439 lines
13 KiB
Go
439 lines
13 KiB
Go
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package openai
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import (
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"bytes"
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"context"
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"encoding/base64"
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"encoding/json"
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"fmt"
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"image"
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_ "image/gif"
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"image/jpeg"
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_ "image/png"
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"io"
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"net/http"
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"net/url"
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"strings"
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"time"
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xdraw "golang.org/x/image/draw"
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)
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const moderationSystemPrompt = "你是中文社区的内容审核助手，负责对“帖子标题、正文、配图”做联合审核。目标是平衡社区安全与正常交流：必须拦截高风险违规内容，但不要误伤正常玩梗、二创、吐槽和轻度调侃。请只输出指定JSON。\n\n审核流程：\n1) 先判断是否命中硬性违规；\n2) 再判断语境（玩笑/自嘲/朋友间互动/作品讨论）；\n3) 做文图交叉判断（文本+图片合并理解）；\n4) 给出 approved 与简短 reason。\n\n硬性违规（命中任一项必须 approved=false）：\nA. 宣传对立与煽动撕裂：\n- 明确煽动群体对立、地域对立、性别对立、民族宗教对立，鼓动仇恨、排斥、报复。\nB. 严重人身攻击与网暴引导：\n- 持续性侮辱贬损、羞辱人格、号召围攻/骚扰/挂人/线下冲突。\nC. 开盒/人肉/隐私暴露：\n- 故意公开、拼接、索取他人可识别隐私信息（姓名+联系方式、身份证号、住址、学校单位、车牌、定位轨迹等）；\n- 图片/截图中出现可识别隐私信息并伴随曝光意图，也按违规处理。\nD. 其他高危违规：\n- 违法犯罪、暴力威胁、极端仇恨、色情低俗、诈骗引流、恶意广告等。\n\n放行规则（以下通常 approved=true）：\n- 正常玩梗、表情包、谐音梗、二次创作、无恶意的吐槽；\n- 非定向、轻度口语化吐槽（无明确攻击对象、无网暴号召、无隐私暴露）；\n- 对社会事件/作品的理性讨论、观点争论（即使语气尖锐，但未煽动对立或人身攻击）。\n\n边界判定：\n- 若只是“梗文化表达”且不指向现实伤害，优先通过；\n- 若存在明确伤害意图（煽动、围攻、曝光隐私），必须拒绝；\n- 对模糊内容不因个别粗口直接拒绝，需结合对象、意图、号召性和可执行性综合判断。\n\nreason 要求：\n- approved=false 时：中文10-30字，说明核心违规点；\n- approved=true 时：reason 为空字符串。\n\n输出格式（严格）：\n仅输出一行JSON对象，不要Markdown，不要额外解释：\n{\"approved\": true/false, \"reason\": \"...\"}"
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const (
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defaultMaxImagesPerModerationRequest = 1
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maxModerationResultRetries = 3
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maxChatCompletionRetries = 3
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initialRetryBackoff = 500 * time.Millisecond
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maxDownloadImageBytes = 10 * 1024 * 1024
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maxModerationImageSide = 1280
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compressedJPEGQuality = 72
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maxCompressedPayloadBytes = 1536 * 1024
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)
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type Client interface {
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IsEnabled() bool
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Config() Config
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ModeratePost(ctx context.Context, title, content string, images []string) (bool, string, error)
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ModerateComment(ctx context.Context, content string, images []string) (bool, string, error)
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}
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type clientImpl struct {
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cfg Config
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httpClient *http.Client
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}
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func NewClient(cfg Config) Client {
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timeout := cfg.RequestTimeoutSeconds
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if timeout <= 0 {
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timeout = 30
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}
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return &clientImpl{
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cfg: cfg,
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httpClient: &http.Client{
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Timeout: time.Duration(timeout) * time.Second,
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},
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}
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}
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func (c *clientImpl) IsEnabled() bool {
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return c.cfg.Enabled && c.cfg.APIKey != "" && c.cfg.BaseURL != ""
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}
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func (c *clientImpl) Config() Config {
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return c.cfg
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}
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func (c *clientImpl) ModeratePost(ctx context.Context, title, content string, images []string) (bool, string, error) {
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if !c.IsEnabled() {
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return true, "", nil
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}
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return c.moderateContentInBatches(ctx, fmt.Sprintf("帖子标题：%s\n帖子内容：%s", title, content), images)
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}
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func (c *clientImpl) ModerateComment(ctx context.Context, content string, images []string) (bool, string, error) {
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if !c.IsEnabled() {
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return true, "", nil
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}
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return c.moderateContentInBatches(ctx, fmt.Sprintf("评论内容：%s", content), images)
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}
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func (c *clientImpl) moderateContentInBatches(ctx context.Context, contentPrompt string, images []string) (bool, string, error) {
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cleanImages := normalizeImageURLs(images)
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optimizedImages := c.optimizeImagesForModeration(ctx, cleanImages)
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maxImagesPerRequest := c.maxImagesPerModerationRequest()
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totalBatches := 1
