Resolve "add VT100 console executing BEC as a widget"

bec_widgets/widgets/console/console.py

@@ -0,0 +1,496 @@
+"""
+BECConsole is a Qt widget that runs a Bash shell. The widget can be used and
+embedded like any other Qt widget.
+
+BECConsole is powered by Pyte, a Python based terminal emulator
+(https://github.com/selectel/pyte).
+"""
+
+import fcntl
+import html
+import os
+import pty
+import subprocess
+import sys
+import threading
+
+import pyte
+from qtpy import QtCore, QtGui, QtWidgets
+from qtpy.QtCore import QSize, QSocketNotifier, Qt
+from qtpy.QtCore import Signal as pyqtSignal
+from qtpy.QtCore import Slot as pyqtSlot
+from qtpy.QtGui import QClipboard, QTextCursor
+from qtpy.QtWidgets import QApplication, QHBoxLayout, QScrollBar, QSizePolicy
+
+ansi_colors = {
+    "black": "#000000",
+    "red": "#CD0000",
+    "green": "#00CD00",
+    "brown": "#996633",  # Brown, replacing the yellow
+    "blue": "#0000EE",
+    "magenta": "#CD00CD",
+    "cyan": "#00CDCD",
+    "white": "#E5E5E5",
+    "brightblack": "#7F7F7F",
+    "brightred": "#FF0000",
+    "brightgreen": "#00FF00",
+    "brightyellow": "#FFFF00",
+    "brightblue": "#5C5CFF",
+    "brightmagenta": "#FF00FF",
+    "brightcyan": "#00FFFF",
+    "brightwhite": "#FFFFFF",
+}
+
+control_keys_mapping = {
+    QtCore.Qt.Key_A: b"\x01",  # Ctrl-A
+    QtCore.Qt.Key_B: b"\x02",  # Ctrl-B
+    QtCore.Qt.Key_C: b"\x03",  # Ctrl-C
+    QtCore.Qt.Key_D: b"\x04",  # Ctrl-D
+    QtCore.Qt.Key_E: b"\x05",  # Ctrl-E
+    QtCore.Qt.Key_F: b"\x06",  # Ctrl-F
+    QtCore.Qt.Key_G: b"\x07",  # Ctrl-G (Bell)
+    QtCore.Qt.Key_H: b"\x08",  # Ctrl-H (Backspace)
+    QtCore.Qt.Key_I: b"\x09",  # Ctrl-I (Tab)
+    QtCore.Qt.Key_J: b"\x0A",  # Ctrl-J (Line Feed)
+    QtCore.Qt.Key_K: b"\x0B",  # Ctrl-K (Vertical Tab)
+    QtCore.Qt.Key_L: b"\x0C",  # Ctrl-L (Form Feed)
+    QtCore.Qt.Key_M: b"\x0D",  # Ctrl-M (Carriage Return)
+    QtCore.Qt.Key_N: b"\x0E",  # Ctrl-N
+    QtCore.Qt.Key_O: b"\x0F",  # Ctrl-O
+    QtCore.Qt.Key_P: b"\x10",  # Ctrl-P
+    QtCore.Qt.Key_Q: b"\x11",  # Ctrl-Q
+    QtCore.Qt.Key_R: b"\x12",  # Ctrl-R
+    QtCore.Qt.Key_S: b"\x13",  # Ctrl-S
+    QtCore.Qt.Key_T: b"\x14",  # Ctrl-T
+    QtCore.Qt.Key_U: b"\x15",  # Ctrl-U
+    QtCore.Qt.Key_V: b"\x16",  # Ctrl-V
+    QtCore.Qt.Key_W: b"\x17",  # Ctrl-W
+    QtCore.Qt.Key_X: b"\x18",  # Ctrl-X
+    QtCore.Qt.Key_Y: b"\x19",  # Ctrl-Y
+    QtCore.Qt.Key_Z: b"\x1A",  # Ctrl-Z
+    QtCore.Qt.Key_Escape: b"\x1B",  # Ctrl-Escape
+    QtCore.Qt.Key_Backslash: b"\x1C",  # Ctrl-\
+    QtCore.Qt.Key_Underscore: b"\x1F",  # Ctrl-_
+}
+
+normal_keys_mapping = {
+    QtCore.Qt.Key_Return: b"\n",
+    QtCore.Qt.Key_Space: b" ",
+    QtCore.Qt.Key_Enter: b"\n",
+    QtCore.Qt.Key_Tab: b"\t",
+    QtCore.Qt.Key_Backspace: b"\x08",
+    QtCore.Qt.Key_Home: b"\x47",
+    QtCore.Qt.Key_End: b"\x4f",
+    QtCore.Qt.Key_Left: b"\x02",
