SwiftUI Food Logging REST API Integration Guide

SwiftUI food logging needs a reliable data source behind every tap. This guide covers SwiftUI food logging REST API integration from URLSession calls to a polished search and log flow using Calorie API through your backend proxy.

Architecture

SwiftUI View → NutritionService → your-backend.com → Calorie API
                      ↑
               no API key in IPA

Read hide nutrition API key mobile backend proxy before TestFlight.

Step 1: Define Codable Models

struct FoodSearchResult: Codable, Identifiable {
    let id: Int
    let name: String
    let brand: String?
    let calories: Double?
}

struct FoodSearchResponse: Codable {
    let results: [FoodSearchResult]
    let total: Int
}

Step 2: NutritionService With async/await

enum NutritionError: Error {
    case badURL, badResponse, decoding
}

final class NutritionService {
    private let baseURL: URL

    init(baseURL: URL) {
        self.baseURL = baseURL
    }

    func searchFoods(query: String, limit: Int = 15) async throws -> [FoodSearchResult] {
        guard query.count >= 2 else { return [] }
        var components = URLComponents(url: baseURL.appendingPathComponent("api/foods/search"), resolvingAgainstBaseURL: false)!
        components.queryItems = [
            URLQueryItem(name: "q", value: query),
            URLQueryItem(name: "limit", value: String(limit))
        ]
        guard let url = components.url else { throw NutritionError.badURL }

        let (data, response) = try await URLSession.shared.data(from: url)
        guard (response as? HTTPURLResponse)?.statusCode == 200 else { throw NutritionError.badResponse }
        let decoded = try JSONDecoder().decode(FoodSearchResponse.self, from: data)
        return decoded.results
    }
}

Inject baseURL from a config plist pointing at your Next.js or Firebase proxy.

Step 3: Search ViewModel

@MainActor
final class FoodSearchViewModel: ObservableObject {
    @Published var query = ""
    @Published var results: [FoodSearchResult] = []
    @Published var isLoading = false

    private let service: NutritionService
    private var searchTask: Task<Void, Never>?

    init(service: NutritionService) {
        self.service = service
    }

    func onQueryChange() {
        searchTask?.cancel()
        searchTask = Task {
            try? await Task.sleep(nanoseconds: 300_000_000)
            guard !Task.isCancelled else { return }
            isLoading = true
            defer { isLoading = false }
            do {
                results = try await service.searchFoods(query: query)
            } catch {
                results = []
            }
        }
    }
}

Step 4: SwiftUI Search View

struct FoodSearchView: View {
    @StateObject var viewModel: FoodSearchViewModel

    var body: some View {
        List(viewModel.results) { food in
            VStack(alignment: .leading) {
                Text(food.name).font(.headline)
                if let brand = food.brand { Text(brand).font(.caption) }
                if let cal = food.calories {
                    Text("\(Int(cal)) kcal / 100g").foregroundStyle(.secondary)
                }
            }
        }
        .searchable(text: $viewModel.query)
        .onChange(of: viewModel.query) { _, _ in viewModel.onQueryChange() }
        .overlay { if viewModel.isLoading { ProgressView() } }
    }
}

Step 5: Daily Log State

Store logged entries in SwiftData or Core Data:

struct FoodLogEntry: Identifiable {
    let id: UUID
    let foodId: Int
    let name: String
    let grams: Double
    let calories: Double
    let proteinG: Double
    let carbsG: Double
    let fatG: Double
    let loggedAt: Date
}

Fetch detail on select, scale nutrients, append to today's section.

Step 6: Barcode With AVFoundation

Use DataScannerViewController (iOS 16+) or a third-party scanner. Send UPC to /api/foods/barcode/{upc} on your backend.

Tips for App Store Quality

Related Guides

• Kotlin Android barcode example
• Secure Next.js API route
• Build a calorie tracker app

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