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if len(optimizedImages) > 0 {
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totalBatches = (len(optimizedImages) + maxImagesPerRequest - 1) / maxImagesPerRequest
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}
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// 图片超过单批上限时分批审核，任一批次拒绝即整体拒绝
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for i := 0; i < totalBatches; i++ {
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start := i * maxImagesPerRequest
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end := start + maxImagesPerRequest
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if end > len(optimizedImages) {
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end = len(optimizedImages)
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}
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batchImages := []string{}
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if len(optimizedImages) > 0 {
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batchImages = optimizedImages[start:end]
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}
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approved, reason, err := c.moderateSingleBatch(ctx, contentPrompt, batchImages, i+1, totalBatches)
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if err != nil {
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return false, "", err
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}
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if !approved {
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if strings.TrimSpace(reason) != "" && totalBatches > 1 {
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reason = fmt.Sprintf("第%d/%d批图片未通过：%s", i+1, totalBatches, reason)
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}
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return false, reason, nil
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}
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}
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return true, "", nil
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}
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func (c *clientImpl) moderateSingleBatch(
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ctx context.Context,
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contentPrompt string,
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images []string,
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batchNo, totalBatches int,
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) (bool, string, error) {
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userPrompt := fmt.Sprintf(
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"%s\n图片批次：%d/%d（本次仅提供当前批次图片）",
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contentPrompt,
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batchNo,
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totalBatches,
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)
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var lastErr error
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for attempt := 0; attempt < maxModerationResultRetries; attempt++ {
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replyText, err := c.chatCompletion(ctx, c.cfg.ModerationModel, moderationSystemPrompt, userPrompt, images, 0.1, 220)
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if err != nil {
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lastErr = err
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} else {
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parsed := struct {
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Approved bool `json:"approved"`
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Reason string `json:"reason"`
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}{}
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if err := json.Unmarshal([]byte(extractJSONObject(replyText)), &parsed); err != nil {
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lastErr = fmt.Errorf("failed to parse moderation result: %w", err)
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} else {
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return parsed.Approved, parsed.Reason, nil
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}
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}
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if attempt == maxModerationResultRetries-1 {
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break
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}
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if sleepErr := sleepWithBackoff(ctx, attempt); sleepErr != nil {
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return false, "", sleepErr
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}
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}
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return false, "", fmt.Errorf(
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"moderation batch %d/%d failed after %d attempts: %w",
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batchNo,
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totalBatches,
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maxModerationResultRetries,
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lastErr,
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)
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}
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type chatCompletionsRequest struct {
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Model string `json:"model"`
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Messages []chatMessage `json:"messages"`
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Temperature float64 `json:"temperature,omitempty"`
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MaxTokens int `json:"max_tokens,omitempty"`
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}
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type chatMessage struct {
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Role string `json:"role"`
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Content interface{} `json:"content"`
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}
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type contentPart struct {
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Type string `json:"type"`
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Text string `json:"text,omitempty"`
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ImageURL *imageURLPart `json:"image_url,omitempty"`
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}
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type imageURLPart struct {
