A single instance of tmpbbs is an ephemeral, anonymous forum site. All posts are stored in memory and lost when the process stops. It's a single static binary and does not require the internet or any disk. It can run on low-powered hardware like older wireless routers.

Multiple instances of tmpbbs can be linked so that posts are replicated in one or both directions. This enables different topologies such as a decentralized mesh where each instance has all the posts, trees, backup instances and read-only replicas. This is how posts are made durable.

It works well with tailscale and similar software to create private forums.

By default all running instances provide everything you need to create your own copy of them. You can get the binary from /self (assuming you are using the same platform) and the data can be pulled and kept up-to-date using --pull-peers.

Features

• Markdown
• emoji shortcodes with suggestions
• optional TLS (using --tls-cert and --tls-key options)
• tripcodes in username#secret format
• shareable URL QR codes
• every instance distributes the software by serving its own binary
• post IDs in URLs are error resistant and pronounceable Crockford Base 32
• pruning of stale posts (using --prune-interval and --prune-max-age)

Installation

go install github.com/mmb/tmpbbs@latest

Container Images

docker run --name tmpbbs --publish 8080:8080 --pull always --rm mm62/tmpbbs:latest

or

docker run --name tmpbbs --publish 8080:8080 --pull always --rm ghcr.io/mmb/tmpbbs:latest

Options

% tmpbbs --help
Usage of tmpbbs:
  -o, --config-file string            path to config file ($TMPBBS_CONFIG_FILE)
  -u, --css-urls strings              comma-separated list of additional CSS URLs ($TMPBBS_CSS_URLS)
  -m, --emoji                         enable emoji shortcode expansion ($TMPBBS_EMOJI) (default true)
  -g, --grpc-listen-address string    <host>:port to listen on for gRPC ($TMPBBS_GRPC_LISTEN_ADDRESS) (default ":8081")
  -j, --json-log                      set log output format to JSON ($TMPBBS_JSON_LOG)
  -l, --listen-address string         <host>:port to listen on for HTTP ($TMPBBS_LISTEN_ADDRESS) (default ":8080")
  -p, --load-posts strings            comma-separated paths of YAML or JSON files of posts to load, format [{"title":"","author":"","body":""}]
                                      ($TMPBBS_LOAD_POSTS)
  -s, --prune-interval duration       how often to check for stale posts to prune ($TMPBBS_PRUNE_INTERVAL) (default 1h0m0s)
  -w, --prune-max-age duration        delete posts that haven't been updated in this long ($TMPBBS_PRUNE_MAX_AGE) (default 720h0m0s)
  -i, --pull-interval duration        peer pull interval ($TMPBBS_PULL_INTERVAL) (default 30s)
  -d, --pull-peers strings            comma-separated list of tmpbbs gRPC <tls://>host:gRPCport to pull posts from ($TMPBBS_PULL_PEERS)
  -q, --qr-codes                      enable shareable URL QR codes ($TMPBBS_QR_CODES) (default true)
  -r, --replies                       enable replies ($TMPBBS_REPLIES) (default true)
  -e, --replies-per-page int          number of replies to show per page ($TMPBBS_REPLIES_PER_PAGE) (default 10)
  -b, --serve-binary                  serve tmpbbs binary at /self ($TMPBBS_SERVE_BINARY) (default true)
  -f, --serve-fs-paths strings        comma-separated list of urlprefix=/local/dir to serve ($TMPBBS_SERVE_FS_PATHS)
  -n, --superuser-tripcodes strings   comma-separated list of superuser tripcodes ($TMPBBS_SUPERUSER_TRIPCODES)
  -t, --title string                  site title ($TMPBBS_TITLE) (default "tmpbbs")
  -c, --tls-cert string               path to PEM server certificate ($TMPBBS_TLS_CERT)
  -k, --tls-key string                path to PEM server key ($TMPBBS_TLS_KEY)
  -a, --tripcode-salt string          random salt to use for generating tripcodes ($TMPBBS_TRIPCODE_SALT)
  -v, --version                       print version

Peering

An instance can pull posts from any number of other instances by adding their host:port to the --pull-peers option, where port is the port in the peer's --grpc-listen-address (default 8081).

If the peer instances were started in TLS mode, their gRPC server will also be in TLS mode. In that case TLS must be enabled on the client instance by prefixing the address with tls:// in --pull-peers. If the peer instances are not using TLS --pull-peers should just have their host:grpcport but in this case the gRPC traffic will not be encrypted.

Two instances can pull from each other and posts will not be duplicated. ULIDs are used for globally unique post identifiers.

Topologies

• Backup - instance A pulls from instance B and vice versa, B is not actively used, can be used to overcome the loss of data if instance A restarts

• Chain - a chain of N instances connected by long distance point-to-point links each pull from their closest neighbor

• Fork - instance A pulls from instance B, creating a "forked" forum where posts on B can be replied to on A but the replies don't go back to B

• Full mesh - N instances all pull from each other, each instance has all the posts and replies are propagated to all instances

• Local offline cache - local instance A can pull from remote instance B and will stay available with intermittent or no connectivity to B, it will catch up when connectivity is available

• Read-only mirror / star - instance A started with --replies=false pulls from instance B, providing a read-only mirror of B, can be used to reduce load on instance B or distributed geographically to reduce latency for users

• Ring - a closed loop of N instances each pull from one other instance, posts propagate in a circle in one direction

• Sneakernet - instances A and B pull from instance C which also pulls from them, instance C is on a portable device that periodically moves betwen A and B

• Tree - an instance has N instances pulling from it, each of those has N instances pulling from it, etc., posts flow down a hierarchy

Deleting Posts

Users can delete their own posts by replying with a post that starts with !delete. The tripcodes for the post being deleted and the reply must match.

A list of superuser tripcodes can be passed in with --superuser-tripcodes. Users with those tripcodes can delete any post. Tripcodes are dependent on the tripcode salt so this option should be used together with --tripcode-salt.

Pruning

By default posts older than 30 days are pruned every hour. This can be controlled (or disabled) with the --prune-interval and --prune-max-age options.

Adding a New Language

Add the new language-region tag to the lang argument (comma-separated) in the go:generate line in internal/tmpbbs/postgethandler.go. Example adding es-ES:

//go:generate gotext -srclang=en-US update -lang=es-ES -out=catalog.go github.com/mmb/tmpbbs/internal/tmpbbs

Install gotext and run go generate:

go install golang.org/x/text/cmd/gotext@latest
go generate ./...

Edit internal/tmpbbs/locales/es-ES/out.gotext.json and fill in the translation fields. Copy that file to messages.gotext.json in the same directory.

Run go generate ./... again. Open a pull request with the new messages.gotext.json file and the changed files.