git.giacomolli.uk - onechat/blob - whatsapp_image.go

   1 package main
   2
   3 import (
   4         "context"
   5         "errors"
   6         "fmt"
   7
   8         "go.mau.fi/whatsmeow"
   9         "go.mau.fi/whatsmeow/proto/waE2E"
  10 )
  11
  12 // whatsappImage downloads only supported images and stores them before the
  13 // event can be acknowledged. Both the declared size and the downloaded bytes
  14 // must fit the image store. Decoded bytes determine the stored format.
  15 func whatsappImage(ctx context.Context, client WhatsAppClient, store *ImageStore, message *waE2E.ImageMessage) (string, error) {
  16         if message.GetFileLength() > imageMaxBytes {
  17                 return "", errImageSize
  18         }
  19
  20         switch message.GetMimetype() {
  21         case "image/jpeg", "image/png", "image/webp":
  22         default:
  23                 return "", errImageFormat
  24         }
  25
  26         if client == nil {
  27                 return "", errors.New("WhatsApp client is not available")
  28         }
  29
  30         data, err := client.Download(ctx, message)
  31         if err != nil {
  32                 return "", fmt.Errorf("download image: %w", whatsappImageDownloadError(err))
  33         }
  34
  35         name, err := store.Save(data)
  36         if err != nil {
  37                 return "", fmt.Errorf("store image: %w", err)
  38         }
  39
  40         return name, nil
  41 }
  42
  43 // whatsappImageDownloadError keeps only known safe causes. Library errors can
  44 // contain signed URLs or direct paths even when request preparation fails, so
  45 // arbitrary error text cannot go to the daemon log.
  46 func whatsappImageDownloadError(err error) error {
  47         switch {
  48         case errors.Is(err, context.Canceled):
  49                 return context.Canceled
  50         case errors.Is(err, context.DeadlineExceeded):
  51                 return context.DeadlineExceeded
  52         }
  53
  54         var response whatsmeow.DownloadHTTPError
  55
  56         if errors.As(err, &response) && response.Response != nil {
  57                 return fmt.Errorf("media server returned HTTP %d", response.StatusCode)
  58         }
  59
  60         return errors.New("media download failed")
  61 }