Amazon.Polly.SynthesizeSpeechUtil.GeneratePresignedUrl C# (CSharp) Method

        public static string GeneratePresignedUrl(AWSCredentials credentials, RegionEndpoint region, SynthesizeSpeechRequest request)
        {
            if (credentials == null)
                throw new ArgumentNullException("credentials");

            if (region == null)
                throw new ArgumentNullException("region");

            if (request == null)
                throw new ArgumentNullException("request");

            // Marshall this request and prepare it to be signed
            var marshaller = new SynthesizeSpeechRequestMarshaller();
            var iRequest = marshaller.Marshall(request);
            iRequest.UseQueryString = true;
            iRequest.HttpMethod = HTTPGet;
            iRequest.Endpoint = new UriBuilder(HTTPS, region.GetEndpointForService(PollyServiceName).Hostname).Uri;
            iRequest.Parameters[XAmzExpires] = ((int)FifteenMinutes.TotalSeconds).ToString(CultureInfo.InvariantCulture);

            if (request.IsSetLexiconNames())
            {
                var sortedLexiconNames = new List<string>(request.LexiconNames);
                sortedLexiconNames.Sort(StringComparer.Ordinal);
                iRequest.Parameters[LexiconNamesParameter] = JsonMapper.ToJson(sortedLexiconNames);
            }

            if (request.IsSetOutputFormat())
                iRequest.Parameters["OutputFormat"] = request.OutputFormat.ToString();

            if (request.IsSetSampleRate())
                iRequest.Parameters["SampleRate"] = request.SampleRate.ToString();

            if (request.IsSetText())
                iRequest.Parameters["Text"] = request.Text;

            if (request.IsSetTextType())
                iRequest.Parameters["TextType"] = request.TextType.ToString();

            if (request.IsSetVoiceId())
                iRequest.Parameters["VoiceId"] = request.VoiceId;

            var immutableCredentials = credentials.GetCredentials();
            if (immutableCredentials.UseToken)
            {
                // Don't use HeaderKeys.XAmzSecurityTokenHeader because Polly treats this as case-sensitive
                iRequest.Parameters["X-Amz-Security-Token"] = immutableCredentials.Token;
            }

            // Only the host header should be signed, and the signer adds that.
            // So clear out headers.
            iRequest.Headers.Clear();

            // Create presigned URL and assign it
            var signingResult = SynthesizeSpeechPresignedUrlSigner.SignSynthesizeSpeechRequest(iRequest, new RequestMetrics(),
                immutableCredentials.AccessKey, immutableCredentials.SecretKey, PollyServiceName, region.SystemName);

            var authorization = "&" + signingResult.ForQueryParameters;

            return ComposeUrl(iRequest).AbsoluteUri + authorization;
        }