1

2025-11-12 14:18:56 +08:00
parent 39d8b3d547
commit afc44cb471
6 changed files with 684 additions and 186 deletions
--- a/CustomKeyboard/Network/KBStreamFetcher.m
+++ b/CustomKeyboard/Network/KBStreamFetcher.m
@@ -0,0 +1,247 @@
+//
+//  KBStreamFetcher.m
+//
+
+#import "KBStreamFetcher.h"
+
+@interface KBStreamFetcher () <NSURLSessionDataDelegate>
+@property (nonatomic, strong) NSURLSession *session;
+@property (nonatomic, strong) NSURLSessionDataTask *task;
+@property (nonatomic, strong) NSMutableData *buffer;           // 网络原始字节累加
+@property (nonatomic, assign) NSStringEncoding textEncoding;   // 推断得到的文本编码（默认 UTF-8）
+@property (nonatomic, assign) BOOL isSSE;                      // 是否为 SSE 响应
+@property (nonatomic, strong) NSMutableString *sseTextBuffer;  // SSE 文本缓冲（已解码）
+@property (nonatomic, assign) NSInteger decodedPrefixBytes;    // 已解码并写入 sseTextBuffer 的字节数（SSE）
+@property (nonatomic, assign) NSInteger deliveredCharCount;    // 已回传的字符数（非 SSE，用于做增量）
+@property (nonatomic, assign) BOOL hasEmitted;                 // 是否已经输出过正文（用于“首段删 1 个 \t”）
+@end
+
+// 计算数据中以 UTF-8 编码可完整解码的“前缀字节长度”，避免切断多字节字符
+static NSUInteger kb_validUTF8PrefixLen(NSData *data) {
+    const unsigned char *bytes = (const unsigned char *)data.bytes;
+    NSUInteger n = data.length;
+    if (n == 0) return 0;
+    NSInteger i = (NSInteger)n - 1;
+    while (i >= 0 && (bytes[i] & 0xC0) == 0x80) { i--; } // 10xxxxxx 续字节
+    if (i < 0) return 0; // 全是续字节，等下次
+    unsigned char b = bytes[i];
+    NSUInteger expected = 1;
+    if ((b & 0x80) == 0x00) expected = 1;        // 0xxxxxxx
+    else if ((b & 0xE0) == 0xC0) expected = 2;   // 110xxxxx
+    else if ((b & 0xF0) == 0xE0) expected = 3;   // 1110xxxx
+    else if ((b & 0xF8) == 0xF0) expected = 4;   // 11110xxx
+    else return (NSUInteger)i;                   // 非法起始，截到 i 之前
+    NSUInteger remain = n - (NSUInteger)i;
+    return (remain >= expected) ? n : (NSUInteger)i;
+}
+
+@implementation KBStreamFetcher
+
+ (instancetype)fetcherWithURL:(NSURL *)url {
+    KBStreamFetcher *f = [[self alloc] init];
+    f.url = url;
+    return f;
+}
+
+- (instancetype)init {
+    if (self = [super init]) {
+        _acceptEventStream = NO;
+        _disableCompression = YES;
+        _treatSlashTAsTab = YES;
+        _trimLeadingTabOnce = YES;
+        _requestTimeout = 30.0;
+        _textEncoding = NSUTF8StringEncoding;
+        _buffer = [NSMutableData data];
+        _sseTextBuffer = [NSMutableString string];
+    }
+    return self;
+}
+
+- (void)start {
+    if (!self.url) return;
+    [self cancel];
+
+    NSURLSessionConfiguration *cfg = [NSURLSessionConfiguration defaultSessionConfiguration];
+    cfg.requestCachePolicy = NSURLRequestReloadIgnoringLocalCacheData;
+    cfg.timeoutIntervalForRequest = self.requestTimeout;
+    cfg.timeoutIntervalForResource = MAX(self.requestTimeout, 60.0);
+
+    self.session = [NSURLSession sessionWithConfiguration:cfg delegate:self delegateQueue:[NSOperationQueue mainQueue]];
+
+    NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:self.url];
+    req.HTTPMethod = @"GET";
+    if (self.disableCompression) { [req setValue:@"identity" forHTTPHeaderField:@"Accept-Encoding"]; }
+    if (self.acceptEventStream) { [req setValue:@"text/event-stream" forHTTPHeaderField:@"Accept"]; }
+    [req setValue:@"no-cache" forHTTPHeaderField:@"Cache-Control"];
+    [req setValue:@"keep-alive" forHTTPHeaderField:@"Connection"];
+    [self.extraHeaders enumerateKeysAndObjectsUsingBlock:^(NSString *k, NSString *v, BOOL *stop){ [req setValue:v forHTTPHeaderField:k]; }];
