Teams File Upload Bot

05/29/2025

This sample demonstrates how to upload files in Microsoft Teams using a bot built with Bot Framework v4. Users can send files as attachments or inline images directly within a chat, and the bot can handle, retrieve, and process these files effectively. The bot also illustrates interaction with adaptive cards and supports file uploads through various methods, making it versatile for file management in Teams.

Included Features

Bots
Adaptive Cards

Interaction with bot

bot-file-upload

Try it yourself - experience the App in your Microsoft Teams client

Please find below demo manifest which is deployed on Microsoft Azure and you can try it yourself by uploading the app manifest (.zip file link below) to your teams and/or as a personal app. (Uploading must be enabled for your tenant, see steps here).

Teams File Upload Bot: Manifest

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
Microsoft 365 Agents Toolkit for Visual Studio

Run the app (Using Microsoft 365 Agents Toolkit for Visual Studio)

The simplest way to run this sample in Teams is to use Microsoft 365 Agents Toolkit for Visual Studio.

Install Visual Studio 2022 Version 17.14 or higher Visual Studio
Install Microsoft 365 Agents Toolkit for Visual Studio Microsoft 365 Agents Toolkit extension
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.
Right-click the 'M365Agent' project in Solution Explorer and select Microsoft 365 Agents Toolkit > Select Microsoft 365 Account
Sign in to Microsoft 365 Agents Toolkit with a Microsoft 365 work or school account
Set Startup Item as Microsoft Teams (browser).
Press F5, or select Debug > Start Debugging menu in Visual Studio to start your app
In the opened web browser, select Add button to install the app in Teams

If you do not have permission to upload custom apps (uploading), Microsoft 365 Agents 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.

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
```
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.)
- Choose "Accounts in any organizational directory (Any Azure AD directory - Multitenant)" in Authentication section in your App Registration to run this sample smoothly.
- 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 tunneling application. Append with the path /api/messages

Clone the repository

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

If you are using Visual Studio
- Launch Visual Studio
- File -> Open -> Project/Solution
- Navigate to samples/bot-file-upload/csharp folder
- Select TeamsFileUpload.csproj or TeamsFileUpload.slnfile
Update the appsettings.json configuration for the bot to use the MicrosoftAppId, MicrosoftAppPassword, MicrosoftAppTenantId generated in Step 2 (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.)
- Also, set MicrosoftAppType in the appsettings.json. (Allowed values are: MultiTenant(default), SingleTenant, UserAssignedMSI)
Run your bot, either from Visual Studio with F5 or using dotnet run in the appropriate folder.
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". Browse to and Open the .zip file. At the next dialog, click the Add button.)
- Add the app to personal scope (Supported app scope)

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

Running the sample

Note this manifest.json specified that the bot will be installed in "personal" scope which is why you immediately entered a one on one chat conversation with the bot. Please refer to Teams documentation for more details.

Adding the bot:
Sending a message to the bot will cause it to respond with a card that will prompt you to upload a file. The file that's being uploaded is the teams-logo.png in the Files directory in this sample. The Accept and Decline events illustrated in this sample are specific to Teams. You can message the bot again to receive another prompt.
You can send a file to the bot as an attachment in the message compose section in Teams. This will be delivered to the bot as a Message Activity and the code in this sample fetches and saves the file.
You can also send an inline image in the message compose section. This will be present in the attachments of the Activity and requires the Bot's access token to fetch the image.