+    QtCore.Qt.Key_Up: b"\x10",
+    QtCore.Qt.Key_Right: b"\x06",
+    QtCore.Qt.Key_Down: b"\x0E",
+    QtCore.Qt.Key_PageUp: b"\x49",
+    QtCore.Qt.Key_PageDown: b"\x51",
+    QtCore.Qt.Key_F1: b"\x1b\x31",
+    QtCore.Qt.Key_F2: b"\x1b\x32",
+    QtCore.Qt.Key_F3: b"\x1b\x33",
+    QtCore.Qt.Key_F4: b"\x1b\x34",
+    QtCore.Qt.Key_F5: b"\x1b\x35",
+    QtCore.Qt.Key_F6: b"\x1b\x36",
+    QtCore.Qt.Key_F7: b"\x1b\x37",
+    QtCore.Qt.Key_F8: b"\x1b\x38",
+    QtCore.Qt.Key_F9: b"\x1b\x39",
+    QtCore.Qt.Key_F10: b"\x1b\x30",
+    QtCore.Qt.Key_F11: b"\x45",
+    QtCore.Qt.Key_F12: b"\x46",
+}
+
+
+def QtKeyToAscii(event):
+    """
+    Convert the Qt key event to the corresponding ASCII sequence for
+    the terminal. This works fine for standard alphanumerical characters, but
+    most other characters require terminal specific control sequences.
+
+    The conversion below works for TERM="linux" terminals.
+    """
+    if sys.platform == "darwin":
+        # special case for MacOS
+        # /!\ Qt maps ControlModifier to CMD
+        # CMD-C, CMD-V for copy/paste
+        # CTRL-C and other modifiers -> key mapping
+        if event.modifiers() == QtCore.Qt.MetaModifier:
+            if event.key() == Qt.Key_Backspace:
+                return control_keys_mapping.get(Qt.Key_W)
+            return control_keys_mapping.get(event.key())
+        elif event.modifiers() == QtCore.Qt.ControlModifier:
+            if event.key() == Qt.Key_C:
+                # copy
+                return "copy"
+            elif event.key() == Qt.Key_V:
+                # paste
+                return "paste"
+            return None
+        else:
+            return normal_keys_mapping.get(event.key(), event.text().encode("utf8"))
+    if event.modifiers() == QtCore.Qt.ControlModifier:
+        return control_keys_mapping.get(event.key())
+    else:
+        return normal_keys_mapping.get(event.key(), event.text().encode("utf8"))
+
+
+class Screen(pyte.HistoryScreen):
+    def __init__(self, stdin_fd, numColumns, numLines, historyLength):
+        super().__init__(numColumns, numLines, historyLength, ratio=1 / numLines)
+        self._fd = stdin_fd
+
+    def write_process_input(self, data):
+        """Response to CPR request for example"""
+        os.write(self._fd, data.encode("utf-8"))
+
+
+class Backend(QtCore.QObject):
+    """
+    Poll Bash.
+
+    This class will run as a qsocketnotifier (started in ``_TerminalWidget``) and poll the
+    file descriptor of the Bash terminal.
+    """
+
+    # Signals to communicate with ``_TerminalWidget``.
+    startWork = pyqtSignal()
+    dataReady = pyqtSignal(object)
+
+    def __init__(self, fd, numColumns, numLines):
+        super().__init__()
+
+        # File descriptor that connects to Bash process.
+        self.fd = fd
+
+        # Setup Pyte (hard coded display size for now).
