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Packaging and Sharing Models Between Server and App

Swift allows you to create packages that can be shared between your server-side Vapor projects and iOS apps, streamlining development and ensuring consistency across platforms.

Details

URL: 🔗 https://swift.org/package-manager/

Source: 🔗 Book: Server-Side Swift

Author: [Author Name]

Tags:
Swift, SPM, Vapor, Code Sharing

Platforms Supported: macOS, Linux, iOS

Swift Version: 5.x

Creating a Reusable Swift Package​

Step 1: Create a Swift Package​

In Xcode, go to File > New > Swift Package and name it TaskModule. This will create a new Swift package project with a structure ready for adding shared models.

Step 2: Define the Model​

Add a new file, TaskViewModel.swift, and define your model:

import Foundation

enum Category: String {
    case shopping = "shopping"
    case work = "work"
}

public final class TaskViewModel {
    var category: Category?
    var title: String?
    var imageUrl: URL?

    public convenience init(title: String, category: String) {
        self.init()
        self.category = Category(rawValue: category)
        self.title = title
        self.imageUrl = URL(string: "https://www.test.com/\(category)")
    }
}

This view model is platform-agnostic, allowing it to be used in both server and client projects.

Step 3: Integrate the Package with the Vapor Project​

In your Vapor project, open Package.swift and add the local path to the new package:

dependencies: [
    .package(path: "/path/to/your/TaskModule")
],
targets: [
    .target(
        name: "App",
        dependencies: [
            .product(name: "TaskModule", package: "TaskModule"),
            // other dependencies
        ]
    )
]

This will link your TaskModule package with your Vapor project, making it available for use.

Step 4: Use the Package in Your Vapor Project​

Import the package into any file where you need the shared model:

import TaskModule

let viewTask = TaskViewModel(title: "Buy milk", category: "shopping")

This allows you to use the same model in both server-side and client-side Swift projects.

Step 5: Use the Package in Your iOS App​

To use the package in your iOS app, ensure your TaskModule is initialized as a Git repository:

git init
git add .
git commit -m "Initial commit"

Then, add it as a dependency in your iOS project using File > Swift Packages > Add Package Dependency... and provide the local path:

file:///Users/username/path/to/TaskModule

Now, you can import and use TaskModule in your iOS app just as in your Vapor project.

How It Works​

Sharing models between server-side and iOS projects using Swift packages simplifies code management and ensures consistency across platforms. By using Swift Package Manager (SPM), you can easily integrate shared code into both your server and client projects, avoiding duplication and improving maintainability.

Platform-Specific Code​

To handle platform-specific code, use conditional compilation:

#if os(Linux)
import LinuxModule
#elseif os(iOS)
import UIKit
#endif

This ensures your package works across different platforms, such as Linux for server-side code and iOS for client-side code.

Conclusion​

Swift's ability to share code between server-side and client-side projects through packages enhances productivity and code reuse. By packaging models and logic into reusable modules, you maintain consistency and reduce duplication in your projects.

Learn More about Swift Package Manager→