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

backend/internal/service/content_moderation_input.go

@@ -0,0 +1,319 @@
+package service
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math/big"
+	"strings"
+
+	"github.com/tidwall/gjson"
+)
+
+func ExtractContentModerationText(protocol string, body []byte) string {
+	return ExtractContentModerationInput(protocol, body).Text
+}
+
+func ExtractContentModerationInput(protocol string, body []byte) ContentModerationInput {
+	if len(body) == 0 || !gjson.ValidBytes(body) {
+		return ContentModerationInput{}
+	}
+	var parts []string
+	var images []string
+	switch protocol {
+	case ContentModerationProtocolAnthropicMessages:
+		collectLastAnthropicUserMessage(gjson.GetBytes(body, "messages"), &parts, &images)
+	case ContentModerationProtocolOpenAIChat:
+		collectLastRoleMessage(gjson.GetBytes(body, "messages"), "user", &parts, &images)
+	case ContentModerationProtocolOpenAIResponses:
+		collectLastResponsesInput(gjson.GetBytes(body, "input"), &parts, &images)
+	case ContentModerationProtocolGemini:
+		collectLastGeminiContent(gjson.GetBytes(body, "contents"), &parts, &images)
+	case ContentModerationProtocolOpenAIImages:
+		addModerationText(&parts, gjson.GetBytes(body, "prompt").String())
+		collectContentValue(gjson.GetBytes(body, "images"), &parts, &images)
+	default:
+		collectLastResponsesInput(gjson.GetBytes(body, "input"), &parts, &images)
+		collectLastRoleMessage(gjson.GetBytes(body, "messages"), "user", &parts, &images)
+		collectLastGeminiContent(gjson.GetBytes(body, "contents"), &parts, &images)
+	}
+	out := ContentModerationInput{
+		Text:   normalizeContentModerationText(strings.Join(parts, "\n")),
+		Images: normalizeModerationImages(images),
+	}
+	out.Normalize()
+	return out
+}
+
+func collectLastRoleMessage(messages gjson.Result, role string, parts *[]string, images *[]string) {
+	if !messages.IsArray() {
+		return
+	}
+	array := messages.Array()
+	if len(array) == 0 {
+		return
+	}
+	last := array[len(array)-1]
+	if strings.ToLower(strings.TrimSpace(last.Get("role").String())) != role {
+		return
+	}
+	var candidate []string
+	var candidateImages []string
+	collectContentValue(last.Get("content"), &candidate, &candidateImages)
+	if normalizeContentModerationText(strings.Join(candidate, "\n")) == "" && len(candidateImages) == 0 {
+		return
+	}
+	*parts = append(*parts, candidate...)
+	*images = append(*images, candidateImages...)
+}
+
+func collectLastAnthropicUserMessage(messages gjson.Result, parts *[]string, images *[]string) {
+	if !messages.IsArray() {
+		return
+	}
+	array := messages.Array()
+	if len(array) == 0 {
+		return
+	}
+	last := array[len(array)-1]
+	if strings.ToLower(strings.TrimSpace(last.Get("role").String())) != "user" {
+		return
+	}
+	var candidate []string
+	var candidateImages []string
+	collectAnthropicUserContentValue(last.Get("content"), &candidate, &candidateImages)
+	if normalizeContentModerationText(strings.Join(candidate, "\n")) == "" && len(candidateImages) == 0 {
+		return
+	}
+	*parts = append(*parts, candidate...)
+	*images = append(*images, candidateImages...)
