SNAC(5)

NAME
snac - message formatting and file format documentation

DESCRIPTION
The snac daemon processes messages from other servers in the Fediverse using the ActivityPub protocol.

This manual describes the allowed formatting of note messages and the disk storage layout of snac server and user data. For the operation manual, see snac(1). For the administration manual, see snac(8).

  Message Formatting
Message notes respect the entered new line breaks rigurously. A special subset of Markdown is allowed, including:

bold
    **text between two pairs of asterisks**

italic
    *text between a pair of asterisks*

strikethrough text
    ~~text between two pairs of tildes~~

underlined text
    __text between two pairs of underscores__

code
    Text `between backticks` is formatted as code.

        ```
        /* text between lines starting with three backticks is preformatted */
        int main(int argc, char *argv[])
        {
            return 0;
        }
        ```

links
    Standalone URLs are converted to links. Also, from version 2.54, markdown-style links in the form of [link label](url) are also supported.

attached images
    Standalone URLs for which the final extension is recognized as an image (.jpg, .gif, .png, etc), are converted to ActivityPub image attachments. Also, from version 2.57, markdown-style image links in the form of ![alt text](image url) are also supported.

line separators
    Horizonal rules can be inserted by typing three minus symbols alone in a line.

quoted text
    Lines starting with > (blockquotes).

bullet points
    Lines starting with an asterisk or hyphen, plus a space (unsorted lists).

headers
    One, two or three # at the beginning of a line plus a space plus some text are converted to HTML headers.

user mentions
    Strings in the format @user@host are requested using the Webfinger protocol and converted to links and mentions if something reasonable is found.

emoticons /emojis / smileys / silly symbols
    (Note: from version 2.51, these symbols are configurable by the instance administrator, so the available ones may differ).

    The following traditional ASCII emoticons or special strings are converted to related emojis:

        :-) :-D X-D ;-) B-) :-( :-* <3 :-/ 8-o
        %-) :_( :-| >:-( :facepalm: :shrug: :shrug2:
        :eyeroll: :beer: :beers: :munch: :thumb:

  Accepted HTML
All HTML tags in entries are neutered except the following ones:

    a p br blockquote ul ol li cite small h2 h3
    span i b u s pre code em strong hr img del

  Disk Layout
This section documents version 2.7 of the disk storage layout.

The base directory contains the following files and folders:

server.json
    Server configuration.

user/
    Directory holding user subdirectories.

object/
    Directory holding the ActivityPub objects. Filenames are hashes of each message Id, stored in subdirectories starting with the first two letters of the hash.

queue/
    This directory contains the global queue of input/output messages as JSON files. File names contain timestamps that indicate when the message will be sent. Messages not accepted by their respective servers will be re-enqueued for later retransmission until a maximum number of retries is reached, then discarded.

inbox/
    Directory storing collected inbox URLs from other instances.

archive/
    If this directory exists, all input and output messages are logged inside it, including HTTP headers. Only useful for debugging. May grow to enormous sizes.

error/
    If this directory exists, HTTP signature check error headers are logged here. Only useful for debugging.

log/
    If this directory exists, log messages are also stored there in daily files.

app/
    This directory stores Mastodon API apps.

token/
    This directory stores Mastodon API tokens.

style.css
    The server-wide CSS. The content of this file is inserted into the HTML output unless a user-specific one exist in the user's static/ folder.

greeting.html
    This file is served when the server base URL is requested from a web browser. See snac(8) for more information about the customization options.

public.idx
    This file contains the list of public posts from all users in the server.

filter_reject.txt
    This (optional) file contains a list of regular expressions, one per line, to be applied to the content of all incoming posts; if any of them match, the post is rejected. This brings the flexibility and destruction power of regular expressions to your Fediverse experience. To be used wisely (see snac(8) for more information).

announcement.txt
    If this file is present, an announcement will be shown to logged in users on every page with its contents. It is also available through the Mastodon API. Users can dismiss the announcement, which works by storing the modification time in the "last_announcement" field of the user.json file. When the file is modified, the announcement will then reappear. It can contain only text and will be ignored if it has more than 2048 bytes.

Each user directory is a subdirectory of BASEDIR/user/, has the user id as name and contains the following subdirectories and files:

user.json
    User configuration file.

user_o.json
    User configuration override file. This file is intended for administrators to override some user preferences. For current version, the fields that can be overridden are 'purge_days' and 'email'.

key.json
    Secret/public key PEM data.

followers.idx
    This file contains the list of followers as a list of hashed object identifiers.

followers/
    This directory stores hard links to the actor objects in the object storage.

following/
    This directory stores the users being followed as hard links to the 'Follow' or 'Accept' objects in the object storage. File names are the hashes of each actor Id.

private/
    This directory stores hard links to the timeline entries in the object storage.

private.idx
    This file contains the list of timeline entries as a list of hashed object identifiers.

public/
    This directory stores hard links to the public timeline entries in the object storage.

public.idx
    This file contains the list of public timeline entries as a list of hashed object identifiers.

pinned/
    This directory stores hard links to pinned posts.

pinned.idx
    This file contains the list of pinned posts as a list of hashed object identifiers.

bookmark/
    This directory stores hard links to bookmarked posts.

bookmark.idx
    This file contains the list of pinned posts as a list of hashed object identifiers.

draft/
    This directory stores post drafts.

draft.idx
    This file contains the list of drafts as a list of hashed object identifiers.

muted/
    This directory contains files which names are hashes of muted actors. The content is a line containing the actor URL. Messages from these actors will be ignored on input and not shown in any timeline.

hidden/
    This directory contains references to the hidden timeline entries.

limited/
    This directory contains references to the actor URLs for limited users (those being followed but with their boosts blocked).

queue/
    This directory contains the output queue of messages generated by the user as JSON files. File names contain timestamps that indicate when the message will be sent. Messages not accepted by their respective servers will be re-enqueued for later retransmission until a maximum number of retries is reached, then discarded.

static/
    Files in this directory are served as-is when requested from the https://HOST/USER/s/... URL path. A special file named style.css can contain user-specific CSS code to be inserted into the HTML of the web interface.

history/
    This directory contains generated HTML files. They may be snapshots of the local timeline in previous months or other cached data.

export/
    This directory will contain exported data in Mastodon-compatible CSV format after executing the 'export_csv' command-line operation.

import/
    Mastodon-compatible CSV files must be copied into this directory to use any of the importing functions.

server.pid
    This file stores the server PID in a single text line.

SEE ALSO
snac(1), snac(8)

AUTHORS
grunfink @grunfink@comam.es: https://comam.es/snac/grunfink

LICENSE
See the LICENSE file for details.