Reduced storage requirements for barcode scanning. Added limit for pages to scan barcodes on.

docs/configuration.md

@@ -1289,6 +1289,18 @@ combination with PAPERLESS_CONSUMER_BARCODE_UPSCALE bigger than 1.0.
 
     Defaults to "300"
 
+#### [`PAPERLESS_CONSUMER_BARCODE_MAX_PAGES=<int>`](#PAPERLESS_CONSUMER_BARCODE_MAX_PAGES) {#PAPERLESS_CONSUMER_BARCODE_MAX_PAGES}
+
+: Barcode detection is a computationaly intensive operation. This setting
+limits the recognition of barcodes to a number of first pages. Since many
+scanners have a limit for the number of pages that can be scanned it is
+sensible to set this as the limit here. If a longer document is encountered
+it is imported directly and not via scanner there should also be no barcodes
+present. By setting this value to 0 the upper limit is disabled. This is also
+the default setting.
+
+    Defaults to "0"
+
 #### [`PAPERLESS_CONSUMER_ENABLE_TAG_BARCODE=<bool>`](#PAPERLESS_CONSUMER_ENABLE_TAG_BARCODE) {#PAPERLESS_CONSUMER_ENABLE_TAG_BARCODE}
 
 : Enables the detection of barcodes in the scanned document and

src/documents/barcodes.py

@@ -1,4 +1,5 @@
 import logging
+import os
 import re
 import tempfile
 from dataclasses import dataclass
@@ -7,6 +8,7 @@ from typing import Optional
 
 from django.conf import settings
 from pdf2image import convert_from_path
+from pdf2image import pdfinfo_from_path
 from pdf2image.exceptions import PDFPageCountError
 from pikepdf import Page
 from pikepdf import Pdf
@@ -231,13 +233,37 @@ class BarcodePlugin(ConsumeTaskPlugin):
             logger.debug("Scanning for barcodes using ZXING")
 
         try:
-            pages_from_path = convert_from_path(
+            # Read number of pages from pdf
+            num_of_pages = pdfinfo_from_path(self.pdf_file)["Pages"]
+            logger.debug(f"PDF has {num_of_pages} pages")
+
+            # Get limit from configuration
+            barcode_max_pages = settings.CONSUMER_BARCODE_MAX_PAGES
+            if barcode_max_pages == 0:
+                barcode_max_pages = num_of_pages
+
+            if barcode_max_pages < num_of_pages:
+                logger.debug(f"Reading of barcodes is limited to the first {barcode_max_pages} pages")
+
+            # Loop al page
+            for current_page_number in range(min(num_of_pages, barcode_max_pages)):
+                logger.debug(f"Processing page {current_page_number}")
+
+                # Convert page to image
+                logger.debug("Converting page to image")
+                page = convert_from_path(
                     self.pdf_file,
                     dpi=settings.CONSUMER_BARCODE_DPI,
                     output_folder=self.temp_dir.name,
-            )
+                    first_page=current_page_number + 1,
+                    last_page=current_page_number + 1,
+                )[0]
 
-            for current_page_number, page in enumerate(pages_from_path):
+                # Remember filename, since it is lost by upscaling
+                page_filename = page.filename
+                logger.debug(f"Image is at {page_filename}")
+
+                # Upscale image if configured
                 factor = settings.CONSUMER_BARCODE_UPSCALE
                 if factor > 1.0:
                     logger.debug(
@@ -248,11 +274,17 @@ class BarcodePlugin(ConsumeTaskPlugin):
                         (int(round(x * factor)), (int(round(y * factor)))),
                     )
 
+                # Detect barcodes
+                logger.debug("Detecting barcodes")
                 for barcode_value in reader(page):
                     self.barcodes.append(
                         Barcode(current_page_number, barcode_value),
                     )
 
+                # Delete temporary image file
+                logger.debug("Cleaning up temporary image file")
+                os.remove(page_filename)
+
         # Password protected files can't be checked
         # This is the exception raised for those
         except PDFPageCountError as e:

src/paperless/settings.py

@@ -925,6 +925,8 @@ CONSUMER_BARCODE_UPSCALE: Final[float] = __get_float(
 
 CONSUMER_BARCODE_DPI: Final[int] = __get_int("PAPERLESS_CONSUMER_BARCODE_DPI", 300)
 
+CONSUMER_BARCODE_MAX_PAGES: Final[int] = __get_int("PAPERLESS_CONSUMER_BARCODE_MAX_PAGES", 0)
+
 CONSUMER_ENABLE_TAG_BARCODE: Final[bool] = __get_boolean(
     "PAPERLESS_CONSUMER_ENABLE_TAG_BARCODE",
 )