/**
* This method reads the key specified in PollyProperties and sets it as the new AWS profile.
* At the moment, the region is always set to EU which is something you might want to care for.
* Except for setting up the account, it is not used or verified at this point.
* The method only fails if there is something wrong with the KeyFile.
*/
private void SetAwsProfile(PollyProperties pollyProps)
{
// Read the Credentials and store them shortly in an array
var path = pollyProps.ApiKey;
var credentialFile = new Dictionary <string, string>();
foreach (var row in File.ReadAllLines(path))
{
credentialFile.Add(row.Split('=')[0], string.Join("=", row.Split('=').Skip(1).ToArray()));
}
// Create Amazon Credentials
var options = new CredentialProfileOptions
{
AccessKey = credentialFile["AWSAccessKeyId"],
SecretKey = credentialFile["AWSSecretKey"]
};
// Make Amazon Credential profile
var profile = new Amazon.Runtime.CredentialManagement.CredentialProfile("polly_profile", options);
profile.Region = RegionEndpoint.EUCentral1;
this._awsProfile = profile;
}
/*
* Makes a new savepoint at index+1.
* If the point is already known, do nothing.
* If a new Point is created while the Memento is in a position of the past,
* all history after the current point will be lost.
*/
public void MakeMemento(PollyProperties ps)
{
var memento = (PollyProperties)ps.Clone();
// Short-Circuit:
// memento is already in history - do nothing, return early.
if (_history.Contains(memento))
{
return;
}
// Case 1: Current Index is last of List
if (_history.Count == 0 || _index == -1 || _index == _history.Count - 1)
{
// "Just" add a copy of current Properties to Memento List
_history.Add(memento);
// Increase Index by 1
_index++;
}
// Case 2: Current Index is not last of the list
else
{
// Drop all items after index, "make current index last index"
this._history = _history.GetRange(0, this._index);
// Do Case 1
_history.Add(memento);
_index++;
}
}
public object Clone()
{
// Cloning is rather easy, as Strings are pass by value (so is the int of sampling rate)
var clone = new PollyProperties()
{
Voice = this.Voice,
ApiKey = this.ApiKey,
TextToPlay = this.TextToPlay,
SamplingRate = this.SamplingRate
};
return(clone);
}
/**
* This method reads the polly props and creates a hashcode for it.
* The used hash-method is MD5, which gets cut down to 8 digits.
* The number of digits is at the moment hardcoded in the PollyCaller as a constant.
* The hashed properties are Text, Voice & SamplingRate.
*/
private string DeriveTemporaryName(PollyProperties pollyProps)
{
var input = pollyProps.TextToPlay + "+" + pollyProps.Voice + "+" + pollyProps.SamplingRate;
string output;
using (var provider = System.Security.Cryptography.MD5.Create())
{
var builder = new StringBuilder();
foreach (byte b in provider.ComputeHash(Encoding.UTF8.GetBytes(input)))
{
builder.Append(b.ToString("x2").ToLower());
}
output = builder.ToString();
}
return(output.Substring(0, PollyCaller.HashCodeLength));
}
/*
* This method reads the polly properties and audio-properties,
* then it checks if the wanted combination of text+voice is known already.
* If the text is known, it will be saved to the given filename,
* otherwise it will be created by Amazon, stored locally and then saved.
*/
public void SaveToFile(string mp3Filename, PollyProperties pollyProps)
{
// There was an issue, when the stream was already played.
// If that was the case, the stream was "at an end" and could not be saved somewhere (file was just empty).
// So if the sound was played, there should be a temp file for it which we just move.
// If the file is not there - remove the key and run again.
SetAwsProfile(pollyProps);
string tempName = DeriveTemporaryName(pollyProps);
string tempFilePath = Path.GetFullPath(tempName + ".mp3", _soundDir.FullName);
if (_knownHashes.ContainsKey(tempName))
{
if (File.Exists(tempFilePath))
{
File.Copy(tempFilePath, mp3Filename);
}
else
{
// The file got lost - that's bad.
// Remove the key, and re-run again. This will also create the file.
_knownHashes.Remove(tempName);
SaveToFile(mp3Filename, pollyProps);
}
}
else // The hash is not known - create it and make the file + temp file
{
Stream audioStream = MakeAwsCall(pollyProps);
_knownHashes[tempName] = audioStream;
// I am not 100% sure, but overwriting did not properly work for audio-streams.
if (File.Exists(mp3Filename))
{
File.Delete(mp3Filename);
}
// use two file-streams, to still save it to temp
using (FileStream fs = File.Create(mp3Filename))
using (FileStream tfs = File.Create(tempFilePath))
{
audioStream.CopyTo(fs);
audioStream.CopyTo(tfs);
fs.Flush();
tfs.Flush();
}
}
}
/*
* This method reads the polly properties and audioproperties,
* then it checks if the wanted combination of text+voice is known already.
* If the text is known, it will be played to the selected audiodevices,
* otherwise it will be created by Amazon, stored locally and then played.
*/
public void Call(PollyProperties pollyProps)
{
SetAwsProfile(pollyProps);
var tempName = DeriveTemporaryName(pollyProps);
var tempFilePath = Path.GetFullPath(tempName + ".mp3", _soundDir.FullName);
Stream audioStream = null;
if (_knownHashes.ContainsKey(tempName))
{
audioStream = _knownHashes[tempName];
}
else
{
audioStream = MakeAwsCall(pollyProps);
_knownHashes[tempName] = audioStream;
}
if (!File.Exists(tempFilePath))
{
/*TODO: Without the existence check, the line below throws a marshal-error
* /*The file-handle does not seem to be closed properly.
*/
using (FileStream fs = File.Create(tempFilePath))
{
audioStream.CopyTo(fs);
fs.Flush();
}
}
// The audio-devices must be decremented by one, as the "default" for NAudio is -1 while its 0 for Windows.
PlaySound(tempFilePath, AudioProps.DeviceA - 1, AudioProps.VolumeA);
// Just play the second audio if there is a different selected
if (AudioProps.DeviceA != AudioProps.DeviceB)
{
PlaySound(tempFilePath, AudioProps.DeviceB - 1, AudioProps.VolumeB);
}
}
/*
* This method reads the polly properties and the ready-made AWS Profile to send a polly request.
* It returns the Stream of the MP3 created.
*
* This method will likely fail in three ways:
* 1) The Profile is bad
* 2) The user is offline
* 3) The specified content for the request is faulty
*
* I tried to address the 3) with value checks in the frontend, the others are not checked for at the moment.
*/
private Stream MakeAwsCall(PollyProperties pollyProps)
{
// Store the Amazon Profile in the Credentials Engine for later use
var netSdkFile = new NetSDKCredentialsFile();
netSdkFile.RegisterProfile(_awsProfile);
// This chain uses the credentials to create a token for usage,
// Later the token is used in the Credentials
// The chain stores it into awsCredentials, that is used for the client.
var chain = new CredentialProfileStoreChain();
AWSCredentials awsCredentials;
Stream audioStream = null;
// use awsCredentials
if (chain.TryGetAWSCredentials("polly_profile", out awsCredentials))
{
using (var client = new AmazonPollyClient(awsCredentials, _awsProfile.Region))
{
var response = client.SynthesizeSpeechAsync(new SynthesizeSpeechRequest
{
OutputFormat = "mp3",
SampleRate = pollyProps.SamplingRate.ToString(),
Text = pollyProps.TextToPlay,
TextType = "text",
VoiceId = pollyProps.Voice // One of Hans, Jenny , ...
});
response.Wait();
var res = response.Result;
audioStream = res.AudioStream;
}
}
return(audioStream);
}