-----Original Message-----
From: R-devel [mailto:r-devel-bounces at r-project.org] On Behalf Of Spencer
Graves
Sent: Friday, 08 January, 2021 13:04
To: r-devel at r-project.org
Subject: Re: [Rd] URL checks
I also would be pleased to be allowed to provide "a list of known
false-positive/exceptions" to the URL tests. I've been challenged
multiple times regarding URLs that worked fine when I checked them. We
should not be required to do a partial lobotomy to pass R CMD check ;-)
Spencer Graves
On 2021-01-07 09:53, Hugo Gruson wrote:
I encountered the same issue today with https://astrostatistics.psu.edu/.
This is a trust chain issue, as explained here:
https://whatsmychaincert.com/?astrostatistics.psu.edu.
I've worked for a couple of years on a project to increase HTTPS
adoption on the web and we noticed that this type of error is very
common, and that website maintainers are often unresponsive to requests
to fix this issue.
Therefore, I totally agree with Kirill that a list of known
false-positive/exceptions would be a great addition to save time to both
the CRAN team and package developers.
Hugo
On 07/01/2021 15:45, Kirill M?ller via R-devel wrote:
One other failure mode: SSL certificates trusted by browsers that are
not installed on the check machine, e.g. the "GEANT Vereniging"
certificate from https://relational.fit.cvut.cz/ .
K
On 07.01.21 12:14, Kirill M?ller via R-devel wrote:
Hi
The URL checks in R CMD check test all links in the README and
vignettes for broken or redirected links. In many cases this improves
documentation, I see problems with this approach which I have
detailed below.
I'm writing to this mailing list because I think the change needs to
happen in R's check routines. I propose to introduce an "allow-list"
for URLs, to reduce the burden on both CRAN and package maintainers.
Comments are greatly appreciated.
Best regards
Kirill
# Problems with the detection of broken/redirected URLs
## 301 should often be 307, how to change?
Many web sites use a 301 redirection code that probably should be a
307. For example, https://www.oracle.com and https://www.oracle.com/
both redirect to https://www.oracle.com/index.html with a 301. I
suspect the company still wants oracle.com to be recognized as the
primary entry point of their web presence (to reserve the right to
move the redirection to a different location later), I haven't
checked with their PR department though. If that's true, the redirect
probably should be a 307, which should be fixed by their IT
department which I haven't contacted yet either.
$ curl -i https://www.oracle.com
HTTP/2 301
server: AkamaiGHost
content-length: 0
location: https://www.oracle.com/index.html
...
## User agent detection
twitter.com responds with a 400 error for requests without a user
agent string hinting at an accepted browser.
$ curl -i https://twitter.com/
HTTP/2 400
...
<body>...<p>Please switch to a supported browser...</p>...</body>
$ curl -s -i https://twitter.com/ -A "Mozilla/5.0 (X11; Ubuntu; Linux
x86_64; rv:84.0) Gecko/20100101 Firefox/84.0" | head -n 1
HTTP/2 200
# Impact
While the latter problem *could* be fixed by supplying a browser-like
user agent string, the former problem is virtually unfixable -- so
many web sites should use 307 instead of 301 but don't. The above
list is also incomplete -- think of unreliable links, HTTP links,
other failure modes...
This affects me as a package maintainer, I have the choice to either
change the links to incorrect versions, or remove them altogether.
I can also choose to explain each broken link to CRAN, this subjects
the team to undue burden I think. Submitting a package with NOTEs
delays the release for a package which I must release very soon to
avoid having it pulled from CRAN, I'd rather not risk that -- hence I
need to remove the link and put it back later.
I'm aware of https://github.com/r-lib/urlchecker, this alleviates the
problem but ultimately doesn't solve it.
# Proposed solution
## Allow-list
A file inst/URL that lists all URLs where failures are allowed --
possibly with a list of the HTTP codes accepted for that link.
Example:
https://oracle.com/ 301
https://twitter.com/drob/status/1224851726068527106 400