csharp

page_type	description	products	languages	extensions	urlFragment
sample	This sample demonstrates a C# Messaging Extension that implements link unfurling for Reddit links in Microsoft Teams.	office-teams office office-365	csharp	contentType createdDate samples 07/07/2021 01:38:27 PM	officedev-microsoft-teams-samples-msgext-link-unfurling-reddit-csharp

Link Unfurling for Reddit Links

This comprehensive C# sample illustrates how to implement a Messaging Extension for Reddit links in Microsoft Teams, featuring robust link unfurling capabilities. With built-in user authentication and configurable settings, the extension streamlines the process of sharing and interacting with Reddit content seamlessly in Teams.

This sample demonstrates the following concepts:

• Link Unfurling
• Bot Token Service & User Authentication
• Message Extension settings page
• Message Extension logout

Setup

You will need to complete the following before running the code

Create Messaging Extension

Follow the directions for creating a messaging extension.

• Register a bot with Azure Bot Service, following the instructions here.
• Ensure that you've enabled the Teams Channel
• While registering the bot, use https://<your_tunnel_domain>/api/messages as the messaging endpoint.

  NOTE: When you create your bot you will create an App ID and App password - make sure you keep these for later.

1. You must use the 'Bot Channel Registration' so Bot Framework token service can be registered to manage tokens.
2. The reddit.com and www.reddit.com domains should be registered in the 'messageHandlers' for the Teams App. If these are not included, the extension will not trigger for reddit links!

Make sure to note the app id and password for later.

Configure Reddit App

Go To The Reddit App Preferences and register a new app for Reddit using the following parameters.

Parameter	Value
Type	web app
redirect uri	Not required
Description	Your own description
About Url	Url to your own about page

Afterwards be sure to save the client id and the secret for the next step.

Configure Bot Framework Authentication

In the Azure portal, navigate to the Bot Channels Registration for the app and select the Settings menu under Bot management

At the bottom of the blade press Add Setting, this will open the New Connection Setting Blade.

Parameter	Value
Name	reddit
Service Provider	Generic Oauth 2
Client Id	Reddit Client Id from Configure Reddit App
Client Secret	Reddit Secret from Configure Reddit App
Authorization Url	https://www.reddit.com/api/v1/authorize.compact
Refresh Url	https://www.reddit.com/api/v1/access_token
Scopes	read

Directory Structure

• /dotnet the ASP.NET Core implementation which uses 2 legged OAuth for Reddit API calls
• /dotnet_user_auth the ASP.NET Core implementation which uses the 3 legged OAuth for Reddit API calls on behalf of the user.

References

• Link Unfurling BotBuilder Sample