Repsond to Options request with reasonable values.

cwms-data-api/src/main/java/cwms/cda/ApiServlet.java

@@ -504,6 +504,12 @@ public void init() {
                     ctx.json(errResponse);
                 })
                 .routes(this::configureRoutes)
+                .options("/*", ctx -> {
+                    ctx.header("Access-Control-Allow-Origin", "*"); // Allow requests from any origin
+                    ctx.header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS"); // Specify allowed methods
+                    ctx.header("Access-Control-Allow-Headers", "Content-Type, Authorization"); // Specify allowed headers
+                    ctx.status(200); // Respond with a 200 OK status
+                })
                 .javalinServlet();
         logger.atInfo().log("Javalin initialized.");
     }

cwms-data-api/src/test/java/cwms/cda/api/BaseLineTestIT.java

@@ -0,0 +1,58 @@
+package cwms.cda.api;
+
+import static io.restassured.RestAssured.given;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.nullValue;
+
+import javax.servlet.http.HttpServletResponse;
+
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import fixtures.CwmsDataApiSetupCallback;
+import io.restassured.filter.log.LogDetail;
+
+/**
+ * Location for tests that aren't specifically related to a given endpoint.
+ */
+@Tag("integration")
+@ExtendWith(CwmsDataApiSetupCallback.class)
+class BaseLineTestIT extends DataApiTestIT {
+
+    @ParameterizedTest
+    @ValueSource(strings = {"/blobs/", "/timeseries", "/levels"})
+    void test_options_handling_known_url(String url) throws Exception {
+        given()
+            .log().ifValidationFails(LogDetail.ALL,true)
+        .when()
+            .redirects().follow(true)
+            .redirects().max(3)
+            .options(url)
+        .then()
+            .log().ifValidationFails(LogDetail.ALL,true)
+            .assertThat()
+            .statusCode(is(HttpServletResponse.SC_OK))
+            .header("Access-Control-Allow-Methods", equalTo("GET, POST, PUT, DELETE, OPTIONS"))
+            .header("Access-Control-Allow-Headers", equalTo("Content-Type, Authorization"));
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"/flurgle/", "/blah/", "/levels-i-do-not-exist"})
+    void test_options_handling_unknown_url(String url) throws Exception {
+        given()
+            .log().ifValidationFails(LogDetail.ALL,true)
+        .when()
+            .redirects().follow(true)
+            .redirects().max(3)
+            .options(url)
+        .then()
+            .log().ifValidationFails(LogDetail.ALL,true)
+            .assertThat()
+            .statusCode(is(HttpServletResponse.SC_OK))
+            .header("Access-Control-Allow-Methods", nullValue())
+            .header("Access-Control-Allow-Headers", nullValue());
+    }
+}