Basic web view implementation for the new viewer

src/calibre/gui2/viewer2/web_view.py

@@ -0,0 +1,153 @@
+#!/usr/bin/env python2
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+from PyQt5.Qt import QApplication, QBuffer, QByteArray
+from PyQt5.QtWebEngineCore import QWebEngineUrlSchemeHandler
+from PyQt5.QtWebEngineWidgets import (
+    QWebEnginePage, QWebEngineProfile, QWebEngineScript
+)
+
+from calibre import prints
+from calibre.constants import (
+    FAKE_HOST, FAKE_PROTOCOL, __version__, is_running_from_develop
+)
+from calibre.gui2 import open_url
+from calibre.gui2.webengine import (
+    Bridge, RestartingWebEngineView, create_script, from_js, insert_scripts,
+    secure_webengine, to_js
+)
+
+try:
+    from PyQt5 import sip
+except ImportError:
+    import sip
+
+# Override network access to load data from the book {{{
+
+
+def get_data(name):
+    raise NotImplementedError('TODO: implement this')
+
+
+class UrlSchemeHandler(QWebEngineUrlSchemeHandler):
+
+    def __init__(self, parent=None):
+        QWebEngineUrlSchemeHandler.__init__(self, parent)
+
+    def requestStarted(self, rq):
+        if bytes(rq.requestMethod()) != b'GET':
+            rq.fail(rq.RequestDenied)
+            return
+        url = rq.requestUrl()
+        if url.host() != FAKE_HOST or url.scheme() != FAKE_PROTOCOL:
+            rq.fail(rq.UrlNotFound)
+            return
+        name = url.path()[1:]
+        try:
+            data, mime_type = get_data(name)
+            if data is None:
+                rq.fail(rq.UrlNotFound)
+                return
+            if isinstance(data, type('')):
+                data = data.encode('utf-8')
+            mime_type = {
+                # Prevent warning in console about mimetype of fonts
+                'application/vnd.ms-opentype':'application/x-font-ttf',
+                'application/x-font-truetype':'application/x-font-ttf',
+                'application/font-sfnt': 'application/x-font-ttf',
+            }.get(mime_type, mime_type)
+            self.send_reply(rq, mime_type, data)
+        except Exception:
+            import traceback
+            traceback.print_exc()
+            rq.fail(rq.RequestFailed)
+
+    def send_reply(self, rq, mime_type, data):
+        if sip.isdeleted(rq):
+            return
+        buf = QBuffer(parent=rq)
+        buf.open(QBuffer.WriteOnly)
+        # we have to copy data into buf as it will be garbage
+        # collected by python
+        buf.write(data)
+        buf.seek(0)
+        buf.close()
+        buf.aboutToClose.connect(buf.deleteLater)
+        rq.reply(mime_type.encode('ascii'), buf)
+
+# }}}
+
+
+def create_profile():
+    ans = getattr(create_profile, 'ans', None)
+    if ans is None:
+        ans = QWebEngineProfile(QApplication.instance())
+        ua = 'calibre-viewer ' + __version__
+        ans.setHttpUserAgent(ua)
+        if is_running_from_develop:
+            from calibre.utils.rapydscript import compile_editor
+            compile_editor()
+        js = P('editor.js', data=True, allow_user_override=False)
+        cparser = P('csscolorparser.js', data=True, allow_user_override=False)
+
+        insert_scripts(ans,
+            create_script('csscolorparser.js', cparser),
+            create_script('editor.js', js),
+        )
+        url_handler = UrlSchemeHandler(ans)
+        ans.installUrlSchemeHandler(QByteArray(FAKE_PROTOCOL.encode('ascii')), url_handler)
+        s = ans.settings()
+        s.setDefaultTextEncoding('utf-8')
+        s.setAttribute(s.FullScreenSupportEnabled, False)
+        s.setAttribute(s.LinksIncludedInFocusChain, False)
+        create_profile.ans = ans
+    return ans
+
+
+class ViewerBridge(Bridge):
+
+    request_sync = from_js(object, object, object)
+    request_split = from_js(object, object)
+    live_css_data = from_js(object)
+
+    go_to_sourceline_address = to_js()
+    go_to_anchor = to_js()
+    set_split_mode = to_js()
+    live_css = to_js()
+
+
+class WebPage(QWebEnginePage):
+
+    def __init__(self, parent):
+        QWebEnginePage.__init__(self, create_profile(), parent)
+        secure_webengine(self, for_viewer=True)
+        self.bridge = ViewerBridge(self)
+
+    def javaScriptConsoleMessage(self, level, msg, linenumber, source_id):
+        prints('%s:%s: %s' % (source_id, linenumber, msg))
+
+    def acceptNavigationRequest(self, url, req_type, is_main_frame):
+        if req_type == self.NavigationTypeReload:
+            return True
+        if url.scheme() in (FAKE_PROTOCOL, 'data'):
+            return True
+        open_url(url)
+        return False
+
+    def go_to_anchor(self, anchor):
+        self.bridge.go_to_anchor.emit(anchor or '')
+
+    def runjs(self, src, callback=None):
+        if callback is None:
+            self.runJavaScript(src, QWebEngineScript.ApplicationWorld)
+        else:
+            self.runJavaScript(src, QWebEngineScript.ApplicationWorld, callback)
+
+
+class WebView(RestartingWebEngineView):
+
+    def __init__(self, parent=None):
+        RestartingWebEngineView.__init__(self, parent)