Skip to content

Fix: Correct SSE streaming JSON parsing (resolves #48) #74

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
AyushInKC wants to merge 1 commit into
base: main
Choose a base branch
from
Open

Fix: Correct SSE streaming JSON parsing (resolves #48) #74

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
73 changes: 16 additions & 57 deletions src/main/java/com/cohere/api/core/Stream.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -224,74 +224,33 @@ private boolean readNextMessage() {
try {
while (sseScanner.hasNextLine()) {
String line = sseScanner.nextLine();

if (line.trim().isEmpty()) {
if (eventDataBuffer.length() > 0) {
try {
nextItem = ObjectMappers.JSON_MAPPER.readValue(eventDataBuffer.toString(), valueType);
hasNextItem = true;
eventDataBuffer.setLength(0);
currentEventType = null;
return true;
} catch (Exception parseEx) {
System.err.println("Failed to parse SSE event: " + parseEx.getMessage());
eventDataBuffer.setLength(0);
currentEventType = null;
continue;
}
}
if (line == null) continue;
line = line.trim();
if (line.isEmpty()) {
continue;
}

if (line.startsWith(DATA_PREFIX)) {
String dataContent = line.substring(DATA_PREFIX.length());
if (dataContent.startsWith(" ")) {
dataContent = dataContent.substring(1);
}

if (eventDataBuffer.length() == 0
&& streamTerminator != null
&& dataContent.trim().equals(streamTerminator)) {
String dataContent = line.substring(DATA_PREFIX.length()).trim();
// Check for stream terminator
if (streamTerminator != null && dataContent.equals(streamTerminator)) {
endOfStream = true;
return false;
}

if (eventDataBuffer.length() > 0) {
eventDataBuffer.append('\n');
}
eventDataBuffer.append(dataContent);
} else if (line.startsWith("event:")) {
String eventValue = line.length() > 6 ? line.substring(6) : "";
if (eventValue.startsWith(" ")) {
eventValue = eventValue.substring(1);
if (!dataContent.isEmpty()) {
try {
nextItem = ObjectMappers.JSON_MAPPER.readValue(dataContent, valueType);
hasNextItem = true;
return true;
} catch (Exception parseEx) {
System.err.println("Failed to parse SSE data line: " + parseEx.getMessage());
continue;
}
}
currentEventType = eventValue;
} else if (line.startsWith("id:")) {
// Event ID field (ignored)
} else if (line.startsWith("retry:")) {
// Retry field (ignored)
} else if (line.startsWith(":")) {
// Comment line (ignored)
}
}

if (eventDataBuffer.length() > 0) {
try {
nextItem = ObjectMappers.JSON_MAPPER.readValue(eventDataBuffer.toString(), valueType);
hasNextItem = true;
eventDataBuffer.setLength(0);
currentEventType = null;
return true;
} catch (Exception parseEx) {
System.err.println("Failed to parse final SSE event: " + parseEx.getMessage());
eventDataBuffer.setLength(0);
currentEventType = null;
}
// Ignore event:, id:, retry:, and comment lines
}

endOfStream = true;
return false;

} catch (Exception e) {
System.err.println("Failed to parse SSE stream: " + e.getMessage());
endOfStream = true;
Expand Down
38 changes: 38 additions & 0 deletions src/test/java/com/cohere/api/StreamTest.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,44 @@ public void testStreamResourceManagement() throws IOException {
assertFalse(testStream.iterator().hasNext());
}

@Test
public void testSseStreamIgnoresEventLinesAndParsesData() {
// Simulate Cohere SSE stream with event: and data: lines
String sse = String.join("\n",
"event: message-start",
"data: {\"id\":\"id1\",\"type\":\"message-start\",\"delta\":{\"message\":{\"role\":\"assistant\",\"content\":[]}}}",
"",
"event: content-delta",
"data: {\"type\":\"content-delta\",\"index\":0,\"delta\":{\"message\":{\"content\":{\"text\":\"hello\"}}}}",
"",
"event: content-delta",
"data: {\"type\":\"content-delta\",\"index\":1,\"delta\":{\"message\":{\"content\":{\"text\":\" world\"}}}}",
""
);
StringReader sseInput = new StringReader(sse);
Stream<Map> sseStream = Stream.fromSse(Map.class, sseInput);
int count = 0;
StringBuilder content = new StringBuilder();
for (Map event : sseStream) {
assertNotNull(event);
assertTrue(event.containsKey("type"));
if ("content-delta".equals(event.get("type"))) {
// Drill down to message.content.text
Map delta = (Map) event.get("delta");
assertNotNull(delta);
Map message = (Map) delta.get("message");
assertNotNull(message);
Map contentMap = (Map) message.get("content");
assertNotNull(contentMap);
String text = (String) contentMap.get("text");
if (text != null) content.append(text);
}
count++;
}
assertEquals(3, count); // 1 message-start + 2 content-delta
assertEquals("hello world", content.toString());
}

private static String mapToJson(Map map) {
try {
return ObjectMappers.JSON_MAPPER.writeValueAsString(map);
Expand Down