internetExists

Simple test for internet availability.

A single key function, 'Require' that makes rerun-tolerant
versions of 'install.packages' and 'require' for CRAN packages, packages
no longer on CRAN (i.e., archived), specific versions of packages,
and GitHub packages. This approach is developed to create reproducible
workflows that are flexible and fast enough to use while in development stages,
while able to build snapshots once a stable package collection is found.
As with other functions in a reproducible workflow, this package
emphasizes functions that return the same result whether it is
the first or subsequent times running the function, with subsequent times being
sufficiently fast that they can be run every time without undue waiting burden on
the user or developer.

Eliot J B

Require

Installing and Loading R Packages for Reproducible Workflows

Eliot J B McIntire

Alex M Chubaty

His Majesty the King in Right of Canada, as represented by the Minister of Natural Resources Canada 

internetExists function

<dl><dt>verbose</dt>
<dd>Numeric or logical indicating how verbose should the function
be. If -1 or -2, then as little verbosity as possible. If 0 or FALSE,
then minimal outputs; if <code>1</code> or TRUE, more outputs; <code>2</code> even more. NOTE: in
<code>Require</code> function, when <code>verbose &gt;= 2</code>, also returns details as if
<code>returnDetails = TRUE</code> (for backwards compatibility).</dd>
<dt>force</dt>
<dd>If <code>TRUE</code>, probe even when <code>options("Require.checkInternet")</code>
is <code>FALSE</code>. Used at points where we're about to do real work (e.g.,
install dispatch) and a 2-second probe is cheap relative to the cost
of failing late. Defaults to <code>FALSE</code> to preserve the no-probe default
behaviour for all other call sites.</dd></dl>

Arguments

Internet Exists query — internetExists

<dl>

<dt>verbose</dt>
<dd>Numeric or logical indicating how verbose should the function
be. If -1 or -2, then as little verbosity as possible. If 0 or FALSE,
then minimal outputs; if <code>1</code> or TRUE, more outputs; <code>2</code> even more. NOTE: in
<code>Require</code> function, when <code>verbose &gt;= 2</code>, also returns details as if
<code>returnDetails = TRUE</code> (for backwards compatibility).</dd>


<dt>force</dt>
<dd>If <code>TRUE</code>, probe even when <code>options("Require.checkInternet")</code>
is <code>FALSE</code>. Used at points where we're about to do real work (e.g.,
install dispatch) and a 2-second probe is cheap relative to the cost
of failing late. Defaults to <code>FALSE</code> to preserve the no-probe default
behaviour for all other call sites.</dd>

</dl>

internetExists: Internet Exists query

Description

Usage

Value

Arguments