Establishing a Connection

The objects available within our connector are accessible from the "cdata.basecamp" module. To use the module's objects directly:

Import the module as follows:
```
import cdata.basecamp as mod
```
To establish a connection string, call the connect() method from the connector object using an appropriate connection string, such as:
```
mod.connect("InitiateOAuth=GETANDREFRESH;AccountId=1234567;Schema=V3;ProjectId=abcd1234")
```

Connecting to Basecamp

In addition to authenticating, set the following connection properties to access Basecamp tables.

Schema: Set this to "V2" or "V3" to connect to a Basecamp 2 or Basecamp 3 account.
ProjectId: This is a required parameter for most table operations. You can query the Projects table to obtain this value.
If you do not specify the ProjectId connection property, the connector will use the first project Id returned from the Projects table in your first authentication to Basecamp.
AccountId: You can find the AccountId in the URL after you log in to Basecamp in a web browser:
```
http://basecamp.com/<AccountId>
```

Authenticating to Basecamp

Basecamp 2 uses basic or OAuth 2.0 authentication. You can use basic authentication to connect to your own account, or you can use OAuth to enable other users to log into their own accounts.

Basecamp 3 requires OAuth 2.0.

Basic

In basic authentication, you use your login credentials to connect. Set the following properties:

User: This is the username you use to log in to Basecamp.
Password: This is the password you use to log in to Basecamp.
AuthScheme: Set this to Basic.

OAuth

AuthScheme must be set to OAuth in all user account flows.

Desktop Applications

CData provides an embedded OAuth application that simplifies OAuth desktop Authentication. Alternatively, you can create a custom application. See Creating a Custom OAuth App for information on creating custom applications and reasons for doing so.

For authentication, the only difference between the two methods is that you must set two additional connection properties when using custom OAuth applications.

After setting the following connection properties, 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 to the Client ID in your application settings.
OAuthClientSecret: (custom applications only) Set to the Client Secret in your application settings.

When you connect, the connector opens the OAuth endpoint in your default browser. Log in and grant permissions to the application. The connector then completes the OAuth process as follows:

Extracts the access token from the callback URL.
Obtains a new access token when the old one expires.
Saves OAuth values in OAuthSettingsLocation so that they persist across connections.

Web Applications

When connecting via a web application, you need to register a custom OAuth application with Basecamp. See Creating a Custom OAuth App for more information. You can then use the driver to get and manage the OAuth token values.

First, get an OAuthAccessToken by setting the following connection properties:

OAuthClientId: Set to the client Id in your application settings.
OAuthClientSecret: Set to the client secret in your application settings.

Then call stored procedures to complete the OAuth exchange:

Call the GetOAuthAuthorizationURL stored procedure. Set the CallbackURL input to the callback URL you specified in your application settings. If necessary, set the Scope parameter to request custom permissions. The stored procedure returns the URL of the OAuth endpoint.
Open the URL, log in, and authorize the application. You are redirected back to the callback URL.
Call the GetOAuthAccessToken stored procedure. Set the AuthMode input to WEB. Set the Verifier input to the "code" parameter in the query string of the callback URL. If necessary, set the Scope parameter to request custom permissions.

After you have obtained the access and refresh tokens, you can connect to data and refresh the OAuth access token either automatically or manually.

Automatic Refresh of the OAuth Access Token

To have the driver automatically refresh the OAuth access token, set the following on the first data connection:

InitiateOAuth: Set this to REFRESH.
OAuthClientId: Set this to the client Id in your application settings.
OAuthClientSecret: Set this to the client secret in your application settings.
OAuthAccessToken: Set this to the access token returned by GetOAuthAccessToken.
OAuthRefreshToken: Set this to the refresh token returned by GetOAuthAccessToken.
OAuthSettingsLocation: Set this to the location where the connector saves the OAuth token values, which persist across connections.

On subsequent data connections, the values for OAuthAccessToken and OAuthRefreshToken are taken from OAuthSettingsLocation.

Manual Refresh of the OAuth Access Token

The only value needed to manually refresh the OAuth access token when connecting to data is the OAuth refresh token.

Use the RefreshOAuthAccessToken stored procedure to manually refresh the OAuthAccessToken after the ExpiresIn parameter value returned by GetOAuthAccessToken has elapsed, then set the following connection properties:

OAuthClientId: Set this to the client Id in your application settings.
OAuthClientSecret: Set this to the client secret in your application settings.

Then call RefreshOAuthAccessToken with OAuthRefreshToken set to the OAuth refresh token returned by GetOAuthAccessToken. After the new tokens have been retrieved, open a new connection by setting the OAuthAccessToken property to the value returned by RefreshOAuthAccessToken.

Finally, store the OAuth refresh token so that you can use it to manually refresh the OAuth access token after it has expired.

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 connector on a machine with a 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 connector 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 click Basecamp OAuth endpoint to open the endpoint in your browser.
- If you are using a Custom OAuthd Application, create the Authorization URL by setting the following properties:
  - InitiateOAuth: Set to OFF.
  - OAuthClientId: Set to the client Id assigned when you registered your application.
  - OAuthClientSecret: Set to the client secret assigned when you registered your application.
  Then call the GetOAuthAuthorizationURL stored procedure with the appropriate CallbackURL. Open the URL returned by the stored procedure in a browser.
Log in and grant permissions to the connector. 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.

Next, you need to exchange the OAuth verifier code for OAuth refresh and access tokens. Set the following properties:

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 verifier code.
OAuthClientId: (custom applications only) Set this to the client Id in your custom OAuth application settings.
OAuthClientSecret: (custom applications only) Set this to the client secret in the custom OAuth application settings.
OAuthSettingsLocation: Set this to persist the encrypted OAuth authentication values to the specified location.

After the OAuth settings file is generated, you need to re-set the following properties to connect:

InitiateOAuth: Set this to REFRESH.
OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
OAuthSettingsLocation: Set this to the location containing the encrypted OAuth authentication values. Make sure this location gives read and write permissions to the connector 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.

After you have successfully tested the connection, 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 client Id assigned when you registered your application.
OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
OAuthSettingsLocation: Set this to the location of your OAuth settings file. Make sure this location gives read and write permissions to the connector to enable the automatic refreshing of the access token.

CData Python Connector for Basecamp