143 lines
4 KiB
Go
143 lines
4 KiB
Go
package reddit
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import (
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"context"
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"io"
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"net/http"
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"github.com/alecthomas/units"
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"github.com/tigorlazuardi/redmage/api/bmessage"
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"github.com/tigorlazuardi/redmage/pkg/errs"
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)
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type DownloadStatusBroadcaster interface {
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Broadcast(bmessage.ImageDownloadMessage)
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}
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type NullDownloadStatusBroadcaster struct{}
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func (NullDownloadStatusBroadcaster) Broadcast(bmessage.ImageDownloadMessage) {}
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type PostImage struct {
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URL string
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File io.ReadCloser
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}
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func (po *PostImage) Read(p []byte) (n int, err error) {
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return po.File.Read(p)
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}
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func (po *PostImage) Close() error {
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return po.File.Close()
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}
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// DownloadImage downloades the image.
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//
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// If downloading image or thumbnail fails
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func (reddit *Reddit) DownloadImage(ctx context.Context, post Post, broadcaster DownloadStatusBroadcaster) (image PostImage, err error) {
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imageUrl := post.GetImageURL()
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image.URL = imageUrl
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image.File, err = reddit.downloadImage(ctx, post, bmessage.KindImage, broadcaster)
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return image, err
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}
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func (reddit *Reddit) DownloadThumbnail(ctx context.Context, post Post, broadcaster DownloadStatusBroadcaster) (image PostImage, err error) {
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imageUrl := post.GetThumbnailURL()
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image.URL = imageUrl
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image.File, err = reddit.downloadImage(ctx, post, bmessage.KindThumbnail, broadcaster)
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return image, err
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}
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func (reddit *Reddit) downloadImage(ctx context.Context, post Post, kind bmessage.ImageKind, broadcaster DownloadStatusBroadcaster) (io.ReadCloser, error) {
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var (
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url string
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height int64
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width int64
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)
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if kind == bmessage.KindImage {
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url = post.GetImageURL()
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width, height = post.GetImageSize()
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} else {
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url = post.GetThumbnailURL()
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width, height = post.GetThumbnailSize()
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}
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ctx, cancel := context.WithTimeout(ctx, reddit.Config.Duration("download.timeout.headers"))
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defer cancel()
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req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
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if err != nil {
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return nil, errs.Wrapw(err, "reddit: failed to create request", "url", url)
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}
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resp, err := reddit.Client.Do(req)
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if err != nil {
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return nil, errs.Wrapw(err, "reddit: failed to execute request", "url", url)
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}
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idleSpeedStr := reddit.Config.String("download.timeout.idlespeed")
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metricSpeed, _ := units.ParseMetricBytes(idleSpeedStr)
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if metricSpeed == 0 {
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metricSpeed = 10 * units.KB
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}
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metadata := bmessage.ImageMetadata{
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URL: url,
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Height: height,
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Width: width,
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Kind: kind,
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}
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idr := &ImageDownloadReader{
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OnProgress: func(downloaded int64, contentLength int64, err error) {
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var event bmessage.DownloadEvent
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if err != nil {
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event = bmessage.DownloadError
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} else {
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event = bmessage.DownloadProgress
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}
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broadcaster.Broadcast(bmessage.ImageDownloadMessage{
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Event: event,
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Metadata: metadata,
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ContentLength: units.MetricBytes(resp.ContentLength),
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Downloaded: units.MetricBytes(downloaded),
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Subreddit: post.GetSubreddit(),
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PostURL: post.GetPermalink(),
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PostID: post.GetID(),
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Error: err,
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})
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},
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OnClose: func(downloaded, contentLength int64, closeErr error) {
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broadcaster.Broadcast(bmessage.ImageDownloadMessage{
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Event: bmessage.DownloadEnd,
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Metadata: metadata,
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ContentLength: units.MetricBytes(resp.ContentLength),
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Downloaded: units.MetricBytes(downloaded),
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Subreddit: post.GetSubreddit(),
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PostURL: post.GetPermalink(),
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PostID: post.GetID(),
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Error: closeErr,
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})
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},
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IdleTimeout: reddit.Config.Duration("download.timeout.idle"),
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IdleSpeedThreshold: metricSpeed,
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}
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resp = idr.WrapHTTPResponse(resp)
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reader, writer := io.Pipe()
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go func() {
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defer resp.Body.Close()
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broadcaster.Broadcast(bmessage.ImageDownloadMessage{
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Event: bmessage.DownloadStart,
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Metadata: bmessage.ImageMetadata{
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URL: url,
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Height: height,
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Width: width,
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Kind: kind,
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},
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Subreddit: post.GetSubreddit(),
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PostURL: post.GetPermalink(),
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PostID: post.GetID(),
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})
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_, err := io.Copy(writer, resp.Body)
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_ = writer.CloseWithError(err)
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}()
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return reader, nil
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}
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