Add support for getting public URL for asset (#11)

* Add support for getting public URL for asset

* Refactor implementation to use URLComponents

Author: bryan-vh

Sources/SupabaseStorage/StorageFileApi.swift

@@ -198,4 +198,35 @@ public class StorageFileApi: StorageApi {
     }
     return data
   }
+    
+    /// Returns a public url for an asset.
+    /// - Parameters:
+    ///  - path: The file path to the asset. For example `folder/image.png`.
+    ///  - download: Whether the asset should be downloaded.
+    ///  - fileName: If specified, the file name for the asset that is downloaded.
+    ///  - options: Transform the asset before retrieving it on the client.
+    public func getPublicUrl(
+        path: String,
+        download: Bool = false,
+        fileName: String = "",
+        options: TransformOptions? = nil
+    ) throws -> URL {
+        guard var components = URLComponents(string: url) else {
+            throw StorageError(message: "badURL")
+        }
+        
+        let renderPath = options != nil ? "render/image" : "object"
+        
+        let downloadQueryItem = download ? [URLQueryItem(name: "download", value: fileName)] : []
+        let optionsQueryItems = options?.queryItems ?? []
+        
+        components.path = "/\(renderPath)/public/\(path)"
+        components.queryItems = downloadQueryItem + optionsQueryItems
+        
+        guard let generatedUrl = components.url else {
+            throw StorageError(message: "badUrl")
+        }
+        
+        return generatedUrl
+    }
 }

Sources/SupabaseStorage/TransformOptions.swift

@@ -0,0 +1,49 @@
+import Foundation
+
+public struct TransformOptions {
+    public var width: Int?
+    public var height: Int?
+    public var resize: String?
+    public var quality: Int?
+    public var format: String?
+    
+    public init(
+        width: Int? = nil,
+        height: Int? = nil,
+        resize: String? = "cover",
+        quality: Int? = 80,
+        format: String? = "origin"
+    ) {
+        self.width = width
+        self.height = height
+        self.resize = resize
+        self.quality = quality
+        self.format = format
+    }
+    
+    var queryItems: [URLQueryItem] {
+        var items = [URLQueryItem]()
+        
+        if let width = width {
+            items.append(URLQueryItem(name: "width", value: String(width)))
+        }
+        
+        if let height = height {
+            items.append(URLQueryItem(name: "height", value: String(height)))
+        }
+        
+        if let resize = resize {
+            items.append(URLQueryItem(name: "resize", value: resize))
+        }
+        
+        if let quality = quality {
+            items.append(URLQueryItem(name: "quality", value: String(quality)))
+        }
+        
+        if let format = format {
+            items.append(URLQueryItem(name: "format", value: format))
+        }
+        
+        return items
+    }
+}

Tests/SupabaseStorageTests/SupabaseStorageTests.swift

@@ -67,4 +67,20 @@ final class SupabaseStorageTests: XCTestCase {
     let objects = try await storage.from(id: "public").list()
     XCTAssertEqual(objects.count, 4)
   }
+    
+    func testGetPublicUrl() throws {
+        let path = "README.md"
+        
+        let baseUrl = try storage.from(id: bucket).getPublicUrl(path: path)
+        XCTAssertEqual(baseUrl.absoluteString, "\(Self.supabaseURL)/object/public/\(path)?")
+        
+        let baseUrlWithDownload = try storage.from(id: bucket).getPublicUrl(path: path, download: true)
+        XCTAssertEqual(baseUrlWithDownload.absoluteString, "\(Self.supabaseURL)/object/public/\(path)?download=")
+        
+        let baseUrlWithDownloadAndFileName = try storage.from(id: bucket).getPublicUrl(path: path, download: true, fileName: "test")
+        XCTAssertEqual(baseUrlWithDownloadAndFileName.absoluteString, "\(Self.supabaseURL)/object/public/\(path)?download=test")
+        
+        let baseUrlWithAllOptions = try storage.from(id: bucket).getPublicUrl(path: path, download: true, fileName: "test", options: TransformOptions(width: 300, height: 300))
+        XCTAssertEqual(baseUrlWithAllOptions.absoluteString, "\(Self.supabaseURL)/render/image/public/\(path)?download=test&width=300&height=300&resize=cover&quality=80&format=origin")
+    }
 }