Added refresh token support to PKCE flow.

Author: CDobbins1

Modules/IntelliTect.PSDropbin/IntelliTect.PSDropBin/DropboxDriveInfo.cs

@@ -10,26 +10,38 @@ public class DropboxDriveInfo : PSDriveInfo
     {
         private const string DropboxCredentialNameBase = "DropboxUserToken";
 
-        public static string GetDropboxCredentialName(string driveName)
+        private static string GetDropboxCredentialName(string driveName)
         {
             return $"{DropboxCredentialNameBase}-{driveName}";
         }
 
+        public static string GetDropboxAccessTokenName(string driveName)
+        {
+            return $"{GetDropboxCredentialName(driveName)}-AccessToken";
+        }
+
+        public static string GetDropboxRefreshTokenName(string driveName)
+        {
+            return $"{GetDropboxCredentialName(driveName)}-RefreshToken";
+        }
+
         public DropboxDriveInfo(PSDriveInfo driveInfo) 
             : base(driveInfo)
         {
-            string userToken;
+            string accessToken;
             if (driveInfo.Credential?.Password == null)
             {
-                string credentialName = GetDropboxCredentialName(driveInfo.Name);
-                userToken = CredentialManager.ReadCredential(credentialName);
+                string credentialName = GetDropboxAccessTokenName(driveInfo.Name);
+                accessToken = CredentialManager.ReadCredential(credentialName);
             }
             else
             {
-                userToken = driveInfo.Credential.GetNetworkCredential().Password;
+                accessToken = driveInfo.Credential.GetNetworkCredential().Password;
             }
 
-            Client = new DropboxClient(userToken);
+            string refreshToken = CredentialManager.ReadCredential(GetDropboxRefreshTokenName(driveInfo.Name));
+
+            Client = new DropboxClient(accessToken, refreshToken, Settings.Default.AccessTokenExpiration, Settings.Default.ApiKey);
         }
 
         public DropboxClient Client { get; private set; }

Modules/IntelliTect.PSDropbin/IntelliTect.PSDropBin/PKCEHelper.cs

@@ -81,26 +81,11 @@ private async Task<Uri> HandleJSRedirect(HttpListener http)
         /// <returns>A valid access token if successful otherwise null.</returns>
         public async Task<string> GetOAuthTokensAsync(string[] scopeList, IncludeGrantedScopes includeGrantedScopes, string driveName)
         {
-            bool accessExpiringSoon = false;
-            DateTime expireDate;
             Settings.Default.Upgrade();
 
-            try
-            {
-                expireDate = Settings.Default.AccessTokenExpiration;
-                if (expireDate <= DateTime.Now)
-                {
-                    accessExpiringSoon = true;
-                }
-            }
-            catch (Exception)
-            {
-                accessExpiringSoon = true;
-            }
-
-            string credentialName = DropboxDriveInfo.GetDropboxCredentialName(driveName);
+            string accessTokencredentialName = DropboxDriveInfo.GetDropboxAccessTokenName(driveName);
 
-            if (string.IsNullOrEmpty(CredentialManager.ReadCredential(credentialName)) || accessExpiringSoon)
+            if (string.IsNullOrEmpty(CredentialManager.ReadCredential(accessTokencredentialName)))
             {
                 string apiKey = GetApiKey();
 
@@ -156,9 +141,13 @@ public async Task<string> GetOAuthTokensAsync(string[] scopeList, IncludeGranted
                         Console.WriteLine("OAuth token acquire complete");
 
                         CredentialManager.WriteCredential(
-                            DropboxDriveInfo.GetDropboxCredentialName(driveName),
+                            DropboxDriveInfo.GetDropboxAccessTokenName(driveName),
                             result.AccessToken
                             );
+                        CredentialManager.WriteCredential(
+                            DropboxDriveInfo.GetDropboxRefreshTokenName(driveName),
+                            result.RefreshToken
+                            );
                         UpdateSettings(result);
                     }
                     catch (Exception e)
@@ -169,7 +158,7 @@ public async Task<string> GetOAuthTokensAsync(string[] scopeList, IncludeGranted
                 }
             }
 
-            return CredentialManager.ReadCredential(credentialName);
+            return CredentialManager.ReadCredential(accessTokencredentialName);
         }
 
         private static void UpdateSettings(OAuth2Response result)

Modules/IntelliTect.PSDropbin/IntelliTect.PSDropBin/RemoveDropboxCredential.cs

@@ -16,11 +16,14 @@ protected override void ProcessRecord()
         {
             try
             {
-                string credentialName = DropboxDriveInfo.GetDropboxCredentialName(Name);
-                bool result = CredentialManager.DeleteCredential(credentialName);
-                WriteObject( result
-                        ? "Credential removed. You may wish to also revoke access in your Dropbox user profile."
-                        : "No credential found." );
+                string accessTokenName = DropboxDriveInfo.GetDropboxAccessTokenName(Name);
+                bool accessTokenResult = CredentialManager.DeleteCredential(accessTokenName);
+                string refreshTokenName = DropboxDriveInfo.GetDropboxRefreshTokenName(Name);
+                bool refreshTokenResult = CredentialManager.DeleteCredential(refreshTokenName);
+                WriteObject(accessTokenResult && refreshTokenResult
+                        ? "Credentials removed. You may wish to also revoke access in your Dropbox user profile."
+                        : "No credential found.");
+                Settings.Default.Reset();
             }
             catch ( Exception e )
             {