[firebase_storage] Fix putFile method's Content-Type auto-detection for iOS

[mono0926]

• putFile should use putFile iOS SDK method correctly
• putFile should auto-detect Content-Type automatically by file extension if not specified

I tested at this sample on iOS:
https://github.com/flutter/plugins/blob/master/packages/firebase_storage/example/lib/main.dart.

This uses putFile here:

plugins/packages/firebase_storage/example/lib/main.dart

Line 66 in 04d6f52

final StorageUploadTask uploadTask = ref.putFile(

Before this pull request

Uploaded file:
https://firebasestorage.googleapis.com/v0/b/flutter-firebase-plugins.appspot.com/o/text%2Ffoob3d87700-3260-11e9-d838-d7a1f7b2a3d4.txt

contentType is application/octet-stream, but this is unintended value because putFile should auto-detect contentType as written this document.

The putFile: method automatically infers the content type from the NSURL filename extension, but you can override the auto-detected type by specifying contentType in the metadata. If you do not provide a contentType and Cloud Storage cannot infer a default from the file extension, Cloud Storage uses application/octet-stream.
https://firebase.google.com/docs/storage/ios/upload-files#add_file_metadata

In this case, the file's extension is txt, so contentType should be plain/text.

After this pull request

Uploaded file:
https://firebasestorage.googleapis.com/v0/b/flutter-firebase-plugins.appspot.com/o/text%2Ffoo09aa2e30-3260-11e9-efe1-e3ed438ea03f.txt

contentType is plain/text, which is intended value.

[mono0926]

Android's uploaded file URL:
https://firebasestorage.googleapis.com/v0/b/flutter-firebase-plugins.appspot.com/o/text%2Ffoo47306190-3260-11e9-a8ff-931a12d4e7ce.txt

contentType is blank(neither application/octet-stream nor plain/text), but I do not know why this happens.

putFile seems to use putFile correctly 🤔

plugins/packages/firebase_storage/android/src/main/java/io/flutter/plugins/firebase/storage/FirebaseStoragePlugin.java

Lines 258 to 272 in 04d6f52

	private void putFile(MethodCall call, Result result) {
	String filename = call.argument("filename");
	String path = call.argument("path");
	Map<String, Object> metadata = call.argument("metadata");
	File file = new File(filename);
	StorageReference ref = firebaseStorage.getReference().child(path);
	UploadTask uploadTask;
	if (metadata == null) {
	uploadTask = ref.putFile(Uri.fromFile(file));
	} else {
	uploadTask = ref.putFile(Uri.fromFile(file), buildMetadataFromMap(metadata));
	}
	final int handle = addUploadListeners(uploadTask);
	result.success(handle);
	}

For your information, if these lines commented out, contentType changed to application/octet-stream 🤔

plugins/packages/firebase_storage/example/lib/main.dart

Lines 68 to 71 in 04d6f52

	StorageMetadata(
	contentLanguage: 'en',
	customMetadata: <String, String>{'activity': 'test'},
	),

https://firebasestorage.googleapis.com/v0/b/flutter-firebase-plugins.appspot.com/o/text%2Ffooe5417810-3260-11e9-c95c-995c37e340ac.txt

[collinjackson]

Thank you so much for this PR.

Could you please write a CHANGELOG and update pubspec.yaml for release?

It looks like it might be possible to update the integration test to include the test for the correct behavior here. Would you be willing to add that?

https://github.com/flutter/plugins/blob/master/packages/firebase_storage/example/test_driver/firebase_storage.dart

[mono0926]

@collinjackson

I've added commits:

Could you please write a CHANGELOG and update pubspec.yaml for release?

1a1563b

It looks like it might be possible to update the integration test to include the test for the correct behavior here. Would you be willing to add that?

778d6a6

Could you check that please?

[collinjackson]

Thanks for the contribution! Since this is a pre-1.0 plugin and this bug fix doesn't affect the public API of the plugin, I'm updating the version to make it a patch change.