Telescope is a Emacs/w3m-inspired browser for the "small internet" that supports Gemini, Gopher and Finger.

In features some expected stuff (tabs, bookmarks, history, client certificates, ...) with an UI that's very much Emacs and w3m inspired, and a privsep design.

There are still various things missing or, if you prefer, various things that you can help develop :)

• other "smol internet" protocols
• subscriptions
• TOFU out-of-band verification and/or DANE
• multiple UIs: at the moment it uses only ncurses, but telescope shouldn't be restricted to TTYs only!

One of the great virtues of Gemini is its simplicity. It means that writing browsers or server is easy and thus a plethora of those exists. I myself routinely switch between a couple of them, depending on my mood.

More browsers means more choice for the users, and more stability for the protocol too.

However, Telescope was ultimately written for fun, on a whim, just to play with ncurses, libtls, async I/O and the macros from sys/queue.h, but I'd like to finish it into a complete Gemini browser.

• Fun: hacking on Telescope should be fun.
• Clean: write readable and clean code mostly following the OpenBSD style(9) guideline. Don't become a kitchen sink.
• Secure: write secure code with privilege separation to mitigate the security risks of possible bugs.
• Fast: it features a modern, fast, event-based asynchronous I/O model.
• Cooperation: re-use existing conventions to allow inter-operations and easy migrations from/to other clients.

Telescope aims to use the "Trust, but Verify (where appropriate)" approach outlined here: gemini://thfr.info/gemini/modified-trust-verify.gmi.

The idea is to define three level of verification for a certificate:

• untrusted: the server fingerprint does NOT match the stored value
• trusted: the server fingerprint matches the stored one
• verified: the fingerprint matches and has been verified out-of-band by the client.

Most of the time, the trusted level is enough, but where is appropriate users should be able to verify out-of-band the certificate.

At the moment there is no UI for out-of-band verification though.

Telescope depends on ncursesw, libtls or libretls, yacc/bison and pkg-config. libgrapheme is an optional dependency: there's a bundled copy but it's reccomended to install it with a package manager if available.

To build execute:

$ ./autogen.sh		# only from git checkouts
$ ./configure
$ make
$ sudo make install	# eventually

The configure script has optional support for building with libraries provided by your distribution instead of using the bundled versions:

• --with-libbsd: link with libbsd
• --with-libimsg: link with the imsg-compat library

The default-editor can be changed at build-time with the following option:

• --with-default-editor: defaults to ed(1)

This is useful for distributions such as Debian, which prefers sensible-editor(1) as a wrapper.

This feature is mostly useful with the mini-edit-external command in telescope.

Any form of contribution is appreciated, not only patches or bug reports: feel free to open an issue or send an email to [email protected].

If you have a sample configuration, custom theme, a script or anything that could be helpful to others, consider adding it to the contrib directory.

Consider also joining the official irc channel, #telescope on libera.chat!

Telescope stores user files according to the XDG Base Directory Specification by default. The usage and contents of these files are described in the man page, under "FILES".

At the moment, only one instance of Telescope can be running at time per user.

Telescope is distributed under a BSD-style licence. The main code is either under the ISC or is Public Domain, but some files under compat/ are 3-Clause BSD or MIT. See the first few lines of every file or about:license inside telescope for the copyright information.

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