+}
+
+func collectAnthropicUserContentValue(value gjson.Result, parts *[]string, images *[]string) {
+	switch {
+	case !value.Exists():
+		return
+	case value.Type == gjson.String:
+		if !isAnthropicSystemReminderText(value.String()) {
+			addModerationText(parts, value.String())
+		}
+	case value.IsArray():
+		value.ForEach(func(_, item gjson.Result) bool {
+			collectAnthropicUserContentValue(item, parts, images)
+			return true
+		})
+	case value.IsObject():
+		typ := strings.ToLower(strings.TrimSpace(value.Get("type").String()))
+		switch typ {
+		case "", "text", "input_text", "message":
+			if value.Get("text").Exists() && !isAnthropicSystemReminderText(value.Get("text").String()) {
+				addModerationText(parts, value.Get("text").String())
+			}
+			if value.Get("content").Exists() {
+				collectAnthropicUserContentValue(value.Get("content"), parts, images)
+			}
+		case "image_url", "input_image", "image":
+			collectContentValue(value, parts, images)
+		}
+	}
+}
+
+func isAnthropicSystemReminderText(text string) bool {
+	return strings.HasPrefix(strings.TrimSpace(text), "<system-reminder>")
+}
+
+func collectLastResponsesInput(input gjson.Result, parts *[]string, images *[]string) {
+	switch {
+	case !input.Exists():
+		return
+	case input.Type == gjson.String:
+		addModerationText(parts, input.String())
+	case input.IsArray():
+		array := input.Array()
+		if len(array) == 0 {
+			return
+		}
+		last := array[len(array)-1]
+		if !isResponsesUserTextItem(last) {
+			return
+		}
+		collectContentValue(last.Get("content"), parts, images)
+		if last.Get("type").String() == "input_text" || last.Get("text").Exists() {
+			collectContentValue(last, parts, images)
+		}
+	case input.IsObject():
+		if isResponsesUserTextItem(input) {
+			collectContentValue(input.Get("content"), parts, images)
+			if input.Get("type").String() == "input_text" || input.Get("text").Exists() {
+				collectContentValue(input, parts, images)
+			}
+		}
+	}
+}
+
+func isResponsesUserTextItem(item gjson.Result) bool {
+	role := strings.ToLower(strings.TrimSpace(item.Get("role").String()))
+	if role == "user" {
+		return responseItemHasModerationText(item)
+	}
+	if role != "" {
+		return false
+	}
+	return responseItemHasModerationText(item)
+}
+
+func responseItemHasModerationText(item gjson.Result) bool {
+	var parts []string
+	var images []string
+	collectContentValue(item.Get("content"), &parts, &images)
+	if item.Get("type").String() == "input_text" || item.Get("text").Exists() {
+		collectContentValue(item, &parts, &images)
+	}
+	return normalizeContentModerationText(strings.Join(parts, "\n")) != "" || len(images) > 0
+}
+
+func collectLastGeminiContent(contents gjson.Result, parts *[]string, images *[]string) {
+	if !contents.IsArray() {
+		return
+	}
+	array := contents.Array()
+	if len(array) == 0 {
+		return
+	}
+	last := array[len(array)-1]
+	role := strings.ToLower(strings.TrimSpace(last.Get("role").String()))
+	if role != "" && role != "user" {
+		return
+	}
+	var candidate []string
+	var candidateImages []string
+	if arr := last.Get("parts"); arr.IsArray() {
+		arr.ForEach(func(_, part gjson.Result) bool {
+			addModerationText(&candidate, part.Get("text").String())
+			addGeminiModerationImage(&candidateImages, part)
+			return true
+		})
+	}
+	if normalizeContentModerationText(strings.Join(candidate, "\n")) == "" && len(candidateImages) == 0 {
+		return
+	}
+	*parts = append(*parts, candidate...)
+	*images = append(*images, candidateImages...)
