Merge pull request #3 from darrarski/feature/download-file

Download File

Author: darrarski

Example/DropboxClientExampleApp/Dependencies.swift

@@ -59,6 +59,9 @@ extension DropboxClient.Client: DependencyKey {
           entries: await entries.value,
           hasMore: false
         )
+      },
+      downloadFile: .init { params in
+        "Preview file content for \(params.path)".data(using: .utf8)!
       }
     )
   }()

Example/DropboxClientExampleApp/ExampleView.swift

@@ -8,6 +8,7 @@ struct ExampleView: View {
   let log = Logger(label: Bundle.main.bundleIdentifier!)
   @State var isSignedIn = false
   @State var list: ListFolder.Result?
+  @State var fileContentAlert: String?
 
   var body: some View {
     Form {
@@ -33,6 +34,20 @@ struct ExampleView: View {
         }
       }
     }
+    .alert(
+      "File content",
+      isPresented: Binding(
+        get: { fileContentAlert != nil },
+        set: { isPresented in
+          if !isPresented {
+            fileContentAlert = nil
+          }
+        }
+      ),
+      presenting: fileContentAlert,
+      actions: { _ in Button("OK") {} },
+      message: { Text($0) }
+    )
   }
 
   var authSection: some View {
@@ -129,6 +144,26 @@ struct ExampleView: View {
         Text("Server modified").font(.caption).foregroundColor(.secondary)
         Text(entry.serverModified.formatted(date: .complete, time: .complete))
       }
+
+      Button {
+        Task<Void, Never> {
+          do {
+            let data = try await client.downloadFile(path: entry.id)
+            if let string = String(data: data, encoding: .utf8) {
+              fileContentAlert = string
+            } else {
+              fileContentAlert = data.base64EncodedString()
+            }
+          } catch {
+            log.error("DownloadFile failure", metadata: [
+              "error": "\(error)",
+              "localizedDescription": "\(error.localizedDescription)"
+            ])
+          }
+        }
+      } label: {
+        Text("Download File")
+      }
     }
   }
 }

README.md

@@ -6,6 +6,8 @@
 Basic Dropbox HTTP API client that does not depend on Dropbox's SDK. No external dependencies.
 
 - Authorize access
+- List folder
+- Download file
 - ...
 
 ## 📖 Usage

Sources/DropboxClient/Client.swift

@@ -1,14 +1,17 @@
 public struct Client: Sendable {
   public init(
     auth: Auth,
-    listFolder: ListFolder
+    listFolder: ListFolder,
+    downloadFile: DownloadFile
   ) {
     self.auth = auth
     self.listFolder = listFolder
+    self.downloadFile = downloadFile
   }
 
   public var auth: Auth
   public var listFolder: ListFolder
+  public var downloadFile: DownloadFile
 }
 
 extension Client {
@@ -32,6 +35,10 @@ extension Client {
       listFolder: .live(
         keychain: keychain,
         httpClient: httpClient
+      ),
+      downloadFile: .live(
+        keychain: keychain,
+        httpClient: httpClient
       )
     )
   }

Sources/DropboxClient/DownloadFile.swift

@@ -0,0 +1,74 @@
+import Foundation
+
+public struct DownloadFile: Sendable {
+  public struct Params: Sendable, Equatable, Encodable {
+    public init(path: String) {
+      self.path = path
+    }
+
+    public var path: String
+  }
+
+  public enum Error: Swift.Error, Sendable, Equatable {
+    case notAuthorized
+    case response(statusCode: Int?, data: Data)
+  }
+
+  public typealias Run = @Sendable (Params) async throws -> Data
+
+  public init(run: @escaping Run) {
+    self.run = run
+  }
+
+  public var run: Run
+
+  public func callAsFunction(_ params: Params) async throws -> Data {
+    try await run(params)
+  }
+
+  public func callAsFunction(path: String) async throws -> Data {
+    try await run(.init(path: path))
+  }
+}
+
+extension DownloadFile {
+  public static func live(
+    keychain: Keychain,
+    httpClient: HTTPClient
+  ) -> DownloadFile {
+    DownloadFile { params in
+      guard let credentials = await keychain.loadCredentials() else {
+        throw Error.notAuthorized
+      }
+
+      let request: URLRequest = try {
+        var components = URLComponents()
+        components.scheme = "https"
+        components.host = "content.dropboxapi.com"
+        components.path = "/2/files/download"
+
+        var request = URLRequest(url: components.url!)
+        request.httpMethod = "POST"
+        request.setValue(
+          "\(credentials.tokenType) \(credentials.accessToken)",
+          forHTTPHeaderField: "Authorization"
+        )
+        request.setValue(
+          String(data: try JSONEncoder.api.encode(params), encoding: .utf8),
+          forHTTPHeaderField: "Dropbox-API-Arg"
+        )
+
+        return request
+      }()
+
+      let (responseData, response) = try await httpClient.data(for: request)
+      let statusCode = (response as? HTTPURLResponse)?.statusCode
+
+      guard let statusCode, (200..<300).contains(statusCode) else {
+        throw Error.response(statusCode: statusCode, data: responseData)
+      }
+
+      return responseData
+    }
+  }
+}

