2020-06-17 Tiny Gemini Client in Bash

This defines the function “gemini” such that you can visit a Gemini URL from the command line.

function gemini () {
    if [[ $1 =~ gemini://([^/:]+)(:([0-9]+))? ]]; then
	echo Contacting $host:$port...
	echo "$1" | openssl s_client -quiet -connect $host:$port 2>/dev/null
	echo $1 is not a Gemini URL

I should write another one that uses a client certificate, too. 🙂

And here’s an uploader using Titan.

function titan () {
    if [[ -z "$2" ]]; then
        echo Usage: $0 URL TOKEN [FILE]
    if [[ $1 =~ titan://([^/:]+)(:([0-9]+))? ]]; then
	echo Reading ${2:-/dev/stdin}
	read -d "" file < "${3:-/dev/stdin}"
	echo Posting $size bytes to $host:$port...
	printf "$1;token=$token;mime=text/plain;size=$size\r\n$file" \
	    | openssl s_client -quiet -connect $host:$port 2>/dev/null
	echo $1 is not a Titan URL

Here’s how to call it:

echo "This is a Titan test." \
    | titan titan://alexschroeder.ch/raw/Test hello

I put these two functions into a git repo.



I guess the URL schema is superfluous. 🙂

If somebody uses a client certificate with a common name set, we could use this to save a username when saving pages. An excellent way to self-identify.

Sadly, on the server side, I have not found a way to learn anything about the client certificate used. 😟

– Alex Schroeder 2020-06-17 21:41 UTC

I depends upon the library you are using for TLS. I use libtls, which makes it not only easy to use TLS, but to obtain information from the client certificate.

Sean Conner 2020-06-17 22:21 UTC

Hm. I use Perl’s IO::Socket::SSL which allows me to examine the peer certificate, according to the do documentation but when I do it, there is nothing. 😕

– Alex Schroeder 2020-06-18 12:42 UTC

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