WKWebView - modern webview for Pythonista

wkwebview.py

#coding: utf-8
'''
WKWebView - modern webview for Pythonista
modified version of https://github.com/mikaelho/pythonista-webview
updated for pythonista 3.4 compatibility
'''

__version__ = '1.1'

from objc_util import  *
import ui, console, webbrowser
import queue, weakref, ctypes, functools, time, os, json, re
from types import SimpleNamespace


# Helpers for invoking ObjC function blocks with no return value

class _block_descriptor (Structure):
    _fields_ = [
        ('reserved', c_ulong),
        ('size', c_ulong),
        ('copy_helper', c_void_p),
        ('dispose_helper', c_void_p),
        ('signature', c_char_p)
    ]

def _block_literal_fields(*arg_types):
    return [
        ('isa', c_void_p),
        ('flags', c_int),
        ('reserved', c_int),
        ('invoke', ctypes.CFUNCTYPE(c_void_p, c_void_p, *arg_types)),
        ('descriptor', _block_descriptor)
    ]


class WKWebView(ui.View):

    # Data detector constants
    NONE = 0
    PHONE_NUMBER = 1
    LINK = 1 << 1
    ADDRESS = 1 << 2
    CALENDAR_EVENT = 1 << 3
    TRACKING_NUMBER = 1 << 4
    FLIGHT_NUMBER = 1 << 5
    LOOKUP_SUGGESTION = 1 << 6
    ALL = 18446744073709551615 # NSUIntegerMax

    # Global webview index for console
    webviews = []
    console_view = UIApplication.sharedApplication().\
        keyWindow().rootViewController().\
        accessoryViewController().\
        consoleViewController()

    def __init__(self,
            swipe_navigation=False,
            data_detectors=NONE,
            log_js_evals=False,
            respect_safe_areas=False,
            inline_media=None,
            airplay_media=True,
            pip_media=True,
            **kwargs):

        dummy = self.dummy_webview()
        del dummy

        WKWebView.webviews.append(self)
        self.delegate = None
        self.log_js_evals = log_js_evals
        self.respect_safe_areas = respect_safe_areas
        super().__init__(**kwargs)

        self.eval_js_queue = queue.Queue()

        custom_message_handler = WKWebView.CustomMessageHandler.\
            new().autorelease()
        retain_global(custom_message_handler)
        custom_message_handler._pythonistawebview = weakref.ref(self)

        user_content_controller = WKWebView.WKUserContentController.\
            new().autorelease()
        self.user_content_controller = user_content_controller
        for key in dir(self):
            if key.startswith('on_'):
                message_name = key[3:]
                user_content_controller.addScriptMessageHandler_name_(
                    custom_message_handler, message_name)

        self.add_script(WKWebView.js_logging_script)

        webview_config = WKWebView.WKWebViewConfiguration.new().autorelease()
        webview_config.userContentController = user_content_controller

        data_detectors = sum(data_detectors) if type(data_detectors) is tuple \
            else data_detectors
        webview_config.setDataDetectorTypes_(data_detectors)

        # Must be set to True to get real js
        # errors, in combination with setting a
        # base directory in the case of load_html
        webview_config.preferences().setValue_forKey_(True,
            'allowFileAccessFromFileURLs')

        if inline_media is not None:
            webview_config.allowsInlineMediaPlayback = inline_media
        webview_config.allowsAirPlayForMediaPlayback = airplay_media
        webview_config.allowsPictureInPictureMediaPlayback = pip_media

        nav_delegate = WKWebView.CustomNavigationDelegate.new()
        retain_global(nav_delegate)
        nav_delegate._pythonistawebview = weakref.ref(self)

        ui_delegate = WKWebView.CustomUIDelegate.new()
        retain_global(ui_delegate)
        ui_delegate._pythonistawebview = weakref.ref(self)

        self._create_webview(webview_config, nav_delegate, ui_delegate)

        self.swipe_navigation = swipe_navigation

    @on_main_thread
    def _create_webview(self, webview_config, nav_delegate, ui_delegate):
        self.webview = WKWebView.WKWebView.alloc().\
            initWithFrame_configuration_(
            ((0,0), (self.width, self.height)), webview_config).autorelease()
        self.webview.autoresizingMask = 2 + 16 # WH
        self.webview.setNavigationDelegate_(nav_delegate)
        self.webview.setUIDelegate_(ui_delegate)
        self.objc_instance.addSubview_(self.webview)

    @on_main_thread
    def dummy_webview(self):
        dummy1 = WKWebView.WKWebView.alloc().initWithFrame_(((0,0), (100, 100))).autorelease()

    def layout(self):
        if self.respect_safe_areas:
            self.update_safe_area_insets()

    @on_main_thread
    def load_url(self, url, no_cache=False, timeout=10):
        """ Loads the contents of the given url
        asynchronously.

