""" This has custom renderers: classes that know how to render certain problem tags (e.g. and ) to html. These tags do not have state, so they just get passed the system (for access to render_template), and the xml element. """ import logging import re import xml.sax.saxutils as saxutils from django.utils import html from lxml import etree from .registry import TagRegistry log = logging.getLogger(__name__) registry = TagRegistry() # ----------------------------------------------------------------------------- class MathRenderer(object): # lint-amnesty, pylint: disable=missing-class-docstring tags = ['math'] def __init__(self, system, xml): r""" Render math using latex-like formatting. Examples: $\displaystyle U(r)=4 U_0 $ $r_0$ We convert these to [mathjax]...[/mathjax] and [mathjaxinline]...[/mathjaxinline] TODO: use shorter tags (but this will require converting problem XML files!) """ self.system = system self.xml = xml mathstr = re.sub(r'\$(.*)\$', r'[mathjaxinline]\1[/mathjaxinline]', xml.text) mtag = 'mathjax' if r'\displaystyle' not in mathstr: mtag += 'inline' else: mathstr = mathstr.replace(r'\displaystyle', '') self.mathstr = mathstr.replace('mathjaxinline]', '%s]' % mtag) def get_html(self): """ Return the contents of this tag, rendered to html, as an etree element. """ # TODO: why are there nested html tags here?? Why are there html tags at all, in fact? # xss-lint: disable=python-interpolate-html html = '%s%s' % ( # lint-amnesty, pylint: disable=redefined-outer-name self.mathstr, saxutils.escape(self.xml.tail)) try: xhtml = etree.XML(html) except Exception as err: # lint-amnesty, pylint: disable=broad-except if self.system.DEBUG: # xss-lint: disable=python-interpolate-html msg = '

Error %s

' % ( str(err).replace('<', '<')) # xss-lint: disable=python-custom-escape # xss-lint: disable=python-interpolate-html msg += ('

Failed to construct math expression from 

%s

' % html.replace('<', '<')) # xss-lint: disable=python-custom-escape msg += "
" log.error(msg) return etree.XML(msg) else: raise return xhtml registry.register(MathRenderer) # ----------------------------------------------------------------------------- class SolutionRenderer(object): """ A solution is just a ... which is given an ID, that is used for displaying an extended answer (a problem "solution") after "show answers" is pressed. Note that the solution content is NOT rendered and returned in the HTML. It is obtained by an ajax call. """ tags = ['solution'] def __init__(self, system, xml): self.system = system self.id = xml.get('id') def get_html(self): context = {'id': self.id} html = self.system.render_template("solutionspan.html", context) # lint-amnesty, pylint: disable=redefined-outer-name return etree.XML(html) registry.register(SolutionRenderer) # ----------------------------------------------------------------------------- class TargetedFeedbackRenderer(object): """ A targeted feedback is just a ... that is used for displaying an extended piece of feedback to students if they incorrectly answered a question. """ tags = ['targetedfeedback'] def __init__(self, system, xml): self.system = system self.xml = xml def get_html(self): """ Return the contents of this tag, rendered to html, as an etree element. """ # xss-lint: disable=python-wrap-html html_str = '
{}
'.format( etree.tostring(self.xml, encoding='unicode')) try: xhtml = etree.XML(html_str) except Exception as err: # pylint: disable=broad-except if self.system.DEBUG: # xss-lint: disable=python-wrap-html msg = """

Error {err}

Failed to construct targeted feedback from 

{html}

""".format(err=html.escape(err), html=html.escape(html_str)) log.error(msg) return etree.XML(msg) else: raise return xhtml registry.register(TargetedFeedbackRenderer) # ----------------------------------------------------------------------------- class ClarificationRenderer(object): """ A clarification appears as an inline icon which reveals more information when the user hovers over it. e.g.

Enter the ROA Return on Assets for 2015:

""" tags = ['clarification'] def __init__(self, system, xml): self.system = system # Get any text content found inside this tag prior to the first child tag. It may be a string or None type. initial_text = xml.text if xml.text else '' self.inner_html = initial_text + ''.join(etree.tostring(element, encoding='unicode') for element in xml) self.tail = xml.tail def get_html(self): """ Return the contents of this tag, rendered to html, as an etree element. """ context = {'clarification': self.inner_html} html = self.system.render_template("clarification.html", context) # lint-amnesty, pylint: disable=redefined-outer-name xml = etree.XML(html) # We must include any text that was following our original ... XML node.: xml.tail = self.tail return xml registry.register(ClarificationRenderer)