+        self.screen = Screen(self.fd, numColumns, numLines, 10000)
+        self.stream = pyte.ByteStream()
+        self.stream.attach(self.screen)
+
+        self.notifier = QSocketNotifier(fd, QSocketNotifier.Read)
+        self.notifier.activated.connect(self._fd_readable)
+
+    def _fd_readable(self):
+        """
+        Poll the Bash output, run it through Pyte, and notify the main applet.
+        """
+        # Read the shell output until the file descriptor is closed.
+        try:
+            out = os.read(self.fd, 2**16)
+        except OSError:
+            return
+
+        # Feed output into Pyte's state machine and send the new screen
+        # output to the GUI
+        self.stream.feed(out)
+        self.dataReady.emit(self.screen)
+
+
+class BECConsole(QtWidgets.QScrollArea):
+    """Container widget for the terminal text area"""
+
+    def __init__(self, parent=None, numLines=50, numColumns=125):
+        super().__init__(parent)
+
+        self.innerWidget = QtWidgets.QWidget(self)
+        QHBoxLayout(self.innerWidget)
+        self.innerWidget.layout().setContentsMargins(0, 0, 0, 0)
+
+        self.term = _TerminalWidget(self.innerWidget, numLines, numColumns)
+        self.term.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)
+        self.innerWidget.layout().addWidget(self.term)
+
+        self.scroll_bar = QScrollBar(Qt.Vertical, self.term)
+        self.innerWidget.layout().addWidget(self.scroll_bar)
+
+        self.term.set_scroll(self.scroll_bar)
+
+        self.setWidget(self.innerWidget)
+
+    def start(self, cmd=["bec", "--nogui"], deactivate_ctrl_d=True):
+        self.term._cmd = cmd
+        self.term.start(deactivate_ctrl_d=deactivate_ctrl_d)
+
+    def push(self, text):
+        """Push some text to the terminal"""
+        return self.term.push(text)
+
+
+class _TerminalWidget(QtWidgets.QPlainTextEdit):
+    """
+    Start ``Backend`` process and render Pyte output as text.
+    """
+
+    def __init__(self, parent, numColumns, numLines, **kwargs):
+        super().__init__(parent)
+
+        # file descriptor to communicate with the subprocess
+        self.fd = None
+        self.backend = None
+        self.lock = threading.Lock()
+        # command to execute
+        self._cmd = None
+        # should ctrl-d be deactivated ? (prevent Python exit)
+        self._deactivate_ctrl_d = False
+
+        # Specify the terminal size in terms of lines and columns.
+        self.numLines = numLines
+        self.numColumns = numColumns
+        self.output = [""] * numLines
+
+        # Use Monospace fonts and disable line wrapping.
+        self.setFont(QtGui.QFont("Courier", 9))
+        self.setFont(QtGui.QFont("Monospace"))
+        self.setLineWrapMode(QtWidgets.QPlainTextEdit.NoWrap)
+
+        # Disable vertical scrollbar (we use our own, to be set via .set_scroll())
+        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
+
+        fmt = QtGui.QFontMetrics(self.font())
+        self._char_width = fmt.width("w")
+        self._char_height = fmt.height()
+        self.setCursorWidth(self._char_width)
+        # self.setStyleSheet("QPlainTextEdit { color: #ffff00; background-color: #303030; } ");
+
+    def start(self, deactivate_ctrl_d=False):
+        self._deactivate_ctrl_d = deactivate_ctrl_d
+
+        # Start the Bash process
+        self.fd = self.forkShell()
+
+        # Create the ``Backend`` object
+        self.backend = Backend(self.fd, self.numColumns, self.numLines)
+        self.backend.dataReady.connect(self.dataReady)
+
+    def minimumSizeHint(self):
+        width = self._char_width * self.numColumns
+        height = self._char_height * self.numLines
+        return QSize(width, height + 20)
+
+    def set_scroll(self, scroll):
+        self.scroll = scroll
+        self.scroll.setMinimum(0)
+        self.scroll.valueChanged.connect(self.scroll_value_change)
+
+    def scroll_value_change(self, value, old={"value": 0}):
+        if value <= old["value"]:
+            # scroll up
+            # value is number of lines from the start
+            nlines = old["value"] - value
+            # history ratio gives prev_page == 1 line
+            for i in range(nlines):
+                self.backend.screen.prev_page()
+        else:
+            # scroll down
+            nlines = value - old["value"]
+            for i in range(nlines):
+                self.backend.screen.next_page()
+        old["value"] = value
+        self.dataReady(self.backend.screen, reset_scroll=False)
+
+    @pyqtSlot(object)
+    def keyPressEvent(self, event):
+        """
+        Redirect all keystrokes to the terminal process.
