KTOR-3419 Exceptions for database call and validation exceptions now have theirs purpose

Author: VGoncharova

postgres/src/main/kotlin/com/example/exceptions/DbElementInsertException.kt

@@ -0,0 +1,3 @@
+package com.example.exceptions
+
+class DbElementInsertException(message: String? = null, throwable: Throwable? = null) : Throwable(message, throwable)

postgres/src/main/kotlin/com/example/plugins/Routing.kt

@@ -1,5 +1,6 @@
 package com.example.plugins
 
+import com.example.exceptions.DbElementInsertException
 import com.example.exceptions.DbElementNotFoundException
 import com.example.models.Article
 import com.example.service.ArticleService
@@ -17,38 +18,44 @@ fun Application.configureRouting(dbConnection: Connection) {
         // Create new Article
         post("/articles") {
             val article = call.receive<Article>()
-            val id = articleService.create(article)
-            call.respond(HttpStatusCode.Created, id)
+            try {
+                val id = articleService.create(article)
+                call.respond(HttpStatusCode.Created, id)
+            } catch (cause: DbElementInsertException) {
+                call.respond(HttpStatusCode.InternalServerError)
+            }
         }
         // Read an Article
         get("/articles/{id}") {
-            val id = call.parameters["id"]?.toInt() ?: throw DbElementNotFoundException("Invalid article ID")
             try {
+                val id = call.parameters["id"]?.toInt() ?: throw IllegalArgumentException("Invalid article ID")
                 val article = articleService.read(id)
                 call.respond(HttpStatusCode.OK, article)
             } catch (cause: DbElementNotFoundException) {
                 call.respond(HttpStatusCode.NotFound)
+            } catch (cause: IllegalArgumentException) {
+                call.respond(HttpStatusCode.BadRequest)
             }
         }
         // Update an Article
         put("/articles/{id}") {
-            val id = call.parameters["id"]?.toInt() ?: throw DbElementNotFoundException("Invalid article ID")
             try {
+                val id = call.parameters["id"]?.toInt() ?: throw IllegalArgumentException("Invalid article ID")
                 val article = call.receive<Article>()
                 articleService.update(id, article)
                 call.respond(HttpStatusCode.OK)
-            } catch (cause: DbElementNotFoundException) {
-                call.respond(HttpStatusCode.NotFound)
+            } catch (cause: IllegalArgumentException) {
+                call.respond(HttpStatusCode.BadRequest)
             }
         }
         // Delete an Article
         delete("/articles/{id}") {
-            val id = call.parameters["id"]?.toInt() ?: throw DbElementNotFoundException("Invalid article ID")
             try {
+                val id = call.parameters["id"]?.toInt() ?: throw IllegalArgumentException("Invalid article ID")
                 articleService.delete(id)
                 call.respond(HttpStatusCode.OK)
-            } catch (cause: DbElementNotFoundException) {
-                call.respond(HttpStatusCode.NotFound)
+            } catch (cause: IllegalArgumentException) {
+                call.respond(HttpStatusCode.BadRequest)
             }
         }
     }

postgres/src/main/kotlin/com/example/service/ArticleService.kt

@@ -1,5 +1,7 @@
 package com.example.service
 
+import com.example.exceptions.DbElementInsertException
+import com.example.exceptions.DbElementNotFoundException
 import com.example.models.Article
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
@@ -33,7 +35,7 @@ class ArticleService(private val connection: Connection) {
         if (generatedKeys.next()) {
             return@withContext generatedKeys.getInt(1)
         } else {
-            throw Exception("Unable to retrieve the id of the newly inserted article")
+            throw DbElementInsertException("Unable to retrieve the id of the newly inserted article")
         }
     }
 
@@ -48,7 +50,7 @@ class ArticleService(private val connection: Connection) {
             val body = resultSet.getString("body")
             return@withContext Article(title, body)
         } else {
-            throw Exception("Record not found")
+            throw DbElementNotFoundException("Record not found")
         }
     }