feat: added postgress search trig and the search endpoint

.env.example

@@ -2,7 +2,8 @@
 
 SECRET_KEY=change-me
 DEBUG=True
-ALLOWED_HOSTS=
+ALLOWED_HOSTS
+HS_CODE_SEARCH_THRESHOLD=0.1
 
 # db
 DATABASE_URL=postgres://hsuser:hspass@localhost:5432/hsdb

app/models.py

@@ -1,8 +1,8 @@
 from django.db import models
 from django.contrib.auth.models import AbstractUser
 
-# from django.contrib.postgres.indexes import GinIndex
-# from django.contrib.postgres.operations import TrigramExtension
+from django.contrib.postgres.indexes import GinIndex
+from django.contrib.postgres.operations import TrigramExtension
 
 
 class User(AbstractUser):
@@ -31,17 +31,19 @@ class Meta:
             models.UniqueConstraint(fields=["hs_code"], name="unique_hs_code")
         ]
 
-
-# class Meta:
-#     indexes = [
-#         GinIndex(
-#             fields=["hs_code"],
-#             opclasses=["gin_trgm_ops"],
-#             name="hscode_hs_code_trgm_idx"
-#         ),
-#         GinIndex(
-#             fields=["description"],
-#             opclasses=["gin_trgm_ops"],
-#             name="hscode_description_trgm_idx"
-#         ),
-#     ]
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(fields=["hs_code"], name="unique_hs_code")
+        ]
+        indexes = [
+            GinIndex(
+                fields=["hs_code"],
+                opclasses=["gin_trgm_ops"],
+                name="hscode_hs_code_trgm_idx",
+            ),
+            GinIndex(
+                fields=["description"],
+                opclasses=["gin_trgm_ops"],
+                name="hscode_description_trgm_idx",
+            ),
+        ]

app/services/file_upload_service.py

@@ -2,8 +2,8 @@
 import io
 from dataclasses import dataclass
 
-from .models import HsCode, HsCodeFile, Category
-from category_service import HS_CHAPTER_CATEGORIES, get_or_create_category_for_hs_code
+from app.models import HsCode, HsCodeFile, Category
+from .category_service import HS_CHAPTER_CATEGORIES, get_or_create_category_for_hs_code
 
 
 @dataclass

app/urls.py

@@ -1,6 +1,11 @@
 from django.urls import path
-from .views import HsCodeUploadView
+from .views import HsCodeUploadView, HsCodeSearchView
 
 urlpatterns = [
+    path(
+        "hs-codes/",
+        HsCodeSearchView.as_view(),
+        name="hs-code-search",
+    ),
     path("hs-codes/upload/", HsCodeUploadView.as_view(), name="hscode-upload"),
 ]

app/views.py

@@ -1,12 +1,20 @@
 from dataclasses import asdict
 
+from django.conf import settings
+from django.contrib.postgres.search import TrigramSimilarity
+
+from rest_framework import generics
+from rest_framework.exceptions import ValidationError
+
+from .models import HsCode
+
 from rest_framework import status
 from rest_framework.parsers import MultiPartParser
 from rest_framework.response import Response
 from rest_framework.views import APIView
 
 from .permissions import IsAdminOrStaff
-from .serializers import HsCodeUploadSerializer
+from .serializers import HsCodeUploadSerializer, HsCodeSerializer
 from .services.file_upload_service import process_hs_code_csv
 
 
@@ -27,3 +35,30 @@ def post(self, request):
             return Response({"error": str(exc)}, status=status.HTTP_400_BAD_REQUEST)
 
         return Response(asdict(result), status=status.HTTP_201_CREATED)
+
+
+class HsCodeSearchView(generics.ListAPIView):
+    serializer_class = HsCodeSerializer
+
+    def get_queryset(self):
+        q = self.request.query_params.get("q")
+
+        if not q:
+            raise ValidationError({"q": ["This query parameter is required."]})
+
+        threshold = getattr(
+            settings,
+            "HS_CODE_SEARCH_THRESHOLD",
+            0.1,
+        )
+
+        return (
+            HsCode.objects.annotate(
+                similarity=(
+                    TrigramSimilarity("description", q) * 2
+                    + TrigramSimilarity("hs_code", q)
+                )
+            )
+            .filter(similarity__gte=threshold)
+            .order_by("-similarity")
+        )

