view cagou/core/simple_xhtml.py @ 448:20a807443c3f

chat: resize attachments (images only for now): if attachments to send contain oversized image, a checkbox will be shown (activated by default) to reduce automatically the size. The background color now cover the whole attachments to send widget. If not already specified, media type is guessed from filename when adding an attachment.
author Goffi <goffi@goffi.org>
date Sun, 22 Mar 2020 14:10:59 +0100
parents efee0e0afb78
children 2d277a3d9cec
line wrap: on
line source

#!/usr/bin/env python3


# Cagou: desktop/mobile frontend for Salut à Toi XMPP client
# Copyright (C) 2016-2020 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


from xml.etree import ElementTree as ET
from kivy.uix.stacklayout import StackLayout
from kivy.uix.label import Label
from kivy.utils import escape_markup
from kivy.metrics import sp
from kivy import properties
from sat.core import log as logging
from sat_frontends.tools import css_color, strings as sat_strings
from cagou import G
from cagou.core.common  import SizedImage


log = logging.getLogger(__name__)


class Escape(str):
    """Class used to mark that a message need to be escaped"""


class SimpleXHTMLWidgetEscapedText(Label):

    def on_parent(self, instance, parent):
        if parent is not None:
            self.font_size = parent.font_size

    def _addUrlMarkup(self, text):
        text_elts = []
        idx = 0
        links = 0
        while True:
            m = sat_strings.RE_URL.search(text[idx:])
            if m is not None:
                text_elts.append(escape_markup(m.string[0:m.start()]))
                link_key = 'link_' + str(links)
                url = m.group()
                escaped_url = escape_markup(url)
                text_elts.append(
                    f'[color=5500ff][ref={link_key}]{escaped_url}[/ref][/color]')
                if not links:
                    self.ref_urls = {link_key: url}
                else:
                    self.ref_urls[link_key] = url
                links += 1
                idx += m.end()
            else:
                if links:
                    text_elts.append(escape_markup(text[idx:]))
                    self.markup = True
                    self.text = ''.join(text_elts)
                break

    def on_text(self, instance, text):
        # do NOT call the method if self.markup is set
        # this would result in infinite loop (because self.text
        # is changed if an URL is found, and in this case markup too)
        if text and not self.markup:
            self._addUrlMarkup(text)

    def on_ref_press(self, ref):
        url = self.ref_urls[ref]
        G.local_platform.open_url(url, self)


class SimpleXHTMLWidgetText(Label):

    def on_parent(self, instance, parent):
        if parent is not None:
            self.font_size = parent.font_size


class SimpleXHTMLWidget(StackLayout):
    """widget handling simple XHTML parsing"""
    xhtml = properties.StringProperty()
    color = properties.ListProperty([1, 1, 1, 1])
    # XXX: bold is only used for escaped text
    bold = properties.BooleanProperty(False)
    font_size = properties.NumericProperty(sp(14))

    # text/XHTML input

    def on_xhtml(self, instance, xhtml):
        """parse xhtml and set content accordingly

        if xhtml is an instance of Escape, a Label with no markup will be used
        """
        self.clear_widgets()
        if isinstance(xhtml, Escape):
            label = SimpleXHTMLWidgetEscapedText(
                text=xhtml, color=self.color, bold=self.bold)
            self.bind(font_size=label.setter('font_size'))
            self.bind(color=label.setter('color'))
            self.bind(bold=label.setter('bold'))
            self.add_widget(label)
        else:
            xhtml = ET.fromstring(xhtml.encode())
            self.current_wid = None
            self.styles = []
            self._callParseMethod(xhtml)
        if len(self.children) > 1:
            self._do_split_labels()

    def escape(self, text):
        """mark that a text need to be escaped (i.e. no markup)"""
        return Escape(text)

