75 lines
2.0 KiB
Go
75 lines
2.0 KiB
Go
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package dash
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import (
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"context"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"time"
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)
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type downloadDeps interface {
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HTTPClient() *http.Client
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NewHTTPRequest(method string, url string, body io.Reader) (*http.Request, error)
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ReadAll(r io.Reader) ([]byte, error)
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Scheme() string
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UserAgent() string
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}
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type downloadConfig struct {
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authorization string
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begin time.Time
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currentRate int64
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deps downloadDeps
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elapsedTarget int64
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fqdn string
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}
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type downloadResult struct {
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elapsed float64
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received int64
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requestTicks float64
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serverURL string
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timestamp int64
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}
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func download(ctx context.Context, config downloadConfig) (downloadResult, error) {
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nbytes := (config.currentRate * 1000 * config.elapsedTarget) >> 3
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var URL url.URL
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URL.Scheme = config.deps.Scheme()
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URL.Host = config.fqdn
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URL.Path = fmt.Sprintf("%s%d", downloadPath, nbytes)
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req, err := config.deps.NewHTTPRequest("GET", URL.String(), nil)
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var result downloadResult
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if err != nil {
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return result, err
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}
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result.serverURL = URL.String()
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req.Header.Set("User-Agent", config.deps.UserAgent())
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req.Header.Set("Authorization", config.authorization)
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savedTicks := time.Now()
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resp, err := config.deps.HTTPClient().Do(req.WithContext(ctx))
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if err != nil {
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return result, err
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}
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if resp.StatusCode != 200 {
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return result, errHTTPRequestFailed
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}
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defer resp.Body.Close()
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data, err := config.deps.ReadAll(resp.Body)
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if err != nil {
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return result, err
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}
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// Implementation note: MK contains a comment that says that Neubot uses
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// the elapsed time since when we start receiving the response but it
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// turns out that Neubot and MK do the same. So, we do what they do. At
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// the same time, we are currently not able to include the overhead that
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// is caused by HTTP headers etc. So, we're a bit less precise.
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result.elapsed = time.Now().Sub(savedTicks).Seconds()
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result.received = int64(len(data))
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result.requestTicks = savedTicks.Sub(config.begin).Seconds()
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result.timestamp = time.Now().Unix()
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return result, nil
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}
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