Add method stream type to generated code

library/src/main/kotlin/com/connectrpc/MethodSpec.kt

@@ -16,11 +16,6 @@ package com.connectrpc
 
 import kotlin.reflect.KClass
 
-internal object Method {
-    internal const val GET_METHOD = "GET"
-    internal const val POST_METHOD = "POST"
-}
-
 /**
  * Represents the minimum set of information to execute an RPC method.
  * Primarily used in generated code.
@@ -29,12 +24,12 @@ internal object Method {
  * @param requestClass The Kotlin Class for the request message.
  * @param responseClass The Kotlin Class for the response message.
  * @param idempotency The declared idempotency of a method.
- * @param method The HTTP method of a request.
+ * @param streamType The method's stream type.
  */
 class MethodSpec<Input : Any, Output : Any>(
     val path: String,
     val requestClass: KClass<Input>,
     val responseClass: KClass<Output>,
     val idempotency: Idempotency = Idempotency.UNKNOWN,
-    val method: String = Method.POST_METHOD,
+    val streamType: StreamType = StreamType.UNKNOWN,
 )

library/src/main/kotlin/com/connectrpc/StreamType.kt

@@ -0,0 +1,35 @@
+// Copyright 2022-2023 The Connect Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.connectrpc
+
+/**
+ * Represents the RPC stream type. Set by the code generator on each [MethodSpec].
+ */
+enum class StreamType {
+    /** Unknown stream type. */
+    UNKNOWN,
+
+    /** Unary RPC. */
+    UNARY,
+
+    /** Client streaming RPC. */
+    CLIENT,
+
+    /** Server streaming RPC. */
+    SERVER,
+
+    /** Bidirectional streaming RPC. */
+    BIDI,
+}

library/src/main/kotlin/com/connectrpc/http/HTTPRequest.kt

@@ -18,6 +18,11 @@ import com.connectrpc.Headers
 import com.connectrpc.MethodSpec
 import java.net.URL
 
+internal object HTTPMethod {
+    internal const val GET = "GET"
+    internal const val POST = "POST"
+}
+
 /**
  * HTTP request used for sending primitive data to the server.
  */
@@ -32,6 +37,9 @@ class HTTPRequest internal constructor(
     val message: ByteArray? = null,
     // The method spec associated with the request.
     val methodSpec: MethodSpec<*, *>,
+    // HTTP method to use with the request.
+    // Almost always POST, but side effect free unary RPCs may be made with GET.
+    val httpMethod: String = HTTPMethod.POST,
 ) {
     /**
      * Clones the [HTTPRequest] with override values.
@@ -50,13 +58,16 @@ class HTTPRequest internal constructor(
         message: ByteArray? = this.message,
         // The method spec associated with the request.
         methodSpec: MethodSpec<*, *> = this.methodSpec,
+        // The HTTP method to use with the request.
+        httpMethod: String = this.httpMethod,
     ): HTTPRequest {
         return HTTPRequest(
             url,
             contentType,
             headers,
             message,
             methodSpec,
+            httpMethod,
         )
     }
 }

library/src/main/kotlin/com/connectrpc/impl/ProtocolClient.kt

@@ -216,7 +216,7 @@ class ProtocolClient(
                     isComplete = true
                     when (streamResult.code) {
                         Code.OK -> channel.close()
-                        else -> channel.close(streamResult.connectException() ?: ConnectException(code = streamResult.code))
+                        else -> channel.close(streamResult.connectException() ?: ConnectException(code = streamResult.code, exception = streamResult.cause))
                     }
                 }
             }

library/src/main/kotlin/com/connectrpc/protocols/ConnectInterceptor.kt

@@ -21,15 +21,15 @@ import com.connectrpc.ConnectException
 import com.connectrpc.Headers
 import com.connectrpc.Idempotency
 import com.connectrpc.Interceptor
-import com.connectrpc.Method.GET_METHOD
-import com.connectrpc.MethodSpec
 import com.connectrpc.ProtocolClientConfig
 import com.connectrpc.RequestCompression
 import com.connectrpc.StreamFunction
 import com.connectrpc.StreamResult
+import com.connectrpc.StreamType
 import com.connectrpc.Trailers
 import com.connectrpc.UnaryFunction
 import com.connectrpc.compression.CompressionPool
+import com.connectrpc.http.HTTPMethod
 import com.connectrpc.http.HTTPRequest
 import com.connectrpc.http.HTTPResponse
 import com.squareup.moshi.Moshi
@@ -189,7 +189,8 @@ internal class ConnectInterceptor(
     }
 
     private fun shouldUseGETRequest(request: HTTPRequest, finalRequestBody: Buffer): Boolean {
-        return request.methodSpec.idempotency == Idempotency.NO_SIDE_EFFECTS &&
+        return request.methodSpec.streamType == StreamType.UNARY &&
+            request.methodSpec.idempotency == Idempotency.NO_SIDE_EFFECTS &&
             clientConfig.getConfiguration.useGET(finalRequestBody)
     }
 
@@ -210,13 +211,8 @@ internal class ConnectInterceptor(
             url = url,
             contentType = "application/${requestCodec.encodingName()}",
             headers = request.headers,
-            methodSpec = MethodSpec(
-                path = request.methodSpec.path,
-                requestClass = request.methodSpec.requestClass,
-                responseClass = request.methodSpec.responseClass,
-                idempotency = request.methodSpec.idempotency,
-                method = GET_METHOD,
-            ),
+            methodSpec = request.methodSpec,
+            httpMethod = HTTPMethod.GET,
         )
     }
 
