csharp

page_type	description	products	languages	extensions	urlFragment
sample	This app enables seamless integration with third-party cloud storage providers for files dragged and dropped in Teams chats or channels. It uses the Microsoft Teams JavaScript SDK's thirdPartyCloudStorage module to fetch and upload files efficiently.	office-teams office office-365	csharp	contentType createdDate samples 01/08/2025 13:38:25 PM	officedev-microsoft-teams-samples-msgext-thirdparty-storage-csharp

Third-Party Storage Integration in Microsoft Teams

Microsoft Teams allows users to integrate third-party cloud storage providers by modifying the default storage options from OneDrive and SharePoint. This capability enables files that are dragged and dropped into the Teams chat or message compose area to be stored in a third-party storage service. Using the Microsoft Teams JavaScript client library (TeamsJS), third-party apps can capture these files through the getDragAndDropFiles API and then upload them to their own cloud storage.

To enable this feature, the latest version of the TeamsJS SDK is required, along with a properly configured app manifest and the app ID of the third-party storage provider. When a file is dragged and dropped, it is temporarily cached in Teams before being fetched by the third-party app and uploaded to its storage. This seamless integration enhances flexibility for businesses using external storage solutions within the Teams environment.

Included Features

• Bots
• Message Extensions

Interaction with Messaging Extension

Prerequisites

• Microsoft Teams is installed and you have an account
• .NET SDK version 6.0
• dev tunnel or ngrok latest version or equivalent tunnelling solution

Run the app (Using Teams Toolkit for Visual Studio)

The simplest way to run this sample in Teams is to use Teams Toolkit for Visual Studio.

1. Install Visual Studio 2022 Version 17.10 Preview 4 or higher Visual Studio
2. Install Teams Toolkit for Visual Studio Teams Toolkit extension
3. In the debug dropdown menu of Visual Studio, select Dev Tunnels > Create A Tunnel (set authentication type to Public) or select an existing public dev tunnel.
4. In the debug dropdown menu of Visual Studio, select default startup project > Microsoft Teams (browser)
5. In Visual Studio, right-click your TeamsApp project and Select Teams Toolkit > Prepare Teams App Dependencies
6. Using the extension, sign in with your Microsoft 365 account where you have permissions to upload custom apps.
7. Select Debug > Start Debugging or F5 to run the menu in Visual Studio.
8. In the browser that launches, select the Add button to install the app to Teams.

If you do not have permission to upload custom apps (sideloading), Teams Toolkit will recommend creating and using a Microsoft 365 Developer Program account - a free program to get your own dev environment sandbox that includes Teams.

Setup

Note these instructions are for running the sample on your local machine, the tunnelling solution is required because the Teams service needs to call into the bot.

1. Run ngrok - point to port 3978

   ngrok http 3978 --host-header="localhost:3978"

   Alternatively, you can also use the dev tunnels. Please follow Create and host a dev tunnel and host the tunnel with anonymous user access command as shown below:

   devtunnel host -p 3978 --allow-anonymous

2. Setup for Bot

   In Azure portal, create a Azure Bot resource.

   • For bot handle, make up a name.
   • Select "Use existing app registration" (Create the app registration in Microsoft Entra ID beforehand.)
   • If you don't have an Azure account create an Azure free account here

   In the new Azure Bot resource in the Portal,

   • Ensure that you've enabled the Teams Channel
   • In Settings/Configuration/Messaging endpoint, enter the current https URL you were given by running the tunnelling application. Append with the path /api/messages

3. Clone the repository

   git clone https://github.com/OfficeDev/Microsoft-Teams-Samples.git

4. If you are using Visual Studio

   • Launch Visual Studio
   • File -> Open -> Project/Solution
   • Navigate to samples/msgext-thirdparty-storage/csharp folder
   • Select TeamsMsgextThirdpartyStorage.csproj or TeamsMsgextThirdpartyStorage.slnfile

5. Update the appsettings.json configuration for the bot to use the MicrosoftAppId, MicrosoftAppPassword, MicrosoftAppTenantId generated in Step 1 (App Registration creation). (Note the App Password is referred to as the "client secret" in the azure portal and you can always create a new client secret anytime.)

   • Set "MicrosoftAppType" in the appsettings.json. (Allowed values are: MultiTenant(default), SingleTenant, UserAssignedMSI)

   • Set "BaseUrl" in the appsettings.json as per your application like the ngrok forwarding url (ie https://xxxx.ngrok-free.app) after starting ngrok and if you are using dev tunnels, your URL will be like: https://12345.devtunnels.ms.

6. Run your bot, either from Visual Studio with F5 or using dotnet run in the appropriate folder.

7. This step is specific to Teams.

   • Edit the manifest.json contained in the appPackage folder to replace your Microsoft App Id (that was created when you registered your bot earlier) everywhere you see the place holder string <<YOUR-MICROSOFT-APP-ID>> (depending on the scenario the Microsoft App Id may occur multiple times in the manifest.json)
   • Edit the manifest.json for validDomains with base Url domain. E.g. if you are using ngrok it would be https://1234.ngrok-free.app then your domain-name will be 1234.ngrok-free.app and if you are using dev tunnels then your domain will be like: 12345.devtunnels.ms.
   • Zip up the contents of the appPackage folder to create a manifest.zip (Make sure that zip file does not contains any subfolder otherwise you will get error while uploading your .zip package)
   • Upload the manifest.zip to Teams (In Teams Apps/Manage your apps click "Upload an app to your org's app catalog". Browse to and Open the .zip file. At the next dialog, click the Add button.)
   • Add the bot to personal/team/groupChat scope (Supported scopes)

Note: If you are facing any issue in your app, please uncomment this line and put your debugger for local debug.

Running the sample

Upload an Application to Teams

Select the Build for Your Organization

Log in to Admin Center and Copy App ID

Admin Settings for File Drag-and-Drop to Third-Party Storage

• Admin settings for file drag-drop to third-party storage

Install the Application in Teams

Select a Channel for File Upload

Open the Channels to Access Files

Drag and Drop All Files into Teams

Files Successfully Dragged and Dropped

All Files Loaded in Task Module

Files Loaded into the Compose Area

Send All Dragged and Dropped Files

Drag and Drop Files in Chat

Drop Files in the Chat Window

Load All Files in the Task Module

Upload All Files in the Chat

Send Files in the Chat

Deploy the bot to Azure

To learn more about deploying a bot to Azure, see Deploy your bot to Azure for a complete list of deployment instructions.

Further reading

• Third-party storage capability
• Turn off Teams Native File Upload policy
• Admin settings for file drag-drop to third-party storage
• App manifest