# Bopher-NG: A better Gopher browser in pure Bash

> “Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.”
> _― Antoine de Saint-Exupéry, Airman's Odyssey_

## What is it?

Bopher-NG is an ambitious attempt to write a full-featured Gopher client/browser in under 300 SLOC of pure Bash code. It started off as a really crude and unoptimized prototype developed right in [this blog post](https://chronovir.us/2023/03/28/I-wrote-a-browser/) for educational purposes.

Improvements over the original Bopher from that post:

- mouse support (where possible)
- smoother rendering and scrolling
- better edge-case stability
- multi-level navigation history (although you can only go back)
- status bar with currently opened resource name
- ability to accept `gopher://` URLs from the command line
- ability to save the URL to the currently viewed resource into the stash text file
- ability to force-download pages instead of viewing regardless of their type

"Pure Bash" means any external commands must only be used if absolutely required. For now, Bopher-NG only depends on three external commands (all POSIX-compliant):

- `cat` (to handle possibly binary data read from the socket)
- `stty` (to fetch current terminal size in rows and columns)
- `date` (to shape entry timestamps when stashing links)

## Which Bash versions are supported?

Bopher-NG was only tested on Bash 5.1, but should support any version from 4.2 and up.

## How to start Bopher-NG?

Just run it specifying all the necessary components of the Gopher resource:

```
bopher-ng.sh host[ port][ selector][ type]
```

Or, you can just specify a valid `gopher://` URL:

```
bopher-ng.sh gopher://host[:port]/[type][selector]
```

E.g. running `bopher-ng.sh gopher://texto-plano.xyz:70/0comandos.txt` is the same as `bopher-ng.sh texto-plano.xyz 70 comandos.txt 0` and will open the same document.

In both cases, only the host is required. If everything else is omitted, the port will default to 70, the selector will default to `/` and the resource type will default to 1.

## How to control Bopher-NG?

- Scrolling: Up/Down arrow keys, k/j keys or mouse scroll wheel (if supported)
- Page scrolling: PgUp/PgDn keys or h/l keys
- Link navigation (keyboard): s - focus on the next link, w - focus on the previous link, Enter/Space - visit the focused link (or download if it points to a binary file), d - force-download the contents of the link
- Link navigation (mouse, if supported): left click on the link - focus and visit (or download if it points to a binary file), middle click - focus and force-download the contents
- Go back: b or right mouse click anywhere (if supported)
- Stash the link to the currently open resource: S (shift+s)
- Quit the browser: q

## What is the link stash?

Link stash is a viable and interoperable alternative to both bookmarks and clipboard that can be implemented with pure Bash. Essentially, it's an append-only text file at a fixed location (`~/.bopher-links.txt` by default) where the user can instruct Bopher-NG to save the link to the currently viewed resource. For your convenience, links are stashed with a UTC-based timestamp and in the `gopher://` format, so they can be copied from the file later and used in other browsers.

You can override the `BOPHER_LINKSTASH` environment variable to change the location and name of this file if you need to.

## Where do the downloads go?

By default, they go to your current working directory, i.e. the directory you are running this script from. To override this with a fixed path, set the `BOPHER_DLDIR` environment variable.

## Which platforms is the mouse supported on?

Bopher-NG's mouse input is supported on any terminals that support the 1000 **and** 1006 mouse reporting modes. This includes but is not limited to:

- Linux GUI terminal emulators (xterm, Konsole, urxvt, any VTE-based terminal emulator);
- Linux bare terminals via GPM + [LCXterm](https://gitlab.com/AutumnMeowMeow/lcxterm) (sorry, I don't know why no one implemented it in GPM itself in 23 years);
- macOS Terminal;
- OpenGL-based xterm-compatible terminal emulators like WezTerm, Kitty, Alacritty etc.

Note that this support is required at the client side only. For instance, you can safely run `bopher-ng.sh` on any compatible Bash version in an SSH session on your terminal and still be able to use mouse there.


## What is the license on this?

Fully public domain