pre-major refactoring + ext api.

2026-03-26 14:10:53 +01:00
parent f8c86e315f
commit 7b996b552b
57 changed files with 3823 additions and 117 deletions
@@ -0,0 +1,72 @@
+package dev.relism.ext.jackson;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.json.JsonMapper;
+import dev.relism.exceptions.HttpException;
+import dev.relism.extension.ExtensionContext;
+import dev.relism.extension.FlashApp;
+import dev.relism.extension.FlashExtension;
+import dev.relism.http.ContentType;
+
+/**
+ * Registers Jackson into the extension layer.
+ *
+ * <p>What this installs:
+ * <ul>
+ *   <li>Exposes the {@link ObjectMapper} in {@link ExtensionContext} — consumed by
+ *       {@code flash-ext-openapi} and any extension that needs JSON serialization.</li>
+ *   <li>Sets a global exception handler that maps {@link HttpException} to a JSON
+ *       error body and catches all other exceptions as 500.</li>
+ *   <li>Injects the mapper into {@link JacksonHandler} so all subclasses gain
+ *       {@code bodyAs} and {@code json} without constructor boilerplate.</li>
+ * </ul>
+ *
+ * <pre>{@code
+ * FlashApp.of(new HttpServer(config))
+ *     .install(new JacksonExtension());
+ *
+ * // Custom mapper:
+ * ObjectMapper mapper = JsonMapper.builder()
+ *     .addModule(new JavaTimeModule())
+ *     .build();
+ * .install(new JacksonExtension(mapper));
+ * }</pre>
+ */
+public class JacksonExtension implements FlashExtension {
+
+    private final ObjectMapper mapper;
+
+    public JacksonExtension() {
+        this(JsonMapper.builder().build());
+    }
+
+    public JacksonExtension(ObjectMapper mapper) {
+        this.mapper = mapper;
+    }
+
+    @Override
+    public void install(FlashApp app, ExtensionContext ctx) {
+        ctx.provide(ObjectMapper.class, mapper);
+        JacksonHandler.mapper = mapper;
+
+        app.onException((ex, req, res) -> {
+            if (ex instanceof HttpException e) {
+                res.setStatusCode(e.status());
+                res.setContentType(ContentType.JSON);
+                return "{\"error\":\"" + escapeJson(e.getMessage()) + "\"}";
+            }
+            res.setStatusCode(500);
+            res.setContentType(ContentType.JSON);
+            return "{\"error\":\"Internal Server Error\"}";
+        });
+    }
+
+    private static String escapeJson(String s) {
+        if (s == null) return "";
+        return s.replace("\\", "\\\\")
+                .replace("\"", "\\\"")
+                .replace("\n", "\\n")
+                .replace("\r", "\\r")
+                .replace("\t", "\\t");
+    }
+}
@@ -0,0 +1,77 @@
+package dev.relism.ext.jackson;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import dev.relism.exceptions.HttpException;
+import dev.relism.http.ContentType;
+import dev.relism.models.Request;
+import dev.relism.models.RequestHandler;
+import dev.relism.models.Response;
+
+/**
+ * Base class for handlers that need JSON I/O via Jackson.
+ *
+ * <p>The {@link ObjectMapper} is injected by {@link JacksonExtension#install} once at
+ * startup — all subclasses share the same instance. If no {@code JacksonExtension} is
+ * installed the field remains {@code null} and the first call to {@link #bodyAs} or
+ * {@link #json} will throw an {@link IllegalStateException}.
+ *
+ * <pre>{@code
+ * @Route(method = HttpMethod.POST, path = "/api/blogs")
+ * public class CreateBlog extends JacksonHandler {
+ *     public Object handle(Request req, Response res) throws Exception {
+ *         CreateBlogRequest body = bodyAs(req, CreateBlogRequest.class);
+ *         Blog created = service.create(body);
+ *         res.setStatusCode(201);
+ *         return json(res, created);
+ *     }
+ * }
+ * }</pre>
+ */
+public abstract class JacksonHandler extends RequestHandler {
+
+    /**
+     * Shared mapper set by {@link JacksonExtension}. Package-visible so the extension
+     * can assign it; {@code volatile} ensures visibility across virtual threads.
+     */
+    static volatile ObjectMapper mapper;
+
+    /**
+     * Deserializes the request body bytes into {@code type}.
+     * Wraps Jackson parse errors as {@link HttpException} 400.
+     */
+    protected <T> T bodyAs(Request req, Class<T> type) throws Exception {
+        requireMapper();
+        try {
+            return mapper.readValue(req.body().bytes(), type);
+        } catch (JsonProcessingException e) {
+            throw HttpException.badRequest("Invalid request body: " + e.getOriginalMessage());
+        }
+    }
+
+    /**
+     * Serializes {@code obj} to JSON, sets {@code Content-Type: application/json},
+     * and returns the JSON string as the response body.
+     */
+    protected String json(Response res, Object obj) throws Exception {
+        requireMapper();
+        res.setContentType(ContentType.JSON);
+        return mapper.writeValueAsString(obj);
+    }
+
+    /**
+     * Like {@link #json} but serializes only fields visible under the given
+     * {@code view} class (see Jackson {@code @JsonView}).
+     */
+    protected String jsonView(Response res, Object obj, Class<?> view) throws Exception {
+        requireMapper();
+        res.setContentType(ContentType.JSON);
+        return mapper.writerWithView(view).writeValueAsString(obj);
+    }
+
+    private static void requireMapper() {
+        if (mapper == null)
+            throw new IllegalStateException(
+                    "JacksonExtension not installed: call FlashApp.install(new JacksonExtension()) first");
+    }
+}