        If the url starts with `file://`, loads a local file. If the remaining
        url starts with `/`, path starts from Pythonista root.

        For remote (non-file) requests, there are
        two additional options:

          * Set `no_cache` to `True` to skip the local cache, default is `False`
          * Set `timeout` to a specific timeout value, default is 10 (seconds)
        """
        if url.startswith('file://'):
            file_path = url[7:]
            if file_path.startswith('/'):
                root = os.path.expanduser('~')
                file_path = root + file_path
            else:
                current_working_directory = os.path.dirname(os.getcwd())
                file_path = current_working_directory+'/' + file_path
            dir_only = os.path.dirname(file_path)
            file_path = NSURL.fileURLWithPath_(file_path)
            dir_only = NSURL.fileURLWithPath_(dir_only)
            self.webview.loadFileURL_allowingReadAccessToURL_(
                file_path, dir_only)
        else:
            cache_policy = 1 if no_cache else 0
            self.webview.loadRequest_(
                WKWebView.NSURLRequest.
                    requestWithURL_cachePolicy_timeoutInterval_(
                        nsurl(url),
                        cache_policy,
                        timeout))

    @on_main_thread
    def load_html(self, html):
        # Need to set a base directory to get
        # real js errors
        current_working_directory = os.path.dirname(os.getcwd())
        root_dir = NSURL.fileURLWithPath_(current_working_directory)
        self.webview.loadHTMLString_baseURL_(html, root_dir)

    def eval_js(self, js):
        self.eval_js_async(js, self._eval_js_sync_callback)
        value = self.eval_js_queue.get()
        return value

    evaluate_javascript = eval_js

    #@on_main_thread
    def _eval_js_sync_callback(self, value):
        self.eval_js_queue.put(value)

    #@on_main_thread
    def eval_js_async(self, js, callback=None):
        if self.log_js_evals:
            self.console.message({'level': 'code', 'content': js})
        handler = functools.partial(
            WKWebView._handle_completion, callback, self)
        block = ObjCBlock(
            handler, restype=None, argtypes=[c_void_p, c_void_p, c_void_p])
        retain_global(block)
        self.webview.evaluateJavaScript_completionHandler_(js, block)

    @ui.in_background
    def clear_cache(self, completion_handler=None):
        store = WKWebView.WKWebsiteDataStore.defaultDataStore()
        data_types = WKWebView.WKWebsiteDataStore.allWebsiteDataTypes()
        from_start = WKWebView.NSDate.dateWithTimeIntervalSince1970_(0)
        def dummy_completion_handler():
            pass
        store.removeDataOfTypes_modifiedSince_completionHandler_(
            data_types, from_start,
            completion_handler or dummy_completion_handler)

    # Javascript evaluation completion handler

    def _handle_completion(callback, webview, _cmd, _obj, _err):
        result = str(ObjCInstance(_obj)) if _obj else None
        if webview.log_js_evals:
            webview._message({'level': 'raw', 'content': str(result)})
        if callback:
            callback(result)

    def add_script(self, js_script, add_to_end=True):
        location = 1 if add_to_end else 0
        wk_script = WKWebView.WKUserScript.alloc().\
            initWithSource_injectionTime_forMainFrameOnly_(
                js_script, location, False)
        self.user_content_controller.addUserScript_(wk_script)

    def add_style(self, css):
        """
        Convenience method to add a style tag with the given css, to every
        page loaded by the view.
        """
        css = css.replace("'", "\'")
        js = f"var style = document.createElement('style');"
        "style.innerHTML = '{css}';"
        "document.getElementsByTagName('head')[0].appendChild(style);"
        self.add_script(js, add_to_end=True)

