pokedex/db/markdown.py

   1 # encoding: utf8
   2 u"""Implements the markup used for description and effect text in the database.
   3
   4 The language used is a variation of Markdown and Markdown Extra.  There are
   5 docs for each at http://daringfireball.net/projects/markdown/ and
   6 http://michelf.com/projects/php-markdown/extra/ respectively.
   7
   8 Pokédex links are represented with the extended syntax `[name]{type}`, e.g.,
   9 `[Eevee]{pokemon}`.  The actual code that parses these is in spline-pokedex.
  10 """
  11 from __future__ import absolute_import
  12
  13 import markdown
  14 import sqlalchemy.types
  15
  16 class MarkdownString(object):
  17     """Wraps a Markdown string.  Stringifies to the original text, but .as_html
  18     will return an HTML rendering.
  19
  20     To add extensions to the rendering (which is necessary for rendering links
  21     correctly, and which spline-pokedex does), you must append to this class's
  22     `markdown_extensions` list.  Yep, that's gross.
  23     """
  24
  25     markdown_extensions = ['extra']
  26
  27     def __init__(self, source_text):
  28         self.source_text = source_text
  29         self._as_html = None
  30
  31     def __unicode__(self):
  32         return self.source_text
  33
  34     @property
  35     def as_html(self):
  36         """Returns the string as HTML4."""
  37
  38         if self._as_html:
  39             return self._as_html
  40
  41         md = markdown.Markdown(
  42             extensions=self.markdown_extensions,
  43             safe_mode='escape',
  44             output_format='xhtml1',
  45         )
  46
  47         self._as_html = md.convert(self.source_text)
  48
  49         return self._as_html
  50
  51     @property
  52     def as_text(self):
  53         """Returns the string in a plaintext-friendly form.
  54
  55         At the moment, this is just the original source text.
  56         """
  57         return self.source_text
  58
  59 def _markdownify_effect_text(move, effect_text):
  60     effect_text = effect_text.replace(
  61         u'$effect_chance',
  62         unicode(move.effect_chance),
  63     )
  64
  65     return MarkdownString(effect_text)
  66
  67 class MoveEffectProperty(object):
  68     """Property that wraps move effects.  Used like this:
  69
  70         MoveClass.effect = MoveEffectProperty('effect')
  71
  72         some_move.effect            # returns a MarkdownString
  73         some_move.effect.as_html    # returns a chunk of HTML
  74
  75     This class attempts to detect if the wrapped property is a dict-based
  76     association proxy, and will act like such a dict if so.  Don't rely on it
  77     for querying, of course.
  78
  79     This class also performs simple substitution on the effect, replacing
  80     `$effect_chance` with the move's actual effect chance.
  81     """
  82
  83     def __init__(self, effect_column):
  84         self.effect_column = effect_column
  85
  86     def __get__(self, obj, cls):
  87         prop = getattr(obj.move_effect, self.effect_column)
  88         if isinstance(prop, dict):
  89             # Looks like a dict proxy; markdownify everyone
  90             newdict = dict(prop)
  91             for key in newdict:
  92                 newdict[key] = _markdownify_effect_text(obj, newdict[key])
  93             return newdict
  94
  95         # Otherwise, scalar prop.  Boring
  96         return _markdownify_effect_text(obj, prop)
  97
  98 class MarkdownColumn(sqlalchemy.types.TypeDecorator):
  99     """Generic SQLAlchemy column type for Markdown text.
 100
 101     Do NOT use this for move effects!  They need to know what move they belong
 102     to so they can fill in, e.g., effect chances.  Use the MoveEffectProperty
 103     property class above.
 104     """
 105     impl = sqlalchemy.types.Unicode
 106
 107     def process_bind_param(self, value, dialect):
 108         if not isinstance(value, basestring):
 109             # Can't assign, e.g., MarkdownString objects yet
 110             raise NotImplementedError
 111
 112         return unicode(value)
 113
 114     def process_result_value(self, value, dialect):
 115         return MarkdownString(value)