51 lines
1.2 KiB
Go
51 lines
1.2 KiB
Go
package message
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import (
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"encoding/base64"
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"errors"
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"strings"
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"aichat/utils"
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)
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const maxImageSize = 4 * 1024 * 1024
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var allowedImageTypes = map[string]bool{
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"image/jpeg": true,
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"image/png": true,
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"image/webp": true,
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"image/gif": true,
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}
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func normalizeImageDataURI(raw string) (string, error) {
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comma := strings.Index(raw, ",")
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if comma < 0 {
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return "", errors.New("图片 base64 数据格式错误")
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}
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meta := strings.ToLower(strings.TrimSpace(raw[5:comma]))
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payload := strings.TrimSpace(raw[comma+1:])
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if payload == "" {
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return "", errors.New("图片 base64 数据不能为空")
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}
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parts := strings.Split(meta, ";")
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if len(parts) < 2 || !utils.Contains(parts[1:], "base64") {
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return "", errors.New("图片 data URI 必须使用 base64 编码")
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}
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mime := parts[0]
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if !allowedImageTypes[mime] {
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return "", errors.New("图片格式不支持，仅支持 jpeg/png/webp/gif")
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}
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decoded, err := base64.StdEncoding.DecodeString(payload)
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if err != nil {
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return "", errors.New("图片 base64 数据无效")
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}
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if len(decoded) > maxImageSize {
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return "", errors.New("图片过大，请选择小于 4MB 的图片")
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}
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return "data:" + mime + ";base64," + payload, nil
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}
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