Merge pull request #318 from MacPaw/317-perplexity-fails-decoding-starting-with-040-version

Fix streaming

Author: nezhyborets

Demo/App/APIProvidedView.swift

@@ -26,26 +26,28 @@ struct APIProvidedView: View {
         idProvider: @escaping () -> String
     ) {
         self._apiKey = apiKey
+        
+        let client = APIProvidedView.makeClient(apiKey: apiKey.wrappedValue)
         self._chatStore = StateObject(
             wrappedValue: ChatStore(
-                openAIClient: OpenAI(apiToken: apiKey.wrappedValue),
+                openAIClient: client,
                 idProvider: idProvider
             )
         )
         self._imageStore = StateObject(
             wrappedValue: ImageStore(
-                openAIClient: OpenAI(apiToken: apiKey.wrappedValue)
+                openAIClient: client
             )
         )
         self._assistantStore = StateObject(
             wrappedValue: AssistantStore(
-                openAIClient: OpenAI(apiToken: apiKey.wrappedValue),
+                openAIClient: client,
                 idProvider: idProvider
             )
         )
         self._miscStore = StateObject(
             wrappedValue: MiscStore(
-                openAIClient: OpenAI(apiToken: apiKey.wrappedValue)
+                openAIClient: client
             )
         )
     }
@@ -58,11 +60,15 @@ struct APIProvidedView: View {
             miscStore: miscStore
         )
         .onChange(of: apiKey) { newApiKey in
-            let client = OpenAI(apiToken: newApiKey)
+            let client = APIProvidedView.makeClient(apiKey: newApiKey)
             chatStore.openAIClient = client
             imageStore.openAIClient = client
             assistantStore.openAIClient = client
             miscStore.openAIClient = client
         }
     }
+    
+    private static func makeClient(apiKey: String) -> OpenAIProtocol {
+        OpenAI(apiToken: apiKey)
+    }
 }

Sources/OpenAI/Private/Streaming/ServerSentEventsStreamParser.swift

@@ -88,8 +88,10 @@ final class ServerSentEventsStreamParser: @unchecked Sendable {
         for i in 0..<streamData.count {
             let currentChar = streamData[i]
             if currentChar == lf {
-                // The description above basically says that "if the char is LF - it's end if line, regardless what precedes or follows it
-                lines.append(streamData.subdata(in: lineBeginningIndex..<i))
+                // The description above basically says that "if the char is LF - it's end if line, regardless what precedes or follows it.
+                // But if previous chat was CR we should exclude that, too
+                let lineEndIndex = previousCharacter == cr ? i - 1 : i
+                lines.append(streamData.subdata(in: lineBeginningIndex..<lineEndIndex))
                 lineBeginningIndex = i + 1
             } else if currentChar == cr {
                 // The description above basically says that "CR is not end of line only if followed by LF"
@@ -103,7 +105,7 @@ final class ServerSentEventsStreamParser: @unchecked Sendable {
                 // Simply skipping
             }
 
-            previousCharacter = 0
+            previousCharacter = currentChar
         }
 
         if lineBeginningIndex < streamData.count - 1 {

Sources/OpenAI/Private/Streaming/StreamingSession.swift

@@ -70,8 +70,8 @@ final class StreamingSession<Interpreter: StreamInterpreter>: NSObject, Identifi
     }
 
     func urlSession(
-        _ session: URLSession,
-        dataTask: URLSessionDataTask,
+        _ session: URLSessionProtocol,
+        dataTask: URLSessionDataTaskProtocol,
         didReceive response: URLResponse,
         completionHandler: @escaping (URLSession.ResponseDisposition) -> Void
     ) {

Sources/OpenAI/Private/URLSessionDataDelegateForwarder.swift

@@ -25,4 +25,12 @@ final class URLSessionDataDelegateForwarder: NSObject, URLSessionDataDelegate {
     func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
         target.urlSession(session, dataTask: dataTask, didReceive: data)
     }
+    
+    func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
+        target.urlSession(session, didReceive: challenge, completionHandler: completionHandler)
+    }
+    
+    func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive response: URLResponse, completionHandler: @escaping (URLSession.ResponseDisposition) -> Void) {
+        target.urlSession(session, dataTask: dataTask, didReceive: response, completionHandler: completionHandler)
+    }
 }

Sources/OpenAI/Private/URLSessionDelegateProtocol.swift

@@ -7,10 +7,27 @@
 
 import Foundation
 
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+
 protocol URLSessionDelegateProtocol: Sendable { // Sendable to make a better match with URLSessionDelegate, it's sendable too
     func urlSession(_ session: URLSessionProtocol, task: URLSessionTaskProtocol, didCompleteWithError error: Error?)
+    
+    func urlSession(
+        _ session: URLSession,
+        didReceive challenge: URLAuthenticationChallenge,
+        completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void
+    )
 }
 
 protocol URLSessionDataDelegateProtocol: URLSessionDelegateProtocol {
     func urlSession(_ session: URLSessionProtocol, dataTask: URLSessionDataTaskProtocol, didReceive data: Data)
+    
+    func urlSession(
+        _ session: URLSessionProtocol,
+        dataTask: URLSessionDataTaskProtocol,
+        didReceive response: URLResponse,
+        completionHandler: @escaping (URLSession.ResponseDisposition) -> Void
+    )
 }

Tests/OpenAITests/ChatGPTGeneratedSSEParserTests.swift renamed to Tests/OpenAITests/ServerSentEventsStreamParserTests.swift

@@ -1,5 +1,5 @@
 //
-//  ChatGPTGeneratedSSEParserTests.swift
+//  ServerSentEventsStreamParserTests.swift
 //  OpenAI
 //
 //  Created by Oleksii Nezhyborets on 04.04.2025.
@@ -8,7 +8,7 @@
 import XCTest
 @testable import OpenAI
 
-final class ChatGPTGeneratedSSEParserTests: XCTestCase {
+final class ServerSentEventsStreamParserTests: XCTestCase {
     private let parser = ServerSentEventsStreamParser()
 
     func testSingleDataLine() {
@@ -87,6 +87,16 @@ final class ChatGPTGeneratedSSEParserTests: XCTestCase {
         XCTAssertEqual(events[0].decodedData, "real")
     }
 
+    // Perplexity is sending such line-end indicators:
+    // \r\n\r\n
+    // and it seems to be valid (per spec), so it should work
+    func testCrLfCrLf() {
+        let input = "data: value1\r\n\r\ndata: value2\n\n"
+        let events = parse(input)
+        XCTAssertEqual(events[0].decodedData, "value1")
+        XCTAssertEqual(events[1].decodedData, "value2")
+    }
+    
     // Helper
     func parse(_ raw: String) -> [ServerSentEventsStreamParser.Event] {
         let parser = ServerSentEventsStreamParser()