YvCeung commented on code in PR #7903: URL: https://github.com/apache/incubator-seata/pull/7903#discussion_r2659612531
########## common/src/main/java/org/apache/seata/common/util/SeataHttpWatch.java: ########## @@ -0,0 +1,286 @@ +/* + * 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.annotation.JsonIgnoreProperties; +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.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 SSE data frames via an iterator-style 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 type and data + */ + public static class Response<T> { + /** + * Event type enum - matches SSE event field values + */ + public enum Type { + /** + * Cluster update event + */ + CLUSTER_UPDATE, + /** + * Keep-alive event (connection established) + */ + KEEPALIVE, + /** + * Timeout event (stream closed due to timeout) + */ + TIMEOUT, + /** + * Error event + */ + 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 SSE + 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 complete SSE event in a loop (not recursive to avoid stack overflow) + // SSE format: "data: {json}\n\n" + // Each event is separated by double newline + // Event type is included in the JSON data, not in a separate "event:" field + + StringBuilder dataBuffer = new StringBuilder(); + + // Read lines until we get a complete event (ending with empty line) + // This loop reads all lines of a single event atomically + while (true) { + String line = source.readUtf8Line(); + + if (line == null) { + // Stream closed + if (dataBuffer.length() > 0) { + // We have partial data, try to parse it + String eventJson = dataBuffer.toString(); + return parseEvent(eventJson); + } + throw new RuntimeException("Stream closed unexpectedly"); + } + + if (line.startsWith("data: ")) { + String jsonData = line.substring(6); + if (dataBuffer.length() > 0) { + dataBuffer.append('\n'); + } + dataBuffer.append(jsonData); + } else if (line.isEmpty()) { + // Empty line indicates end of event + if (dataBuffer.length() > 0) { + String eventJson = dataBuffer.toString(); + return parseEvent(eventJson); + } + // Empty line but no data, continue reading (skip blank lines between events) + } else { + LOGGER.debug("Unknown SSE line format, ignoring: {}", line); + } + } + + } catch (IOException e) { + throw new RuntimeException("IO Exception during next()", e); + } + } + + /** + * Parse SSE event JSON into Response object + * + * @param json the JSON string to parse (contains type field) + * @return the parsed Response object + * @throws IOException if parsing fails + */ + private Response<T> parseEvent(String json) throws IOException { + try { + // Parse JSON once to get both event type and full data + // First, parse to extract event type + EventMetadata metadata = objectMapper.readValue(json, EventMetadata.class); + + // Map event type from JSON to Response.Type + Response.Type responseType = mapEventTypeToResponseType(metadata.type); + + // Deserialize the full event data (parse once, reuse if possible) + T eventData = objectMapper.readValue(json, eventType); Review Comment: done in [3e77c68](https://github.com/apache/incubator-seata/pull/7903/commits/3e77c681040a885ac861f82d5013b78155b246ad) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
