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wire v3.0.0-alpha01 Release Notes

Release Date: 2019-03-14 // about 5 years ago

  • 2019-03-14

    • New: Kotlin Generator

    Wire 3 can generate Kotlin data classes. To enable this feature via the command line API, pass in the --kotlin_out parameter that should specify the output directory for the generated *.kt files.

    Given the following simple proto:

       message Person {
     required string name = 1;
     required int32 id = 2;
     optional string email = 3;
   }

    the generated Kotlin code will look like the following:

       data class Person(
     @field:WireField(tag = 1, adapter = "com.squareup.wire.ProtoAdapter#STRING") 
     val name: String,
     @field:WireField(tag = 2, adapter = "com.squareup.wire.ProtoAdapter#INT32") 
     val id: Int,
     @field:WireField(tag = 3, adapter = "com.squareup.wire.ProtoAdapter#STRING") 
     val email: String? = null,
     val unknownFields: ByteString = ByteString.EMPTY
   ) : Message<Person, Person.Builder>(ADAPTER, unknownFields) {
     companion object {
       @JvmField
       val ADAPTER: ProtoAdapter<Person> = ... // code omitted for brevity

    The copy() method of a data class replaces most usages of the builder. If your code relies on the Builder, you can enable full Builder generation by passing the --java_interop parameter to the compiler.

    • New: gRPC support

    In addition to generating Kotlin code from proto messages, Wire can now generate code for gRPC endpoints. Here's an example schema:

       service RouteGuide {
     // A simple RPC.
     //
     // Obtains the feature at a given position.
     //
     // A feature with an empty name is returned if there's no feature at the given
     // position.
     rpc GetFeature(Point) returns (Feature) {}
   }

    The generated code will look like the following (message protos, referenced by the schema, are omitted):

       interface RouteGuide : Service {
     @WireRpc(
         path = "/routeguide.RouteGuide/GetFeature",
         requestAdapter = "routeguide.Point#ADAPTER",
         responseAdapter = "routeguide.Feature#ADAPTER"
     )
     suspend fun GetFeature(request: Point): Feature
   }

    All four gRPC modes are supported: the generated code uses suspendable functions to implement non-blocking asynchronous execution. In streaming modes, ReceiveChannel and SendChannel are used to listen to asynchronous data in a non-blocking fashion.

    This feature works out of the box in Wire 3 compiler as long as the input file contains a gRPC schema.

    • New: Gradle plugin

    Here's an example Gradle configuration:

       apply plugin: 'com.squareup.wire'

   wire {
     // Keeps only 'Dinosaur#name' as the root of the object graph
     roots 'squareup.dinosaurs.Dinosaur#name'

     // Keeps all fields, except 'name', in 'Dinosaur'
     prunes 'squareup.dinosaurs.Dinosaur#name'

     // Both roots and prunes in an external file
     rules 'rules.txt'

     kotlin {
       javaInterop true
       out "${buildDir}/generated/custom"
     }
   }

    The wire extension introduces the concept of compilation targets, such as kotlin and java, where each target has its own configuration properties. Multiple targets can be supplied, which benefits use cases such as migrating Java protos to Kotlin.

    • New: Decouple the option of using Android annotations for nullability from the option of having messages implement Parcelable.
    • New: Wire Moshi adapter for serializing proto JSON representation using the Moshi library.
    • New: Implement support for custom enum types.
    • New: Generate AndroidX nullability annotations instead of old support library annotations.
    • New: Import JSR 305 and use it to mark nullability of public API.
    • New: Allow inline multiline comments.
    • New: Generate an empty class when a nested message is retained but its parent was pruned.
    • New: Support rendering a ProtoFile to its schema.
    • New: Support hexadecimal numeric literals.
    • New: Allow custom types to be constrained with a 'with' clause.
    • New: Generate a constructor which takes in a Message.Builder instead of all fields separately.
    • New: Add location to the error message about unsupported group elements.
    • New: Permit single files to be used on the proto path.
    • Fix: Emit '=' for syntax declaration.
    • Fix: Don't crash when a comment has a dollar sign.
    • Fix: Return subclass type instead of abstract parameterized type for newBuilder.
    • Fix: Validate enum namespace in file context are unique.