appkit-launcher only injected when event_handler is present (#183)

* appkit-launcher only injected when event_handler is present * add test * add news and docs * pre-commit * Apply suggestions from code review Co-authored-by: Bianca Henderson <beeankha@gmail.com> --------- Co-authored-by: Bianca Henderson <beeankha@gmail.com>
conda · Feb 6, 2024 · db52885 · db52885
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diff --git a/docs/source/defining-shortcuts.md b/docs/source/defining-shortcuts.md
@@ -69,21 +69,36 @@ Unix systems have the notion of MIME types, while Windows relies more on file na
 - On Windows, use `file_extensions`. Remember to add the `%1` or `%*` placeholders to your command
   so the path of the opened file(s) is passed adequately.
 - On macOS, use `CFBundleDocumentTypes`. Requires no placeholder. The opened document will be
-  automatically passed as a regular command-line argument. The file will be dispatched via events.
-  You need to define the `event_handler` field to define a logic that will forward the caught files
-  to your application (via sockets, API calls, inotify or any other inter-process communication
-  mechanism) The association happens via UTI strings (Uniform Type Identifiers). If you need UTIs
-  not defined by Apple, use the `UTImportedTypeDeclarations` field if they are provided by other
-  apps, or `UTExportedTypeDeclarations` if you are defining them yourself.
-
-:::{note}
-On macOS, this feature uses an additional launcher written in Swift to handle the Apple events.
-The Swift runtime libraries are only guaranteed to be available on macOS 10.14.4 and later.
-If you need to support older versions of macOS, you will need to instruct your users to install
-the Swift runtime libraries manually, available at https://support.apple.com/kb/DL1998.
-You can add a dependency on `__osx>=10.14.4` on your conda package if you wish to enforce it.
+  automatically passed as a regular command-line argument. The association happens via UTI strings
+  (Uniform Type Identifiers). If you need UTIs not defined by Apple, use the
+  `UTImportedTypeDeclarations` field if they are provided by other apps, or
+  `UTExportedTypeDeclarations` if you are defining them yourself.
+
+(macos-event-handler)=
+
+:::{admonition} Event handlers in macOS
+:class: note
+
+On macOS, opened files are dispatched via system events. If your application knows how to handle
+these events, then you don't need anything else. However, if your app is not aware of system
+events, you need to set the `event_handler` field to define a logic that will forward the caught
+files to your application (via sockets, API calls, `inotify` or any other inter-process communication
+mechanism). [See `event_handler` example](https://github.com/conda/menuinst/blob/e992e76/tests/data/jsons/file_types.json#L35-L57).
+
+When `event_handler` is set, `menuinst` will inject an additional launcher written in Swift to
+handle the Apple events. The Swift runtime libraries are only guaranteed to be available on macOS
+10.14.4 and later. If you need to support older versions of macOS, you will need to instruct your
+users to install the Swift runtime libraries manually, available at
+https://support.apple.com/kb/DL1998. You can add a dependency on `__osx>=10.14.4` on your conda
+package if you wish to enforce it.
 :::
 
+:::{admonition} Dock blip on macOS
+:class: tip
+
+Note that setting `CFBundleTypeRole` will make the wrapper blip in the dock when the URL is
+opened. If you don't want that, do not set it.
+:::
 
 A multi-platform example:
 
