Telescope

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

Features:

tabs
bookmarks
privsep
minibuffer live narrowing
multiple protocols support
fully customizable

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

subscriptions
tofu oob verification
client certificates
add other GUIs: at the moment it uses only ncurses, but telescope shouldn't be restricted to TTYs only!

Why yet another browser?

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 brings more stability as it became more difficult to change the protocol, too.

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

Goals

Fun: hacking on Telescope should be fun.
Clean: write readable and clean code mostly following the 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.

TOFU

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 oob-verification though.

Building

Telescope depends on ncursesw, libtls (from either LibreSSL or libretls), libevent (either v1 or v2) and pkg-config. When building from a git checkout, yacc (or bison) is also needed.

To build from a release tarball just execute:

./configure
make
sudo make install

The configure script has optional support for building with libraries provided by your distribution instead of internal compatibility funcs:

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

If you want to build from the git checkout, something that's discouraged for users that don't intend to hack on telescope

./autogen.sh
./configure
make
sudo make install	# eventually

Please keep in mind that the main branch, from time to time, may be accidentally broken on some platforms. Telescope is developed primarily on OpenBSD/amd64 and commits on the main branch don't get always tested in other OSes. Before tagging a release however, a comprehensive testing on various platforms is done to ensure everything is working as intended.

Contributing

Any form of contribution is appreciated, not only patches or bug reports: feel free to open an issue or send an email to telescope@omarpolo.com.

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.

User files

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".

Only one instance of Telescope can be running at time per user.

License

Telescope is distributed under a BSD-style licence. The main code is under the ISC but for files under compat/ it varies.

ThomasAdam/telescope