KTOR-8232 Make OutgoingContent headers available in the StatusPages handlers (#4980)

Author: marychatte

ktor-server/ktor-server-plugins/ktor-server-status-pages/build.gradle.kts

@@ -12,6 +12,7 @@ kotlin {
     sourceSets {
         commonTest.dependencies {
             implementation(projects.ktorServerCallId)
+            implementation(projects.ktorServerAuth)
         }
     }
 }

ktor-server/ktor-server-plugins/ktor-server-status-pages/common/src/io/ktor/server/plugins/statuspages/StatusPages.kt

@@ -68,6 +68,12 @@ public val StatusPages: ApplicationPlugin<StatusPagesConfig> = createApplication
             return@on
         }
 
+        content.headers.entries().forEach { (key, values) ->
+            values.forEach { value ->
+                call.response.headers.append(key, value)
+            }
+        }
+
         call.attributes.put(statusPageMarker, Unit)
         try {
             LOGGER.trace("Executing $handler for status code $status for call: ${call.request.uri}")

ktor-server/ktor-server-plugins/ktor-server-status-pages/common/test/io/ktor/server/plugins/statuspages/StatusPagesTest.kt

@@ -9,6 +9,7 @@ import io.ktor.client.statement.*
 import io.ktor.http.*
 import io.ktor.http.content.*
 import io.ktor.server.application.*
+import io.ktor.server.auth.*
 import io.ktor.server.plugins.*
 import io.ktor.server.plugins.callid.*
 import io.ktor.server.request.*
@@ -567,4 +568,60 @@ class StatusPagesTest {
         assertEquals("Custom-Value", responseWithRoute.headers["Custom-Header"])
         assertEquals("body", responseWithRoute.bodyAsText())
     }
+
+    @Test
+    fun testHeadersOfOutgoingContent() = testApplication {
+        install(StatusPages) {
+            status(HttpStatusCode.Unauthorized) { call, _ ->
+                if (call.response.headers[HttpHeaders.WWWAuthenticate] == "Basic realm=myRealm, charset=UTF-8") {
+                    call.respond(HttpStatusCode.OK)
+                } else {
+                    call.respond(HttpStatusCode.InternalServerError)
+                }
+            }
+            status(HttpStatusCode.OK) { call, _ ->
+                assertEquals("Custom-Value-Response", call.response.headers["Custom-Header-Response"])
+                assertEquals("Custom-Value-Content", call.response.headers["Custom-Header-Content"])
+            }
+        }
+
+        install(Authentication) {
+            basic {
+                realm = "myRealm"
+                validate {
+                    null
+                }
+            }
+        }
+
+        routing {
+            authenticate {
+                get("/auth") {
+                    throw IllegalStateException("This should not be called")
+                }
+            }
+
+            get("/custom-headers") {
+                call.response.headers.append("Custom-Header-Response", "Custom-Value-Response")
+                call.respond(object : OutgoingContent.ReadChannelContent() {
+                    override val status: HttpStatusCode
+                        get() = HttpStatusCode.OK
+                    override fun readFrom() = ByteReadChannel("hello world")
+                    override val headers: Headers
+                        get() = Headers.build {
+                            append("Custom-Header-Content", "Custom-Value-Content")
+                        }
+                })
+            }
+        }
+
+        assertEquals(HttpStatusCode.OK, client.get("/auth").status)
+
+        client.get("/custom-headers").apply {
+            assertEquals(HttpStatusCode.OK, status)
+            assertEquals("hello world", bodyAsText())
+            assertEquals("Custom-Value-Content", headers["Custom-Header-Content"])
+            assertEquals("Custom-Value-Response", headers["Custom-Header-Response"])
+        }
+    }
 }