Creating the Data Source Name
This section describes how to edit the DSN configuration and then authenticate and connect to OData 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:
- Select Start > Search, and enter ODBC Data Sources in the Search box.
- Choose the version of the ODBC Administrator that corresponds to the bitness of your Power BI Desktop installation (32-bit or 64-bit).
- Select the system data source and click Configure.
- 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 OData
To connect to OData, you must set the Url to a valid OData service root URI. If your OData service does not have a root document, have FeedURL point to the specific entity you want to expose as a table.
Authenticating to OData
OData supports authentication via:- HTTP
- Kerberos
- SharePoint Online
- OAuth (Azure AD)
HTTP Auth Schemes
For authenticating via HTTP, set AuthScheme according to the following table.
Scheme | AuthScheme | Other Settings |
None | None | Use if no authentication is desired. |
Basic | Basic | User, Password |
NTLM (1) | NTLM | User, Password |
Digest (if supported) | Digest | User, Password |
(1) NTLM is a type of Windows authentication often used across a LAN using your Windows user credentials. Set the User and Password if you are not connecting from a Windows machine, or if your currently logged in user account should not be used for the connection.
Kerberos
To authenticate to OData using Kerberos, set these properties:
- hive.server2.authentication: Kerberos.
- AuthScheme: NEGOTIATE.
- KerberosKDC: The host name or IP Address of your Kerberos KDC machine.
- KerberosSPN: The service and host of the OData Kerberos Principal. Find this value just before the '@' symbol of the principal value.
SharePoint Online
SharePoint Online connections are established by retrieving a SharePoint Online cookie. To authenticate, set these properties:
- AuthScheme: SharePointOnline.
- User: Your SharePoint Online user account.
- Password: Your SharePoint Online password.
OAuth
To enable this authentication from all OAuth flows in OData, you must create a custom OAuth application, and set AuthScheme to OAuth.The following subsections describe how to authenticate to OData from three common authentication flows. For information about how to create a custom OAuth application, see Creating a Custom OAuth Application. For a complete list of connection string properties available in OData, see Connection.
Desktop Applications
To authenticate with the credentials for a custom OAuth application, you must get and refresh the OAuth access token. After you do that, you are ready to connect.Get and refresh the OAuth access token:
- OAuthClientId: The client Id assigned when you registered your application.
- OAuthClientSecret: The client secret that was assigned when you registered your application.
- CallbackURL: The redirect URI that was defined when you registered your application.
When you connect, the connector opens OData'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.
Automatic refresh of the OAuth access token:
To have the connector automatically refresh the OAuth access token:
- Before connecting to data for the first time, set these connection parameters:
- InitiateOAuth: REFRESH.
- OAuthClientId: The client Id in your custom OAuth application settings.
- OAuthClientSecret: The client secret in your custom OAuth application settings.
- OAuthAccessToken: The access token returned by GetOAuthAccessToken.
- OAuthSettingsLocation: The path where you want the connector to save the OAuth values, which persist across connections.
- On subsequent data connections, set:
- InitiateOAuth
- OAuthSettingsLocation
Manual refresh of the OAuth access token:
The only value needed to manually refresh the OAuth access token is the OAuth refresh token.
- To manually refresh the OAuthAccessToken after the ExpiresIn period (returned by GetOAuthAccessToken) has elapsed, call the RefreshOAuthAccessToken stored procedure.
- Set these connection properties:
- OAuthClientId: The Client Id in your custom OAuth application settings.
- OAuthClientSecret: The Client Secret in your custom OAuth application settings.
- Call RefreshOAuthAccessToken with OAuthRefreshToken set to the OAuth refresh token returned by GetOAuthAccessToken.
- After the new tokens have been retrieved, set the OAuthAccessToken property to the value returned by RefreshOAuthAccessToken. This opens a new connection.
Store the OAuth refresh token so that you can use it to manually refresh the OAuth access token after it has expired.
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:
-
Authenticate from the machine with an internet browser, and obtain the OAuthVerifier connection property.
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.
-
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.
-
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.
-
Exchange the OAuth verifier code for OAuth refresh and access tokens. On the headless machine, to obtain the OAuth authentication values, set these 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.
- OAuthClientId: The client Id in your custom OAuth application settings.
- OAuthClientSecret: The client secret in the custom OAuth application settings.
-
Test the connection to generate the OAuth settings file.
-
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.
- 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.
- OAuthClientId: The client Id assigned when you registered your custom OAuth application.
- OAuthClientSecret: The client secret assigned when you registered your custom OAuth application.
Azure AD
Azure AD supports a form of OAuth that goes through Azure. Set the AuthScheme to AzureAD.The CData Power BI Connector for OData automatically takes care of known Azure URLs internally, so it is not necessary to specify any of the usual OAuth connection properties, such as OAuthAccessTokenURL, OAuthAuthorizationURL, OAuthRefreshTokenURL, and OAuthRequestTokenURL.
Other connection properties may be required for this connection method, including:
- Scope: Must be specified if InitiateOAuth is set to GETANDREFRESH as the Scope is submitted to Microsoft during retrieval of credentails. This varies depending on the service, but is generally a combination of the resource (hostname in the URL) and permission name. For example: https://host/user_impersonation.
- AzureADResource: The specific Azure Resource to authenticate against during Microsoft login. If none is specified, your user account's default resource is used.
- AzureADTenant: The specific Azure Tenant to authenticate against during Microsoft login. If none is specified, your user account's default tenant via the common login endpoint is used. This may not be correct, depending on the specific resource you are connecting to, or if the resource is stored on a seperate tenant.
Otherwise, the steps to authenticate are identical to the descriptions of Desktop, Web, and Headless Machine authentication, above.
For information about how to create a custom OAuth application for use with Azure AD, see Creating a Custom OAuth Application.
Securing OData Connections
By default, the connector attempts to negotiate SSL/TLS by checking the server's certificate against the system's trusted certificate store. To specify another certificate, see the SSLServerCert property for the available formats to do so.