feat: add exif orientation tag value to mss docs

Author: jrdh

dataimporter/emu/views/mss.py

@@ -66,6 +66,20 @@ def transform(self, record: SourceRecord) -> dict:
             "file": identifiers[0],
         }
 
+        # add the orientation tag data from exif if specified
+        tags = record.get_all_values("ExiTag", reduce=False)
+        tag_values = record.get_all_values("ExiValue", reduce=False)
+        if tags and tag_values:
+            try:
+                # the orientation tag is 274 (0x0112), so look up the index of that in
+                # the tags tuple and then the value will be at the same index in the
+                # values tuple. Because EMu, the value can be either a number or the
+                # text version, e.g. "7" or "Rotate 270 CW"
+                data["orientation"] = tag_values[tags.index("274")]
+            except ValueError:
+                # no orientation in the tags so there's nothing to do
+                pass
+
         # add old MAM asset IDs if found
         old_asset_id = record.get_first_value("GenDigitalMediaId")
         if old_asset_id and old_asset_id != "Pending":

tests/emu/views/test_mss.py

@@ -39,6 +39,7 @@ def test_transform(mss_view: MSSView):
         "file": "BM000019319.tif",
         "width": 6638,
         "height": 10199,
+        "orientation": "Horizontal (normal)",
         "derivatives": [
             {"file": "BM000019319.thumb.jpg", "width": 59, "height": 90},
             {"file": "BM000019319.120x10199.jpeg", "width": 120, "height": 184},
@@ -67,3 +68,16 @@ def test_transform_no_derivatives(mss_view: MSSView):
         "width": 6638,
         "height": 10199,
     }
+
+
+def test_transform_no_orientation(mss_view: MSSView):
+    data = SAMPLE_IMAGE_DATA.copy()
+    # remove the exif tag in our sample data which stores the orientation value (and all
+    # the associated tag and tag name bits EMu exports)
+    for field in ["ExiTag", "ExiName", "ExiValue"]:
+        # in the test data the orientation tag is the 8th element of the exif lists
+        del data[field][8]
+    record = SourceRecord(SAMPLE_IMAGE_ID, data, "test")
+
+    data = mss_view.transform(record)
+    assert "orientation" not in data