+        """
+        # Convert the Qt key to the correct ASCII code.
+        if (
+            self._deactivate_ctrl_d
+            and event.modifiers() == QtCore.Qt.ControlModifier
+            and event.key() == QtCore.Qt.Key_D
+        ):
+            return None
+
+        code = QtKeyToAscii(event)
+        if code == "copy":
+            # MacOS only: CMD-C handling
+            self.copy()
+        elif code == "paste":
+            # MacOS only: CMD-V handling
+            self._push_clipboard()
+        elif code is not None:
+            os.write(self.fd, code)
+
+    def push(self, text):
+        """
+        Write 'text' to terminal
+        """
+        os.write(self.fd, text.encode("utf-8"))
+
+    def contextMenuEvent(self, event):
+        menu = self.createStandardContextMenu()
+        for action in menu.actions():
+            # remove all actions except copy and paste
+            if "opy" in action.text():
+                # redefine text without shortcut
+                # since it probably clashes with control codes (like CTRL-C etc)
+                action.setText("Copy")
+                continue
+            if "aste" in action.text():
+                # redefine text without shortcut
+                action.setText("Paste")
+                # paste -> have to insert with self.push
+                action.triggered.connect(self._push_clipboard)
+                continue
+            menu.removeAction(action)
+        menu.exec_(event.globalPos())
+
+    def _push_clipboard(self):
+        clipboard = QApplication.instance().clipboard()
+        self.push(clipboard.text())
+
+    def mouseReleaseEvent(self, event):
+        if event.button() == Qt.MiddleButton:
+            # push primary selection buffer ("mouse clipboard") to terminal
+            clipboard = QApplication.instance().clipboard()
+            if clipboard.supportsSelection():
+                self.push(clipboard.text(QClipboard.Selection))
+            return None
+        elif event.button() == Qt.LeftButton:
+            # left button click
+            textCursor = self.textCursor()
+            if textCursor.selectedText():
+                # mouse was used to select text -> nothing to do
+                pass
+            else:
+                # a simple 'click', make cursor going to end
+                textCursor.setPosition(0)
+                textCursor.movePosition(
+                    QTextCursor.Down, QTextCursor.MoveAnchor, self.backend.screen.cursor.y
+                )
+                textCursor.movePosition(
+                    QTextCursor.Right, QTextCursor.MoveAnchor, self.backend.screen.cursor.x
+                )
+                self.setTextCursor(textCursor)
+                self.ensureCursorVisible()
+                return None
+        return super().mouseReleaseEvent(event)
+
+    def dataReady(self, screenData, reset_scroll=True):
+        """
+        Render the new screen as text into the widget.
+
+        This method is triggered via a signal from ``Backend``.
