How can I invoke and use Google Cloud Functions in a Flutter app? - json

Question

I have created a url scraper function, working and tested on Google Cloud, but I am really drawing a blank on how to invoke it. I have tried two methods, one using the cloud_functions package, and the other using a standard HTTPS get. I've tried looking online, but none of the solutions/guides involve functions with an input from the Flutter app, and an output back to the app.
Here's the structure of the function (which is working alright). I've named this function Parse in Google Cloud Platform.
<PYTHON PACKAGE IMPORTS>
def Parser(url):
<URL PARSE FUNCTIONS>
return source, datetime, imageurl, keyword
def invoke_parse(request):
request_json = request.get_json(silent=True)
file = Parser(request_json['url'])
return jsonify({
"source": file[0],
"datetime": file[1],
"imageurl": file[2],
"keyword": file[3],
})
The first method I tried was using an HTTP CALL to get the function. But that isn't working, even though there are no errors - I suspect it's just returning nothing.
parser(String url) async{ // Here I honestly don't know where to use the url input within the function
var uri = Uri.parse(<Function URL String>);
HttpClient client;
try {
var request = await client.getUrl(uri);
var response = await request.close();
if (response.statusCode == HttpStatus.ok) {
var json = await response.transform(utf8.decoder).join();
Map data = jsonDecode(json) as Map;
source = data['source']; // These are the variables used in the main Flutter app
postedAt = data['datetime'];
_imageUrl = data['image'];
keyword = data['keyword'];
} else {
print('Error running parse:\nHttp status ${response.statusCode}');
}
} catch (exception) {
print('Failed invoking the parse function.');
}
}
That didn't work, so I thought I might alternatively use the cloud_functions package as follows (in lieu of the previous):
parser(String url) async {
var functionUrl = <FUNCTION URL>;
HttpsCallable callable = CloudFunctions.instance.getHttpsCallable(functionName: 'Parse')
..timeout = const Duration(seconds: 30);
try {
final HttpsCallableResult result = await callable.call(
<String, dynamic>{
'url': url,
}
);
setState(() {
source = result.data['source']; //THESE ARE VARIABLES USED IN THE FLUTTER APP
postedAt = result.data['datetime'];
_imageUrl = result.data['image'];
keyword = result.data['keyword'];
});
}
on CloudFunctionsException catch (e) {
print('caught firebase functions exception');
print(e.code);
print(e.message);
print(e.details);
} catch (e) {
print('caught generic exception');
print(e);
}
}
In the latter case, the code ran without errors but doesn't work. My flutter log states the following error:
I/flutter ( 2821): caught generic exception
I/flutter ( 2821): PlatformException(functionsError, Cloud function failed with exception., {code: NOT_FOUND, details: null, message: NOT_FOUND})
which I'm assuming is also an error at not being able to read the function.
Any help on how I should go about processing my function would be appreciated. Apologies if something is a really obvious solution, but I am not familiar as much with HTTP requests and cloud platforms.
Thanks and cheers.

Answer 1

Node Js Backend Function
const functions = require("firebase-functions");
const admin = require("firebase-admin");
admin.initializeApp();
exports.test = functions.https.onCall(async (data, context) => {
functions.logger.info("Hello logs: ", {structuredData: true});
functions.logger.info( data.token, {structuredData: true});
}
Flutter frontend
1- pubspec.yaml
cloud_functions: ^1.1.2
2 - Code
HttpsCallable callable = FirebaseFunctions.instance.httpsCallable('test');
final HttpsCallableResult results = await callable.call<Map>( {
'token': token,
});