Tests/DropboxClientTests/DownloadFileTests.swift

@@ -0,0 +1,107 @@
+import XCTest
+@testable import DropboxClient
+
+final class DownloadFileTests: XCTestCase {
+  func testDownloadFile() async throws {
+    let credentials = Credentials.test
+    let httpRequests = ActorIsolated<[URLRequest]>([])
+    let downloadFile = DownloadFile.live(
+      keychain: {
+        var keychain = Keychain.unimplemented()
+        keychain.loadCredentials = { credentials }
+        return keychain
+      }(),
+      httpClient: .init { request in
+        await httpRequests.withValue { $0.append(request) }
+        return (
+          "test file content".data(using: .utf8)!,
+          HTTPURLResponse(
+            url: URL(filePath: "/"),
+            statusCode: 200,
+            httpVersion: nil,
+            headerFields: nil
+          )!
+        )
+      }
+    )
+    let params = DownloadFile.Params(path: "test-path")
+
+    let result = try await downloadFile(params)
+
+    await httpRequests.withValue {
+      let expectedRequest: URLRequest = {
+        let url = URL(string: "https://content.dropboxapi.com/2/files/download")!
+        var request = URLRequest(url: url)
+        request.httpMethod = "POST"
+        request.allHTTPHeaderFields = [
+          "Authorization": "\(credentials.tokenType) \(credentials.accessToken)",
+          "Dropbox-API-Arg": String(
+            data: try! JSONEncoder.api.encode(params),
+            encoding: .utf8
+          )!
+        ]
+        return request
+      }()
+
+      XCTAssertEqual($0, [expectedRequest])
+      XCTAssertNil($0.first?.httpBody)
+    }
+    XCTAssertEqual(result, "test file content".data(using: .utf8)!)
+  }
+
+  func testDownloadFileWhenNotAuthorized() async {
+    let downloadFile = DownloadFile.live(
+      keychain: {
+        var keychain = Keychain.unimplemented()
+        keychain.loadCredentials = { nil }
+        return keychain
+      }(),
+      httpClient: .unimplemented()
+    )
+
+    do {
+      _ = try await downloadFile(path: "")
+      XCTFail("Expected to throw, but didn't")
+    } catch {
+      XCTAssertEqual(
+        error as? DownloadFile.Error, .notAuthorized,
+        "Expected to throw .notAuthorized, got \(error)"
+      )
+    }
+  }
+
+  func testDownloadFileErrorResponse() async {
+    let downloadFile = DownloadFile.live(
+      keychain: {
+        var keychain = Keychain.unimplemented()
+        keychain.loadCredentials = { .test }
+        return keychain
+      }(),
+      httpClient: .init { _ in
+        (
+          "Error!!!".data(using: .utf8)!,
+          HTTPURLResponse(
+            url: URL(filePath: "/"),
+            statusCode: 500,
+            httpVersion: nil,
+            headerFields: nil
+          )!
+        )
+      }
+    )
+
+    do {
+      _ = try await downloadFile(path: "")
+      XCTFail("Expected to throw, but didn't")
+    } catch {
+      XCTAssertEqual(
+        error as? DownloadFile.Error,
+        .response(
+          statusCode: 500,
+          data: "Error!!!".data(using: .utf8)!
+        ),
+        "Expected to throw response error, got \(error)"
+      )
+    }
+  }
+}