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URL string `json:"url"`
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}
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type chatCompletionsResponse struct {
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Choices []struct {
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Message struct {
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Content string `json:"content"`
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} `json:"message"`
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} `json:"choices"`
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}
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func (c *clientImpl) chatCompletion(
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ctx context.Context,
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model string,
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systemPrompt string,
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userPrompt string,
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images []string,
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temperature float64,
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maxTokens int,
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) (string, error) {
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if model == "" {
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return "", fmt.Errorf("model is empty")
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}
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cleanImages := normalizeImageURLs(images)
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userParts := []contentPart{
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{Type: "text", Text: userPrompt},
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}
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for _, image := range cleanImages {
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userParts = append(userParts, contentPart{
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Type: "image_url",
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ImageURL: &imageURLPart{URL: image},
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})
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}
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reqBody := chatCompletionsRequest{
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Model: model,
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Messages: []chatMessage{
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{Role: "system", Content: systemPrompt},
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{Role: "user", Content: userParts},
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},
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Temperature: temperature,
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MaxTokens: maxTokens,
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}
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data, err := json.Marshal(reqBody)
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if err != nil {
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return "", fmt.Errorf("marshal request: %w", err)
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}
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baseURL := strings.TrimRight(c.cfg.BaseURL, "/")
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endpoint := baseURL + "/v1/chat/completions"
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if strings.HasSuffix(baseURL, "/v1") {
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endpoint = baseURL + "/chat/completions"
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}
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var lastErr error
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for attempt := 0; attempt < maxChatCompletionRetries; attempt++ {
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body, statusCode, err := c.doChatCompletionRequest(ctx, endpoint, data)
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if err != nil {
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lastErr = err
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} else if statusCode >= 400 {
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lastErr = fmt.Errorf("openai error status=%d body=%s", statusCode, string(body))
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if !isRetryableStatusCode(statusCode) {
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return "", lastErr
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}
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} else {
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var parsed chatCompletionsResponse
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if err := json.Unmarshal(body, &parsed); err != nil {
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return "", fmt.Errorf("decode response: %w", err)
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}
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if len(parsed.Choices) == 0 {
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return "", fmt.Errorf("empty response choices")
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}
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return parsed.Choices[0].Message.Content, nil
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}
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if attempt == maxChatCompletionRetries-1 {
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break
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}
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if sleepErr := sleepWithBackoff(ctx, attempt); sleepErr != nil {
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return "", sleepErr
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}
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}
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return "", lastErr
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}
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func (c *clientImpl) doChatCompletionRequest(ctx context.Context, endpoint string, data []byte) ([]byte, int, error) {
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req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(data))
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if err != nil {
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return nil, 0, fmt.Errorf("create request: %w", err)
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}
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req.Header.Set("Content-Type", "application/json")
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req.Header.Set("Authorization", "Bearer "+c.cfg.APIKey)
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resp, err := c.httpClient.Do(req)
