Publish (Instance)

{{#images:versionlatest-32x32.png|stock}} <source lang='delphi'>procedure Publish(const iTopic:string; const iParam:variant);</source>

Cette procédure permet d'envoyer un message aux abonnés d'un sujet.

iTopic	Sujet du message.
iParam	Paramètre du message.

Exemple :

Utilisation basique :

<source lang='delphi'>

procedure MyObject.Handler(const iTopic:string; const iEvent:Variant); begin

 unEntier := unEntier+1;

end;

function MyObject.doPublishSubscribe(const sTopic:string; const pTopic:string):boolean; begin

 unEntier := 0;
 Subscribe(sTopic,Handler);
 try
   // if pTopic match sTopic the Handler method will be called.
   // This message has no parameter, we can pass anything in the parameter 
   Publish(pTopic,0);
   Result := unEntier=1;
 finally
 UnSubscribe(sTopic);
 end;

end;

</source>

Utilisation d'un paramètre objet :

<source lang='delphi'>

procedure Handler(const iTopic:string; const iEvent:variant); var obj:TitObject; begin

 obj := iEvent;
 if (obj is ClassNPA) then
  unEntier := (obj as ClassNPA).unEntier;

end;

function doPublishSubscribe(const sTopic:string; const pTopic:string):boolean; var event:ClassNPA; begin

 unEntier := 0;
 event := ClassNPA.Create;
 event.unEntier := 1;
 Subscribe(sTopic,Handler);
 try
   Publish(pTopic,event);
   Result := unEntier=1;
 finally
 UnSubscribe(sTopic);
 end;

end;

</source>

Souscription dans une règle d'initialisation :

<source lang='delphi'> unit TestSYFREWF; interface

Type

 PublishSubscribe = Class(TitObject)
 private
   procedure Action_Initialize:boolean;
 public
   Procedure doPublish;
   Procedure Handler(const iTopic:string; const iEvent:variant);
 end;

Implementation

{PublishSubscribe}

procedure PublishSubscribe.Action_Initialize:boolean; //procedure Action_Initialize:boolean; begin

 // We subscribe in an initialization rule.
 SubScribe('/MyTopic/*','Handler');

end;

Procedure PublishSubscribe.Handler(const iTopic:string; const iEvent:variant); //Procedure Handler(const iTopic:string; const iEvent:variant); var url:string; begin

 // This handler is a router which republish a message to the UI

 // Build a first message with the current datetime.
 // The value is passed inside the topic which is formatted as an URL.
 url := 'forms://testpublishsubscribe/controls/memo';
 urlConcatParameter(url,'text', FormatDatetime('c',now));
 Publish(url,0);
 
 // Republish the message
 // The value is passed in the parameter
 Publish('forms://testpublishsubscribe/controls/memo/text',iEvent);

end;

Procedure PublishSubscribe.doPublish; //Procedure doPublish; begin

 // Test case
 // Publish a message to my topic so that the handler will republish it 
 Publish('/MyTopic/subject', 'some text');

end;

</source>

Voir aussi :

• Subscribe

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