Compression

The rpc_dart_compression package provides a cross-platform gzip codec for rpc_dart. It replaces the built-in dart:io gzip implementation, which is native-only, with one backed by package:archive that works on all platforms — native, web, JS, and Wasm.

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Setup

dependencies:
  rpc_dart_compression: ^0.1.0

Call RpcGzipCodec.register() once at application startup, before creating any endpoints:

import 'package:rpc_dart_compression/rpc_dart_compression.dart';

void main() {
  RpcGzipCodec.register();
  // ...
}

That's it. Registration adds the codec to the RpcGrpcCompression registry under the 'gzip' encoding key. Any endpoint with compression enabled will use it automatically.

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How It Works

rpc_dart uses a compression registry (RpcGrpcCompression) that maps encoding names to codec implementations. When a message is sent over a transport that has compression enabled, the framework looks up the codec by name, compresses the payload, and sets the compression flag in the 5-byte gRPC message header.

RpcGzipCodec.register() is equivalent to:

RpcGrpcCompression.register(RpcGrpcCompression.gzip, const RpcGzipCodec());

Registering a second time replaces the previous codec for that encoding — so calling register() on web overrides the native dart:io codec if it was registered earlier.

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Enabling Compression on an Endpoint

Compression is controlled on the RpcCallerEndpoint:

final callerEndpoint = RpcCallerEndpoint(
  transport: transport,
  compressionEnabled: true,
);

Note

Compression is automatically disabled for RpcInMemoryTransport regardless of the flag — zero-copy transfer makes it pointless.

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Custom Codecs

You can register additional compression codecs by implementing RpcCompressionCodec:

class MyBrotliCodec implements RpcCompressionCodec {
  @override
  Uint8List compress(Uint8List data) { ... }

  @override
  Uint8List decompress(Uint8List data) { ... }
}

RpcGrpcCompression.register('br', const MyBrotliCodec());