    def _do_split_labels(self):
        """Split labels so their content can flow with images"""
        # XXX: to make things easier, we split labels in words
        log.debug("labels splitting start")
        children = self.children[::-1]
        self.clear_widgets()
        for child in children:
            if isinstance(child, Label):
                log.debug("label before split: {}".format(child.text))
                styles = []
                tag = False
                new_text = []
                current_tag = []
                current_value = []
                current_wid = self._createText()
                value = False
                close = False
                # we will parse the text and create a new widget
                # on each new word (actually each space)
                # FIXME: handle '\n' and other white chars
                for c in child.text:
                    if tag:
                        # we are parsing a markup tag
                        if c == ']':
                            current_tag_s = ''.join(current_tag)
                            current_style = (current_tag_s, ''.join(current_value))
                            if close:
                                for idx, s in enumerate(reversed(styles)):
                                    if s[0] == current_tag_s:
                                        del styles[len(styles) - idx - 1]
                                        break
                            else:
                                styles.append(current_style)
                            current_tag = []
                            current_value = []
                            tag = False
                            value = False
                            close = False
                        elif c == '/':
                            close = True
                        elif c == '=':
                            value = True
                        elif value:
                            current_value.append(c)
                        else:
                            current_tag.append(c)
                        new_text.append(c)
                    else:
                        # we are parsing regular text
                        if c == '[':
                            new_text.append(c)
                            tag = True
                        elif c == ' ':
                            # new word, we do a new widget
                            new_text.append(' ')
                            for t, v in reversed(styles):
                                new_text.append('[/{}]'.format(t))
                            current_wid.text = ''.join(new_text)
                            new_text = []
                            self.add_widget(current_wid)
                            log.debug("new widget: {}".format(current_wid.text))
                            current_wid = self._createText()
                            for t, v in styles:
                                new_text.append('[{tag}{value}]'.format(
                                    tag = t,
                                    value = '={}'.format(v) if v else ''))
                        else:
                            new_text.append(c)
                if current_wid.text:
                    # we may have a remaining widget after the parsing
                    close_styles = []
                    for t, v in reversed(styles):
                        close_styles.append('[/{}]'.format(t))
                    current_wid.text = ''.join(close_styles)
                    self.add_widget(current_wid)
                    log.debug("new widget: {}".format(current_wid.text))
            else:
                # non Label widgets, we just add them
                self.add_widget(child)
        self.splitted = True
        log.debug("split OK")

    # XHTML parsing methods

    def _callParseMethod(self, e):
        """Call the suitable method to parse the element

        self.xhtml_[tag] will be called if it exists, else
        self.xhtml_generic will be used
        @param e(ET.Element): element to parse
        """
        try:
            method = getattr(self, f"xhtml_{e.tag}")
        except AttributeError:
            log.warning(f"Unhandled XHTML tag: {e.tag}")
            method = self.xhtml_generic
        method(e)

    def _addStyle(self, tag, value=None, append_to_list=True):
        """add a markup style to label

        @param tag(unicode): markup tag
        @param value(unicode): markup value if suitable
        @param append_to_list(bool): if True style we be added to self.styles
            self.styles is needed to keep track of styles to remove
            should most probably be set to True
        """
        label = self._getLabel()
        label.text += '[{tag}{value}]'.format(
            tag = tag,
            value = '={}'.format(value) if value else ''
            )
        if append_to_list:
            self.styles.append((tag, value))

    def _removeStyle(self, tag, remove_from_list=True):
        """remove a markup style from the label

        @param tag(unicode): markup tag to remove
        @param remove_from_list(bool): if True, remove from self.styles too
            should most probably be set to True
        """
        label = self._getLabel()
        label.text += '[/{tag}]'.format(
            tag = tag
            )
        if remove_from_list:
            for rev_idx, style in enumerate(reversed(self.styles)):
                if style[0] == tag:
                    tag_idx = len(self.styles) - 1 - rev_idx
                    del self.styles[tag_idx]
                    break

    def _getLabel(self):
        """get current Label if it exists, or create a new one"""
        if not isinstance(self.current_wid, Label):
            self._addLabel()
        return self.current_wid

    def _addLabel(self):
        """add a new Label

        current styles will be closed and reopened if needed
        """
        self._closeLabel()
        self.current_wid = self._createText()
        for tag, value in self.styles:
            self._addStyle(tag, value, append_to_list=False)
        self.add_widget(self.current_wid)