    def add_meta(self, name, content):
        """
        Convenience method to add a meta tag with the given name and content,
        to every page loaded by the view."
        """
        name = name.replace("'", "\'")
        content = content.replace("'", "\'")
        js = f"var meta = document.createElement('meta');"
        "meta.setAttribute('name', '{name}');"
        "meta.setAttribute('content', '{content}');"
        "document.getElementsByTagName('head')[0].appendChild(meta);"
        self.add_script(js, add_to_end=True)

    def disable_zoom(self):
        name = 'viewport'
        content = 'width=device-width, initial-scale=1.0,'
        'maximum-scale=1.0, user-scalable=no'
        self.add_meta(name, content)

    def disable_user_selection(self):
        css = '* { -webkit-user-select: none; }'
        self.add_style(css)

    def disable_font_resizing(self):
        css = 'body { -webkit-text-size-adjust: none; }'
        self.add_style(css)

    def disable_scrolling(self):
        """
        Included for consistency with the other `disable_x` methods, this is
        equivalent to setting `scroll_enabled` to false."
        """
        self.scroll_enabled = False

    def disable_all(self):
        """
        Convenience method that calls all the `disable_x` methods to make the
        loaded pages act more like an app."
        """
        self.disable_zoom()
        self.disable_scrolling()
        self.disable_user_selection()
        self.disable_font_resizing()

    @property
    def user_agent(self):
        "Must be called outside main thread"
        return self.eval_js('navigator.userAgent')

    @on_main_thread
    def _get_user_agent2(self):
        return str(self.webview.customUserAgent())

    @user_agent.setter
    def user_agent(self, value):
        value = str(value)
        self._set_user_agent(value)

    @on_main_thread
    def _set_user_agent(self, value):
        self.webview.setCustomUserAgent_(value)

    @on_main_thread
    def go_back(self):
        self.webview.goBack()

    @on_main_thread
    def go_forward(self):
        self.webview.goForward()

    @on_main_thread
    def reload(self):
        self.webview.reload()

    @on_main_thread
    def stop(self):
        self.webview.stopLoading()

    @property
    def scales_page_to_fit(self):
        raise NotImplementedError(
            'Not supported on iOS. Use the "disable_" methods instead.')

    @scales_page_to_fit.setter
    def scales_page_to_fit(self, value):
        raise NotImplementedError(
            'Not supported on iOS. Use the "disable_" methods instead.')

    @property
    def swipe_navigation(self):
        return self.webview.allowsBackForwardNavigationGestures()

    @swipe_navigation.setter
    def swipe_navigation(self, value):
        self.webview.setAllowsBackForwardNavigationGestures_(value == True)

    @property
    def scroll_enabled(self):
        """
        Controls whether scrolling is enabled.
        Disabling scrolling is applicable for pages that need to look like an
        app.
        """
        return self.webview.scrollView().scrollEnabled()

    @scroll_enabled.setter
    def scroll_enabled(self, value):
        self.webview.scrollView().setScrollEnabled_(value == True)

    def update_safe_area_insets(self):
        insets = self.objc_instance.safeAreaInsets()
        self.frame = self.frame.inset(
            insets.top, insets.left, insets.bottom, insets.right)

    def _javascript_alert(self, host, message):
        console.alert(host, message, 'OK', hide_cancel_button=True)

    def _javascript_confirm(self, host, message):
        try:
            console.alert(host, message, 'OK')
            return True
        except KeyboardInterrupt:
            return False

    def _javascript_prompt(self, host, prompt, default_text):
        try:
            return console.input_alert(host, prompt, default_text, 'OK')
        except KeyboardInterrupt:
            return None

    js_logging_script = '''console = new Object();
    console.info = function(message) { 
     window.webkit.messageHandlers.javascript_console_message.postMessage(
      JSON.stringify({ level: "info", content: message})
     ); return false; };
    console.log = function(message) { 
     window.webkit.messageHandlers.javascript_console_message.postMessage(
      JSON.stringify({ level: "log", content: message})
     ); return false; };
    console.warn = function(message) { 
     window.webkit.messageHandlers.javascript_console_message.postMessage(
      JSON.stringify({ level: "warn", content: message})
     ); return false; };
    console.error = function(message) {
     window.webkit.messageHandlers.javascript_console_message.postMessage(
      JSON.stringify({ level: "error", content: message})
     ); return false; };
    window.onerror = (function(error, url, line, col, errorobj) {
     console.error(
      "" + error + " (" + url + ", line: " + line + ", column: " + col + ")"
     );
    });'''

    def on_javascript_console_message(self, message):
        log_message = json.loads(message)
        #self.console.message(log_message)
        self._message(log_message)

    def _message(self, message):
        level, content = message['level'], message['content']
        if level == 'code':
            print('>>> ' + content)
        elif level == 'raw':
            print(content)
        else:
            print(level.upper() + ': ' + content)

    class Theme:

