YvCeung commented on code in PR #7903: URL: https://github.com/apache/incubator-seata/pull/7903#discussion_r2777303366
########## common/src/main/java/org/apache/seata/common/util/SeataHttpWatch.java: ########## @@ -0,0 +1,217 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.seata.common.util; + +import com.fasterxml.jackson.databind.ObjectMapper; +import okhttp3.Call; +import okhttp3.OkHttpClient; +import okhttp3.Request; +import okhttp3.ResponseBody; +import okio.BufferedSource; +import org.apache.seata.common.Constants; +import org.apache.seata.common.exception.FrameworkException; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.Iterator; + +/** + * Seata HTTP/2 Watch implementation. + * Consumes server-pushed event stream via an iterator-style API. + * Each line contains a single event in "data: {json}" format, similar to Kubernetes watch API. + * + * @param <T> event data type + */ +public class SeataHttpWatch<T> + implements Iterator<SeataHttpWatch.Response<T>>, Iterable<SeataHttpWatch.Response<T>>, AutoCloseable { + + private static final Logger LOGGER = LoggerFactory.getLogger(SeataHttpWatch.class); + + private final ResponseBody responseBody; + private final BufferedSource source; + private final Call call; + private final ObjectMapper objectMapper; + private final Class<T> eventType; + + /** + * Response wrapper containing event data. + * Since event format is simplified (no type field), all successful events are treated the same. + * Client can determine the nature of the event by comparing metadata.term. + */ + public static class Response<T> { + /** + * Response type enum + */ + public enum Type { + /** + * Normal event with data (connection established or cluster changed) + */ + UPDATE, + /** + * Error event (parse error or connection error) + */ + ERROR + } + + public final Type type; + + public final T object; + + public Response(Type type, T object) { + this.type = type; + this.object = object; + } + } + + /** + * Create a Watch instance from an OkHttp call + * + * @param call the prepared HTTP call + * @param eventType the class type for deserializing event data + * @param <T> the event data type + * @return a Watch instance + * @throws IOException if the request fails + */ + public static <T> SeataHttpWatch<T> createWatch(Call call, Class<T> eventType) throws IOException { + + okhttp3.Response response = call.execute(); + + if (!response.isSuccessful()) { + String respBody = null; + try (ResponseBody body = response.body()) { + if (body != null) { + respBody = body.string(); + } + } catch (IOException e) { + throw new FrameworkException(e, "Watch request failed: " + response.message()); + } + throw new FrameworkException( + String.format("Watch request failed with code %d: %s", response.code(), respBody)); + } + + // Verify Content-Type is event stream + String contentType = response.header("Content-Type"); + if (contentType == null || !contentType.contains("text/event-stream")) { + LOGGER.warn("Expected Content-Type: text/event-stream, got: {}", contentType); + } + + return new SeataHttpWatch<>(response.body(), call, eventType); + } + + /** + * Create a Watch instance with a prepared request + * + * @param client the OkHttpClient instance + * @param request the HTTP request + * @param eventType the class type for deserializing event data + * @param <T> the event data type + * @return a Watch instance + * @throws IOException if the request fails + */ + public static <T> SeataHttpWatch<T> createWatch(OkHttpClient client, Request request, Class<T> eventType) + throws IOException { + + Call call = client.newCall(request); + return createWatch(call, eventType); + } + + private SeataHttpWatch(ResponseBody responseBody, Call call, Class<T> eventType) { + this.responseBody = responseBody; + this.source = responseBody.source(); + this.call = call; + this.objectMapper = new ObjectMapper(); + this.eventType = eventType; + } + + @Override + public boolean hasNext() { + try { + // Check if source is exhausted (stream closed) + return !source.exhausted(); + } catch (IOException e) { + LOGGER.error("Error checking if stream has more data", e); + return false; + } + } + + @Override + public Response<T> next() { + try { + /* + Read a single line and parse it as an event. + Format: "{prefix}{json}\n" where prefix is defined in Constants.WATCH_EVENT_PREFIX. + Each line is a complete event, event type is included in the JSON data. + */ + String line = source.readUtf8Line(); + if (line == null) { + throw new RuntimeException("Stream closed unexpectedly"); + } + + if (!line.startsWith(Constants.WATCH_EVENT_PREFIX)) { + throw new RuntimeException("Invalid event format: expected prefix '" + Constants.WATCH_EVENT_PREFIX + + "', got: " + (line.length() > 20 ? line.substring(0, 20) + "..." : line)); + } + + String jsonData = line.substring(Constants.WATCH_EVENT_PREFIX.length()); + return parseEvent(jsonData); + + } catch (IOException e) { + throw new RuntimeException("IO Exception during next()", e); + } + } + + /** + * Parse event JSON into Response object. + * Simplified format: only contains group, timestamp, and metadata fields. + * + * @param json the JSON string to parse + * @return the parsed Response object + * @throws IOException if parsing fails + */ + private Response<T> parseEvent(String json) throws IOException { + try { + T eventData = objectMapper.readValue(json, eventType); + return new Response<>(Response.Type.UPDATE, eventData); + + } catch (Exception e) { + LOGGER.error("Failed to parse event JSON: {}", json, e); + // Return error response + return new Response<>(Response.Type.ERROR, null); + } Review Comment: This is unnecessary. -- This is an automated message from the Apache Git Service. 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