fpc-msgbase

A unified Free Pascal library for reading and writing classic BBS message bases.

Implements every supported format from the FTSC specifications and the original format authors' published documentation, behind one polymorphic API (TMessageBase). BBS software, mail tossers, message editors, and utilities can target a single interface regardless of the underlying format on disk.

Supported formats

Format	Files	Backend unit
Hudson	MSGINFO/IDX/HDR/TXT/TOIDX.BBS	mb.fmt.hudson.pas
JAM	*.JHR *.JDT *.JDX *.JLR	mb.fmt.jam.pas
Squish	*.SQD *.SQI *.SQL	mb.fmt.squish.pas
FTS-1 MSG	numbered *.MSG per directory	mb.fmt.msg.pas
PCBoard	*.MSG + *.IDX	mb.fmt.pcboard.pas
EzyCom	MH#####.BBS / MT#####.BBS	mb.fmt.ezycom.pas
GoldBase	MSGINFO/IDX/HDR/TXT/TOIDX.DAT	mb.fmt.goldbase.pas
Wildcat 4	WC SDK databases	mb.fmt.wildcat.pas

FTN PKT is a transport-tier wire format and lives in the sibling fpc-ftn-transport library (units tt.pkt.reader, tt.pkt.writer, tt.pkt.format, tt.pkt.batch). The mbfPkt factory enum stays in fpc-msgbase so consumers wanting to iterate .pkt files via the unified API (MessageBaseOpen(mbfPkt, ...)) just add uses tt.pkt.reader alongside fpc-msgbase. PKT was here through 0.3.x; moved out in 0.4.0 because PKT is a wire format, not a storage format.

Features

• One TMessageBase abstract class — read, write, pack, reindex through the same methods regardless of format.
• Lossless two-area message model. TUniMessage = Body (just the message text) + Attributes (key/value bag holding from/to/subject/dates/ addresses/MSGID/SEEN-BY/PATH and per-format extras). Same shape as RFC 822 email. Round-trip preservation enforced by the test suite.
• Capabilities API — base.SupportsAttribute('attr.returnreceipt') lets UIs hide controls the underlying backend has no slot for. Each backend publishes its key list via ClassSupportedAttributes. Full per-format matrix in docs/attributes-registry.md.
• Per-user High-Water Mark — base.GetHWM('NetReader') / base.SetHWM(...) plus auto-bump via base.ActiveUser. Native for JAM (.JLR), Squish (.SQL), Hudson + GoldBase (LASTREAD.BBS/DAT, with MapUser + Board context). Tossers and scanners register as named users in the format's native lastread file, so multiple consumers coexist without colliding. Unsupported formats return -1 honestly.
• Layered locking: in-process TRTLCriticalSection + cross-process advisory lock (fpflock on Unix, LockFileEx on Windows, .LCK sentinel fallback)
  • the existing fmShareDenyWrite / fmShareDenyNone share modes.
• Event hooks for logging, progress, and status reporting.
• Path / filename auto-derivation per format from a base directory plus optional area tag (area attribute auto-populated on Read).
• Shared FTSC kludge plumbing in mb.kludge — single source of truth for kludge-line parse/emit (ParseKludgeLine, SplitKludgeBlob, BuildKludgePrefix/Suffix). Unknown FTSC kludges round-trip uniformly as kludge.<lowername> regardless of which backend stored them, so consumers don't switch on format to find passthrough kludges.

Building

Use both the native and .uni adapter units in your uses clause — the .uni adapter's initialization block is what registers the backend with the unified-API factory. Forgetting it produces EMessageBase: No backend registered for <format>.

uses
  mb.types, mb.events, mb.api,
  mb.fmt.jam, mb.fmt.jam.uni;     { both — .uni registers }

Native Linux:

fpc -Fusrc -Fusrc/formats examples/example_read.pas

Lazarus package:

lazbuild fpc-msgbase.lpk

The repo includes a fpc.cfg template covering the multi-target build (i386-go32v2, i386-win32, i386-linux, i386-os2).

Layout

src/                mb.api, mb.types, mb.events, mb.lock, mb.paths, mb.kludge
src/formats/        mb.fmt.<format>.pas — one per supported format
docs/               architecture, locking semantics, format notes
tests/              FPCUnit tests, sample data
examples/           small CLI programs that double as smoke tests

Units are named mb.<category>.<name>.pas. All units use {$mode objfpc}{$H+}.

Documentation

• docs/API.md — full API reference with examples
• docs/architecture.md — layered design + Body/Attributes contract
• docs/attributes-registry.md — canonical attribute keys + per-format support matrix
• docs/ftsc-compliance.md — spec notes
• docs/format-notes/ — per-format quirks

Status

Early development. APIs may move until 1.0.

Current: 0.6.3 — see CHANGELOG.md for the full release history. Downstream consumers should pin by tag (v0.6.3), not commit hash.

0.2 is a breaking change vs 0.1. TUniMessage lost its 13 named fields (WhoFrom/WhoTo/Subject/MsgNum/Attr/etc.) in favour of a strict Body + Attributes two-area model. Migration:

{ before }                       { after }
msg.WhoFrom                       msg.Attributes.Get('from')
msg.Subject := 'foo';             msg.Attributes.SetValue('subject', 'foo');
msg.Attr := MSG_ATTR_LOCAL;       msg.Attributes.SetBool('attr.local', true);
msg.OrigAddr                      msg.Attributes.GetAddr('addr.orig')
msg.DateWritten                   msg.Attributes.GetDate('date.written')

This change makes the unified API lossless — kludges (MSGID, SEEN-BY, PATH, etc.) round-trip cleanly, where 0.1 silently dropped them. See docs/attributes-registry.md for the full key catalog.

Format backends are spec-driven implementations validated against real-world sample bases.