refs #4646 allow REST handlers to set custom headers in error respons…

…es (#4648)

refs #4647 ensure that deserialization errors in requests result in a 400 Bad Request response

doxygen/lang/900_release_notes.dox.tmpl

@@ -8,13 +8,23 @@
     - <a href="../../modules/DebugUtil/html/index.html">DebugUtil</a> module
       - fixed bugs in log handling
         (<a href="https://github.com/qorelanguage/qore/issues/4635">issue 4635</a>)
-    - <a href="../../modules/Schema/html/index.html">Schema</a> module
-      - allow the user to determine if a schema alignment operation was a first-time creation or an update
-        (<a href="https://github.com/qorelanguage/qore/issues/4637">issue 4637</a>)
+    - <a href="../../modules/RestHandler/html/index.html">RestHandler</a> module
+      - implemented the @ref RestHandler::RestHandler::errorResponseHeaders() to allow subclasses to return custom
+        headers in error responses, such as when a request cannot be deserialized
+        (<a href="https://github.com/qorelanguage/qore/issues/4646">issue 4646</a>)
     - <a href="../../modules/RestSchemaValidator/html/index.html">RestSchemaValidator</a> module
+      - REST handlers must throw a \c DESERIALIZATION-ERROR when deserialization errors occur, so that a
+        <tt>400 Bad Request</tt> response is returned
+        (<a href="https://github.com/qorelanguage/qore/issues/4647">issue 4647</a>)
       - allow for the client's time zone locale to be set for data serialization / deserialization
         (<a href="https://github.com/qorelanguage/qore/issues/4639">issue 4639</a>)
+    - <a href="../../modules/Schema/html/index.html">Schema</a> module
+      - allow the user to determine if a schema alignment operation was a first-time creation or an update
+        (<a href="https://github.com/qorelanguage/qore/issues/4637">issue 4637</a>)
     - <a href="../../modules/Swagger/html/index.html">Swagger</a> module
+      - REST handlers must throw a \c DESERIALIZATION-ERROR when deserialization errors occur, so that a
+        <tt>400 Bad Request</tt> response is returned
+        (<a href="https://github.com/qorelanguage/qore/issues/4647">issue 4647</a>)
       - do not reserialize already deserialized data when processing responses
         (<a href="https://github.com/qorelanguage/qore/issues/4640">issue 4640</a>)
       - allow for the client's time zone locale to be set for data serialization / deserialization

examples/test/qlib/RestHandler/RestHandler.qtest

@@ -146,6 +146,12 @@ class MyRestHandler inherits RestHandler {
     hash<HttpHandlerResponseInfo> getAction(hash<auto> cx, *hash<auto> ah) {
         return RestHandler::makeResponse(200, exists ah.action);
     }
+
+    private *hash<auto> errorResponseHeaders() {
+        return {
+            "Error": "True",
+        };
+    }
 }
 
 class SwaggerRestHandler inherits RestHandler {
@@ -318,6 +324,7 @@ public class RestHandlerTest inherits QUnit::Test {
     }
 
     constructor() : Test("RestHandlerTest", "1.0") {
+        addTestCase("test bad request", \badRequestTest());
         addTestCase("Test direct interface", \directTest());
         addTestCase("Test external serialization", \serializationTest());
         addTestCase("Test xml", \xmlTest());
@@ -364,6 +371,30 @@ public class RestHandlerTest inherits QUnit::Test {
         delete mServer;
     }
 
+    badRequestTest() {
+        HTTPClient client({"url": mClient.getURL()});
+
+        hash<auto> info;
+        on_error printf("info: %N\n", info);
+
+        string body = make_yaml(LargerHashValue);
+        hash<auto> hdr = {
+            "Content-Type": MimeTypeYaml,
+            "Accept": MimeTypeYaml,
+        };
+        hash<auto> h = client.send(body, "PUT", "test?action=echo", hdr, False, \info);
+        assertEq(body, h.body);
+
+        hdr = {
+            "Content-Type": MimeTypeJson,
+            "Accept": MimeTypeJson,
+        };
+        assertThrows("HTTP-CLIENT-RECEIVE-ERROR", \client.send(),
+            ("[x x]", "PUT", "test?action=echo", hdr, False, \info));
+        assertEq(400, info."response-headers".status_code);
+        assertEq("True", info."response-headers".error);
+    }
+
     directTest() {
         # test direct interface
         auto val = mHandler.handleExternalRequest("GET", "test?action=echo", LargerHashValue);