Search engine for over 5000 entities from .txt files - regex

Question

I have over 5000 .txt files stored locally on my app each file is at least 15 lines of words
So am trying to search with multiple words all over the 5000 list
Finally i was able to search in all of them but with only one problem
The app freezes until the whole process finished
Future<List<FatwaModel>> searchFatawy(String searchText) async {
if (searchText.isEmpty) return [];
emit(SearchFatawyLoadingState());
searchFatawyTxt.clear();
RegExp regExp = RegExp(
RemoveExtinctionsAtWord()
.normalise(searchText)
.trim()
.split(' ')
.where((element) => element.length > 1)
.join('|'),
caseSensitive: false,
);
Future.forEach(fullFatawy, (FatwaModel fatwa) {
bool check = regExp.hasMatch(RemoveExtinctionsAtWord().normalise(
RegExp(r'(?<=:)(.*)(?=)').firstMatch(fatwa.fatwaBody)?.group(0) ?? '',
));
if (check) searchFatawyTxt.add(fatwa);
}).then((value) {
emit(SearchFatawySuccessState());
});
// searchFatawyTxt = fullFatawy
// .where((fatwa) => regExp.hasMatch(RemoveExtinctionsAtWord().normalise(
// RegExp(r'(?<=:)(.*)(?=)').firstMatch(fatwa.fatwaBody)?.group(0) ??
// '',
// )))
// .toList();
//Sorting the list depending on how many keywords found in a single txt file
searchFatawyTxt.sort(
(FatwaModel a, FatwaModel b) {
int aMatchCount = regExp
.allMatches(
RemoveExtinctionsAtWord().normalise(
RegExp(r'(?<=:)(.*)(?=)').firstMatch(a.fatwaBody)?.group(0) ??
'',
),
)
.length;
int bMatchCount = regExp
.allMatches(
RemoveExtinctionsAtWord().normalise(
RegExp(r'(?<=:)(.*)(?=)').firstMatch(b.fatwaBody)?.group(0) ??
'',
),
)
.length;
return bMatchCount.compareTo(aMatchCount);
},
);
return searchFatawyTxt;
}
All am trying to do is showing a progress bar while the search is being process without freezing the app.

Answer 1

Instead of calling that method directly on your app ( on the main thread ), you will need to call it in another isolate that doesn't share a memory with the main thread.
ad the quickest and easiest way to do it is by calling a compute() method which spawns an isolate and runs the provided callback on that isolate, passes it the provided message, and (eventually) returns the value returned by callback.
Future<List<FatwaModel>> isolatedMethod = compute(searchFatawy, searchText);
Note that I am passing your method declaration, not calling it inside the compute().
and now you can use that isolatedMethod as the Future which you will use in your app.