core/settings/base.py

@@ -19,6 +19,7 @@
     "django.contrib.sessions",
     "django.contrib.messages",
     "django.contrib.staticfiles",
+    "django.contrib.postgres",
     # third_party
     "rest_framework",
     # custom
@@ -108,3 +109,9 @@
         "user": "300/minute",
     },
 }
+
+HS_CODE_SEARCH_THRESHOLD = config(
+    "HS_CODE_SEARCH_THRESHOLD",
+    default=0.1,
+    cast=float,
+)

logfile

@@ -0,0 +1,15 @@
+2026-06-01 15:25:18.444 CAT [15141] LOG:  starting PostgreSQL 18.2 on aarch64-unknown-linux-android, compiled by Android (13989888, +pgo, +bolt, +lto, +mlgo, based on r563880c) clang version 21.0.0 (https://android.googlesource.com/toolchain/llvm-project 5e96669f06077099aa41290cdb4c5e6fa0f59349), 64-bit
+2026-06-01 15:25:18.445 CAT [15141] LOG:  listening on IPv4 address "127.0.0.1", port 5432
+2026-06-01 15:25:18.446 CAT [15141] LOG:  listening on Unix socket "/data/data/com.termux/files/usr/tmp/.s.PGSQL.5432"
+2026-06-01 15:25:18.468 CAT [15149] LOG:  database system was shut down at 2026-06-01 15:24:53 CAT
+2026-06-01 15:25:18.497 CAT [15141] LOG:  database system is ready to accept connections
+2026-06-01 15:26:48.604 CAT [15454] ERROR:  database "hsdb" already exists
+2026-06-01 15:26:48.604 CAT [15454] STATEMENT:  CREATE DATABASE hsdb OWNER hsuser;
+2026-06-01 15:27:05.786 CAT [15147] LOG:  checkpoint starting: immediate force wait
+2026-06-01 15:27:05.979 CAT [15147] LOG:  checkpoint complete: wrote 52 buffers (0.3%), wrote 3 SLRU buffers; 1 WAL file(s) added, 0 removed, 0 recycled; write=0.022 s, sync=0.008 s, total=0.193 s; sync files=21, longest=0.001 s, average=0.001 s; distance=4745 kB, estimate=4745 kB; lsn=0/1C06188, redo lsn=0/1C06130
+2026-06-01 15:27:12.309 CAT [15573] ERROR:  role "hsuser" already exists
+2026-06-01 15:27:12.309 CAT [15573] STATEMENT:  CREATE USER hsuser WITH PASSWORD 'hspass';
+2026-06-01 15:32:06.078 CAT [15147] LOG:  checkpoint starting: time
+2026-06-01 15:33:46.511 CAT [15147] LOG:  checkpoint complete: wrote 991 buffers (6.0%), wrote 1 SLRU buffers; 0 WAL file(s) added, 0 removed, 1 recycled; write=100.306 s, sync=0.084 s, total=100.433 s; sync files=310, longest=0.004 s, average=0.001 s; distance=4696 kB, estimate=4740 kB; lsn=0/209C228, redo lsn=0/209C198
+2026-06-01 15:42:06.686 CAT [15147] LOG:  checkpoint starting: time
+2026-06-01 15:42:22.571 CAT [15147] LOG:  checkpoint complete: wrote 157 buffers (1.0%), wrote 1 SLRU buffers; 0 WAL file(s) added, 0 removed, 0 recycled; write=15.837 s, sync=0.015 s, total=15.886 s; sync files=122, longest=0.005 s, average=0.001 s; distance=941 kB, estimate=4360 kB; lsn=0/2193BC8, redo lsn=0/2187958