private HttpResponseMessage Get(Uri uri, string accept, int retries)
{
//work out the basic scope + action we'd need to perform this GET
string scope = null;
if (_TokenSource.TryParseScope(uri, out var scopePath))
{
var action = scopePath == "registry:catalog" ? "*" : "pull";
scope = $"{scopePath}:{action}";
}
using (var client = new HttpClient(new HttpClientHandler {
AllowAutoRedirect = false
}))
{
client.Timeout = Timeout;
HttpResponseMessage result;
var message = new HttpRequestMessage {
RequestUri = uri
};
message.Headers.Authorization = _TokenSource.GetAuthorization(scope);
if (!string.IsNullOrEmpty(accept))
{
message.Headers.Add("Accept", accept);
}
try
{
result = client.SendAsync(message).Result;
}
catch
{
if (retries > 0)
{
result = Get(uri, accept, retries - 1);
}
else
{
throw;
}
}
if (result.IsSuccessStatusCode)
{
return(result);
}
else if (retries > 0)
{
if (result.StatusCode == HttpStatusCode.Unauthorized && !string.IsNullOrEmpty(scope))
{
var authRequest = _TokenSource.ParseWwwAuthenticate(result.Headers.WwwAuthenticate.First());
if (authRequest.scope != scope)
{
throw new ArgumentException($"The scope requested by the server ({authRequest.scope}) does not match that expected by the auth engine ({scope})");
}
// skip service check for dockerhub, since it returns inconsistent values
//if (!IsDockerHub && authRequest.service != Host) { throw new ArgumentException($"The service indicated by the server ({authRequest.service}), does not match that expected by the auth engine ({Host})."); }
if (_TokenSource.UpdateAuthorization(authRequest.scope))
{
return(Get(uri, accept, retries - 1));
}
else
{
throw new Exception($"Access was denied to the remote resource, and authorization could not be obtained.");
}
}
else if (result.StatusCode == HttpStatusCode.Redirect || result.StatusCode == HttpStatusCode.RedirectKeepVerb)
{
//decriment retries even though nothing failed, to ensure we don't get caught in a redirect loop
return(Get(result.Headers.Location, accept, retries - 1));
}
else if (result.StatusCode == HttpStatusCode.NotFound)
{
throw new NotFoundException();
}
else
{
System.Threading.Thread.Sleep(1000);
return(Get(uri, accept, retries - 1));
}
}
else
{
throw new Exception($"The remote request failed with status {result.StatusCode}");
}
}
}