public string GetSignedUrl(SigningOption options)
{
ValidateOptions(options);
var signingPayloadAsString = string.Join("\n", BuildSigningPayload(options));
var encryptedBase64String = EncryptPayload(signingPayloadAsString);
return(PrepareSignedUrl(options, encryptedBase64String));
}
private string PrepareSignedUrl(SigningOption options, string signature)
{
var uri = new UriBuilder();
uri.Scheme = "https";
uri.Host = $"{_firebaseConfiguration.StorageBaseAuthority.TrimSlashes().Replace("https://", "")}/{_credentials.GetDefaultBucket().TrimSlashes()}";
uri.Path = options.Path.Trim().TrimSlashes();
uri.Query = string.Format("GoogleAccessId={0}&Expires={1}&Signature={2}", _credentials.GetServiceAccountEmail(),
BuildExpiration(options.ExpireDate), WebUtility.UrlEncode(signature));
return(uri.Uri.AbsoluteUri);
}
private IList <string> BuildSigningPayload(SigningOption options)
{
var payload = new List <string>()
{
BuildActionMethod(options.Action),
BuildContentMD5(options.ContentMD5),
BuildContentType(options.ContentType),
BuildExpiration(options.ExpireDate),
BuilCanonicalizedResource(options.Path)
};
return(payload);
}
private void ValidateOptions(SigningOption options)
{
if (options == null)
{
throw new ArgumentNullException(nameof(options));
}
if (options.ExpireDate.ToUnixSeconds() == 0)
{
throw new ArgumentOutOfRangeException(nameof(options.ExpireDate), "ExpireDate should be reasonable value");
}
if (String.IsNullOrWhiteSpace(options.Path))
{
throw new ArgumentNullException(nameof(options.Path));
}
}