gistfile1.py

class ExtractRelevantTextNode(template.Node):
    def __init__(self, field_name, query, fieldtext):
        self.field_name, self.query, self.fieldtext = field_name.strip(), query.strip(), fieldtext.strip()
    def render(self, context):
        efffield_name = Variable(self.field_name).resolve(context)
        effquery = Variable(self.query).resolve(context)
        efffieldtext = Variable(self.fieldtext).resolve(context)

        if type(self.query) == type(u""):
            effquery = lucene.QueryParser(efffield_name, lu.getAnalyzer()).parse(effquery)

        scorer = lucene.QueryScorer(effquery)
        highlighter = lucene.Highlighter(lucene.SimpleHTMLFormatter('<span class="highlight">', "</span>"),scorer)
        highlighter.setTextFragmenter(lucene.SimpleFragmenter(200))
        return unicode(highlighter.getBestFragment(lu.getAnalyzer(), efffield_name, efffieldtext))