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https://github.com/ichizero/connect-ktor
Connect-Ktor: Bring Connect Protocol support to your Ktor servers.
https://github.com/ichizero/connect-ktor
connectrpc grpc java kotlin ktor ktor-server protobuf
Last synced: about 2 months ago
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Connect-Ktor: Bring Connect Protocol support to your Ktor servers.
- Host: GitHub
- URL: https://github.com/ichizero/connect-ktor
- Owner: ichizero
- License: apache-2.0
- Created: 2024-10-20T17:49:17.000Z (4 months ago)
- Default Branch: main
- Last Pushed: 2024-12-15T18:09:45.000Z (about 2 months ago)
- Last Synced: 2024-12-15T19:19:22.927Z (about 2 months ago)
- Topics: connectrpc, grpc, java, kotlin, ktor, ktor-server, protobuf
- Language: Kotlin
- Homepage:
- Size: 154 KB
- Stars: 9
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Connect-Ktor
[](https://central.sonatype.com/artifact/io.github.ichizero/protoc-gen-connect-ktor)
[](https://opensource.org/licenses/Apache-2.0)
Connect-Ktor is a library developed as an extension of
[Connect-Kotlin](https://github.com/connectrpc/connect-kotlin)
for [Ktor](https://github.com/ktorio/ktor) servers.
It aims to gradually introduce the Connect Protocol into existing Ktor REST servers.
## Features
- connect-ktor
- Serialize/Deserialize Protocol Buffers JSON messages with Connect-Kotlin.
- Request validation support with [protovalidate](https://github.com/bufbuild/protovalidate).
- protoc-gen-connect-ktor
- Generate Ktor route handler interfaces from Protocol Buffers service definitions.
## Usage
### Add dependencies
Add the conenct-ktor library to your build.gradle.kts.
```kotlin
dependencies {
implementation("io.github.ichizero:connect-ktor:0.0.3")
}
```
### Generation
#### 1. Setup protoc-gen-connect-ktor
On Linux or macOS, install the plugin with [Homebrew](https://brew.sh/).
```bash
brew install ichizero/tap/protoc-gen-connect-ktor
```
Alternatively, you can download the plugin executable file from
[releases](https://github.com/ichizero/connect-ktor/releases)
and place it in your PATH.
#### 2. Add plugins to your buf.gen.yaml
```yaml
version: v2
clean: true
managed:
enabled: true
plugins:
- remote: buf.build/protocolbuffers/java
out: path/to/code
- remote: buf.build/protocolbuffers/kotlin
out: path/to/code
- remote: buf.build/connectrpc/kotlin
out: path/to/code
- local: protoc-gen-connect-ktor
out: path/to/code
```
#### 3. Generate the Ktor route handler interfaces
```bash
buf generate
```
Generated handler interface is like below:
```kotlin
public interface ElizaServiceHandler {
public suspend fun say(request: SayRequest, call: ApplicationCall): ResponseMessage
public object Procedures {
@Resource("/connectrpc.eliza.v1.ElizaService/Say")
public class Say
}
}
public fun Route.elizaService(handler: ElizaServiceHandler) {
post(handle(handler::say))
}
```
### Implementation
#### 1. Implement the generated handler interface
```kotlin
object ElizaServiceHandlerImpl : ElizaServiceHandler {
override suspend fun say(
request: SayRequest,
call: ApplicationCall,
): ResponseMessage = ResponseMessage.Success(
sayResponse { sentence = request.sentence },
emptyMap(),
emptyMap(),
)
}
```
#### 2. Register the handler in the Ktor server
```kotlin
fun main() {
embeddedServer(CIO, port = 8080) {
install(Resources)
routing {
install(ContentNegotiation) {
connectJson()
}
elizaService(ElizaServiceHandlerImpl)
}
}.start(wait = false)
}
```
### Request Validation with protovalidate
The plugin named ProtoRequestValidation is provided to validate the request message with protovalidate.
If the request message is invalid, the server will respond with a 400 Bad Request status code with details.
```protobuf
syntax = "proto3";
package stricteliza.v1;
import "buf/validate/validate.proto";
message SayRequest {
string sentence = 1 [(buf.validate.field).string.max_len = 100];
}
```
```kotlin
fun main() {
embeddedServer(CIO, port = 8080) {
install(Resources)
install(StatusPages) {
exception { call, cause ->
call.respondBytes(
bytes = cause.toErrorJsonBytes(),
status = HttpStatusCode.BadRequest,
contentType = ContentType.Application.Json,
)
}
}
routing {
install(ContentNegotiation) {
connectJson()
}
install(ProtoRequestValidation)
strictElizaService(StrictElizaServiceHandlerImpl)
}
}.start(wait = false)
}
```
## License
Offered under the [Apache 2 license](https://github.com/ichizero/connect-ktor/blob/main/LICENSE).
## Acknowledgements
I'm very grateful for the [Connect Protocol](https://github.com/connectrpc/connect-go),
[Connect-Kotlin](https://github.com/connectrpc/connect-kotlin) and its authors.
Their pioneering work and contributions to the open-source community made the development of Connect-Ktor possible.
I encourage you to try Connect-Ktor and experience a new level of communication with your Ktor server!