Gophor

A Gopher server written in GoLang as a means of learning about the Gopher protocol, and more GoLang.

Possibly beta quality soon? More likely alpha right now.

build.sh and you're set to go! Just put gophor somewhere in your path.

Linux only for now.

I'm unemployed (not due to lack of effort...) and work on open-source projects like this and many others for free. If you would like to help support my work that would be hugely appreciated 💕 https://liberapay.com/grufwub/

Usage

gophor [args]
       -root           Change server root directory.
       -port           Change server listening port.
       -hostname       Change server hostname (FQDN, used to craft dir lists).
       -bind-addr      Change server bind-address (used in creating socket).
       -uid            Change UID to drop privileges to.
       -gid            Change GID to drop privileges to.
       -system-log     Path to gophor system log file, else use stderr.
       -access-log     Path to gophor access log file, else use stderr.
       -cache-check    Change file-cache freshness check frequency (in secs).
       -cache-size     Change max no. files in file-cache.
       -cache-file-max Change maximum allowed size of a cached file.
       -page-width     Change page width used when formatting output.
       -gc-ballast     Change garbage-collector ballast size, default off.

Features

• Built with concurrency and efficiency in mind.

• ZERO external dependencies.

• Security focused -- chroots into server direrctory and drops privileges. maybe wait until stable release before use outside of hobby setups.

• LRU file caching -- with user-controlled cache size, max cached file size and cache refresh frequency.

• Insert files within gophermaps, including automating reflowing of lines longer than (user definable) page width.

• Automatic replacement of $hostname with your server's selected hostname if you put $hostname in your gophermap... Wanna hear me say hostname one more time?

• Item type characters beyond RFC 1436 standard (see below).

• Separate system and access logging with output to file if requested (or to disable both).

• Support for a garbage-collector ballast of user-defined size, which works to reduce the frequency of garbage collection (see (here).

  Realistically, you're unlikely to run into issues anywhere even close to the scale mentioned in the linked blog post. But in a situation where you're running this on a low-powered device and hitting CPU constraints when many users are accessing resources, this could help, maybe. Ultimately, I just read the blog post and liked the idea so I implemented it.

Supported gophermap item types

0 -- regular file (text)
1 -- directory (menu)
2 -- CSO phone-book server... should you be using this in 2020 lmao
3 -- Error
4 -- Binhexed macintosh file
5 -- DOS bin archive
6 -- Unix uuencoded file
7 -- Index-search server
8 -- Text-based telnet session
9 -- Binary file
T -- Text-based tn3270 session... in 2020???
g -- Gif format graphic
I -- Image file of some kind

+ -- Redundant server

. -- Lastline if this followed by CrLf

i -- Info message
h -- HTML document
s -- Audio file
p -- PNG image
d -- Document

M -- MIME type file
; -- Video file
c -- Calendar file
! -- Title
# -- Comment (not displayed)
- -- Hide file from directory listing
= -- Include subgophermap (prints file output here)
* -- Act as-if lastline and print directory listing below

Unavailable for now due to issues with accessing path within chroot:
$ -- Execute shell command and print stdout here

Todos

• TLS support

• Connection throttling + timeouts

• Header + footer text

• Rotating logs

• Set default charset

• Autogenerated caps.txt

• Toggleable server status page (?)

• Proxy over HTTP support

• Finish inline shell scripting support

• Allow setting UID+GID via username string

• Fix file cache only updating if main gophermap changes (but not sub files)

• More fine-tuned handling of OS signals

• Add support for banned file extensions (i.e. not shown in dir listing)

Please note

During the initial writing phase the quality of git commit messages may be low and many changes are likely to be bundled together at a time, just because the pace of development right now is rather break-neck.

As soon as we reach a stable point in development, or if other people start contributing issues or PRs, whichever comes first, this will be changed right away.

Standards followed

Gopher-II (The Next Generation Gopher WWIS): https://tools.ietf.org/html/draft-matavka-gopher-ii-00

All of the below can be viewed from your standard web browser using floodgap's Gopher proxy: https://gopher.floodgap.com/gopher/gw

RFC 1436 (The Internet Gopher Protocol: gopher://gopher.floodgap.com:70/0/gopher/tech/rfc1436.txt

Gopher+ (upward compatible enhancements): gopher://gopher.floodgap.com:70/0/gopher/tech/gopherplus.txt