feat: format Delhivery carrier packing slip PDF into exact 4x6 thermal dimensions

api/shipping_client.py

@@ -135,6 +135,46 @@ def resolve_city_state_from_address(address_str, pincode=""):
 
     return city, state, clean_pin
 
+def format_pdf_to_4x6(pdf_bytes: bytes) -> bytes:
+    """
+    Format a Delhivery packing slip PDF into an exact 4x6 inch (288x432 pt) thermal page.
+    Delhivery returns vector labels inside an A4 (595x842 pt) canvas.
+    This crops out the empty canvas and maps the vector label directly to 4x6 dimensions.
+    """
+    try:
+        import pymupdf
+        src_doc = pymupdf.open(stream=pdf_bytes, filetype="pdf")
+        if len(src_doc) == 0:
+            return pdf_bytes
+        src_page = src_doc[0]
+
+        # Auto-detect label border/drawings from the original page
+        drawings = src_page.get_drawings()
+        outer_rects = [d["rect"] for d in drawings if d["rect"].width > 200 and d["rect"].height > 350]
+        if outer_rects:
+            label_rect = outer_rects[0]
+        else:
+            label_rect = pymupdf.Rect(211.0, 19.0, 470.0, 469.0)
+
+        # 4x6 inches in PDF points (72 points/inch)
+        TARGET_WIDTH = 288.0   # 4 inches
+        TARGET_HEIGHT = 432.0  # 6 inches
+
+        out_doc = pymupdf.open()
+        new_page = out_doc.new_page(width=TARGET_WIDTH, height=TARGET_HEIGHT)
+
+        padding = 4.0
+        target_rect = pymupdf.Rect(padding, padding, TARGET_WIDTH - padding, TARGET_HEIGHT - padding)
+        new_page.show_pdf_page(target_rect, src_doc, 0, clip=label_rect)
+
+        out_bytes = out_doc.tobytes()
+        out_doc.close()
+        src_doc.close()
+        return out_bytes
+    except Exception as e:
+        logger.warning("Failed to format PDF to 4x6: %s", e)
+        return pdf_bytes
+
 class ShippingServiceClient:
     """
     Client for interacting with Tradhox Shipping Microservice (shippingservice).
@@ -1081,7 +1121,18 @@ class ShippingServiceClient:
                     pdf_pkgs = pdf_json.get('packages', [])
                     if pdf_pkgs and isinstance(pdf_pkgs[0], dict):
                         pdf_url = pdf_pkgs[0].get('pdf_download_link')
-                        pdf_encoding = pdf_pkgs[0].get('pdf_encoding')
+                        raw_encoding = pdf_pkgs[0].get('pdf_encoding')
+                        if raw_encoding:
+                            import base64
+                            raw_bytes = base64.b64decode(raw_encoding.strip())
+                            formatted_4x6 = format_pdf_to_4x6(raw_bytes)
+                            pdf_encoding = base64.b64encode(formatted_4x6).decode('utf-8')
+                        elif pdf_url:
+                            s3_res = requests.get(pdf_url, timeout=6)
+                            if s3_res.status_code == 200:
+                                import base64
+                                formatted_4x6 = format_pdf_to_4x6(s3_res.content)
+                                pdf_encoding = base64.b64encode(formatted_4x6).decode('utf-8')
             except Exception as pdf_exc:
                 logger.warning("Delhivery PDF link lookup notice: %s", pdf_exc)
 

api/views.py

@@ -1640,20 +1640,23 @@ class OrderViewSet(viewsets.ModelViewSet):
         token = getattr(settings, 'DELHIVERY_API_TOKEN', 'e70dfd63665335ee6e0a1094f6d34e17a126f5a6')
         d_url = f"https://track.delhivery.com/api/p/packing_slip?wbns={awb}&pdf=true"
         try:
+            from .shipping_client import format_pdf_to_4x6
             res = requests.get(d_url, headers={"Authorization": f"Token {token}"}, timeout=8)
             if res.status_code == 200:
                 pkgs = res.json().get('packages', [])
                 if pkgs and pkgs[0].get('pdf_encoding'):
                     import base64
                     pdf_bytes = base64.b64decode(pkgs[0]['pdf_encoding'])
-                    response = HttpResponse(pdf_bytes, content_type='application/pdf')
+                    pdf_4x6_bytes = format_pdf_to_4x6(pdf_bytes)
-                    response['Content-Disposition'] = f'inline; filename="delhivery_label_{awb}.pdf"'
+                    response = HttpResponse(pdf_4x6_bytes, content_type='application/pdf')
+                    response['Content-Disposition'] = f'inline; filename="delhivery_label_4x6_{awb}.pdf"'
                     return response
                 elif pkgs and pkgs[0].get('pdf_download_link'):
                     s3_res = requests.get(pkgs[0]['pdf_download_link'], timeout=8)
                     if s3_res.status_code == 200:
-                        response = HttpResponse(s3_res.content, content_type='application/pdf')
+                        pdf_4x6_bytes = format_pdf_to_4x6(s3_res.content)
-                        response['Content-Disposition'] = f'inline; filename="delhivery_label_{awb}.pdf"'
+                        response = HttpResponse(pdf_4x6_bytes, content_type='application/pdf')
+                        response['Content-Disposition'] = f'inline; filename="delhivery_label_4x6_{awb}.pdf"'
                         return response
         except Exception as e:
             logger.error("Failed to fetch label PDF: %s", e)

requirements.txt

@@ -13,3 +13,4 @@ boto3
 djangorestframework-simplejwt
 
 requests
+pymupdf