Establishing a Connection

With the CData Cmdlets users can install a data module, set the connection properties, and start scripting. This section provides examples of using our GitHub Cmdlets with native PowerShell cmdlets, like the CSV import and export cmdlets.

Installing and Connecting

If you have PSGet, installing the cmdlets can be accomplished from the PowerShell Gallery with the following command. You can also obtain a setup from the CData site.

Install-Module GitHubCmdlets

The following line is then added to your profile, loading the cmdlets on the next session:

Import-Module GitHubCmdlets;

You can then use the Connect-GitHub cmdlet to create a connection object that can be passed to other cmdlets:

$conn = Connect-GitHub -OAuthClientId 'MyOAuthClientId' -OAuthClientSecret 'MyOAuthClientSecret' -CallbackURL 'http://localhost:33333'

Connecting to GitHub

To authenticate to GitHub you must connect using OAuth authentication.

Desktop Applications

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

Get and Refresh the OAuth Access Token

After setting the following, you are ready to connect:

OAuthClientId (custom applications only): The client Id assigned when you registered your application.
OAuthClientSecret (custom applications only): The client secret assigned when you registered your application.
CallbackURL (custom application only): The redirect URI defined when you registered your application.
OwnerLogin (optional): The name of the user or organization whose repository and projects you plan to query. If you do not explicitly specify an OwnerLogin, the driver uses the currently authenticated user.

When you connect, the cmdlet opens GitHub's OAuth endpoint in your default browser. Log in and grant permissions to the application. The cmdlet refreshes the access token automatically when it expires.

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 cmdlet 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 cmdlet 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 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 cmdlet. You are then redirected to the redirect URI. There will be a parameter called code appended to the redirect URI. Note the value of this parameter. 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.

On the headless machine, set the following connection properties to obtain the OAuth authentication values:

InitiateOAuth: REFRESH
OAuthVerifier: The noted verifier code (the value of the code parameter in the redirect URI).
OAuthClientId: (custom applications only) The client Id in your custom OAuth application settings.
OAuthClientSecret: (custom applications only) The client secret in the custom OAuth application settings.
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: REFRESH
OAuthClientId: (custom applications only) The client Id assigned when you registered your application.
OAuthClientSecret: (custom applications only) The client secret assigned when you registered your application.
OAuthSettingsLocation: The location containing the encrypted OAuth authentication values. Make sure this location gives read and write permissions to the cmdlet 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: REFRESH
OAuthClientId: (custom applications only) The client Id assigned when you registered your application.
OAuthClientSecret: (custom applications only) The client secret assigned when you registered your application.
OAuthSettingsLocation: 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 cmdlet to enable the automatic refreshing of the access token.

Retrieving Data

The Select-GitHub cmdlet provides a native PowerShell interface for retrieving data:

$results = Select-GitHub -Connection $conn -Table "Repositories" -Columns @("Name, OwnerLogin") -Where "OwnerLogin='mojombo'"

The Invoke-GitHub cmdlet provides an SQL interface. This cmdlet can be used to execute an SQL query via the Query parameter.

Piping Cmdlet Output

The cmdlets return row objects to the pipeline one row at a time. The following line exports results to a CSV file:

Select-GitHub -Connection $conn -Table Repositories -Where "OwnerLogin = 'mojombo'" | Select -Property * -ExcludeProperty Connection,Table,Columns | Export-Csv -Path c:\myRepositoriesData.csv -NoTypeInformation

You will notice that we piped the results from Select-GitHub into a Select-Object cmdlet and excluded some properties before piping them into an Export-CSV cmdlet. We do this because the CData Cmdlets append Connection, Table, and Columns information onto each row object in the result set, and we do not necessarily want that information in our CSV file.

However, this makes it easy to pipe the output of one cmdlet to another. The following is an example of converting a result set to JSON:

 
PS C:\> $conn  = Connect-GitHub -OAuthClientId 'MyOAuthClientId' -OAuthClientSecret 'MyOAuthClientSecret' -CallbackURL 'http://localhost:33333'
PS C:\> $row = Select-GitHub -Connection $conn -Table "Repositories" -Columns (Name, OwnerLogin) -Where "OwnerLogin = 'mojombo'" | select -first 1
PS C:\> $row | ConvertTo-Json
{
  "Connection":  {

  },
  "Table":  "Repositories",
  "Columns":  [

  ],
  "Name":  "MyName",
  "OwnerLogin":  "MyOwnerLogin"
}

Deleting Data

The following line deletes any records that match the criteria:

Select-GitHub -Connection $conn -Table Repositories -Where "OwnerLogin = 'mojombo'" | Remove-GitHub

Modifying Data

The cmdlets make data transformation easy as well as data cleansing. The following example loads data from a CSV file into GitHub, checking first whether a record already exists and needs to be updated instead of inserted.

Import-Csv -Path C:\MyRepositoriesUpdates.csv | %{
  $record = Select-GitHub -Connection $conn -Table Repositories -Where ("Id = `'"+$_.Id+"`'")
  if($record){
    Update-GitHub -Connection $conn -Table Repositories -Columns @("Name","OwnerLogin") -Values @($_.Name, $_.OwnerLogin) -Where "Id  = `'$_.Id`'"
  }else{
    Add-GitHub -Connection $conn -Table Repositories -Columns @("Name","OwnerLogin") -Values @($_.Name, $_.OwnerLogin)
  }
}

Cmdlets for GitHub