This section describes how to edit the DSN configuration and then authenticate and connect to Slack APIs.

DSN Configuration

You can use the Microsoft ODBC Data Source Administrator to edit the DSN configuration. Note that the installation process creates a both a user DSN and a system DSN, as described in Installing the Connector.

Note: The connector stores connection information in the Windows registry. To ensure that the connector can write to the registry, either run Power BI as an administrator or use a User DSN for your connection instead of a System DSN.

User DSN

Complete the following steps to edit the DSN configuration:

1. Select Start > Search, and enter ODBC Data Sources in the Search box.
2. Choose the version of the ODBC Administrator that corresponds to the bitness of your Power BI Desktop installation (32-bit or 64-bit).
3. Select the system data source and click Configure.
4. Edit the information on the Connection tab and click OK.

System DSN

Configure the system DSN the same way as the user DSN, except you will need to switch to the System DSN tab before performing Step 3.

If you're using Power BI's On-Premises Data Gateway with Standard mode, you must use the system DSN.

You must also specify a valid location for OAuthSettingsLocation (a path where OAuth credentials are locally stored to avoid repeated OAuth prompts).

This is because the Standard mode runs on service mode and can only access permitted locations, such as C:\Windows\ServiceProfiles\PBIEgwService\AppData\Local\Microsoft\On-premises data gateway.

Connecting to Slack

The connector supports the following authentication mechanisms:

• OAuth (Slack's "V2" implementation of OAuth 2.0 and OAuth via OpenId Connect are supported)
• user token authentication

OAuth

Set AuthScheme to OAuth.

The following subsections describe how to authenticate to Slack via the available OAuth flows.

There are two supported OAuth authentication methods available. The setup process is the same for all OAuth methods (aside from the scopes set for custom apps), so configure the connector in accordance with the type of app you're using to authenticate.

• Set OAuthVersion to v2 for Modern Slack apps.
• Set OAuthVersion to openid for Slack apps using "Sign in with Slack".

Desktop Applications

CData provides an embedded OAuth application that simplifies authentication at the desktop; that is, in situations where the user is using a local server not connected to the internet.

You can also authenticate from the desktop via a custom OAuth application, which you configure and register at the Slack console. For further information, see Creating a Custom OAuth Application.

Before you connect, set these properties:

• InitiateOAuth: GETANDREFRESH. Used to automatically get and refresh the OAuthAccessToken.
• Custom OAuth applications only:
  • OAuthClientId: The client Id assigned when you registered your custom OAuth application.
  • OAuthClientSecret: The client secret assigned when you registered your custom OAuth application.
  • CallbackURL: The redirect URI defined when you registered your custom OAuth application.

When you connect, the connector opens Slack's OAuth endpoint in your default browser. Log in and grant permissions to the application.

When the access token expires, the connector refreshes it automatically.

Headless Machines

If you need to log in to a resource that resides on a headless machine, you must authenticate on another device that has an internet browser. You can do this in either of the following ways:

• Option 1: Obtain the OAuthVerifier value.
• Option 2: Install the connector on a machine with an internet browser and transfer the OAuth authentication values after you authenticate through the usual browser-based flow.

After you execute either Option 1 or Option 2, configure the driver to automatically refresh the access token on the headless machine.

Option 1: Obtaining and Exchanging a Verifier Code

To obtain a verifier code, you must authenticate at the OAuth authorization URL as follows:

1. Authenticate from the machine with an internet browser, and obtain the OAuthVerifier connection property.

   If you are using the embedded OAuth application, call the GetOAuthAuthorizationURL stored procedure. Open the URL returned by the stored procedure in a browser.

   If you are using a custom OAuth application, set these properties:

   • InitiateOAuth: OFF.
   • OAuthClientId: The client Id assigned when you registered your application.
   • OAuthClientSecret: The client secret assigned when you registered your application.

2. Call the GetOAuthAuthorizationURL stored procedure. The stored procedure returns the CallbackURL established when the custom OAuth application was registered. (See Creating a Custom OAuth Application.)

   Copy this URL and paste it into a new browser tab.

3. Log in and grant permissions to the connector. The OAuth application redirects you the redirect URI, with a parameter called code appended. Note the value of this parameter; you will need it later, to configure the OAuthVerifier connection property.

4. Exchange the OAuth verifier code for OAuth refresh and access tokens. On the headless machine, to obtain the OAuthAccessToken, set these connection properties:

   • InitiateOAuth: REFRESH.
   • OAuthVerifier: The noted verifier code (the value of the code parameter in the redirect URI).
   • OAuthSettingsLocation: persist the encrypted OAuth authentication values to the specified file.
   • Custom OAuth applications only:
     • OAuthClientId: The client Id in your custom OAuth application settings.
     • OAuthClientSecret: The client secret in the custom OAuth application settings.

5. Test the connection to generate the OAuth settings file.

6. You are ready to connect after you re-set these properties:

   • InitiateOAuth: REFRESH.
   • OAuthSettingsLocation: The file containing the encrypted OAuth authentication values. To enable the automatic refreshing of the access token, be sure that this file gives read and write permissions to the connector.
   • Custom OAuth applications only:
     • OAuthClientId: The client Id assigned when you registered your application.
     • OAuthClientSecret: The client secret assigned when you registered your application.

Option 2: Transferring OAuth Settings

Prior to connecting on a headless machine, you must install and create a connection with the driver on a device that supports an internet browser. Set the connection properties as described above in "Desktop Applications".

After completing the instructions in "Desktop Applications", the resulting authentication values are encrypted and written to the path specified by OAuthSettingsLocation. The default filename is OAuthSettings.txt.

Test the connection to generate the OAuth settings file, then copy the OAuth settings file to your headless machine.

To connect to data via the headless machine, set these connection properties:

• InitiateOAuth: REFRESH
• OAuthSettingsLocation: The path to the OAuth settings file you copied from the machine with the browser. To enable automatic refreshing of the access token, ensure that this file gives read and write permissions to the connector.
• Custom OAuth applications only:
  • OAuthClientId: The client Id assigned when you registered your custom OAuth application.
  • OAuthClientSecret: The client secret assigned when you registered your custom OAuth application.

User Token

After Creating a Custom OAuth Application and selecting scopes, as an alternative to configuring the standard OAuth credentials (client, client secret, and callback URL), you can use a User OAuth Token to authenticate.

To use a token, set AuthScheme to UserToken and set UserToken to the value of the "User OAuth Token", found in your app settings in Features > OAuth & Permissions.