Source code for mediaquerybuilder
# python 2
from __future__ import absolute_import, print_function, unicode_literals
# builtins
import logging
# plugins
from cssutils.css import Property
from xml.dom import SyntaxErr
# custom
from blowdrycss.classpropertyparser import ClassPropertyParser
from blowdrycss.breakpointparser import BreakpointParser
from blowdrycss.scalingparser import ScalingParser
__author__ = 'chad nelson'
__project__ = 'blowdrycss'
[docs]class MediaQueryBuilder(object):
""" Builds a set of CSS media queries from valid classes found in ``ClassPropertyParser.class_set``.
| Takes a set of classes that may or may not contain media query flags.
| Mixing breakpoint and scaling syntax is not allowed. Classes that contain mixed syntax like the following:
| ``small-down-s`` or ``font-size-28-medium-only-s`` are invalidated.
:type property_parser: ClassPropertyParser
:param property_parser: ClassPropertyParser object containing ``class_set``.
:return: None
**Example Usage:**
>>> import blowdrycss_settings as settings
>>> from classpropertyparser import ClassPropertyParser
>>> class_set = {'bold', 'large-down', 'font-size-25-s'}
>>> # Filter class names. Only keep classes matching the defined class encoding.
>>> property_parser = ClassPropertyParser(class_set=class_set)
>>> class_set = property_parser.class_set.copy()
>>> # Build Media Queries
>>> if settings.media_queries_enabled:
>>> unassigned_class_set = class_set.difference(property_parser.class_set)
>>> # Only use unassigned classes
>>> property_parser.class_set = unassigned_class_set
>>> property_parser.removed_class_set = set()
>>> media_query_builder = MediaQueryBuilder(property_parser=property_parser)
>>> css_text = bytes(media_query_builder.get_css_text(), 'utf-8')
>>> print(media_query_builder.property_parser.class_set)
{'large-down', 'font-size-25-s'}
"""
def __init__(self, property_parser=ClassPropertyParser()):
message = 'MediaQueryBuilder Running...'
print(message)
logging.debug(msg=message)
self.property_parser = property_parser
self.css_media_queries = set()
self.media_query_text = ''
not_media_classes = dict()
for css_class in self.property_parser.class_set:
name = self.property_parser.get_property_name(css_class=css_class)
priority = self.property_parser.get_property_priority(css_class=css_class)
clean_css_class = '' # Prevents css_class from being modified.
if name:
# value='inherit' since we do not know if the class is valid yet.
inherit_property = Property(name=name, value='inherit', priority=priority)
scaling_parser = ScalingParser(css_class=css_class, css_property=inherit_property)
is_scaling = scaling_parser.is_scaling
if is_scaling:
clean_css_class = scaling_parser.strip_scaling_flag()
breakpoint_parser = BreakpointParser(css_class=css_class, css_property=inherit_property)
is_breakpoint = breakpoint_parser.is_breakpoint
if is_breakpoint:
clean_css_class = breakpoint_parser.strip_breakpoint_limit()
if is_breakpoint and is_scaling: # Mixed syntax
not_media_classes[css_class] = ' (Breakpoint and scaling media query syntax cannot be combined.)'
continue
if not is_breakpoint and not is_scaling: # Missing syntax
not_media_classes[css_class] = ' is not a media query css_class selector.'
continue
else:
not_media_classes[css_class] = ' is not a media query css_class selector.'
continue
if clean_css_class and property_parser.is_important(css_class=clean_css_class):
clean_css_class = property_parser.strip_priority_designator(css_class=clean_css_class)
# Set property value.
# Handles case where css_class equals 'small-down', 'large-only', 'medium-up', etc.
# Specifically handle the 'display' case.
if clean_css_class and clean_css_class != 'display':
# Can return an empty string '' if css_class does not match any patterns in the property_alias_dict.
try:
encoded_property_value = self.property_parser.get_encoded_property_value(
property_name=name,
css_class=clean_css_class
)
value = self.property_parser.get_property_value(
property_name=name,
encoded_property_value=encoded_property_value
)
except ValueError: # Impossible to get here if get_property_name() is working properly.
not_media_classes[css_class] = ' property_name not found in property_alias_dict.'
continue
else:
value = 'none' # Breakpoint Parser Case -> display: none;
# Build CSS Property AND Add to css_media_queries OR Remove invalid css_class from class_set.
try:
css_property = Property(name=name, value=value, priority=priority)
if css_property.valid:
if is_breakpoint and breakpoint_parser:
breakpoint_parser.css_property = css_property
media_query = breakpoint_parser.build_media_query()
self.css_media_queries.add(media_query)
if is_scaling:
scaling_parser.css_property = css_property
media_query = scaling_parser.build_media_query()
self.css_media_queries.add(media_query)
else:
not_media_classes[css_class] = ' (cssutils invalid property value: ' + value + ')'
continue
# This exception can't be tested as clean_class_set() and get_property_value() prevent it.(Triple Redundant)
except SyntaxErr: # Special Case - Not Tested
not_media_classes[css_class] = ' (cssutils SyntaxErr invalid property value: ' + value + ')'
continue
# Clean out invalid CSS Classes.
for invalid_css_class, reason in not_media_classes.items():
self.property_parser.class_set.remove(invalid_css_class)
self.property_parser.removed_class_set.add(invalid_css_class + reason)
[docs] def get_css_text(self):
""" Joins ``css_media_queries`` together with an empty separator string ``''``.
:return: str -- Returns all media queries as CSS text.
**Example**
>>> from classpropertyparser import ClassPropertyParser
>>> class_set = {'bold', 'large-down', 'font-size-24-s'}
>>> # Filter class names. Only keep classes matching the defined class encoding.
>>> property_parser = ClassPropertyParser(class_set=class_set)
>>> media_query_builder = MediaQueryBuilder(property_parser=property_parser)
>>> print(media_query_builder.get_css_text())
@media only screen and (min-width: 64.0em) {
.large-down {
display: none;
}
}
.font-size-24-s {
font-size: 24px;
@media only screen and (max-width: 45.0em) {
font-size: 21.3px;
}
@media only screen and (max-width: 30.0em) {
font-size: 19.2px;
}
}
"""
return str.join(str(''), self.css_media_queries)
