[dart-misc] Send a file via POST (server-side only)

[Rodrigo Muniz]

Hi folks!

I am developing a Telegram Bot, and I need to send a file via POST as
attachment to an user (e.g. a .txt file). Upon this, I have two questions:


- Which file type should I use in order to send a file? I heard about
Stream, but I am unsure about it;
- Having the right file type, how can I send it as a parameter for the
url POST? I tried the http library and built-in solutions. Here is a
snippet of the code I'm using right now:

Future<dynamic> sendRequest(String method, url, {json}) async {
BaseClient bs = new IOClient();
var request = new Request(method, url);
request.headers['Content-Type'] = 'application/json';
request.body = JSON.encode(json);
var streamedResponse = await bs.send(request);
var response = await Response.fromStream(streamedResponse);

var bodyJson;
try {
bodyJson = JSON.decode(response.body);
} on FormatException {
var contentType = response.headers['content-type'];
if (contentType != null && !contentType.contains('application/json'))
{
throw new Exception(
'Returned value was not JSON. Did the uri end with ".json"?');
}
rethrow;
}

if (response.statusCode != 200) {
if (bodyJson is Map) {
var error = bodyJson['error'];
if (error != null) {
throw error;
}
}
throw bodyJson;
}

return bodyJson;
}

Any ideas?