Find a knowledge base article by words from different fields

shopdb/core/api/search.py

@@ -31,7 +31,7 @@ search_bp = Blueprint('search', __name__)
 # cannot reorder. Relevance is applied afterwards in Python, over a stable set.
 
 
-def _word_match(query, *columns):
+def _word_match(query, *columns, extra=None):
     """SQL clause matching rows that contain EVERY word of the query, each word
     in any of the columns, in any order.
 
@@ -39,14 +39,25 @@ def _word_match(query, *columns):
     multi-word search returned nothing. This splits the query into words and ANDs
     them (OR across the columns per word): 'CSF Roles' matches a row with 'CSF'
     and 'Roles' anywhere in the searched fields.
+
+    `extra` is an optional callable taking one word and returning a further
+    clause to OR in for that word. Use it where a word may be satisfied by a
+    RELATED row rather than a column of this table - a knowledge base article
+    matching on its topic's name, say. Splitting per word matters there: without
+    it a word can only ever be matched by the columns, so a query naming the
+    topic and a keyword ('CMM Community') matches neither side alone.
     """
     words = [w for w in query.split() if w]
     if not words:
         words = ['']
-    return db.and_(*[
-        db.or_(*[c.ilike(f'%{w}%') for c in columns])
-        for w in words
-    ])
+
+    def per_word(word):
+        clauses = [c.ilike(f'%{word}%') for c in columns]
+        if extra is not None:
+            clauses.append(extra(word))
+        return db.or_(*clauses)
+
+    return db.and_(*[per_word(w) for w in words])
 
 
 def _require_enabled(name):
@@ -253,6 +264,10 @@ def _search_knowledgebase(query, search_term):
     subject, which reads as though it were still in service.
 
     A null topic still matches. Not every article is about an application.
+
+    The topic's NAME is searched too, per word. An article tagged 'community'
+    under the CMM topic has neither word in both of its own columns, so a search
+    for 'CMM Community' found it in neither the plugin's listing nor here.
     """
     results = []
     try:
@@ -260,12 +275,24 @@ def _search_knowledgebase(query, search_term):
         from plugins.knowledgebase.models import KnowledgeBase
         retired = db.session.query(Application.appid).filter(
             Application.isactive.is_(False))
+
+        def topic_named(word):
+            """Articles whose topic is an ACTIVE application named like word.
+
+            Active only, for the same reason the retired filter above exists: a
+            decommissioned application is not a topic anyone should be offered.
+            """
+            return KnowledgeBase.appid.in_(
+                db.session.query(Application.appid).filter(
+                    Application.appname.ilike(f'%{word}%'),
+                    Application.isactive.is_(True)))
+
         kb_articles = KnowledgeBase.query.filter(
             KnowledgeBase.isactive == True,
             db.or_(KnowledgeBase.appid.is_(None),
                    KnowledgeBase.appid.notin_(retired)),
             _word_match(query, KnowledgeBase.shortdescription,
-                        KnowledgeBase.keywords)
+                        KnowledgeBase.keywords, extra=topic_named)
         ).order_by(KnowledgeBase.clicks.desc(),
                    KnowledgeBase.linkid).limit(20).all()