oauth2
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Published
20 hours ago •
golang
golang
oauth2: automatically retry token refreshes
Maybe only feasible for known token endpoints, but here's a token refresh request we could have retried:
oauth2: cannot fetch token: 502 Bad Gateway
Response: <!DOCTYPE html>
<html lang=en>
<meta charset=utf-8>
<meta name=viewport content="initial-scale=1, minimum-scale=1, width=device-width">
<title>Error 502 (Server Error)!!1</title>
<style>
*{margin:0;padding:0}html,code{font:15px/22px arial,sans-serif}html{background:#fff;color:#222;padding:15px}body{margin:7% auto 0;max-width:390px;min-height:180px;padding:30px 0 15px}* > body{background:url(//www.google.com/images/errors/robot.png) 100% 5px no-repeat;padding-right:205px}p{margin:11px 0 22px;overflow:hidden}ins{color:#777;text-decoration:none}a img{border:0}@media screen and (max-width:772px){body{background:none;margin-top:0;max-width:none;padding-right:0}}#logo{background:url(//www.google.com/images/branding/googlelogo/1x/googlelogo_color_150x54dp.png) no-repeat;margin-left:-5px}@media only screen and (min-resolution:192dpi){#logo{background:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) no-repeat 0% 0%/100% 100%;-moz-border-image:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) 0}}@media only screen and (-webkit-min-device-pixel-ratio:2){#logo{background:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) no-repeat;-webkit-background-size:100% 100%}}#logo{display:inline-block;height:54px;width:150px}
</style>
<a href=//www.google.com/><span id=logo aria-label=Google></span></a>
<p><b>502.</b> <ins>That’s an error.</ins>
<p>The server encountered a temporary error and could not complete your request.<p>Please try again in 30 seconds. <ins>That’s all we know.</ins>
This should be easy enough to implement using your own HTTP transport, something like:
type retryTransport struct {
base http.RoundTripper
shouldRetry func(err error, numRetries int) bool // implementation here
}
func (t *retryTransport) RoundTrip(req *http.Request) (res *http.Response, err error) {
res, err = base.RoundTrip(req)
var numRetries int
for err != nil && t.shouldRetry(err, numRetries) {
numRetries++
res, err = base.RoundTrip(req)
}
}
func NewClient(config *oauth2.Config, token *oauth2.Token) *http.Client {
base := &http.Client{
Transport: &retryTransport{base: http.Default},
}
refreshCtx := context.WithValue(context.Background(), oauth2.HTTPClient, base)
return oauth2.NewClient(context.Background(), config.TokenSource(refreshCtx, token))
}
Is there a sane way to refresh a token on a given HTTP status code (specifically 401)?
