BFG: a multiprotocol "small web" browser in Tcl/Tk

BFG (stands for Back/Forward/Go) is a: free (absolutely), open-source, cross-platform, single-script, self-contained GUI client for a number of "small web" protocols like Gopher, Finger, Nex, Spartan and Gemini.

BFG is written in under 1000 SLOC of Tcl 8.6 and depends upon Tcllib, Tk (obviously) and TclTLS.

If you found any bugs, feel free to submit an issue into this repo!

Supported features

The following features are already (fully or partially) supported in BFG.

Complete

• Finger protocol (finger:// URLs)
• Gopher protocol with optional TLS support (gopher:// and gophers:// URLs)
• Nex protocol (nex:// URLs)
• Spartan protocol (spartan:// URLs) with single-line text query support
• Gemini protocol (gemini:// URLs) with single-line custom input support
• Gophermap rendering (entry types 0, 1, 3, 5, 7, 8, 9, i, h)
• Single-line search query support for Gopher type 7 resources
• UTF-8 support for text content
• Basic history support (back/forward actions)
• Page refresh action
• Page/file download action
• Status bar
• Bookmarks
• Opening a URL from the command line
• Opening unknown URL schemes in the outside OS environment
• Opening the links in a new window
• Easy keybindings for fully mouseless navigation (see "Usage" section)
• Dynamic window title based on the current URL
• In-page text search
• Ini-based customization of the current Ttk theme, content fonts and colors

Non-supported features

The following features aren't supported by BFG as of now, some of them never will be. In general, there are two reasons why a feature might not be implemented in BFG:

• it bloats the scope too much (making the codebase over 1000 SLOC with no space for optimization),
• it requires more third-party package dependencies (other than Tk, Tcllib and TclTLS).

Still pending (might be imlpemented someday)

• Source view toggle (between plaintext and rendered gophermap/Gemtext/etc)
• Local plaintext/Gemtext reader (file:// URL scheme)
• ANSI terminal coloring (basic 16 colors only)
• Image viewer (non-embedded, only PNG/GIF/PPM/PGM types)
• Gemini client certificates (might never be implemented; don't ask for it unless absolutely necessary)

Unsupported by design

• Tabs (they complicate the architecture a lot; use your WM's tabbing functionality instead)
• Horizontal scrolling (word wrapping is mandatory; expand the window if the content doesn't fit)
• Saved history (unsupported for security reasons; use bookmarks if you want to save a page URL)
• Any other text content encoding except UTF-8
• Context menus
• Any sort of sound or video output
• Any sort of embedded non-text content
• NPS and Titan protocols and other means of content uploading *
• Guppy protocol (UDP-based, don't want to introduce another third-party dependency)

(* probably will be implemented in a separate program)

Usage

You can run the script with an optional URL to open, e.g.: wish bfg.tcl gopher://hoi.st

The following keybindings are currently supported:

• b: bo back in history
• f: go forward in history
• g: focus the address bar and select the current address (to be able to easily overwrite it)
• r or F5: refresh the content
• a: select and highlight the previous link
• s: select and highlight the next link
• d: download the file or page contents under the selected link
• Shift+d: download the file or page contents under the selected link and open it with your default application
• Space / Return (Enter): click on the selected link
• Shift + Space / Shift + Return (Enter): open the selected link in a new window
• h / Arrow Left / PgUp: scroll the content up 10 lines
• j / Arrow Down: scroll the content down 1 line
• k / Arrow Up: scroll the content up 1 line
• l / Arrow Right / PgDn: scroll the content down 10 lines
• / (forward slash) or ctrl+f: enter a term to find in the text (enter nothing to find the next one)
• Esc: reset all search highlights
• Ctrl+b: open bookmarks menu (you can navigate with arrows after opening)
• Ctrl+q: quit BFG

The following mouse bindings are currently supported:

• Left click: open the link
• Shift + Left click or Middle click: open the link in a new window
• Right click: download the link contents
• Shift + Right click: download the link contents and open it with your default application
• Scroll wheel: scroll the page content
• Mouse button 8 ("Back") if present: go back in history
• Mouse button 9 ("Forward") if present: go forward in history

Customization

BFG ships with a bfg.ini file that holds your configuration values and bookmarks. The main configuration sections are:

• [net]: network-related configs, currently only has "timeout" parameter
• [widget]: general UI widget appearance (ttkTheme, font (button font), entryfont, statusfont)
• [style.general]: general content area appearance (textfont, foreground color, background color)
• [style.link.normal]: normal link colors (foreground, background)
• [style.link.focused]: currently focused link colors (foreground, background)
• [style.highlight]: highlighted area colors (foreground, background) - used with search functionality
• [style.error]: error message colors (foreground, background)

Feel free to modify the bfg.ini file according to your own preferences, the one shipped is just an example.

FAQ

Why yet another "small web" client?

I like the idea of browsing without bloatware. I also like Lagrange but it already looks too bloated to me. I also like the idea of Tcl/Tk as the universal tool for creating lightweight and portable GUI applications. BFG was created as a great playground to combine those ideas and as the next iteration over Bopher-NG. Which, as you might have guessed, only supports Gopher.

Contrary to most GUI clients, BFG is:

• keyboard-friendly (everything that can be done with a mouse can be done with a keyboard),
• trackball-friendly (the middle click action can be substituted with Shift + left click),
• not overloaded with menus,
• under 40K bytes in size.

Why such keybindings?

When using "normal" browsers, we don't fully utilize the keyboard. BFG combines the best practices from:

• Links/Elinks,
• less,
• Bopher-NG to create the most comfortable UX in case you choose to not use the mouse at all. In fact, the browser name itself contains the first three keybindings to start using it without a mouse.

Can you build a binary distribuition of BFG?

The main idea of BFG is to be as portable as possible, so no, binaries will not be distributed here. However, you always can do it yourself. Here's how.

1. Obtain the tclkits for your host and target platforms, e.g. build them here. Make sure you're building the target tclkit with Metakit, Tcllib, Tk and TLS packages enabled. Optionally you can select "TLS: Statically link to LibSSL" and/or "TLS: Build LibreSSL for this platform". If the host and target platform are the same, you still need two kit binaries (just make a copy).

2. Download sdx.kit from somewhere, e.g. from here

3. Put the two binaries and sdx.kit into the same directory as bfg.tcl, then run from this directory:

[/path/to/host/tclkit] sdx.kit qwrap bfg.tcl -runtime [/path/to/target/tclkit] 

A file just named bfg should appear, this is your executable.

4. If building for Windows, rename bfg to bfg.exe.

I want this feature X to be implemented! Can you do this?

If the feature doesn't belong to the pending items list above, the answer most probably is no. The pending list can be updated from time to time, so please check it periodically. Alternatively, you can do a proposal in the "Issues" section or even create a patch or a pull request. However, one of the BFG's goals is to stay under 1000 SLOC no matter what. If you want feature creep, feel free to switch to more suitable clients like Lagrange.

Why does a Gopher-over-TLS (gophers:// URL) resource still show plain gopher:// links?

Due to a limitation of the Gopher-over-TLS protocol itself, we cannot determine if the Gophermap entry points to a plain Gopher or a Gopher-over-TLS resource. Hence, only the links belonging to the same host/port pair that was already opened with a gophers:// link are displayed as gophers:// links. Everything else needs to be adjusted manually for now. Sorry for the inconvenience.

Credits

Created by Luxferre in 2024, released into the public domain.