Establishing a Connection
You can create and manage connections with the Data Explorer and the FireDAC Connection Editor wizards. See Connection Definitions for more information on creating connections from code and creating persistent, private, or temporary connections.
Connecting to Twitter (OAuth)
NOTE: Which version of OAuth you use depends on the table or view you want to access. For the StreamRules table and the TweetStream view, you must use OAuth 2.0 App-Only. For all other tables and views, use OAuth 1.1.OAuth 2.0 App-Only (Bearer Token)
To establish a connection for the StreamRules table or the TweetStream view, you need to authenticate using OAuth 2.0 App-Only authentication.First, generate a bearer token from Twitter's website. The YourBearerToken value is generated from: Twitter's Developer Portal > ProjectOfInterest > Keys and Tokens. For more information, see the Twitter Developers Portal Documentation.
After generating the token and setting the following, you are ready to connect:
- InitiateOAuth: Set this to OFF
- OAuthAccessToken: Set this to YourBearerToken's value.
If you want to access any other tables and views (besides StreamRules and TweetStream), follow the OAuth 1.1 procedures described below.
OAuth 1.1
Desktop Applications
You can connect without setting any connection properties for your user credentials. Or you can create a custom OAuth application. See Creating a Custom OAuth App for more information about custom OAuth applications.The only difference between the two is that you must set additional connection properties if you choose to use a custom application.
After setting the following, you are ready to connect:
- InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
- OAuthClientId (custom applications only): Set this to the consumer key in your app settings.
- OAuthClientSecret (custom applications only): Set this to the consumer secret in your app settings.
- Extracts the access token from the callback URL and authenticates requests.
- Obtains a new access token when the old one expires.
- Saves OAuth values in OAuthSettingsLocation. These values persist across connections.
Web Applications
When connecting via a Web application, or if the component is not authorized to open a browser window, use stored procedures and set InitiateOAuth to manage the temporary OAuth tokens. Get an Access Token To obtain the access token, set the following connection properties:
- OAuthClientId: Set this to the ClientId that you received.
- OAuthClientSecret: Set this to the ClientSecret that you received.
With these properties set, follow the steps below to call stored procedures to obtain the OAuthAccessToken:
- Call GetOAuthAuthorizationURL. The stored procedure returns the URL to the OAuth endpoint, along with the request token and secret.
-
Go to that URL and log in to authorize the application. Afterwards, you are redirected back to the callback URL, which contains the code query string parameter.
- Set the following parameters and call GetOAuthAccessToken:
Name Value AuthMode WEB Verifier Set this to the verifier code.
Set the following to authenticate your requests for data:
- OAuthAccessToken: Set this to the OAuthAccessToken returned by the GetOAuthAccessToken stored procedure.
You can set InitiateOAuth to REFRESH to automatically refresh the OAuth access token when it expires.
To connect to data and automatically refresh the OAuthAccessToken, set the following on the first data connection:
- InitiateOAuth
- OAuthSettingsLocation
- OAuthClientId
- OAuthClientSecret
- OAuthAccessToken
- OAuthRefreshToken
On subsequent data connections, set the following:
- InitiateOAuth
- OAuthSettingsLocation
Headless Machines
To configure the driver to use OAuth with a user account on a headless machine, you need to authenticate on another device that has an internet browser.
- Choose one of two options:
- Option 1: Obtain the OAuthVerifier value as described in "Obtain and Exchange a Verifier Code" below.
- Option 2: Install the component on a machine with an internet browser and transfer the OAuth authentication values after you authenticate through the usual browser-based flow, as described in "Transfer OAuth Settings" below.
- Then configure the component to automatically refresh the access token on the headless machine.
Option 1: Obtain and Exchange a Verifier Code
To obtain a verifier code, you must authenticate at the OAuth authorization URL.
Follow the steps below to authenticate from the machine with an internet browser and obtain the OAuthVerifier connection property.
- Choose one of these options:
- 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 the following properties:
- InitiateOAuth: Set to OFF.
- OAuthClientId: Set this to the Client Id in your app settings.
- OAuthClientSecret: Set this to the Client Secret in your app settings.
- Log in and grant permissions to the component. You are then redirected to the callback URL, which contains the verifier code. Save the value of the verifier code. Later you will set this in the OAuthVerifier connection property.
On the headless machine, set the following connection properties to obtain the OAuth authentication values:
- InitiateOAuth: Set this to REFRESH.
- OAuthVerifier: Set this to the noted verifier code (the value of the code parameter in the redirect URI).
- OAuthClientId: (custom applications only) Set this to the noted App key value from your OAuth app settings.
- OAuthClientSecret: (custom applications only) Set this to the App secret from your OAuth app settings.
- AuthToken: Set to the authentication token returned by the GetOAuthAuthorizationURL stored procedure.
- AuthKey: Set to the authentication key returned by the GetOAuthAuthorizationURL stored procedure.
- OAuthSettingsLocation: Set this to persist the encrypted OAuth authentication values to the specified location.
Test the connection to generate the OAuth settings file, then re-set the following properties to connect:
- InitiateOAuth: Set this to REFRESH.
- OAuthClientId: (custom applications only) Set this to the noted App key value from your OAuth app settings.
- OAuthClientSecret: (custom applications only) Set this to the App secret from your OAuth app settings.
- OAuthSettingsLocation: Set this to the location containing the encrypted OAuth authentication values. Make sure this location gives read and write permissions to the component to enable the automatic refreshing of the access token.
Option 2: Transfer OAuth Settings
Prior to connecting on a headless machine, you need to install and create a connection with the driver on a device that supports an internet browser. Set the connection properties as described in "Desktop Applications" above.
After completing the instructions in "Desktop Applications", the resulting authentication values are encrypted and written to the location 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.
On the headless machine, set the following connection properties to connect to data:
- InitiateOAuth: Set this to REFRESH.
- OAuthClientId: (custom applications only) Set this to the noted App key value from your OAuth app settings.
- OAuthClientSecret: (custom applications only) Set this to the App secret from your OAuth app settings.
- OAuthSettingsLocation: Set this to the location of the OAuth settings file you copied from the machine with the browser. Make sure this location gives read and write permissions to the component to enable the automatic refreshing of the access token.
Using the FireDAC Connection Editor
Complete the following steps to use the FireDAC Connection Editor to assign a Twitter connection to a TFDConnection object:
- Open a project and drop a TFDPhysCDataTwitterDriverLink from the Tool Palette onto the Form Designer.
- Drop a TFDConnection object onto the Form Designer.
- Double-click the TFDConnection and select CDataTwitter in the Driver Id menu.
- Define the necessary connection properties.
- To execute ad-hoc SQL statements based on this connection, enter SQL commands on the SQL Script tab.
- In the Form Designer, select the TFDConnection object and set the Connected property to true.
Using the Data Explorer
Complete the following steps to use the Data Explorer to define persistent connections that can be shared across applications and projects:
- Click View > Tool Windows > Data Explorer in RAD Studio and expand the FireDAC node.
- Right-click the CData Twitter Data Source node and click Add New Connection.
- Enter a name for the connection. The FireDAC Connection Editor opens.
Working with Persistent Connections
The connections you define in the Data Explorer can be assigned to a TFDConnection object by specifying the connection name in the TFDConnection object's ConnectionDefName property.
Browsing Data and Metadata
The Data Explorer also provides options for browsing Twitter objects at design time:
- Expand the CData Twitter Data Source node in the Data Explorer to view the defined connections.
- Expand a connection node to find the database objects available for a connection.
- Drill down to a database object to find metadata such as primary keys.
- To display data, double-click a table or view or right-click and click View.