00642 Cannot send a file (stream) without caption

On trying (build 00642) await Context.Channel.SendFileAsync(stream, $"{mod}.png", null); I get:

Exception: The server responded with error 50006: Cannot send an empty message

This is strange behaviour, as the default value for text is null. The file sends without errors if I specify a caption. Haven’t tested when passing a path.

Edit: TC: I was using client.GetStreamAsync, the following example will result in the mentioned error:

                using (var client = new System.Net.Http.HttpClient())
                using (var testStream = await client.GetStreamAsync(url))
                        await Context.Channel.SendFileAsync(testStream, "image.png");

while the following does not give this error:

                using (var client = new System.Net.Http.HttpClient())
                {
                    var response = await client.GetByteArrayAsync(url);
                    using (var stream = new MemoryStream(response))
                        await Context.Channel.SendFileAsync(stream, "image.png");
                }

[Auralytical]

I suspect it’s related to this part of HttpClient: https://github.com/dotnet/corefx/blob/master/src/System.Net.Http/src/System/Net/Http/StreamContent.cs#L69

Since the download stream is not seekable, the stream length is unknown and I assume it doesn’t report content-length to Discord. https://github.com/RogueException/Discord.Net/commit/35d7a0cec89398a69fd5d3472fe6980f327f5d00 should fix this by copying to a memory stream if the provided stream’s CanSeek is false.

[Jofairden]

@RogueException Yup, seems to work properly now. Thanks.