AuthGoogle Lazarus Pascal Reference Documentation

AuthGoogle

Current Version: 11.6.0

Chilkat.AuthGoogle

Obtain Google OAuth 2.0 access tokens using a service account.

Chilkat.AuthGoogle obtains OAuth 2.0 access tokens for Google Cloud Platform APIs and Google Apps APIs using a Google service account. It supports JSON private keys and P12 private keys, OAuth scopes, optional delegated user access, custom JWT claims, access-token validity tracking, token lifetime settings, and integration with Chilkat request classes that need a Google bearer token.

Service account auth

Authenticate server-to-server using a Google service account rather than an interactive browser-based user consent flow.

JSON or P12 keys

Load service account credentials from modern JSON private keys or from legacy P12 private key files.

Scopes and claims

Specify the OAuth scopes required by the target Google API and add custom JWT claims when needed.

Delegated user access

Use domain-wide delegation by setting a subject email when the service account is authorized to act on behalf of a Google Workspace user.

Access-token tracking

Inspect the generated access token, expiration time, remaining lifetime, and validity state before using or refreshing credentials.

Chilkat API integration

Pass the resulting bearer token to Chilkat HTTP, REST, storage, mail, or other Google API request workflows.

Common pattern: Load the service account JSON key or P12 key, set the service account email, required Scope, optional delegated SubEmailAddress, and token lifetime, then call ObtainAccessToken. Use AuthGoogle for service-account OAuth flows; use Chilkat.OAuth2 when the application needs an interactive three-legged OAuth flow involving a user's browser consent.

Create / Free

uses
  Chilkat.AuthGoogle;

var
  obj: TAuthGoogle;
begin
  obj := TAuthGoogle.Create;
  try
    if not obj.IsValid then
      raise Exception.Create('Failed to create a TAuthGoogle instance.');

    // ... use obj ...

  finally
    obj.Free;
  end;
end;
constructor Create;

Allocates the underlying CkAuthGoogle object and returns a new TAuthGoogle instance. Simply adding Chilkat.AuthGoogle to the unit's uses clause is enough to locate and bind to the Chilkat shared library (DLL / .so / .dylib) at runtime — no separate load step is required. Check obj.IsValid after calling Create; it is False if the underlying library could not be found/loaded or the object could not be allocated (for example, when unlicensed).

destructor Destroy; override;

Every TAuthGoogle created by calling Create should eventually be released by calling .Free (inherited from TObject). The destructor automatically disposes the underlying CkAuthGoogle handle. A native (unmanaged) memory leak occurs if the object is never freed.

Properties

AccessToken
property AccessToken: string read GetAccessToken write SetAccessToken;
Introduced in version 9.5.0.58

The access token to be used in Google API requests. This property is set on a successful call to ObtainAccessToken.

Important: This class is used for authenticating calls to the Google Cloud Platform API and Google Apps API using a service account.. For 3-legged OAuth2, where a browser must be used to interactively get permission from the Google account owner, use the Chilkat OAuth2 class/object.

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DebugLogFilePath
property DebugLogFilePath: string read GetDebugLogFilePath write SetDebugLogFilePath;

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
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EmailAddress
property EmailAddress: string read GetEmailAddress write SetEmailAddress;
Introduced in version 9.5.0.58

The client email address of the service account. If a JSON key is used, then the client_email should already be specified within the JSON key, and this property is unused. This property must be set if using a P12 key.

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ExpireNumSeconds
property ExpireNumSeconds: Integer read GetExpireNumSeconds write SetExpireNumSeconds;
Introduced in version 9.5.0.58

The expiration time, in seconds, of the access token to be requested. The maximum value is 1 hour (3600 seconds). The default value is 3600.

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Iat
property Iat: Integer read GetIat write SetIat;
Introduced in version 9.5.0.77

This property can be set to override the default current date/time value for the iat claim of the JWT. It can be set to a value indicating the number of seconds from 1970-01-01T00:00:00Z UTC.

The default value is 0, which indicates to use the iat value for the current system date/time. Unless explicitly needed, always leave this property at the default value.

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JsonKey
property JsonKey: string read GetJsonKey write SetJsonKey;
Introduced in version 9.5.0.58

The JSON key for obtaining an access token. An application must set either the P12 or JSON private key, but not both.

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LastErrorHtml
property LastErrorHtml: string read GetLastErrorHtml;

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText
property LastErrorText: string read GetLastErrorText;

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorXml
property LastErrorXml: string read GetLastErrorXml;

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastMethodSuccess
property LastMethodSuccess: Boolean read GetLastMethodSuccess write SetLastMethodSuccess;

Indicates the success or failure of the most recent method call: True means success, False means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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NumSecondsRemaining
property NumSecondsRemaining: Integer read GetNumSecondsRemaining;
Introduced in version 9.5.0.58

If the access token is valid, contains the number of seconds remaining until it expires. A value of 0 indicates an invalid or expired access token.

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Scope
property Scope: string read GetScope write SetScope;
Introduced in version 9.5.0.58

A space-delimited list of the permissions that the application requests.

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SubEmailAddress
property SubEmailAddress: string read GetSubEmailAddress write SetSubEmailAddress;
Introduced in version 9.5.0.58

The email address of the user for which the application is requesting delegated access.