        @classmethod
        def get_theme(cls):
            theme_dict = json.loads(cls.clean_json(cls.get_theme_data()))
            theme = SimpleNamespace(**theme_dict)
            theme.dict = theme_dict
            return theme

        @classmethod
        def get_theme_data(cls):
            # Name of current theme
            defaults = ObjCClass("NSUserDefaults").standardUserDefaults()
            name = str(defaults.objectForKey_("ThemeName"))
            # Theme is user-created
            if name.startswith("User:"):
                home = os.getenv("CFFIXED_USER_HOME")
                user_themes_path = os.path.join(home,
                    "Library/Application Support/Themes")
                theme_path = os.path.join(user_themes_path, name[5:] + ".json")
            # Theme is built-in
            else:
                res_path = str(ObjCClass("NSBundle").mainBundle().
                    resourcePath())
                theme_path = os.path.join(res_path, "Themes2/%s.json" % name)
            # Read theme file
            with open(theme_path, "r") as f:
                data = f.read()
            # Return contents
            return data

        @classmethod
        def clean_json(cls, string):
            # From http://stackoverflow.com/questions/23705304
            string = re.sub(",[ \t\r\n]+}", "}", string)
            string = re.sub(",[ \t\r\n]+\]", "]", string)
            return string

    @classmethod
    def console(self, webview_index=0):
        webview = WKWebView.webviews[webview_index]
        theme = WKWebView.Theme.get_theme()

        print('Welcome to WKWebView console.')
        print('Evaluate javascript in any active WKWebView.')
        print('Special commands: list, switch #, load <url>, quit')
        console.set_color(*ui.parse_color(theme.tint)[:3])
        while True:
            value = input('js> ').strip()
            self.console_view.history().insertObject_atIndex_(ns(value+'\n'),0)
            if value == 'quit':
                break
            if value == 'list':
                for i in range(len(WKWebView.webviews)):
                    wv = WKWebView.webviews[i]
                    print(i, '-', wv.name, '-', wv.eval_js('document.title'))
            elif value.startswith('switch '):
                i = int(value[len('switch '):])
                webview = WKWebView.webviews[i]
            elif value.startswith('load '):
                url = value[len('load '):]
                webview.load_url(url)
            else:
                print(webview.eval_js(value))
        console.set_color(*ui.parse_color(theme.default_text)[:3])


    # MAIN OBJC SECTION

    WKWebView = ObjCClass('WKWebView')
    UIViewController = ObjCClass('UIViewController')
    WKWebViewConfiguration = ObjCClass('WKWebViewConfiguration')
    WKUserContentController = ObjCClass('WKUserContentController')
    NSURLRequest = ObjCClass('NSURLRequest')
    WKUserScript = ObjCClass('WKUserScript')
    WKWebsiteDataStore = ObjCClass('WKWebsiteDataStore')
    NSDate = ObjCClass('NSDate')

    # Navigation delegate

    class _block_decision_handler(Structure):
        _fields_ = _block_literal_fields(ctypes.c_long)

    def webView_decidePolicyForNavigationAction_decisionHandler_(
            _self, _cmd, _webview, _navigation_action, _decision_handler):
        delegate_instance = ObjCInstance(_self)
        webview = delegate_instance._pythonistawebview()
        deleg = webview.delegate
        nav_action = ObjCInstance(_navigation_action)
        ns_url = nav_action.request().URL()
        url = str(ns_url)
        nav_type = int(nav_action.navigationType())

        allow = True
        if deleg is not None:
            if hasattr(deleg, 'webview_should_start_load'):
                allow = deleg.webview_should_start_load(webview, url, nav_type)

        scheme = str(ns_url.scheme())
        if not WKWebView.WKWebView.handlesURLScheme_(scheme):
            allow = False
            webbrowser.open(url)