+
+    // 状态复位
+    [self.buffer setLength:0];
+    [self.sseTextBuffer setString:@""];
+    self.isSSE = NO;
+    self.textEncoding = NSUTF8StringEncoding;
+    self.decodedPrefixBytes = 0;
+    self.deliveredCharCount = 0;
+    self.hasEmitted = NO;
+
+    self.task = [self.session dataTaskWithRequest:req];
+    [self.task resume];
+}
+
+- (void)cancel {
+    [self.task cancel];
+    self.task = nil;
+    [self.session invalidateAndCancel];
+    self.session = nil;
+    [self.buffer setLength:0];
+    [self.sseTextBuffer setString:@""];
+    self.decodedPrefixBytes = 0;
+    self.deliveredCharCount = 0;
+    self.hasEmitted = NO;
+}
+
+#pragma mark - NSURLSessionDataDelegate
+
+- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler {
+    self.isSSE = NO;
+    self.textEncoding = NSUTF8StringEncoding;
+    if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
+        NSHTTPURLResponse *r = (NSHTTPURLResponse *)response;
+        NSString *ct = r.allHeaderFields[@"Content-Type"] ?: r.allHeaderFields[@"content-type"];
+        if ([ct isKindOfClass:[NSString class]]) {
+            NSString *lower = [ct lowercaseString];
+            if ([lower containsString:@"text/event-stream"]) self.isSSE = YES;
+            NSRange pos = [lower rangeOfString:@"charset="];
+            if (pos.location != NSNotFound) {
+                NSString *charset = [[lower substringFromIndex:pos.location + pos.length] componentsSeparatedByString:@";"][0];
+                if ([charset containsString:@"utf-8"] || [charset containsString:@"utf8"]) {
+                    self.textEncoding = NSUTF8StringEncoding;
+                } else if ([charset containsString:@"iso-8859-1"] || [charset containsString:@"latin1"]) {
+                    self.textEncoding = NSISOLatin1StringEncoding;
+                }
+            }
+        }
+    }
+    [self.sseTextBuffer setString:@""];
+    self.decodedPrefixBytes = 0;
+    if (completionHandler) completionHandler(NSURLSessionResponseAllow);
+}
+
+- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
+    if (data.length == 0) return;
+    [self.buffer appendData:data];
+
+    NSUInteger validLen = (self.textEncoding == NSUTF8StringEncoding)
+        ? kb_validUTF8PrefixLen(self.buffer)
+        : self.buffer.length;
+    if (validLen == 0) return; // 末尾可能卡着半个字符
+
+    if (self.isSSE) {
+        if ((NSUInteger)self.decodedPrefixBytes < validLen) {
+            NSRange rng = NSMakeRange((NSUInteger)self.decodedPrefixBytes, validLen - (NSUInteger)self.decodedPrefixBytes);
+            NSString *piece = [[NSString alloc] initWithBytes:(const char *)self.buffer.bytes + rng.location
+                                                       length:rng.length
+                                                     encoding:self.textEncoding];
+            if (piece.length > 0) {
+                [self.sseTextBuffer appendString:piece];
+                self.decodedPrefixBytes = (NSInteger)validLen;
+            }
+        }
+        // 统一换行并按 SSE 事件 \n\n 切开
+        if (self.sseTextBuffer.length > 0) {
+            NSString *normalized = [self.sseTextBuffer stringByReplacingOccurrencesOfString:@"\r\n" withString:@"\n"];
+            [self.sseTextBuffer setString:normalized];
+            while (1) {
+                NSRange sep = [self.sseTextBuffer rangeOfString:@"\n\n"]; // 完整事件
+                if (sep.location == NSNotFound) break;
+                NSString *event = [self.sseTextBuffer substringToIndex:sep.location];