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Valid
property Valid: Boolean read GetValid;
Introduced in version 9.5.0.58

True if the AccessToken property contains a valid non-expired access token obtained via the call to ObtainAccessToken.

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VerboseLogging
property VerboseLogging: Boolean read GetVerboseLogging write SetVerboseLogging;

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
property Version: string read GetVersion;

Version of the component/library, such as "10.1.0"

More Information and Examples
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Methods

AddClaims
// json is a TJsonObject object.
function AddClaims(json: TChilkatBase): Boolean;
Introduced in version 9.5.0.99

Adds additional custom claims to the JWT claims set.

Returns True for success, False for failure.

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GetP12
// Return value is a TPfx object.
function GetP12: TChilkatBase;
Introduced in version 9.5.0.58

Returns the private key in a PFX (P12) object. This is only possible if the private key was previously set by calling SetP12.

Returns nil on failure

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LoadTaskCaller
// task is a TTask object.
function LoadTaskCaller(task: TChilkatBase): Boolean;
Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns True for success, False for failure.

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ObtainAccessToken
// connection is a TSocket object.
function ObtainAccessToken(connection: TChilkatBase): Boolean;
Introduced in version 9.5.0.58

Sends the HTTP request to fetch the access token. When this method completes successfully, the access token is available in the AccessToken property. The connection is an existing connection to www.googleapis.com.

Important: Make sure your computer's date/time is accurately set to the current date/time, otherwise you'll get a 400 response status code with this error: Invalid JWT: Token must be a short-lived token (60 minutes) and in a reasonable timeframe. Check your iat and exp values and use a clock with skew to account for clock differences between systems..

Returns True for success, False for failure.

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SetP12
// key is a TPfx object.
function SetP12(key: TChilkatBase): Boolean;
Introduced in version 9.5.0.58

Sets the P12 private key to be used for obtaining an access token. An application must set either the P12 or JSON private key, but not both.

Returns True for success, False for failure.

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Events

Chilkat for Pascal supports three synchronous event callbacks: OnAbortCheck, OnPercentDone, and OnProgressInfo. Each is a property of the class; assign a method of one of your own objects (an of object handler) to receive the callbacks, or assign nil to unhook. The handler types are declared in the Chilkat.Base unit:

TChilkatAbortCheckEvent   = function(Sender: TChilkatBase): Boolean of object;
TChilkatPercentDoneEvent  = function(Sender: TChilkatBase; PctDone: Integer): Boolean of object;
TChilkatProgressInfoEvent = procedure(Sender: TChilkatBase; const Name, Value: string) of object;

All Chilkat methods are synchronous, so callbacks are invoked on the thread that called the method -- if the method was called from the main thread, it is safe to access UI elements from the handler. The HeartbeatMs property controls the frequency of OnAbortCheck callbacks (the default of 0 means no AbortCheck events fire). Returning True from an OnAbortCheck or OnPercentDone handler aborts the running method.

AbortCheck
// TChilkatAbortCheckEvent = function(Sender: TChilkatBase): Boolean of object;
property OnAbortCheck: TChilkatAbortCheckEvent;

Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.

More Information and Examples

Event callback implementation:

// A handler is a method of one of your own classes, e.g. a form:
function TMyObject.AuthGoogleAbortCheck(Sender: TChilkatBase): Boolean;
begin
  // Called every HeartbeatMs milliseconds while a method is running.
  // Return True to abort the method; return False to continue.
  Result := False;
end;

To add an event handler:

authgoogle := TAuthGoogle.Create;
authgoogle.HeartbeatMs := 250;   // fire OnAbortCheck 4 times per second
authgoogle.OnAbortCheck := MyObject.AuthGoogleAbortCheck;
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PercentDone
// TChilkatPercentDoneEvent = function(Sender: TChilkatBase; PctDone: Integer): Boolean of object;
property OnPercentDone: TChilkatPercentDoneEvent;

This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).

The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.

To abort the operation, set the abort output argument to True. This will cause the method to terminate and return a failure status or corresponding failure value.

More Information and Examples

Event callback implementation:

// A handler is a method of one of your own classes, e.g. a form:
function TMyObject.AuthGooglePercentDone(Sender: TChilkatBase; PctDone: Integer): Boolean;
begin
  // PctDone ranges from 1 to 100.
  WriteLn('Percent done: ', PctDone);
  // Return True to abort the method; return False to continue.
  Result := False;
end;

To add an event handler:

authgoogle := TAuthGoogle.Create;
authgoogle.OnPercentDone := MyObject.AuthGooglePercentDone;
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ProgressInfo
// TChilkatProgressInfoEvent = procedure(Sender: TChilkatBase; const Name, Value: string) of object;
property OnProgressInfo: TChilkatProgressInfoEvent;

This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.

Note: Some Chilkat methods don't fire any ProgressInfo events.

More Information and Examples

Event callback implementation:

// A handler is a method of one of your own classes, e.g. a form:
procedure TMyObject.AuthGoogleProgressInfo(Sender: TChilkatBase; const Name, Value: string);
begin
  WriteLn(Name, ': ', Value);
end;

To add an event handler:

authgoogle := TAuthGoogle.Create;
authgoogle.OnProgressInfo := MyObject.AuthGoogleProgressInfo;
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