gh-2: adds exception handling example

code/tic-tac-tow-service/docs/problems/insecure-password

@@ -0,0 +1 @@
+The provided password doesn't comply with the minimum security requirements...

code/tic-tac-tow-service/docs/problems/invalid-request-content

@@ -0,0 +1 @@
+The request content is not valid.

code/tic-tac-tow-service/docs/problems/user-already-exists

@@ -0,0 +1 @@
+The user being created already exists.

code/tic-tac-tow-service/docs/problems/user-or-password-are-invalid

@@ -0,0 +1 @@
+The provided username or password are invalid.

code/tic-tac-tow-service/src/main/kotlin/pt/isel/daw/tictactow/http/model/Problem.kt

@@ -13,7 +13,7 @@ class Problem(
         fun response(status: Int, problem: Problem) = ResponseEntity
             .status(status)
             .header("Content-Type", MEDIA_TYPE)
-            .body(problem)
+            .body<Any>(problem)
 
         val userAlreadyExists = Problem(
             URI(
@@ -34,5 +34,12 @@ class Problem(
                     "docs/problems/user-or-password-are-invalid"
             )
         )
+
+        val invalidRequestContent = Problem(
+            URI(
+                "https://github.com/isel-leic-daw/s2223i-51d-51n-public/tree/main/code/tic-tac-tow-service/" +
+                    "docs/problems/invalid-request-content"
+            )
+        )
     }
 }

code/tic-tac-tow-service/src/main/kotlin/pt/isel/daw/tictactow/http/pipeline/CustomExceptionHandler.kt

@@ -0,0 +1,48 @@
+package pt.isel.daw.tictactow.http.pipeline
+
+import org.slf4j.LoggerFactory
+import org.springframework.http.HttpHeaders
+import org.springframework.http.HttpStatus
+import org.springframework.http.ResponseEntity
+import org.springframework.http.converter.HttpMessageNotReadableException
+import org.springframework.validation.BindException
+import org.springframework.web.bind.annotation.ControllerAdvice
+import org.springframework.web.bind.annotation.ExceptionHandler
+import org.springframework.web.context.request.WebRequest
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler
+import pt.isel.daw.tictactow.http.model.Problem
+
+@ControllerAdvice
+class CustomExceptionHandler : ResponseEntityExceptionHandler() {
+
+    override fun handleBindException(
+        ex: BindException,
+        headers: HttpHeaders,
+        status: HttpStatus,
+        request: WebRequest
+    ): ResponseEntity<Any> {
+        log.info("Handling BindException: {}", ex.message)
+        return Problem.response(400, Problem.invalidRequestContent)
+    }
+
+    override fun handleHttpMessageNotReadable(
+        ex: HttpMessageNotReadableException,
+        headers: HttpHeaders,
+        status: HttpStatus,
+        request: WebRequest
+    ): ResponseEntity<Any> {
+        log.info("Handling HttpMessageNotReadableException: {}", ex.message)
+        return Problem.response(400, Problem.invalidRequestContent)
+    }
+
+    @ExceptionHandler(
+        Exception::class,
+    )
+    fun handleAll(): ResponseEntity<Unit> {
+        return ResponseEntity.status(500).build()
+    }
+
+    companion object {
+        private val log = LoggerFactory.getLogger(CustomExceptionHandler::class.java)
+    }
+}

code/tic-tac-tow-service/src/test/kotlin/pt/isel/daw/tictactow/http/InternalErrorTests.kt

@@ -0,0 +1,55 @@
+package pt.isel.daw.tictactow.http
+
+import org.hamcrest.CoreMatchers.equalTo
+import org.jdbi.v3.core.Jdbi
+import org.junit.jupiter.api.Test
+import org.postgresql.ds.PGSimpleDataSource
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.boot.test.context.TestConfiguration
+import org.springframework.boot.test.web.server.LocalServerPort
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Primary
+import org.springframework.test.web.reactive.server.WebTestClient
+import pt.isel.daw.tictactow.repository.jdbi.configure
+import java.util.*
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+class InternalErrorTests {
+
+    @TestConfiguration
+    class TestConfig {
+        @Bean
+        @Primary
+        fun testJdbi() = Jdbi.create(
+            PGSimpleDataSource().apply {
+                setURL("jdbc:postgresql://bad-host:5432/db?user=dbuser&password=changeit")
+            }
+        ).configure()
+    }
+
+    @LocalServerPort
+    var port: Int = 0
+
+    @Test
+    fun `Unknown exceptions are mapped into a 500 without a response content`() {
+        // given: an HTTP client
+        val client = WebTestClient.bindToServer().baseUrl("http://localhost:$port").build()
+
+        // and: a random user
+        val username = UUID.randomUUID().toString()
+        val password = "is-this-strong?"
+
+        // when: creating a user
+        // then: the response is a 400 with the proper type
+        client.post().uri("/users")
+            .bodyValue(
+                mapOf(
+                    "username" to username,
+                    "password" to password
+                )
+            )
+            .exchange()
+            .expectStatus().value(equalTo(500))
+            .expectHeader().doesNotExist("Content-Type")
+    }
+}

code/tic-tac-tow-service/src/test/kotlin/pt/isel/daw/tictactow/http/UserTests.kt

@@ -1,10 +1,13 @@
 package pt.isel.daw.tictactow.http
 
 import org.junit.jupiter.api.Test
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.MethodSource
 import org.springframework.boot.test.context.SpringBootTest
 import org.springframework.boot.test.web.server.LocalServerPort
 import org.springframework.test.web.reactive.server.WebTestClient
 import java.util.*
+import java.util.stream.Stream
 import kotlin.test.assertTrue
 
 @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@@ -170,4 +173,49 @@ class UserTests {
                     "tic-tac-tow-service/docs/problems/insecure-password"
             )
     }
+
+    @ParameterizedTest
+    @MethodSource
+    fun `user creation produces an error request content is not valid`(input: Any) {
+        // given: an HTTP client
+        val client = WebTestClient.bindToServer().baseUrl("http://localhost:$port").build()
+
+        // when: creating a user with invalid data
+        // then: the response is a 400 with the proper type
+        client.post().uri("/users")
+            .bodyValue(
+                input
+            )
+            .exchange()
+            .expectStatus().isBadRequest
+            .expectHeader().contentType("application/problem+json")
+            .expectBody()
+            .jsonPath("type").isEqualTo(
+                "https://github.com/isel-leic-daw/s2223i-51d-51n-public/tree/main/code/" +
+                    "tic-tac-tow-service/docs/problems/invalid-request-content"
+            )
+    }
+
+    companion object {
+        @JvmStatic
+        fun `user creation produces an error request content is not valid`(): Stream<Any> =
+            Stream.of(
+                mapOf<String, Any>(
+                    // no username or password
+                ),
+                mapOf(
+                    "username" to "alice"
+                    // no password
+                ),
+                mapOf(
+                    "password" to "bad",
+                    // no username
+                ),
+                mapOf(
+                    "username" to listOf<String>(),
+                    "password" to "changeit",
+                    // invalid username type
+                ),
+            )
+    }
 }