Find hadiths stored under a combined number (#614)

hadith_number.py

@@ -0,0 +1,3 @@
+def matches_hadith_number(stored, number):
+    """Check if `number` is one part of a combined number like "6924, 6925" or "6924-6925"."""
+    return any(part.strip() == number for separator in (",", "-") for part in stored.split(separator))

main.py

@@ -3,6 +3,8 @@
 from sqlalchemy import and_, func, or_
 from werkzeug.exceptions import HTTPException
 
+from hadith_number import matches_hadith_number
+
 app = Flask(__name__)
 app.config.from_object("config.Config")
 
@@ -76,6 +78,18 @@ def ref_match(results, collection, hadith_number):
     return None
 
 
+def filter_hadith_number(query, hadith_number):
+    """Match `hadith_number` exactly, else as one part of a combined number like "6924, 6925"."""
+    exact = query.filter(Hadith.hadithNumber == hadith_number)
+
+    if exact.first() is not None:
+        return exact
+
+    candidates = query.filter(Hadith.hadithNumber.contains(hadith_number, autoescape=True)).with_entities(Hadith.arabicURN, Hadith.hadithNumber)
+    urns = [urn for urn, stored in candidates if matches_hadith_number(stored, hadith_number)]
+    return query.filter(Hadith.arabicURN.in_(urns))
+
+
 @app.before_request
 def verify_secret():
     if not app.debug and request.headers.get("x-aws-secret") != app.config["AWS_SECRET"]:
@@ -198,12 +212,12 @@ def api_collection_book_hadiths(collection_name, bookNumber):
 def api_collection_hadith(collection_name, hadithNumber):
     collection, book_number = resolve_collection(collection_name)
     # `forty` numbers each of its books from 1, so order to keep the pick stable
-    query = Hadith.query.filter_by(collection=collection, hadithNumber=hadithNumber).order_by(Hadith.englishURN)
+    query = Hadith.query.filter_by(collection=collection).order_by(Hadith.englishURN)
 
     if book_number is not None:
         query = query.filter_by(bookNumber=book_number)
 
-    return query, serialize_as(collection_name)
+    return filter_hadith_number(query, hadithNumber), serialize_as(collection_name)
 
 
 @app.route("/v1/collections/<string:collection_name>/books/<string:bookNumber>/chapters", methods=["GET"])
@@ -245,7 +259,7 @@ def api_hadiths():
 
     hadith_number = request.args.get("hadithNumber")
     if hadith_number:
-        query = query.filter_by(hadithNumber=hadith_number)
+        query = filter_hadith_number(query, hadith_number)
 
     # Order by URN for consistent results
     return query.order_by(Hadith.englishURN), serialize_as(collection)

tests/test_hadith_number.py

@@ -0,0 +1,28 @@
+import unittest
+
+from hadith_number import matches_hadith_number
+
+
+class TestMatchesHadithNumber(unittest.TestCase):
+    """Regression test for sunnah-com/api#614.
+
+    Some hadiths are stored under a combined number such as "6924, 6925",
+    so looking up either number on its own must still find that hadith.
+    """
+
+    def test_comma_separated_parts(self):
+        for number in ("6924", "6925"):
+            self.assertTrue(matches_hadith_number("6924, 6925", number))
+        self.assertTrue(matches_hadith_number("6924,6925,6926", "6926"))
+
+    def test_dash_separated_parts(self):
+        for number in ("6924", "6925"):
+            self.assertTrue(matches_hadith_number("6924 - 6925", number))
+
+    def test_exact_number(self):
+        self.assertTrue(matches_hadith_number("6924", "6924"))
+
+    def test_substring_is_not_a_match(self):
+        for number in ("692", "924", "69246", ""):
+            self.assertFalse(matches_hadith_number("6924, 6925", number))
+        self.assertFalse(matches_hadith_number("16924", "6924"))