Merge branch 'image-download-output-none' into 'main'

New decorator to make sure output is defined when it should be

See merge request !455

dan/datasets/download/images.py

@@ -3,6 +3,7 @@
 
 # -*- coding: utf-8 -*-
 
+import functools
 import json
 import logging
 import pickle
@@ -39,6 +40,19 @@ IIIF_FULL_SIZE = "full"
 logger = logging.getLogger(__name__)
 
 
+def output_attr_required(func):
+    """
+    Always check that the output attribute is not null.
+    """
+
+    @functools.wraps(func)
+    def wrapper(self, *args, **kwargs):
+        assert self.output is not None, "Define an output folder to download images."
+        return func(self, *args, **kwargs)
+
+    return wrapper
+
+
 class ImageDownloader:
     """
     Download images from extracted data
@@ -46,21 +60,22 @@ class ImageDownloader:
 
     def __init__(
         self,
-        output: Path,
+        output: Path | None = None,
         max_width: int | None = None,
         max_height: int | None = None,
         image_extension: str = "",
         unknown_token: str = "⁇",
     ) -> None:
-        self.output = output
+        self.output: Path | None = output
 
-        self.max_width = max_width
-        self.max_height = max_height
-        self.image_extension = image_extension
-        self.data: Dict = defaultdict(dict)
-        self.unknown_token = unknown_token
+        self.max_width: int | None = max_width
+        self.max_height: int | None = max_height
+        self.image_extension: str = image_extension
+        self.data: dict[str, dict] = defaultdict(dict)
+        self.unknown_token: str = unknown_token
 
-    def load_split_data(self):
+    @output_attr_required
+    def load_split_data(self) -> None:
         """
         Load the dataset stored in `split.json` and initializes the charset.
         """
@@ -136,6 +151,7 @@ class ImageDownloader:
         # Rotations are done using the lib
         return IIIF_URL.format(image_url=image_url, bbox=get_bbox(polygon), size=size)
 
+    @output_attr_required
     def build_tasks(self) -> List[Dict[str, str]]:
         tasks = []
         for split, items in self.split.items():
@@ -264,6 +280,7 @@ class ImageDownloader:
             logger.error(f"Failed to download {len(failed_downloads)} image(s).")
             print(*list(map(": ".join, failed_downloads)), sep="\n")
 
+    @output_attr_required
     def export(self) -> None:
         """
         Writes a `labels.json` file containing a mapping of the images that have been correctly uploaded (identified by its path)
@@ -281,6 +298,7 @@ class ImageDownloader:
             pickle.dumps(sorted(list(self.charset)))
         )
 
+    @output_attr_required
     def run(self) -> None:
         """
         Download the missing images from a `split.json` file and build a `labels.json` file containing
@@ -288,7 +306,7 @@ class ImageDownloader:
         to the ground-truth transcription (with NER tokens if needed).
         """
         self.load_split_data()
-        tasks: List[Dict[str, str]] = self.build_tasks()
+        tasks: list[dict[str, str]] = self.build_tasks()
         self.download_images(tasks)
         self.export()
 

tests/test_download.py

@@ -11,7 +11,11 @@ from pathlib import Path
 import pytest
 from PIL import Image, ImageChops
 
-from dan.datasets.download.images import IIIF_FULL_SIZE, ImageDownloader
+from dan.datasets.download.images import (
+    IIIF_FULL_SIZE,
+    ImageDownloader,
+    output_attr_required,
+)
 from dan.datasets.download.utils import download_image
 from dan.utils import parse_tokens
 from line_image_extractor.image_utils import BoundingBox
@@ -250,3 +254,23 @@ def test_download_image_error_try_max(responses, caplog):
 
     # We should only have WARNING levels
     assert set(level for _, level, _ in caplog.record_tuples) == {logging.WARNING}
+
+
+def test_output_attr_required():
+    class TestImageDownloader:
+        output: Path | None = None
+
+        @output_attr_required
+        def image_downloader_method(self, *args, **kwargs):
+            return True
+
+    downloader = TestImageDownloader()
+
+    with pytest.raises(
+        AssertionError, match="Define an output folder to download images."
+    ):
+        downloader.image_downloader_method()
+
+    # Set downloader.output
+    downloader.output = Path()
+    assert downloader.image_downloader_method()