Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/openai_image_dimensions.go

@@ -0,0 +1,92 @@
+package service
+
+import (
+	"bufio"
+	"encoding/base64"
+	"encoding/binary"
+	"fmt"
+	"image"
+	_ "image/jpeg"
+	_ "image/png"
+	"io"
+	"strings"
+)
+
+const maxOpenAIImageDimensionProbeBytes int64 = 1 << 20
+
+func detectOpenAIImageResultSize(encoded string) string {
+	payload := strings.TrimSpace(encoded)
+	if strings.HasPrefix(strings.ToLower(payload), "data:") {
+		comma := strings.IndexByte(payload, ',')
+		if comma < 0 || comma+1 >= len(payload) {
+			return ""
+		}
+		payload = strings.TrimSpace(payload[comma+1:])
+	}
+	if payload == "" {
+		return ""
+	}
+
+	for _, encoding := range []*base64.Encoding{base64.StdEncoding, base64.RawStdEncoding} {
+		decoded := base64.NewDecoder(encoding, strings.NewReader(payload))
+		buffered := bufio.NewReader(io.LimitReader(decoded, maxOpenAIImageDimensionProbeBytes))
+		prefix, _ := buffered.Peek(30)
+		if width, height, ok := detectOpenAIWebPDimensions(prefix); ok {
+			return fmt.Sprintf("%dx%d", width, height)
+		}
+		cfg, _, err := image.DecodeConfig(buffered)
+		if err != nil || cfg.Width <= 0 || cfg.Height <= 0 {
+			continue
+		}
+		return fmt.Sprintf("%dx%d", cfg.Width, cfg.Height)
+	}
+	return ""
+}
+
+func detectOpenAIWebPDimensions(header []byte) (int, int, bool) {
+	if len(header) < 16 || string(header[:4]) != "RIFF" || string(header[8:12]) != "WEBP" {
+		return 0, 0, false
+	}
+
+	switch string(header[12:16]) {
+	case "VP8X":
+		if len(header) < 30 {
+			return 0, 0, false
+		}
+		width := 1 + int(header[24]) + int(header[25])<<8 + int(header[26])<<16
+		height := 1 + int(header[27]) + int(header[28])<<8 + int(header[29])<<16
+		return width, height, width > 0 && height > 0
+	case "VP8 ":
+		if len(header) < 30 || string(header[23:26]) != "\x9d\x01\x2a" {
+			return 0, 0, false
+		}
+		width := int(binary.LittleEndian.Uint16(header[26:28]) & 0x3fff)
+		height := int(binary.LittleEndian.Uint16(header[28:30]) & 0x3fff)
+		return width, height, width > 0 && height > 0
+	case "VP8L":
+		if len(header) < 25 || header[20] != 0x2f {
+			return 0, 0, false
+		}
+		width := 1 + int(header[21]) + int(header[22]&0x3f)<<8
+		height := 1 + int(header[22]>>6) + int(header[23])<<2 + int(header[24]&0x0f)<<10
+		return width, height, width > 0 && height > 0
+	default:
+		return 0, 0, false
+	}
+}
+
+func reconcileOpenAIResponsesImageResultSizes(results []openAIResponsesImageResult, firstMeta *openAIResponsesImageResult) {
+	for i := range results {
+		// ChatGPT OAuth can normalize requested controls to "auto". The final
+		// image bytes are authoritative for response metadata and tier billing.
+		if actualSize := detectOpenAIImageResultSize(results[i].Result); actualSize != "" {
+			results[i].Size = actualSize
+		}
+	}
+	if firstMeta == nil || len(results) == 0 {
+		return
+	}
+	if size := strings.TrimSpace(results[0].Size); size != "" {
+		firstMeta.Size = size
+	}
+}