    def _createText(self):
        label = SimpleXHTMLWidgetText(color=self.color, markup=True)
        self.bind(color=label.setter('color'))
        label.bind(texture_size=label.setter('size'))
        return label

    def _closeLabel(self):
        """close current style tags in current label

        needed when you change label to keep style between
        different widgets
        """
        if isinstance(self.current_wid, Label):
            for tag, value in reversed(self.styles):
                self._removeStyle(tag, remove_from_list=False)

    def _parseCSS(self, e):
        """parse CSS found in "style" attribute of element

        self._css_styles will be created and contained markup styles added by this method
        @param e(ET.Element): element which may have a "style" attribute
        """
        styles_limit = len(self.styles)
        styles = e.attrib['style'].split(';')
        for style in styles:
            try:
                prop, value = style.split(':')
            except ValueError:
                log.warning(f"can't parse style: {style}")
                continue
            prop = prop.strip().replace('-', '_')
            value = value.strip()
            try:
                method = getattr(self, f"css_{prop}")
            except AttributeError:
                log.warning(f"Unhandled CSS: {prop}")
            else:
                method(e, value)
        self._css_styles = self.styles[styles_limit:]

    def _closeCSS(self):
        """removed CSS styles

        styles in self._css_styles will be removed
        and the attribute will be deleted
        """
        for tag, __ in reversed(self._css_styles):
            self._removeStyle(tag)
        del self._css_styles

    def xhtml_generic(self, elem, style=True, markup=None):
        """Generic method for adding HTML elements

        this method handle content, style and children parsing
        @param elem(ET.Element): element to add
        @param style(bool): if True handle style attribute (CSS)
        @param markup(tuple[unicode, (unicode, None)], None): kivy markup to use
        """
        # we first add markup and CSS style
        if markup is not None:
            if isinstance(markup, str):
                tag, value = markup, None
            else:
                tag, value = markup
            self._addStyle(tag, value)
        style_ = 'style' in elem.attrib and style
        if style_:
            self._parseCSS(elem)

        # then content
        if elem.text:
            self._getLabel().text += escape_markup(elem.text)

        # we parse the children
        for child in elem:
            self._callParseMethod(child)

        # closing CSS style and markup
        if style_:
            self._closeCSS()
        if markup is not None:
            self._removeStyle(tag)

        # and the tail, which is regular text
        if elem.tail:
            self._getLabel().text += escape_markup(elem.tail)

    # method handling XHTML elements

    def xhtml_br(self, elem):
        label = self._getLabel()
        label.text+='\n'
        self.xhtml_generic(style=False)

    def xhtml_em(self, elem):
        self.xhtml_generic(elem, markup='i')

    def xhtml_img(self, elem):
        try:
            src = elem.attrib['src']
        except KeyError:
            log.warning("<img> element without src: {}".format(ET.tostring(elem)))
            return
        try:
            target_height = int(elem.get('height', 0))
        except ValueError:
            log.warning(f"Can't parse image height: {elem.get('height')}")
            target_height = None
        try:
            target_width = int(elem.get('width', 0))
        except ValueError:
            log.warning(f"Can't parse image width: {elem.get('width')}")
            target_width = None

        img = SizedImage(
            source=src, target_height=target_height, target_width=target_width)
        self.current_wid = img
        self.add_widget(img)

    def xhtml_p(self, elem):
        if isinstance(self.current_wid, Label):
            self.current_wid.text+="\n\n"
        self.xhtml_generic(elem)

    def xhtml_span(self, elem):
        self.xhtml_generic(elem)

    def xhtml_strong(self, elem):
        self.xhtml_generic(elem, markup='b')

    # methods handling CSS properties

    def css_color(self, elem, value):
        self._addStyle("color", css_color.parse(value))

    def css_text_decoration(self, elem, value):
        if value == 'underline':
            self._addStyle('u')
        elif value == 'line-through':
            self._addStyle('s')
        else:
            log.warning("unhandled text decoration: {}".format(value))