examples/deepzoom: load OpenSlide DLL from OPENSLIDE_PATH on Windows

We can't read the path from a command-line option because WSGI apps aren't necessarily invoked as __main__.
openslide · Apr 3, 2021 · 57cca2d · 57cca2d
1 parent bb4c9b6
commit 57cca2d
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Showing 4 changed files with 62 additions and 10 deletions.
diff --git a/.github/workflows/python.yml b/.github/workflows/python.yml
@@ -63,7 +63,7 @@ jobs:
     - name: Install Python tools
       run: |
         python -m pip install --upgrade pip
-        pip install pytest wheel
+        pip install flask pytest wheel
     - name: Install OpenSlide
       run: |
         case "${{ matrix.python-arch }}" in
@@ -87,6 +87,12 @@ jobs:
     - name: Run tests
       # Reads OPENSLIDE_PATH
       run: pytest -v
+    - name: Test library loading in examples
+      # Reads OPENSLIDE_PATH
+      run: |
+        python examples/deepzoom/deepzoom_multiserver.py -h >/dev/null
+        python examples/deepzoom/deepzoom_server.py -h >/dev/null
+        python examples/deepzoom/deepzoom_tile.py -h >/dev/null
     - name: Archive wheel
       uses: actions/upload-artifact@v2
       with:

diff --git a/examples/deepzoom/deepzoom_multiserver.py b/examples/deepzoom/deepzoom_multiserver.py
@@ -21,13 +21,28 @@
 from collections import OrderedDict
 from flask import Flask, abort, make_response, render_template, url_for
 from io import BytesIO
-import openslide
-from openslide import OpenSlide, OpenSlideError
-from openslide.deepzoom import DeepZoomGenerator
 import os
 from optparse import OptionParser
 from threading import Lock
 
+if os.name == 'nt':
+    _dll_path = os.getenv('OPENSLIDE_PATH')
+    if _dll_path is not None:
+        if hasattr(os, 'add_dll_directory'):
+            # Python >= 3.8
+            with os.add_dll_directory(_dll_path):
+                import openslide
+        else:
+            # Python < 3.8
+            _orig_path = os.environ.get('PATH', '')
+            os.environ['PATH'] = _orig_path + ';' + _dll_path
+            import openslide
+            os.environ['PATH'] = _orig_path
+else:
+    import openslide
+from openslide import OpenSlide, OpenSlideError
+from openslide.deepzoom import DeepZoomGenerator
+
 SLIDE_DIR = '.'
 SLIDE_CACHE_SIZE = 10
 DEEPZOOM_FORMAT = 'jpeg'

diff --git a/examples/deepzoom/deepzoom_server.py b/examples/deepzoom/deepzoom_server.py
@@ -20,13 +20,29 @@
 
 from flask import Flask, abort, make_response, render_template, url_for
 from io import BytesIO
-import openslide
-from openslide import ImageSlide, open_slide
-from openslide.deepzoom import DeepZoomGenerator
 from optparse import OptionParser
+import os
 import re
 from unicodedata import normalize
 
+if os.name == 'nt':
+    _dll_path = os.getenv('OPENSLIDE_PATH')
+    if _dll_path is not None:
+        if hasattr(os, 'add_dll_directory'):
+            # Python >= 3.8
+            with os.add_dll_directory(_dll_path):
+                import openslide
+        else:
+            # Python < 3.8
+            _orig_path = os.environ.get('PATH', '')
+            os.environ['PATH'] = _orig_path + ';' + _dll_path
+            import openslide
+            os.environ['PATH'] = _orig_path
+else:
+    import openslide
+from openslide import ImageSlide, open_slide
+from openslide.deepzoom import DeepZoomGenerator
+
 DEEPZOOM_SLIDE = None
 DEEPZOOM_FORMAT = 'jpeg'
 DEEPZOOM_TILE_SIZE = 254

diff --git a/examples/deepzoom/deepzoom_tile.py b/examples/deepzoom/deepzoom_tile.py
@@ -22,16 +22,31 @@
 
 import json
 from multiprocessing import Process, JoinableQueue
-import openslide
-from openslide import open_slide, ImageSlide
-from openslide.deepzoom import DeepZoomGenerator
 from optparse import OptionParser
 import os
 import re
 import shutil
 import sys
 from unicodedata import normalize
 
+if os.name == 'nt':
+    _dll_path = os.getenv('OPENSLIDE_PATH')
+    if _dll_path is not None:
+        if hasattr(os, 'add_dll_directory'):
+            # Python >= 3.8
+            with os.add_dll_directory(_dll_path):
+                import openslide
+        else:
+            # Python < 3.8
+            _orig_path = os.environ.get('PATH', '')
+            os.environ['PATH'] = _orig_path + ';' + _dll_path
+            import openslide
+            os.environ['PATH'] = _orig_path
+else:
+    import openslide
+from openslide import open_slide, ImageSlide
+from openslide.deepzoom import DeepZoomGenerator
+
 VIEWER_SLIDE_NAME = 'slide'
 
 class TileWorker(Process):