file-upload

Bot Framework File Upload Sample

This Microsoft Teams bot example uses the msbotbuilder-go library. It shows how to handle invoke activity and upload local file from Bot to use.

As documented here, following is the workflow for sending files from Bot to user:

1. Request permission to upload the file: First, ask the user for permission to upload a file by sending a file consent card.
2. User accepts or declines the file When the user presses either “Allow” or “Decline”, your bot will receive an invoke activity.
3. Handle invoke activity If the file was accepted, activity value contains an uploadInfo property. To set the file contents, issue PUT requests to the URL in uploadInfo.uploadUrl as described here
4. Delete consent card Once user responds to file upload request, the consent card is deleted.
5. Send the user a link to the uploaded file After you finish the upload, send a link to the file with file info card.

Run the example

Step 1: Register MS BOT

Follow the official documentation to create and register your BOT.

Copy APP_ID and APP_PASSWORD generated for your BOT.

Do not set any messaging endpoint for now.

Step 2: Run echo local server

Set two variables for the session as APP_ID and APP_PASSWORD to the values of your BotFramework APP_ID and APP_PASSWORD. Then run the main.go file.

export APP_PASSWORD=MICROSOFT_APP_PASSWORD
export APP_ID=MICROSOFT_APP_ID

go run main.go

This will start a server which will listen on port 3978

Step 3: Expose local server with ngrok

Now, in separate terminal, run ngrok command to expose your local server to outside world.

$ ngrok http 3978

Copy https endpoint, go to Bot Framework dashboard and set messaging endpoint under Settings.

Step 4: Test the BOT

You can either test BOT on BotFramework portal or you can create app manifest and install the App on Teams as mentioned here.

Understanding the example

The program starts by creating a handler structs of type activity.HandlerFuncs.

This example contains following handlers:

OnMessageFunc - sends upload request to user using file consent card

OnInvokeFunc - parses invoke activity, uploads file and notifies user with file info card

The init function picks up the APP_ID and APP_PASSWORD from the environment session and creates an adapter using this.

The consent cleanup cleanupConsents() is started as a go routine to delete processed consent cards.

A webserver is started with a handler which passes the received payload to adapter.ParseRequest. This methods authenticates the payload, parses the request and returns an Activity value.

activity, err := adapter.ParseRequest(ctx, req)

The Activity is then passed to adapter.ProcessActivity with the handler created to process the activity as per the handler functions and send the response to the connector service.

err = adapter.ProcessActivity(ctx, activity, customHandler)

Once the incoming activity is processed, file consent card is sent to ask user for file upload permission

e.g

{
    "contentType": "application/vnd.microsoft.teams.card.file.consent",
    "name": "data.txt",
    "content": {
        "description": "Sample data",
        "sizeInBytes": 29,
        "acceptContext": {
            "resultId": <unique-id>
        },
        "declineContext": {
            "resultId": <unique-id>
        }
    }

Based on user's response, invoke activity is sent to Bot, which we handle in OnInvokeFunc

In OnInvokeFunc, we find uploadInfo from the invoke activity which has following fields:

    "type": "invoke",
    "name": "fileConsent/invoke",
    ...
    "value": {
        "type": "fileUpload",
        "action": "accept",
        "context": {
            "resultId": <unique-id>
        },
        "uploadInfo": {
            "contentUrl": "https://<onedrive_url>/data.txt",
            "name": "data.txt",
            "uploadUrl": "https://<onedrive_upload_url>",
            "uniqueId": <unique-id>,
            "fileType": "txt"
        }

Then, the file contents are uploaded on uploadUrl using PUT request

err = putRequest(uploadInfo.UploadURL, data)

Finally, user is notified with the file info using file info card

{
    "contentType": "application/vnd.microsoft.teams.card.file.info",
    "contentUrl": "<uploadInfo.contentUrl>",
    "name": "<uploadInfo.name>",
    "content": {
        "uniqueId": "<uploadInfo.uniqueId>",
        "fileType": "<uploadInfo.fileType>",
    }
}

In case of no error, this web server responds with a 200 status.