url-retrieve-synchronously: How to retrieve Github gist list

Question

Q: How to retrieve a list of Github gists using url-retrieve-synchronously?

I am able to visit my gist list in a web browser:

https://api.github.com/users/lawlist/gists

When I try evaluating:

(url-retrieve-synchronously "https://api.github.com/users/lawlist/gists")

I get this:

Debugger entered--Lisp error: (error "Could not create connection to api.github.com:443")
signal(error ("Could not create connection to api.github.com:443"))
error("Could not create connection to %s:%d" "api.github.com" 443)
url-http(#s(url :type "https" :user nil :password nil :host "api.github.com" :portspec nil :filename "/users/lawlist/gists" :target nil :attributes nil :fullness t :silent nil :use-cookies t :asynchronous nil) #f(compiled-function (&rest ignored) #<bytecode 0x40e4195f>) (nil) nil tls)
url-https(#s(url :type "https" :user nil :password nil :host "api.github.com" :portspec nil :filename "/users/lawlist/gists" :target nil :attributes nil :fullness t :silent nil :use-cookies t :asynchronous nil) #f(compiled-function (&rest ignored) #<bytecode 0x40e4195f>) (nil))
url-retrieve-internal("https://api.github.com/users/lawlist/gists" #f(compiled-function (&rest ignored) #<bytecode 0x40e4195f>) (nil) nil nil)
url-retrieve("https://api.github.com/users/lawlist/gists" #f(compiled-function (&rest ignored) #<bytecode 0x40e4195f>) nil nil nil)
url-retrieve-synchronously("https://api.github.com/users/lawlist/gists")
eval((url-retrieve-synchronously "https://api.github.com/users/lawlist/gists") nil)
eval-expression((url-retrieve-synchronously "https://api.github.com/users/lawlist/gists") nil nil 127)
funcall-interactively(eval-expression (url-retrieve-synchronously "https://api.github.com/users/lawlist/gists") nil nil 127)
call-interactively(eval-expression nil nil)
command-execute(eval-expression)

Emacs Version: This is GNU Emacs 26.1 (build 1, x86_64-apple-darwin10.8.0, NS appkit-1038.36 Version 10.6.8 (Build 10K549)) of 2018-05-30

---

I have tried adding a username/password, but the result was similar:

(url-retrieve-synchronously "https://USERNAME:[email protected]/users/lawlist/gists")

Answer 1

The computer that was used to run the test described in the question is running OpenSSL version 0.9.8r 8 Feb 2011.

Although I am uncertain what the minimum OpenSSL requirements are at this point in time, I was able to get the test to complete successfully with OpenSSL version 1.0.2g 1 Mar 2016.

I chose not to modify my default installation of OpenSSL so as to avoid opening a can of worms. Instead, I had a slightly newer version of OpenSSL installed through Macports a few years ago in a separate directory and I adjusted the path as follows:

(setq tls-program
  '("gnutls-cli --x509cafile %t -p %p %h"
    "gnutls-cli --x509cafile %t -p %p %h --protocols ssl3"
    "/absolute/path/openssl s_client -connect %h:%p -no_ssl2 -ign_eof"))

After evaluating the above snippet that utilizes the more recent version of OpenSSL mentioned above, evaluating the following:

(url-retrieve-synchronously "https://api.github.com/users/lawlist/gists")

produces a buffer named  *http api.github.com:443* containing the desired information.