@@ -147,19 +162,8 @@ shortcut.
   so the URLs are passed adequately.
 - On Windows, use `url_protocols`. Remember to add the `%1` or `%*` placeholders to your command so
   the URLs are passed adequately.
-- On macOS, use `CFBundleURLTypes`. Requires no placeholders. The URL will be dispatched via
-  events. You need to define the `event_handler` field to define a logic that will forward the
-  caught URLs to your application (via sockets, API calls, inotify or any other inter-process
-  communication mechanism). Note that setting `CFBundleTypeRole` will make the wrapper blip in the
-  dock when the URL is opened. If you don't want that, do not set it.
-
-:::{note}
-On macOS, this feature uses an additional launcher written in Swift to handle the Apple events.
-The Swift runtime libraries are only guaranteed to be available on macOS 10.14.4 and later.
-If you need to support older versions of macOS, you will need to instruct your users to install
-the Swift runtime libraries manually, available at https://support.apple.com/kb/DL1998.
-You can add a dependency on `__osx>=10.14.4` on your conda package if you wish to enforce it.
-:::
+- On macOS, use `CFBundleURLTypes`. Requires no placeholders. See
+  {ref}`relevant note in File Types <macos-event-handler>`.
 
 ```json
 {

diff --git a/menuinst/platforms/osx.py b/menuinst/platforms/osx.py
@@ -312,15 +312,15 @@ def _needs_appkit_launcher(self) -> bool:
         In macOS, file type and URL protocol associations are handled by the
         Apple Events system. When the user opens on a file or URL, the system
         will send an Apple Event to the application that was registered as a handler.
-        We need a special launcher to handle these events and pass them to the
-        wrapped application in the shortcut.
+        Some apps might not have the needed listener to process the event. In that case,
+        we provide a generic one. This is decided by the presence of "event_handler".
+        If that key is absent or null, we assume the app has its own listener.
 
         See:
         - https://developer.apple.com/library/archive/documentation/Carbon/Conceptual/LaunchServicesConcepts/LSCConcepts/LSCConcepts.html  # noqa
         - The source code at /src/appkit-launcher in this repository
         """
-        needed_keys = ("CFBundleURLTypes", "CFBundleDocumentTypes")
-        return any([self.metadata.get(k) for k in needed_keys])
+        return bool(self.metadata.get("event_handler"))
 
 
 def _lsregister(*args, check=True, **kwargs):

diff --git a/news/183-event-handler b/news/183-event-handler
@@ -0,0 +1,19 @@
+### Enhancements
+
+* <news item>
+
+### Bug fixes
+
+* Do not inject the AppKit launcher unless `event_handler` has been set. Only affects macOS. (#179 via #183)
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>
diff --git a/tests/data/jsons/file_types_no_event_handler.json b/tests/data/jsons/file_types_no_event_handler.json
@@ -0,0 +1,41 @@
+{
+    "$schema": "https://json-schema.org/draft-07/schema",
+    "$id": "https://schemas.conda.io/menuinst-1.schema.json",
+    "menu_name": "Example with file type association and no event handler (macOS only)",
+    "menu_items": [
+        {
+            "name": "FileTypeAssociationNoEventHandler",
+            "description": "Testing file type association without event handler",
+            "icon": null,
+            "command": [
+                "{{ PYTHON }}",
+                "-c",
+                "import sys, pathlib as p; p.Path(r'__OUTPUT_FILE__').write_text(sys.argv[1])"
+            ],
+            "platforms": {
+                "osx": {
+                    "command": [
+                        "bash", "-c", "nc -l 40258 > __OUTPUT_FILE__"
+                    ],
+                    "CFBundleDocumentTypes": [
+                        {
+                            "CFBundleTypeName": "org.conda.menuinst.filetype-example-no-event-handler",
+                            "CFBundleTypeRole": "Viewer",
+                            "LSItemContentTypes": ["org.conda.menuinst.main-file-util-no-event-handler"],
+                            "LSHandlerRank": "Default"
+                        }
+                    ],
+                    "UTExportedTypeDeclarations": [
+                        {
+                            "UTTypeConformsTo": ["public.data", "public.content"],
+                            "UTTypeIdentifier": "org.conda.menuinst.main-file-util-no-event-handler",
+                            "UTTypeTagSpecification": {
+                                "public.filename-extension": ["menuinst-no-event-handler"]
+                            }
+                        }
+                    ]
+                }
+            }
+        }
+    ]
+}
diff --git a/tests/test_api.py b/tests/test_api.py
@@ -43,8 +43,9 @@ def check_output_from_shortcut(
     file_to_open=None,
     url_to_open=None,
 ) -> Tuple[Path, Iterable[Path], str]:
-    assert action in ("run_shortcut", "open_file", "open_url")
+    assert action in ("run_shortcut", "open_file", "open_url", None)
 
+    output = None
     output_file = None
     abs_json_path = DATA / "jsons" / json_path
     contents = abs_json_path.read_text()
@@ -87,7 +88,7 @@ def check_output_from_shortcut(
                     cmd = [str(executable)]
                 process = logged_run(cmd, check=True)
                 output = process.stdout
-        else:
+        elif action is not None:
             if action == "open_file":
                 assert file_to_open is not None
                 with NamedTemporaryFile(suffix=file_to_open, delete=False) as f:
@@ -263,6 +264,25 @@ def test_file_type_association(delete_files):
     assert output.strip().endswith(test_file)
 
 
+@pytest.mark.skipif(sys.platform != "darwin", reason="Only run on macOS")
+@pytest.mark.skipif("CI" not in os.environ, reason="Only run on CI. Export CI=1 to run locally.")
+def test_file_type_association_no_event_handler(delete_files, request):
+    test_file = "test.menuinst-no-event-handler"
+    abs_json_path, paths, tmp_base_path, _ = check_output_from_shortcut(
+        delete_files,
+        "file_types_no_event_handler.json",
+        action=None,
+        file_to_open=test_file,
+        remove_after=False,
+    )
+    request.addfinalizer(lambda: remove(abs_json_path, base_prefix=tmp_base_path))
+    app_dir = next(p for p in paths if p.name.endswith(".app"))
+    info = app_dir / "Contents" / "Info.plist"
+    plist = plistlib.loads(info.read_bytes())
+    cf_bundle_type_name = "org.conda.menuinst.filetype-example-no-event-handler"
+    assert plist["CFBundleDocumentTypes"][0]["CFBundleTypeName"] == cf_bundle_type_name
+
+
 @pytest.mark.skipif("CI" not in os.environ, reason="Only run on CI. Export CI=1 to run locally.")
 def test_url_protocol_association(delete_files):
     url = "menuinst://test/"