Method handleExecuteRequest

kernel.go:435–537

handleExecuteRequest runs code from an execute_request method, and sends the various reply messages.

(receipt msgReceipt)

// handleExecuteRequest runs code from an execute_request method,
// and sends the various reply messages.
func (kernel *Kernel) handleExecuteRequest(receipt msgReceipt) error {

	// Extract the data from the request.
	reqcontent := receipt.Msg.Content.(map[string]interface{})
	code := reqcontent["code"].(string)
	silent := reqcontent["silent"].(bool)

	if !silent {
		ExecCounter++
	}

	// Prepare the map that will hold the reply content.
	content := make(map[string]interface{})
	content["execution_count"] = ExecCounter

	// Tell the front-end what the kernel is about to execute.
	if err := receipt.PublishExecutionInput(ExecCounter, code); err != nil {
		log.Printf("Error publishing execution input: %v\n", err)
	}

	// Redirect the standard out from the REPL.
	oldStdout := os.Stdout
	rOut, wOut, err := os.Pipe()
	if err != nil {
		return err
	}
	os.Stdout = wOut

	// Redirect the standard error from the REPL.
	oldStderr := os.Stderr
	rErr, wErr, err := os.Pipe()
	if err != nil {
		return err
	}
	os.Stderr = wErr

	var writersWG sync.WaitGroup
	writersWG.Add(2)

	jupyterStdOut := JupyterStreamWriter{StreamStdout, &receipt}
	jupyterStdErr := JupyterStreamWriter{StreamStderr, &receipt}
	outerr := OutErr{&jupyterStdOut, &jupyterStdErr}

	// Forward all data written to stdout/stderr to the front-end.
	go func() {
		defer writersWG.Done()
		io.Copy(&jupyterStdOut, rOut)
	}()

	go func() {
		defer writersWG.Done()
		io.Copy(&jupyterStdErr, rErr)
	}()

	// inject the actual "Display" closure that displays multimedia data in Jupyter
	ir := kernel.ir
	displayPlace := ir.ValueOf("Display")
	displayPlace.Set(xreflect.ValueOf(receipt.PublishDisplayData))