Dart/Flutter: URI/HTTPClient - disable automatic escaping of %

Question

I have a problem with the dart/flutter URI implementation. % is automatically replaced by %25.

i want to access the following URL: http://some.domain/json.php?key=%DF [%DF=ß in ASCII/latin1]

the code:

    final uri = Uri.http('some.domain', 'json.php', {'key': 'ß'});

results in http://some.domain/json.php?key=%C3%9F [ß in UTF-8]

when trying

    final uri = Uri.http('some.domain', 'json.php', {'key': '%DF'});

it results in: http://some.domain/json.php?key=%25DF [% automatically escaped to %25]

when trying explicit encoding:

    final uri = Uri.http('some.domain', 'json.php',
        {'key': Uri.encodeQueryComponent('ß', encoding: latin1)});      

it results in: http://some.domain/json.php?key=%25DF [% automatically escaped to %25]

How can I disable the automatic encoding of % to %25?!

any ideas?

Solution

The queryParameters parameter of the Uri.http constructor expects an unencoded map of data that it encodes using it's own standard, since you need to use another standard for this case might be better to use the Uri constructor and build your own query string and pass to the query parameter.

Something like this should do the trick:

final uri = Uri(
  scheme: 'http',
  host: 'some.domain',
  path: 'json.php',
  query: 'key=${Uri.encodeQueryComponent('ß', encoding: latin1)}'
);

Comments

[Bridystone]

YES YES YES! :) Thanks very much for this fast support - IT WORKS. I debugged 2 hours with a short deep dive into the dart core code, to see that there is enforced encoding in queryParameters that this circumvents the issue is great!