Interface PollyPresigner

All Superinterfaces:
AutoCloseable, SdkAutoCloseable, SdkPresigner
All Known Implementing Classes:
DefaultPollyPresigner
public interface PollyPresigner extends SdkPresigner
Enables signing a PollyRequest so that it can be executed without requiring any additional authentication on the part of the caller.

Signature Duration

Pre-signed requests are only valid for a finite period of time, referred to as the signature duration. This signature duration is configured when the request is generated, and cannot be longer than 7 days. Attempting to generate a signature longer than 7 days in the future will fail at generation time. Attempting to use a pre-signed request after the signature duration has passed will result in an access denied response from the service.

Example Usage 

 
     // Create a PollyPresigner using the default region and credentials.
     // This is usually done at application startup, because creating a presigner can be expensive.
     PollyPresigner presigner = PollyPresigner.create();

     // Create a SynthesizeSpeechRequest to be pre-signed
     SynthesizeSpeechRequest synthesizeSpeechRequest =
             SynthesizeSpeechRequest.builder()
                                    .text("Hello Polly!")
                                    .voiceId(VoiceId.SALLI)
                                    .outputFormat(OutputFormat.PCM)
                                    .build();

     // Create a SynthesizeSpeechRequest to specify the signature duration
     SynthesizeSpeechPresignRequest synthesizeSpeechPresignRequest =
         SynthesizeSpeechPresignRequest.builder()
                                .signatureDuration(Duration.ofMinutes(10))
                                .synthesizeSpeechRequest(synthesizeSpeechRequest)
                                .build();

     // Generate the presigned request
     PresignedSynthesizeSpeechRequest presignedSynthesizeSpeechRequest =
         presigner.presignSynthesizeSpeech(SynthesizeSpeechPresignRequest);

     // Log the presigned URL, for example.
     System.out.println("Presigned URL: " + presignedSynthesizeSpeechRequest.url());

     // It is recommended to close the presigner when it is done being used, because some credential
     // providers (e.g. if your AWS profile is configured to assume an STS role) require system resources
     // that need to be freed. If you are using one presigner per application (as recommended), this
     // usually is not needed.
     presigner.close();

Browser Compatibility

Some pre-signed requests can be executed by a web browser. These "browser compatible" pre-signed requests do not require the customer to send anything other than a "host" header when performing an HTTP GET against the pre-signed URL.

Whether a pre-signed request is "browser compatible" can be determined by checking the PresignedRequest.isBrowserExecutable() flag. It is recommended to always check this flag when the pre-signed request needs to be executed by a browser, because some request fields will result in the pre-signed request not being browser-compatible.

Executing a Pre-Signed Request from Java code

Browser-compatible requests (see above) can be executed using a web browser. All pre-signed requests can be executed from Java code. This documentation describes two methods for executing a pre-signed request: (1) using the JDK's URLConnection class, (2) using an SDK synchronous SdkHttpClient class.

Using {code URLConnection}: 

     // Create a pre-signed request using one of the "presign" methods on PollyPresigner
     PresignedRequest presignedRequest = ...;

     // Create a JDK HttpURLConnection for communicating with Polly
     HttpURLConnection connection = (HttpURLConnection) presignedRequest.url().openConnection();

     // Specify any headers that are needed by the service (not needed when isBrowserExecutable is true)
     presignedRequest.httpRequest().headers().forEach((header, values) -> {
         values.forEach(value -> {
             connection.addRequestProperty(header, value);
         });
     });

     // Download the result of executing the request
     try (InputStream content = connection.getInputStream()) {
         System.out.println("Service returned response: ");
         IoUtils.copy(content, myFileOutputstream);
     }