@@ -261,7 +257,7 @@ internal class ConnectInterceptor(
                     errorJSON,
                 )
             } catch (e: Exception) {
-                return ConnectException(code, serializationStrategy.errorDetailParser(), errorJSON)
+                return ConnectException(code, serializationStrategy.errorDetailParser(), errorJSON, e)
             }
             val errorDetails = parseErrorDetails(errorPayloadJSON)
             ConnectException(

library/src/test/kotlin/com/connectrpc/InterceptorChainTest.kt

@@ -26,10 +26,18 @@ import org.junit.Test
 import org.mockito.kotlin.mock
 import java.net.URL
 
-private val METHOD_SPEC = MethodSpec(
+private val UNARY_METHOD_SPEC = MethodSpec(
     path = "",
     requestClass = Any::class,
     responseClass = Any::class,
+    streamType = StreamType.UNARY,
+)
+
+private val STREAM_METHOD_SPEC = MethodSpec(
+    path = "",
+    requestClass = Any::class,
+    responseClass = Any::class,
+    streamType = StreamType.BIDI,
 )
 
 class InterceptorChainTest {
@@ -64,7 +72,7 @@ class InterceptorChainTest {
 
     @Test
     fun fifo_request_unary() {
-        val response = unaryChain.requestFunction(HTTPRequest(URL("https://connectrpc.com"), "", emptyMap(), null, METHOD_SPEC))
+        val response = unaryChain.requestFunction(HTTPRequest(URL("https://connectrpc.com"), "", emptyMap(), null, UNARY_METHOD_SPEC))
         assertThat(response.headers.get("id")).containsExactly("1", "2", "3", "4")
     }
 
@@ -76,7 +84,7 @@ class InterceptorChainTest {
 
     @Test
     fun fifo_request_stream() {
-        val request = streamingChain.requestFunction(HTTPRequest(URL("https://connectrpc.com"), "", emptyMap(), null, METHOD_SPEC))
+        val request = streamingChain.requestFunction(HTTPRequest(URL("https://connectrpc.com"), "", emptyMap(), null, STREAM_METHOD_SPEC))
         assertThat(request.headers.get("id")).containsExactly("1", "2", "3", "4")
     }
 
@@ -112,7 +120,7 @@ class InterceptorChainTest {
                         it.contentType,
                         headers,
                         it.message,
-                        METHOD_SPEC,
+                        UNARY_METHOD_SPEC,
                     )
                 },
                 responseFunction = {
@@ -144,7 +152,7 @@ class InterceptorChainTest {
                         it.contentType,
                         headers,
                         it.message,
-                        METHOD_SPEC,
+                        STREAM_METHOD_SPEC,
                     )
                 },
                 requestBodyFunction = {

library/src/test/kotlin/com/connectrpc/impl/BiDirectionalStreamTest.kt

@@ -18,6 +18,7 @@ import com.connectrpc.Codec
 import com.connectrpc.MethodSpec
 import com.connectrpc.ProtocolClientConfig
 import com.connectrpc.SerializationStrategy
+import com.connectrpc.StreamType
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
@@ -54,6 +55,7 @@ class BiDirectionalStreamTest {
                     path = "com.connectrpc.SomeService/Service",
                     String::class,
                     String::class,
+                    streamType = StreamType.BIDI,
                 ),
             )
             stream.sendClose()
@@ -83,6 +85,7 @@ class BiDirectionalStreamTest {
                     path = "com.connectrpc.SomeService/Service",
                     String::class,
                     String::class,
+                    streamType = StreamType.BIDI,
                 ),
             )
             val result = stream.send("input")

library/src/test/kotlin/com/connectrpc/impl/ProtocolClientTest.kt

@@ -18,6 +18,7 @@ import com.connectrpc.Codec
 import com.connectrpc.MethodSpec
 import com.connectrpc.ProtocolClientConfig
 import com.connectrpc.SerializationStrategy
+import com.connectrpc.StreamType
 import com.connectrpc.http.HTTPClientInterface
 import com.connectrpc.http.HTTPRequest
 import kotlinx.coroutines.CoroutineScope
@@ -57,6 +58,7 @@ class ProtocolClientTest {
                 path = "com.connectrpc.SomeService/Service",
                 String::class,
                 String::class,
+                streamType = StreamType.UNARY,
             ),
         ) { _ -> }
     }
@@ -81,6 +83,7 @@ class ProtocolClientTest {
                 path = "com.connectrpc.SomeService/Service",
                 String::class,
                 String::class,
+                streamType = StreamType.UNARY,
             ),
         ) { _ -> }
     }
@@ -105,6 +108,7 @@ class ProtocolClientTest {
                     path = "com.connectrpc.SomeService/Service",
                     String::class,
                     String::class,
+                    streamType = StreamType.BIDI,
                 ),
             )
         }
@@ -130,6 +134,7 @@ class ProtocolClientTest {
                     path = "com.connectrpc.SomeService/Service",
                     String::class,
                     String::class,
+                    streamType = StreamType.BIDI,
                 ),
             )
         }
@@ -154,6 +159,7 @@ class ProtocolClientTest {
                 path = "com.connectrpc.SomeService/Service",
                 String::class,
                 String::class,
+                streamType = StreamType.UNARY,
             ),
         ) {}
 
@@ -182,6 +188,7 @@ class ProtocolClientTest {
                 path = "com.connectrpc.SomeService/Service",
                 String::class,
                 String::class,
+                streamType = StreamType.UNARY,
             ),
         ) {}