/// <summary>
/// This Compress message method is called whenever the module is sent a message from the EdgeHub.
/// It just pipe the messages without any change.
/// It prints all the incoming messages.
/// </summary>
static async Task <MessageResponse> CompressMessage(Message message, object userContext)
{
var moduleClient = userContext as ModuleClient;
if (moduleClient == null)
{
throw new InvalidOperationException("UserContext doesn't contain expected values");
}
await moduleClient.CompleteAsync(message);
byte[] messageBytes = message.GetBytes(); //returns the BodyStream of the message as bytes
Console.WriteLine($"Received message with body size: {messageBytes.Length}");
if (messageBytes.Length > 0)
{
var compressedMessageData = CompressionClass.Compress(messageBytes);
var outMessage = new Message(compressedMessageData);
// copy properties from original message to new message
foreach (var prop in message.Properties)
{
outMessage.Properties.Add(prop.Key, prop.Value);
}
// add a new property indicating the message is compressed with gzip so the backend can handle compressed and non-compressed messages
outMessage.Properties.Add("compression", "gzip");
await moduleClient.SendEventAsync("compressMessageOutput", outMessage);
Console.WriteLine($"Sent compressed message with body size: {compressedMessageData.Length}");
}
else
{
var outMessage = new Message(messageBytes);
foreach (var prop in message.Properties)
{
outMessage.Properties.Add(prop.Key, prop.Value);
}
await moduleClient.SendEventAsync("compressMessageOutput", outMessage);
Console.WriteLine("Message had no body and was passed as-is.");
}
return(MessageResponse.None);
}
public void Compress_Decompress_Returns_Original_Data()
{
var compressedData = CompressionClass.Compress(decompressedContentData);
Assert.Equal(decompressedContentData, CompressionClass.Decompress(compressedData));
}
public void Compress_Empty_Buffer_Returns_Empty_Buffer()
{
Assert.Equal(emptyMsgData, CompressionClass.Compress(emptyMsgData));
}