dart - Write body of HttpClientReques failing? - dart

Question

I was trying to send data to a local server using HttpClient. However, the data is never added to the request, I'm using this code:
new HttpClient().put('127.0.0.1', 4040, '/employees/1').then((request) {
request.cookies.add(new Cookie('DARTSESSID',sessionId)..path = '/');
request.headers.add(HttpHeaders.ACCEPT_ENCODING, "");
request.headers.add(HttpHeaders.CONTENT_TYPE, "text/json");
request.write('{"id": 1, "name": "luis"}');
print(request.contentLength);
return request.close();
}).then(expectAsync((HttpClientResponse response) {
expect(response.statusCode, 200);
UTF8.decodeStream(response).then(expectAsync((body) {
expect(body, equals('"employee: 1"'));
}));
}));
but that always prints that the request.contentLenght is -1. I saw those links before without luck:
https://code.google.com/p/dart/issues/detail?id=13293
dart - HttpClientRequest failing on adding data
https://code.google.com/p/dart/issues/detail?id=10026

Answer 1

A ContentLength of -1 does not mean that there is no data, it means that the length of the content is unknown and that a streaming content mode is used - for HTTP 1.1, this will usually mean Chunked ContentEncoding.
I've tried to insert your code in a setup including a server, but without the unittest stuff:
import 'dart:convert';
import 'dart:io';
void main() {
HttpServer.bind('127.0.0.1', 4040).then((server) {
server.listen((request) {
UTF8.decodeStream(request).then((body) {
print(body);
request.response.close();
});
});
new HttpClient().put('127.0.0.1', 4040, '/employees/1').then((request) {
request.cookies.add(new Cookie('DARTSESSID', "1")..path = '/');
request.headers.add(HttpHeaders.ACCEPT_ENCODING, "");
request.headers.add(HttpHeaders.CONTENT_TYPE, "text/json");
request.write('{"id": 1, "name": "luis"}');
print(request.contentLength);
return request.close();
}).then((HttpClientResponse response) {
UTF8.decodeStream(response).then((body) {
print(body);
});
});
});
}
When I run the code, I get
-1
{"id": 1, "name": "luis"}
as expected. Perhaps the problem you are having are on the server?

Answer 2

Writing to the request is an asynchronous operation. Just because the contentLength says that it still is -1 doesn't mean that the data isn't added to the request before sending it to the server.
Also: the content-length is not supposed to update whenever you add new data. It is the value that is sent to the server. -1 means that you don't know the size yet.
I'm not sure, if the library automatically updates it, if it knows the size, but it doesn't need to.