I am doing a post request like this in flutter using HTTP dart package but sometimes when the network fails a ClientException is thrown from IOClient class but I don't get anything in catch block and app crashes.
http.post(url, headers: headers, body: body).then((response) {
//response parsing
}).catchError((error) {
//ClientException is never catched in this block.
});
As mentioned in package:http/src/io_client.dart:
Any internal HTTP errors should be wrapped as [ClientException]s.
As mentioned in the docs this is a clear case of:
Potential problem: accidentally mixing synchronous and asynchronous errors
To resolve this issue, you need to wrap your code in Future.sync().
Future.sync() makes your code resilient against uncaught exceptions. If your function has a lot of code packed into it, chances are that you could be doing something dangerous without realizing it:
return new Future.sync(() {
http.post(url, headers: headers, body: body).then((response) {});
});
Future.sync() not only allows you to handle errors you know might occur, but also prevents errors from accidentally leaking out of your function.
In my case the call was to an https address using Microsoft Internet Information Services as backend, in the SSL settings of the website in IIS i had mistakenly set "Client certificates: Accept" instead of "Client certificates: Ignore", setting "Ignore" solved the problem.
Just goto your C:\Users{user}\AppData\Local\Pub and delete the cache folder.
From the IOClient class docs, here's how ClientException class is used to handle exceptions coming from pkg/http client;
final client = http.Client();
late String data;
try {
data = await client.post(url, headers: headers, body: body);
} on SocketException catch (e) {
// Exception is transport-related, check `e.osError` for more details.
} on http.ClientException catch (e) {
// Exception is HTTP-related (e.g. the server returned a 404 status code).
// If the handler for `SocketException` were removed then all exceptions
// would be caught by this handler.
}
try{ ... } catch (e) { }?onErroras shown in dartlang.org/guides/libraries/futures-error-handling