+}
+
+func collectContentValue(value gjson.Result, parts *[]string, images *[]string) {
+	switch {
+	case !value.Exists():
+		return
+	case value.Type == gjson.String:
+		addModerationText(parts, value.String())
+	case value.IsArray():
+		value.ForEach(func(_, item gjson.Result) bool {
+			collectContentValue(item, parts, images)
+			return true
+		})
+	case value.IsObject():
+		typ := strings.ToLower(strings.TrimSpace(value.Get("type").String()))
+		addModerationImage(images, value.Get("image_url.url").String())
+		addModerationImage(images, value.Get("image_url").String())
+		addModerationImage(images, value.Get("url").String())
+		addModerationImageData(images, value.Get("source.media_type").String(), value.Get("source.data").String())
+		addModerationImageData(images, value.Get("source.mediaType").String(), value.Get("source.data").String())
+		addModerationImageData(images, value.Get("media_type").String(), value.Get("data").String())
+		addModerationImageData(images, value.Get("mime_type").String(), value.Get("data").String())
+		addModerationImageData(images, value.Get("mimeType").String(), value.Get("data").String())
+		addModerationImage(images, value.Get("source.data").String())
+		addModerationImage(images, value.Get("data").String())
+		addModerationImage(images, value.Get("base64").String())
+		switch typ {
+		case "", "text", "input_text", "message":
+			if value.Get("text").Exists() {
+				addModerationText(parts, value.Get("text").String())
+			}
+			if value.Get("content").Exists() {
+				collectContentValue(value.Get("content"), parts, images)
+			}
+		case "image_url", "input_image", "image":
+		}
+	}
+}
+
+func addGeminiModerationImage(images *[]string, part gjson.Result) {
+	if inlineData := part.Get("inline_data"); inlineData.IsObject() {
+		mimeType := strings.TrimSpace(inlineData.Get("mime_type").String())
+		data := strings.TrimSpace(inlineData.Get("data").String())
+		if mimeType != "" && data != "" {
+			addModerationImage(images, fmt.Sprintf("data:%s;base64,%s", mimeType, data))
+		}
+	}
+	if inlineData := part.Get("inlineData"); inlineData.IsObject() {
+		mimeType := strings.TrimSpace(inlineData.Get("mimeType").String())
+		data := strings.TrimSpace(inlineData.Get("data").String())
+		if mimeType != "" && data != "" {
+			addModerationImage(images, fmt.Sprintf("data:%s;base64,%s", mimeType, data))
+		}
+	}
+	addModerationImage(images, part.Get("file_data.file_uri").String())
+	addModerationImage(images, part.Get("fileData.fileUri").String())
+}
+
+func addModerationImageData(images *[]string, mimeType string, data string) {
+	mimeType = strings.TrimSpace(mimeType)
+	data = strings.TrimSpace(data)
+	if mimeType == "" || data == "" {
+		return
+	}
+	addModerationImage(images, fmt.Sprintf("data:%s;base64,%s", mimeType, data))
+}
+
+func addModerationImage(images *[]string, image string) {
+	image = strings.TrimSpace(image)
+	if image == "" {
+		return
+	}
+	if strings.HasPrefix(image, "data:") || strings.HasPrefix(image, "http://") || strings.HasPrefix(image, "https://") {
+		*images = append(*images, image)
+	}
+}
+
+func normalizeModerationImages(images []string) []string {
+	out := make([]string, 0, len(images))
+	seen := make(map[string]struct{}, len(images))
+	for _, image := range images {
+		image = strings.TrimSpace(image)
+		if image == "" {
+			continue
+		}
+		if _, ok := seen[image]; ok {
+			continue
+		}
+		seen[image] = struct{}{}
+		out = append(out, image)
+	}
+	return out
+}
+
+func limitContentModerationImages(images []string) []string {
+	if len(images) <= maxContentModerationInputImages {
+		return images
+	}
+	idx, err := rand.Int(rand.Reader, big.NewInt(int64(len(images))))
+	if err != nil {
+		return images[:maxContentModerationInputImages]
+	}
+	return []string{images[int(idx.Int64())]}
+}
+
+func addModerationText(parts *[]string, text string) {
+	text = strings.TrimSpace(text)
+	if text == "" {
+		return
+	}
+	if strings.Contains(text, "<system-reminder>") {
+		return
+	}
+	*parts = append(*parts, text)
+}
+
+func normalizeContentModerationText(text string) string {
+	return strings.Join(strings.Fields(strings.TrimSpace(text)), " ")
+}