create a application call extension in order to make it more easier to return the correct content type

Author: JohannesHepp

README.md

@@ -38,11 +38,7 @@ install(StatusPages) {
             cause.message,
             "https://example.org"
         )
-        call.respondText(
-            problem.toJson(),
-            ContentType.Application.ProblemJson,
-            httpStatus,
-        )
+        call.respondProblem(httpStatus, problem)
     }
 }
 ```

build.gradle.kts

@@ -2,71 +2,73 @@ val ktorVersion: String by project
 val kotestVersion: String by project
 
 plugins {
-    kotlin("jvm") version "2.0.0"
-    id("org.jetbrains.kotlin.plugin.serialization") version "2.0.0"
-    id("maven-publish")
-    id("jacoco")
+   kotlin("jvm") version "2.0.0"
+   id("org.jetbrains.kotlin.plugin.serialization") version "2.0.0"
+   id("maven-publish")
+   id("jacoco")
 }
 
 group = "schwarz.it"
 version = "1.0.0"
 
 repositories {
-    mavenCentral()
+   mavenCentral()
 }
 
 dependencies {
-    implementation(kotlin("reflect"))
-    implementation("io.ktor:ktor-serialization-kotlinx-json:$ktorVersion")
+   implementation(kotlin("reflect"))
+   implementation("io.ktor:ktor-server-core:$ktorVersion")
+   implementation("io.ktor:ktor-serialization-kotlinx-json:$ktorVersion")
 
-    testImplementation(kotlin("test"))
-    testImplementation("io.kotest:kotest-runner-junit5:$kotestVersion")
-    testImplementation("io.kotest:kotest-assertions-core:$kotestVersion")
+   testImplementation(kotlin("test"))
+   testImplementation("io.kotest:kotest-runner-junit5:$kotestVersion")
+   testImplementation("io.kotest:kotest-assertions-core:$kotestVersion")
 }
 
 tasks.test {
-    useJUnitPlatform()
+   useJUnitPlatform()
 }
 kotlin {
-    jvmToolchain(21)
+   jvmToolchain(21)
 }
 
 publishing {
-    publications {
-        create<MavenPublication>("mavenPublication") {
-            from(components["java"])
-        }
-    }
-    repositories {
-        maven {
-            name = "artifactory"
-            credentials {
-                username = project.findProperty("artifactoryUsername") as String? ?: System.getenv("ARTIFACTORY_USER")
-                password = project.findProperty("artifactoryPassword") as String? ?: System.getenv("ARTIFACTORY_PASSWORD")
-            }
-            url = uri("https://schwarzit.jfrog.io/artifactory/xx-sit-odj-psftp-maven-release-local/")
-        }
-    }
+   publications {
+      create<MavenPublication>("mavenPublication") {
+         from(components["java"])
+      }
+   }
+   repositories {
+      maven {
+         name = "artifactory"
+         credentials {
+            username = project.findProperty("artifactoryUsername") as String? ?: System.getenv("ARTIFACTORY_USER")
+            password =
+               project.findProperty("artifactoryPassword") as String? ?: System.getenv("ARTIFACTORY_PASSWORD")
+         }
+         url = uri("https://schwarzit.jfrog.io/artifactory/xx-sit-odj-psftp-maven-release-local/")
+      }
+   }
 }
 
 jacoco {
-    reportsDirectory.set(layout.buildDirectory.dir("reports/jacoco/"))
+   reportsDirectory.set(layout.buildDirectory.dir("reports/jacoco/"))
 }
 
 with(tasks) {
-    test {
-        useJUnitPlatform()
-        finalizedBy(jacocoTestReport)
-    }
+   test {
+      useJUnitPlatform()
+      finalizedBy(jacocoTestReport)
+   }
 
-    jacocoTestReport {
-        dependsOn(test)
-        reports {
-            xml.required.set(true)
-            csv.required.set(false)
-            html.required.set(true)
-            xml.outputLocation.set(layout.buildDirectory.file("reports/jacoco/report.xml"))
-            html.outputLocation.set(layout.buildDirectory.dir("reports/jacoco/html"))
-        }
-    }
+   jacocoTestReport {
+      dependsOn(test)
+      reports {
+         xml.required.set(true)
+         csv.required.set(false)
+         html.required.set(true)
+         xml.outputLocation.set(layout.buildDirectory.file("reports/jacoco/report.xml"))
+         html.outputLocation.set(layout.buildDirectory.dir("reports/jacoco/html"))
+      }
+   }
 }

src/main/kotlin/schwarz/it/problem/details/Problem.kt

@@ -1,6 +1,9 @@
 package schwarz.it.problem.details
 
+import io.ktor.http.ContentType
 import io.ktor.http.HttpStatusCode
+import io.ktor.server.application.ApplicationCall
+import io.ktor.server.response.respondText
 import kotlinx.serialization.json.Json
 
 /**
@@ -13,6 +16,20 @@ private const val TYPE_DEFAULT = "about:blank"
  */
 public fun problem(block: ProblemBuilder.() -> Unit): Problem = ProblemBuilder().apply(block).build()
 
+/**
+ * Application Call extension in order to return problem details with correct content type in ktor
+ */
+suspend fun ApplicationCall.respondProblem(
+   status: HttpStatusCode,
+   problem: Problem,
+) {
+   respondText(
+      problem.toJson(),
+      ContentType.Application.ProblemJson,
+      status,
+   )
+}
+
 /**
  * Builder for a problem detail including all mutable components
  * Problem implements RFC 9457 (https://datatracker.ietf.org/doc/rfc9457/)