        allow_or_cancel = 1 if allow else 0
        decision_handler = ObjCInstance(_decision_handler)
        retain_global(decision_handler)
        blk = WKWebView._block_decision_handler.from_address(_decision_handler)
        blk.invoke(_decision_handler, allow_or_cancel)

    f = webView_decidePolicyForNavigationAction_decisionHandler_
    f.argtypes = [c_void_p]*3
    f.restype = None
    f.encoding = b'v@:@@@?'
    # https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html

    def webView_didCommitNavigation_(_self, _cmd, _webview, _navigation):
        delegate_instance = ObjCInstance(_self)
        webview = delegate_instance._pythonistawebview()
        deleg = webview.delegate
        if deleg is not None:
            if hasattr(deleg, 'webview_did_start_load'):
                deleg.webview_did_start_load(webview)

    def webView_didFinishNavigation_(_self, _cmd, _webview, _navigation):
        delegate_instance = ObjCInstance(_self)
        webview = delegate_instance._pythonistawebview()
        deleg = webview.delegate
        if deleg is not None:
            if hasattr(deleg, 'webview_did_finish_load'):
                deleg.webview_did_finish_load(webview)

    def webView_didFailNavigation_withError_(
            _self, _cmd, _webview, _navigation, _error):

        delegate_instance = ObjCInstance(_self)
        webview = delegate_instance._pythonistawebview()
        deleg = webview.delegate
        err = ObjCInstance(_error)
        error_code = int(err.code())
        error_msg = str(err.localizedDescription())
        if deleg is not None:
            if hasattr(deleg, 'webview_did_fail_load'):
                deleg.webview_did_fail_load(webview, error_code, error_msg)
                return
        raise RuntimeError(
            f'WKWebView load failed with code {error_code}: {error_msg}')

    def webView_didFailProvisionalNavigation_withError_(
            _self, _cmd, _webview, _navigation, _error):
        WKWebView.webView_didFailNavigation_withError_(
            _self, _cmd, _webview, _navigation, _error)

    CustomNavigationDelegate = create_objc_class(
        'CustomNavigationDelegate', superclass=NSObject, methods=[
            webView_didCommitNavigation_,
            webView_didFinishNavigation_,
            webView_didFailNavigation_withError_,
            webView_didFailProvisionalNavigation_withError_,
            webView_decidePolicyForNavigationAction_decisionHandler_
        ],
        protocols=['WKNavigationDelegate'])

    # Script message handler

    def userContentController_didReceiveScriptMessage_(
            _self, _cmd, _userContentController, _message):
        controller_instance = ObjCInstance(_self)
        webview = controller_instance._pythonistawebview()
        wk_message = ObjCInstance(_message)
        name = str(wk_message.name())
        content = str(wk_message.body())
        handler = getattr(webview, 'on_'+name, None)
        if handler:
            handler(content)
        else:
            raise Exception(
                f'Unhandled message from script - name: {name}, '
                'content: {content}')

    CustomMessageHandler = create_objc_class(
        'CustomMessageHandler', UIViewController, methods=[
            userContentController_didReceiveScriptMessage_
        ], protocols=['WKScriptMessageHandler'])


    # UI delegate (for alerts etc.)

    class _block_alert_completion(Structure):
        _fields_ = _block_literal_fields()

    def webView_runJavaScriptAlertPanelWithMessage_initiatedByFrame_completionHandler_(
            _self, _cmd, _webview, _message, _frame, _completion_handler):
        delegate_instance = ObjCInstance(_self)
        webview = delegate_instance._pythonistawebview()
        message = str(ObjCInstance(_message))
        host = str(ObjCInstance(_frame).request().URL().host())
        webview._javascript_alert(host, message)
        #console.alert(host, message, 'OK', hide_cancel_button=True)
        completion_handler = ObjCInstance(_completion_handler)
        retain_global(completion_handler)
        blk = WKWebView._block_alert_completion.from_address(
            _completion_handler)
        blk.invoke(_completion_handler)

    f = webView_runJavaScriptAlertPanelWithMessage_initiatedByFrame_completionHandler_
    f.argtypes = [c_void_p]*4
    f.restype = None
    f.encoding = b'v@:@@@@?'