+        """
+        with self.lock:
+            # Clear the widget
+            self.clear()
+
+            # Prepare the HTML output
+            for line_no in screenData.dirty:
+                line = text = ""
+                style = old_style = ""
+                for ch in screenData.buffer[line_no].values():
+                    style = f"{'background-color:%s;' % ansi_colors.get(ch.bg, ansi_colors['black']) if ch.bg!='default' else ''}{'color:%s;' % ansi_colors.get(ch.fg, ansi_colors['white']) if ch.fg!='default' else ''}{'font-weight:bold;' if ch.bold else ''}{'font-style:italic;' if ch.italics else ''}"
+                    if style != old_style:
+                        if old_style:
+                            line += f"<span style={repr(old_style)}>{html.escape(text, quote=True)}</span>"
+                        else:
+                            line += html.escape(text, quote=True)
+                        text = ""
+                        old_style = style
+                    text += ch.data
+                if style:
+                    line += f"<span style={repr(style)}>{html.escape(text, quote=True)}</span>"
+                else:
+                    line += html.escape(text, quote=True)
+                self.output[line_no] = line
+            # fill the text area with HTML contents in one go
+            self.appendHtml(f"<pre>{chr(10).join(self.output)}</pre>")
+            # done updates, all clean
+            screenData.dirty.clear()
+
+            # Activate cursor
+            textCursor = self.textCursor()
+            textCursor.setPosition(0)
+            textCursor.movePosition(QTextCursor.Down, QTextCursor.MoveAnchor, screenData.cursor.y)
+            textCursor.movePosition(QTextCursor.Right, QTextCursor.MoveAnchor, screenData.cursor.x)
+            self.setTextCursor(textCursor)
+            self.ensureCursorVisible()
+
+            # manage scroll
+            if reset_scroll:
+                self.scroll.valueChanged.disconnect(self.scroll_value_change)
+                tmp = len(self.backend.screen.history.top) + len(self.backend.screen.history.bottom)
+                self.scroll.setMaximum(tmp if tmp > 0 else 0)
+                self.scroll.setSliderPosition(len(self.backend.screen.history.top))
+                self.scroll.valueChanged.connect(self.scroll_value_change)
+
+    # def resizeEvent(self, event):
+    #    with self.lock:
+    #        self.numColumns = int(self.width() / self._char_width)
+    #        self.numLines = int(self.height() / self._char_height)
+    #        self.output = [""] * self.numLines
+    #        print("RESIZING TO", self.numColumns, "x", self.numLines)
+    #        self.backend.screen.resize(self.numLines, self.numColumns)
+
+    def wheelEvent(self, event):
+        y = event.angleDelta().y()
+        if y > 0:
+            self.backend.screen.prev_page()
+        else:
+            self.backend.screen.next_page()
+        self.dataReady(self.backend.screen, reset_scroll=False)
+
+    def forkShell(self):
+        """
+        Fork the current process and execute bec in shell.
+        """
+        try:
+            pid, fd = pty.fork()
+        except (IOError, OSError):
+            return False
+        if pid == 0:
+            # Safe way to make it work under BSD and Linux
+            try:
+                ls = os.environ["LANG"].split(".")
+            except KeyError:
+                ls = []
+            if len(ls) < 2:
+                ls = ["en_US", "UTF-8"]
+            try:
+                os.putenv("COLUMNS", str(self.numColumns))
+                os.putenv("LINES", str(self.numLines))
+                os.putenv("TERM", "linux")
+                os.putenv("LANG", ls[0] + ".UTF-8")
+                if isinstance(self._cmd, str):
+                    os.execvp(self._cmd, self._cmd)
+                else:
+                    os.execvp(self._cmd[0], self._cmd)
+                # print "child_pid", child_pid, sts
+            except (IOError, OSError):
+                pass
+            # self.proc_finish(sid)
+            os._exit(0)
+        else:
+            # We are in the parent process.
+            # Set file control
+            fcntl.fcntl(fd, fcntl.F_SETFL, os.O_NONBLOCK)
+            print("Spawned Bash shell (PID {})".format(pid))
+            return fd
+
+
+if __name__ == "__main__":
+    import os
+    import sys
+
+    from qtpy import QtGui, QtWidgets
+
+    # Terminal size in characters.
+    numLines = 25
+    numColumns = 100
+
+    # Create the Qt application and QBash instance.
+    app = QtWidgets.QApplication([])
+    mainwin = QtWidgets.QMainWindow()
+    title = "BECConsole ({}x{})".format(numColumns, numLines)
+    mainwin.setWindowTitle(title)
+
+    console = BECConsole(mainwin, numColumns, numLines)
+    mainwin.setCentralWidget(console)
+    console.start()
+
+    # Show widget and launch Qt's event loop.
+    mainwin.show()
+    sys.exit(app.exec_())

pyproject.toml

@@ -22,6 +22,7 @@ dependencies = [
     "pyqtdarktheme~=2.1",
     "qtconsole~=5.5, >=5.5.1",  # needed for jupyter console
     "qtpy~=2.4",
+    "pyte",                     # needed for vt100 console
 ]