kenjreno
128ddcb4df
Verbatim port of Fastway-Server's TFWEventBus from fw_plugin_host.pas
per feedback_copy_dont_reinterpret.md. Adjustments limited to:
- Type renames (TFW* -> T*).
- uses clause: drop fw_log; add log.types from fpc-log so the
optional Logger property uses the canonical ecosystem-wide
TLogProc shape, matching every other fpc-* library.
- Per-handler exception logging now calls Logger with
Level=llError, Category='events', and includes the source
plugin (ASourcePlugin parameter) in the message text so the
canonical signature stays meaningful.
Behaviours preserved verbatim: APluginName bulk-Unsubscribe key,
wildcard '*' subscriber, OnBroadcast external-listener tap,
snapshot-iterate-outside-lock pattern, per-handler exception
isolation, TCriticalSection.
docs/DEVELOPER_GUIDE.md added covering threading, payload
ownership, recursive Fire, OnBroadcast, logger plumbing, and
the relationship between fpc-events (ecosystem-wide pub/sub)
and per-library typed observer callbacks (bp.events / cm.events
pattern).
Tests: 44 assertions across 14 scenarios pass on x86_64-linux.
Pre-tag -vh audit on src/ev.bus.pas reports zero hints/warnings.
75 lines
1.6 KiB
ObjectPascal
75 lines
1.6 KiB
ObjectPascal
{ pubsub -- minimal "subscribe in one place, fire in another" demo.
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Build:
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bash build.sh
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/opt/fpcup/fpc/bin/x86_64-linux/fpc -O2 -Sh \
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-Fusrc -FUbuild -FEbuild -obuild/pubsub examples/pubsub.pas
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Run:
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./build/pubsub }
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program pubsub;
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{$mode objfpc}{$H+}
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uses
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{$IFDEF UNIX}cthreads,{$ENDIF}
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Classes, SysUtils, fpjson, events.bus;
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type
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TListener = class
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public
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procedure HandleLogin(const AEventType: string; AData: TJSONObject);
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procedure HandleAny(const AEventType: string; AData: TJSONObject);
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end;
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procedure TListener.HandleLogin(const AEventType: string; AData: TJSONObject);
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begin
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Writeln('login listener: user=', AData.Get('username', '?'));
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end;
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procedure TListener.HandleAny(const AEventType: string; AData: TJSONObject);
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begin
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Writeln('audit log: type=', AEventType);
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end;
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var
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Bus: TEventBus;
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L: TListener;
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Data: TJSONObject;
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begin
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Bus := TEventBus.Create;
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L := TListener.Create;
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try
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{ Subscribe to a specific event. }
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Bus.Subscribe('demo', 'user.login', @L.HandleLogin);
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{ Subscribe to every event. }
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Bus.Subscribe('audit', '*', @L.HandleAny);
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Data := TJSONObject.Create;
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try
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Data.Add('username', 'alice');
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Bus.Fire('auth', 'user.login', Data);
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finally
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Data.Free;
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end;
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Data := TJSONObject.Create;
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try
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Data.Add('node', 1);
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Bus.Fire('telnet', 'session.start', Data);
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finally
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Data.Free;
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end;
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{ Bulk Unsubscribe by group key. }
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Bus.Unsubscribe('audit');
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Writeln('after Unsubscribe(audit), count=', Bus.GetSubscriptionCount);
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finally
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L.Free;
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Bus.Free;
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end;
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end.
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