Explicit XFA Host Transport

Unit: HPDFXFARuntime

Declaration

Options := TXFAWidgetRuntimeOptions.Default;
Options.ScriptOptions.EnableJavaScript := True;
Options.HostTransport := ApplicationHost.Transport;
Options.OnHostTransactionCompleted := ApplicationHost.Completed;

Behaviour

Configure explicit application callbacks to run xfa.host.messageBox, response, beep, print, gotoURL, submitForm, importData and exportData, and FormCalc Get, Post and Put

The library itself invokes no dialog, reader, network request or file transfer automatically; the callback implements the application transport and returns a typed response

Each dispatched request runs once within an enclosing runtime transaction; QuickJS suspension retries and committed-session replay consume recorded responses without repeating callbacks

Requests preserve positional arguments as Unicode strings, including empty arguments; request numbering starts at zero for each transaction

Failed transactions restore document and script-object state and notify the completion callback with Committed=False; the application must stage or compensate its external effects because document rollback cannot undo an external operation

Completion callbacks run once after successful document validation and layout or after rollback, before normal success observers; callbacks must not raise exceptions or re-enter the runtime

Host callbacks require the shipped QuickJS session; custom JavaScriptEvaluator callbacks do not provide the checkpoint and replay contract

Request count, argument count, encoded request bytes and response bytes have independent positive limits; callback elapsed time counts against the transaction deadline, but synchronous application code cannot be forcibly interrupted

Script functions receive number, Boolean, string, null or undefined according to the response Kind; numeric responses must be finite and Unicode responses must contain valid surrogate pairs

Explicit XFA Host Transport

Declaration

Behaviour

Related APIs