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if err != nil {
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return nil, 0, fmt.Errorf("request openai: %w", err)
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}
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defer resp.Body.Close()
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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return nil, 0, fmt.Errorf("read response: %w", err)
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}
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return body, resp.StatusCode, nil
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}
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func isRetryableStatusCode(statusCode int) bool {
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if statusCode == http.StatusTooManyRequests {
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return true
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}
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return statusCode >= 500 && statusCode <= 599
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}
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func sleepWithBackoff(ctx context.Context, attempt int) error {
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delay := initialRetryBackoff * time.Duration(1<<attempt)
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timer := time.NewTimer(delay)
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defer timer.Stop()
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select {
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case <-ctx.Done():
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return fmt.Errorf("request cancelled: %w", ctx.Err())
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case <-timer.C:
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return nil
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}
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}
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func normalizeImageURLs(images []string) []string {
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clean := make([]string, 0, len(images))
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for _, image := range images {
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trimmed := strings.TrimSpace(image)
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if trimmed == "" {
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continue
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}
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clean = append(clean, trimmed)
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}
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return clean
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}
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func extractJSONObject(raw string) string {
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text := strings.TrimSpace(raw)
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|
|
start := strings.Index(text, "{")
|
|||
|
|
end := strings.LastIndex(text, "}")
|
|||
|
|
if start >= 0 && end > start {
|
|||
|
|
return text[start : end+1]
|
|||
|
|
}
|
|||
|
|
return text
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
func (c *clientImpl) maxImagesPerModerationRequest() int {
|
|||
|
|
// 审核固定单图请求，降低单次payload体积，减少超时风险。
|
|||
|
|
if c.cfg.ModerationMaxImagesPerRequest <= 0 {
|
|||
|
|
return defaultMaxImagesPerModerationRequest
|
|||
|
|
}
|
|||
|
|
if c.cfg.ModerationMaxImagesPerRequest > 1 {
|
|||
|
|
return 1
|
|||
|
|
}
|
|||
|
|
return c.cfg.ModerationMaxImagesPerRequest
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
func (c *clientImpl) optimizeImagesForModeration(ctx context.Context, images []string) []string {
|
|||
|
|
if len(images) == 0 {
|
|||
|
|
return images
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
optimized := make([]string, 0, len(images))
|
|||
|
|
for _, imageURL := range images {
|
|||
|
|
optimized = append(optimized, c.tryCompressImageForModeration(ctx, imageURL))
|
|||
|
|
}
|
|||
|
|
return optimized
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
func (c *clientImpl) tryCompressImageForModeration(ctx context.Context, imageURL string) string {
|
|||
|
|
parsed, err := url.Parse(imageURL)
|
|||
|
|
if err != nil || (parsed.Scheme != "http" && parsed.Scheme != "https") {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
req, err := http.NewRequestWithContext(ctx, http.MethodGet, imageURL, nil)
|
|||
|
|
if err != nil {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
resp, err := c.httpClient.Do(req)
|
|||
|
|
if err != nil {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
defer resp.Body.Close()
|
|||
|
|
|
|||
|
|
if resp.StatusCode >= 400 {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
if !strings.HasPrefix(strings.ToLower(resp.Header.Get("Content-Type")), "image/") {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
originBytes, err := io.ReadAll(io.LimitReader(resp.Body, maxDownloadImageBytes))
|
|||
|
|
if err != nil || len(originBytes) == 0 {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
srcImg, _, err := image.Decode(bytes.NewReader(originBytes))
|
|||
|
|
if err != nil {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
dstImg := resizeIfNeeded(srcImg, maxModerationImageSide)
|
|||
|
|
var buf bytes.Buffer
|
|||
|
|
if err := jpeg.Encode(&buf, dstImg, &jpeg.Options{Quality: compressedJPEGQuality}); err != nil {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
compressed := buf.Bytes()
|
|||
|
|
if len(compressed) == 0 || len(compressed) > maxCompressedPayloadBytes {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
// 压缩效果不明显时直接使用原图URL，避免增大请求体。
|
|||
|
|
if len(compressed) >= int(float64(len(originBytes))*0.95) {
|
|||
|
|
return imageURL
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
return "data:image/jpeg;base64," + base64.StdEncoding.EncodeToString(compressed)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
func resizeIfNeeded(src image.Image, maxSide int) image.Image {
|
|||
|
|
bounds := src.Bounds()
|
|||
|
|
w := bounds.Dx()
|
|||
|
|
h := bounds.Dy()
|
|||
|
|
if w <= 0 || h <= 0 || max(w, h) <= maxSide {
|
|||
|
|
return src
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
newW, newH := w, h
|
|||
|
|
if w >= h {
|
|||
|
|
newW = maxSide
|
|||
|
|
newH = int(float64(h) * (float64(maxSide) / float64(w)))
|
|||
|
|
} else {
|
|||
|
|
newH = maxSide
|
|||
|
|
newW = int(float64(w) * (float64(maxSide) / float64(h)))
|
|||
|
|
}
|
|||
|
|
if newW < 1 {
|
|||
|
|
newW = 1
|
|||
|
|
}
|
|||
|
|
if newH < 1 {
|
|||
|
|
newH = 1
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
dst := image.NewRGBA(image.Rect(0, 0, newW, newH))
|
|||
|
|
xdraw.CatmullRom.Scale(dst, dst.Bounds(), src, bounds, xdraw.Over, nil)
|
|||
|
|
return dst
|
|||
|
|
}
|