

\endgroup. \href{\include{1.txt}} line 10: Overfull \hbox (15.0pt too

wide) in paragraph

EDIT:

based on @Ulrike Fischer, I tried

% !TeX program = lualatex
\documentclass{article}%
\usepackage{graphicx}


\usepackage{hyperref,catchfile}% for the links
\usepackage{verbatim}% for the input

\begin{document}%

\CatchFileDef\myurl{1.txt}{}
\href{\myurl}{\includegraphics[width=\linewidth]{example-image}}

\end{document}%

but I got:

Package catchfile Error: File `1.txt' not found. \CatchFileDef\myurl{1.txt}{} Suppressing link with empty target Overfull \hbox (15.0pt too wide) in paragraph

EDIT 2:

Also tried to create a new command, but did not work: http://www.emerson.emory.edu/services/latex/latex_19.html

\newcommand\urlFromFile[1]{\CatchFileDef{#1}{}}

EDIT 3:

% !TeX program = lualatex
\documentclass{article}%
\usepackage{graphicx}


\usepackage{hyperref,catchfile}% for the links
\usepackage{verbatim}% for the input


\usepackage{hyperref,catchfile}
\newcommand\urlFromFile[1]{%
    \CatchFileDef\myurl{#1}{\catcode`\#=12\catcode`\%=12}%
    \expandafter\url\expandafter{\myurl}}

\begin{document}
    \href{\urlFromFile{1.txt}}{\includegraphics[width=\linewidth]{example-image}}
\end{document}
%

I get:

line 16: TeX capacity exceeded, sorry [parameter stack size=10000]. \href{\urlFromFile{1.txt}}

Answer 1

You can use catchfile to load the url:

\begin{filecontents*}{1.txt}
https://www.youtube.com/
\end{filecontents*}

\documentclass{report}
\usepackage{hyperref,catchfile}
\CatchFileDef\myurl{1.txt}{}
\begin{document}
\expandafter\url\expandafter{\myurl}
\end{document}

If the url contains special chars like % or _ or # you can use the last argument of the command to setup the catcodes.

An extended example with some special chars and a command:

\begin{filecontents*}{1.txt}
https://www.youtube_blub#%.com/
\end{filecontents*}

\documentclass{report}
\usepackage{hyperref,catchfile}
\newcommand\urlFromFile[1]{%
 \CatchFileDef\myurl{#1}{\catcode`\#=12\catcode`\%=12}%
 \expandafter\url\expandafter{\myurl}}
\begin{document}
\urlFromFile{1.txt}
\end{document}