    class _block_confirm_completion(Structure):
        _fields_ = _block_literal_fields(ctypes.c_bool)

    def webView_runJavaScriptConfirmPanelWithMessage_initiatedByFrame_completionHandler_(
            _self, _cmd, _webview, _message, _frame, _completion_handler):
        delegate_instance = ObjCInstance(_self)
        webview = delegate_instance._pythonistawebview()
        message = str(ObjCInstance(_message))
        host = str(ObjCInstance(_frame).request().URL().host())
        result = webview._javascript_confirm(host, message)
        completion_handler = ObjCInstance(_completion_handler)
        retain_global(completion_handler)
        blk = WKWebView._block_confirm_completion.from_address(_completion_handler)
        blk.invoke(_completion_handler, result)

    f = webView_runJavaScriptConfirmPanelWithMessage_initiatedByFrame_completionHandler_
    f.argtypes = [c_void_p]*4
    f.restype = None
    f.encoding = b'v@:@@@@?'


    class _block_text_completion(Structure):
        _fields_ = _block_literal_fields(c_void_p)

    def webView_runJavaScriptTextInputPanelWithPrompt_defaultText_initiatedByFrame_completionHandler_(
            _self, _cmd, _webview, _prompt, _default_text, _frame,
            _completion_handler):
        delegate_instance = ObjCInstance(_self)
        webview = delegate_instance._pythonistawebview()
        prompt = str(ObjCInstance(_prompt))
        default_text = str(ObjCInstance(_default_text))
        host = str(ObjCInstance(_frame).request().URL().host())
        result = webview._javascript_prompt(host, prompt, default_text)
        completion_handler = ObjCInstance(_completion_handler)
        retain_global(completion_handler)
        blk = WKWebView._block_text_completion.from_address(
            _completion_handler)
        blk.invoke(_completion_handler, ns(result))

    f = webView_runJavaScriptTextInputPanelWithPrompt_defaultText_initiatedByFrame_completionHandler_
    f.argtypes = [c_void_p]*5
    f.restype = None
    f.encoding = b'v@:@@@@@?'

    CustomUIDelegate = create_objc_class(
        'CustomUIDelegate', superclass=NSObject, methods=[
            webView_runJavaScriptAlertPanelWithMessage_initiatedByFrame_completionHandler_,
            webView_runJavaScriptConfirmPanelWithMessage_initiatedByFrame_completionHandler_,
            webView_runJavaScriptTextInputPanelWithPrompt_defaultText_initiatedByFrame_completionHandler_
        ],
        protocols=['WKUIDelegate'])


if __name__ == '__main__':

    class MyWebViewDelegate:

        def webview_should_start_load(self, webview, url, nav_type):
            """
            See nav_type options at
            https://developer.apple.com/documentation/webkit/wknavigationtype?language=objc
            """
            print('Will start loading', url)
            return True

        def webview_did_start_load(self, webview):
            print('Started loading')

        @ui.in_background
        def webview_did_finish_load(self, webview):
            print('Finished loading ' +
                  str(webview.eval_js('document.title')))


    class MyWebView(WKWebView):

        def on_greeting(self, message):
            console.alert(message, 'Message passed to Python', 'OK',
                hide_cancel_button=True)


    html = '''
  <html>
  <head>
    <title>WKWebView tests</title>
    <script>
      function initialize() {
        //result = prompt('Initialized', 'Yes, indeed');
        //if (result) {
          //window.webkit.messageHandlers.greeting.postMessage(
          //    result ? result : "<Dialog cancelled>");
        //}
      }
    </script>
  </head>
  <body onload="initialize()" style="font-size: xx-large; text-align: center">
    <p>
      Hello world
    </p>
    <p>
      <a href="http://omz-software.com/pythonista/">Pythonista home page</a>
    </p>
    <p>
      +358 40 1234567
    </p>
    <p>
      http://omz-software.com/pythonista/
    </p>
  </body>
  '''

    r = ui.View(background_color='black')

    v = MyWebView(
        name='DemoWKWebView',
        delegate=MyWebViewDelegate(),
        swipe_navigation=True,
        data_detectors=(WKWebView.PHONE_NUMBER,WKWebView.LINK),
        frame=r.bounds, flex='WH')
    r.add_subview(v)

    r.present() # Use 'panel' if you want to view console in another tab

    #v.disable_all()
    #v.load_html(html)
    v.load_url('http://omz-software.com/pythonista/',
        no_cache=False, timeout=5)
    #v.load_url('file://some/local/file.html')
    #v.clear_cache()