Compression

By default, the body of the HTTP packets is uncompressed. When only small messages are sent and received, this is usually no problem. But if traffic should be reduced or if large objects are transmitted, it may be worth compressing the payload.

Compression strategies

Messages can be compressed in both directions, i.e. the requests and the responses can be compressed or not. The possible strategies are:

• Disabled: Do not compress messages (default setting)
• Auto: Compress messages which are at least CompressionThresholdBytes bytes long (default value is 1 kB)
• Enabled: Compress all messages (little effect on small messages, but higher workload for compressing and uncompressing)

The setting CompressionThresholdBytes applies only, when the Auto strategy is used.

Default settings

When initializing the library (both on server side, using IServiceCollection.InitRpcServer, and client side, using RpcMain.InitRpcClient), the default compression strategy can be given. Here is an example for the client:

RpcMain.InitRpcClient(/*...*/ new RpcSettings {
    Compression = RpcCompressionStrategy.Auto,
    CompressionThresholdBytes = 1500
});

Settings per method

Additionally, the used compression strategy may be changed for each method individually. For example:

interface IRemoteLogger : IRpcFunctions {
   [RpcOptions(Compression = RpcCompressionStrategy.Enabled)]
   Task SaveMessage(string message);
}

The CompressionDemo project demonstrates this in the ITextRpc interface. When running the demo (starting the client and the server simultaneously) and having a look at the HTTP network traffic (using a tool like Fiddler for example), the effects can be observed.

Compression technique

Uncompressed messages are transferred in plaintext JSON (application/json). When a message is compressed, the whole body of the HTTP packet (the RPC object including its serialized method and parameters) is gzipped to binary data and the Content-Type changes to application/gzip. Uncompressing this data will result in the original JSON object.