iOS 26: SpeechRecognizer example

SpeechRecognizer.swift

//
//  SpeechTranscribeView.swift
//  WWDC25Demo
//
//  Created by Anton Gubarenko on 20.07.2025.
//

import SwiftUI
import Playgrounds
import Speech

/// Demo View for SpeechRecognizer
struct SpeechTranscribeView: View {
    
    @State private var transcribedText: AttributedString = ""
    
    var body: some View {
        VStack {
            Text("Transcribe speech")
            ScrollView(.vertical, content: {
                Text(transcribedText)
                    .frame(maxHeight: .infinity)
                    .multilineTextAlignment(.leading)
            })
            Spacer()
        }.task{
            do {
                try await transcribeFile()
            } catch {
                print(error)
            }
        }
        
    }
    
    /// Main recognition task
    private func transcribeFile() async throws {
        var finalStr: AttributedString = ""
        let fileUrl = try loadAudioFile(named: "dragon_sample", withExtension: "mp3")
        
        let locale = Locale(identifier: "it_IT")
        
        
        let transcriber = transcriber(for: locale)
        print("transcriber ready")
        try await ensureModel(transcriber: transcriber, locale: locale)
        print("ensureModel ready")
        let analyzer = SpeechAnalyzer(modules: [transcriber])


        if let lastSample = try await analyzer.analyzeSequence(from: AVAudioFile(forReading: fileUrl)) {
            try await analyzer.finalizeAndFinish(through: lastSample)
        } else {
            await analyzer.cancelAndFinishNow()
        }

        for try await recResponse in  transcriber.results {
            if recResponse.isFinal {
                finalStr.append(recResponse.text)
            }
        }
        transcribedText = finalStr
    }
    
    /// Loading audio file
    /// - Parameters:
    ///   - name: file name
    ///   - ext: extension
    /// - Returns: URL of file
    private func loadAudioFile(named name: String, withExtension ext: String) throws -> URL {
        guard let url = Bundle.main.url(forResource: name, withExtension: ext) else {
            throw NSError(domain: "SpeechAnalyzerExample", code: 1, userInfo: [NSLocalizedDescriptionKey: "Audio file not found in bundle."])
        }
        return url
    }
    
    /// Transcriber for locale
    /// - Parameter locale: locale to recognize
    /// - Returns: Transcriber
    private func transcriber(for locale: Locale) -> SpeechTranscriber {
        SpeechTranscriber(locale: locale,
                          transcriptionOptions: [],
                          reportingOptions: [.volatileResults],
                          attributeOptions: [.audioTimeRange])
    }
    
    /// Chekc that model exists
    /// - Parameters:
    ///   - transcriber: transcriber to use for this model
    ///   - locale: locale to recognize
    private func ensureModel(transcriber: SpeechTranscriber, locale: Locale) async throws {
        guard await supported(locale: locale) else {
            throw NSError(domain: "SpeechAnalyzerExample", code: 1, userInfo: [NSLocalizedDescriptionKey: "Locale not supported"])
        }
        
        if await installed(locale: locale) {
            return
        } else {
            try await downloadIfNeeded(for: transcriber)
        }
    }
    
    /// Is locale supported
    /// - Parameter locale: locale to recognize
    /// - Returns: true if supported, fasle - else
    private func supported(locale: Locale) async -> Bool {
        print(SpeechTranscriber.isAvailable)
        guard SpeechTranscriber.isAvailable else {return false}
        let supported = await DictationTranscriber.supportedLocales
        print("Have locales \(supported)")
        return supported.map { $0.identifier(.bcp47) }.contains(locale.identifier(.bcp47))
    }
    
    /// Is locale file installed locally
    /// - Parameter locale: locale to recognize
    /// - Returns: true is installed locally
    private func installed(locale: Locale) async -> Bool {
        let installed = await Set(SpeechTranscriber.installedLocales)
        return installed.map { $0.identifier(.bcp47) }.contains(locale.identifier(.bcp47))
    }
    
    /// Download module assets
    /// - Parameter module: module to use
    private func downloadIfNeeded(for module: SpeechTranscriber) async throws {
        if let downloader = try await AssetInventory.assetInstallationRequest(supporting: [module]) {
            try await downloader.downloadAndInstall()
        }
    }
}

#Preview {
    SpeechTranscribeView()
}