+                [self.sseTextBuffer deleteCharactersInRange:NSMakeRange(0, sep.location + sep.length)];
+
+                // 合并 data: 行为正文
+                NSArray<NSString *> *lines = [event componentsSeparatedByString:@"\n"];
+                NSMutableString *payload = [NSMutableString string];
+                for (NSString *ln in lines) {
+                    if ([ln hasPrefix:@"data:"]) {
+                        NSString *v = [ln substringFromIndex:5];
+                        if (v.length > 0 && [v hasPrefix:@" "]) v = [v substringFromIndex:1];
+                        [payload appendString:v ?: @""];
+                        [payload appendString:@"\n"]; // 多 data 行合并
+                    }
+                }
+                if (payload.length > 0 && [payload hasSuffix:@"\n"]) {
+                    [payload deleteCharactersInRange:NSMakeRange(payload.length - 1, 1)];
+                }
+                if (payload.length > 0) {
+                    [self emitChunk:payload];
+                }
+            }
+        }
+        return;
+    }
+
+    // 非 SSE：直接对“可解码前缀”做增量输出
+    NSString *prefix = [[NSString alloc] initWithBytes:self.buffer.bytes length:validLen encoding:self.textEncoding];
+    if (!prefix) return;
+    if (self.deliveredCharCount < (NSInteger)prefix.length) {
+        NSString *delta = [prefix substringFromIndex:self.deliveredCharCount];
+        self.deliveredCharCount = prefix.length;
+        [self emitChunk:delta];
+    }
+}
+
+- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
+    if (!error && self.isSSE && self.sseTextBuffer.length > 0) {
+        // 处理最后一条未以 \n\n 结束的事件
+        NSString *normalized = [self.sseTextBuffer stringByReplacingOccurrencesOfString:@"\r\n" withString:@"\n"];
+        NSArray<NSString *> *lines = [normalized componentsSeparatedByString:@"\n"];
+        NSMutableString *payload = [NSMutableString string];
+        for (NSString *ln in lines) {
+            if ([ln hasPrefix:@"data:"]) {
+                NSString *v = [ln substringFromIndex:5];
+                if (v.length > 0 && [v hasPrefix:@" "]) v = [v substringFromIndex:1];
+                [payload appendString:v ?: @""];
+                [payload appendString:@"\n"]; 
+            }
+        }
+        if (payload.length > 0 && [payload hasSuffix:@"\n"]) {
+            [payload deleteCharactersInRange:NSMakeRange(payload.length - 1, 1)];
+        }
+        if (payload.length > 0) {
+            [self emitChunk:payload];
+        }
+    }
+
+    if (self.onFinish) dispatch_async(dispatch_get_main_queue(), ^{ self.onFinish(error); });
+    [self cancel];
+}
+
+#pragma mark - Helpers
+
+- (void)emitChunk:(NSString *)rawText {
+    if (rawText.length == 0) return;
+    NSString *text = rawText;
+    if (self.treatSlashTAsTab) {
+        text = [text stringByReplacingOccurrencesOfString:@"/t" withString:@"\t"];
+    }
+    if (!self.hasEmitted && self.trimLeadingTabOnce) {
+        // 跳过前导空白，只删除“一个”起始的 \t
+        NSUInteger i = 0;
+        while (i < text.length) {
+            unichar c = [text characterAtIndex:i];
+            if (c == ' ' || c == '\r' || c == '\n') { i++; continue; }
+            break;
+        }
+        if (i < text.length && [text characterAtIndex:i] == '\t') {
+            NSMutableString *m = [text mutableCopy];
+            [m deleteCharactersInRange:NSMakeRange(i, 1)];
+            text = m;
+        }
+    }
+    if (text.length == 0) return;
+    if (self.onChunk) dispatch_async(dispatch_get_main_queue(), ^{ self.onChunk(text); });
+    self.hasEmitted = YES;
+}
+
+@end
+