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media.go
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81 строка
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1.8 KB
| 1 | package handlers |
| 2 | |
| 3 | import ( |
| 4 | "encoding/base64" |
| 5 | "errors" |
| 6 | "io" |
| 7 | "net/http" |
| 8 | "strings" |
| 9 | |
| 10 | "github.com/gofiber/fiber/v2" |
| 11 | ) |
| 12 | |
| 13 | const ( |
| 14 | maxAvatarImageBytes = 2 << 20 |
| 15 | maxBackgroundImageBytes = 6 << 20 |
| 16 | ) |
| 17 | |
| 18 | var ( |
| 19 | errImageTooLarge = errors.New("image is too large") |
| 20 | errImageType = errors.New("unsupported image type") |
| 21 | ) |
| 22 | |
| 23 | func validImageDataURI(value string) bool { |
| 24 | for _, prefix := range []string{ |
| 25 | "data:image/png;base64,", |
| 26 | "data:image/jpeg;base64,", |
| 27 | "data:image/webp;base64,", |
| 28 | "data:image/gif;base64,", |
| 29 | } { |
| 30 | if strings.HasPrefix(value, prefix) { |
| 31 | return true |
| 32 | } |
| 33 | } |
| 34 | return false |
| 35 | } |
| 36 | |
| 37 | // readImageField accepts either a browser-resized data URI or a multipart |
| 38 | // upload for one image field. An empty result means the field was not changed. |
| 39 | func readImageField(c *fiber.Ctx, dataField, fileField string, maxBytes int64) (string, error) { |
| 40 | if data := strings.TrimSpace(c.FormValue(dataField)); data != "" { |
| 41 | if !validImageDataURI(data) { |
| 42 | return "", errImageType |
| 43 | } |
| 44 | if int64(len(data)) > maxBytes*4/3+4096 { |
| 45 | return "", errImageTooLarge |
| 46 | } |
| 47 | return data, nil |
| 48 | } |
| 49 | |
| 50 | file, err := c.FormFile(fileField) |
| 51 | if err != nil || file == nil || file.Size <= 0 { |
| 52 | return "", nil |
| 53 | } |
| 54 | if file.Size > maxBytes { |
| 55 | return "", errImageTooLarge |
| 56 | } |
| 57 | |
| 58 | f, err := file.Open() |
| 59 | if err != nil { |
| 60 | return "", err |
| 61 | } |
| 62 | defer f.Close() |
| 63 | |
| 64 | buf, err := io.ReadAll(io.LimitReader(f, maxBytes+1)) |
| 65 | if err != nil { |
| 66 | return "", err |
| 67 | } |
| 68 | if int64(len(buf)) > maxBytes { |
| 69 | return "", errImageTooLarge |
| 70 | } |
| 71 | mime := http.DetectContentType(buf) |
| 72 | if semi := strings.IndexByte(mime, ';'); semi >= 0 { |
| 73 | mime = mime[:semi] |
| 74 | } |
| 75 | switch mime { |
| 76 | case "image/png", "image/jpeg", "image/gif", "image/webp": |
| 77 | default: |
| 78 | return "", errImageType |
| 79 | } |
| 80 | return "data:" + mime + ";base64," + base64.StdEncoding.EncodeToString(buf), nil |
| 81 | } |
| 82 |