FB4D Interface Reference

This document describes all FB4D class interfaces locatable in the unit FB4D.Interfaces. To simplify the interface description the synchronous method call will be described only. The asynchronous method requires the same parameters together with two call back methods for success and failure situation. Keep in mind that for asynchronous calls the caller class must be alive as long the call is ongoing.

Interface for Firebase Configuration and Class Factory

The interface IFirebaseConfiguration provides an easy way to access all other interfaces of FB4D. It contains a class factory to store the instances of the interface to authentication, both databases, the storage, the Firebase functions, and the VisionML.

  IFirebaseConfiguration = interface(IInterface)
    function ProjectID: string;
    function Auth: IFirebaseAuthentication;
    function RealTimeDB: IRealTimeDB;
    function Database(const DatabaseID: string = cDefaultDatabaseID): IFirestoreDatabase;
    function Storage: IFirebaseStorage;
    function Functions: IFirebaseFunctions;
    function VisionML: IVisionML;
    procedure SetBucket(const Bucket: string);
  end;

Because all instances are returned as interfaces, Auto Reference Counting (ARC) is used, where you do not have to release any instances yourself.

There are two ways to create an instance of the class TFirebaseConfiguration: Either you pass all credentials of the firebase project as parameters or you let parse the google-services JSON file to retrieve these parameters at application run time.

constructor TFirebaseConfiguration.Create(const ApiKey, ProjectID: string;
  const Bucket: string = ''; const FirebaseURL: string = ''; 
  const ServerRegion: string = cRegionUSCent1); overload;

If the bucket for the storage is not yet known when the config class is created, for example, because this information is still being requested by the user, the bucket can still be provided with the following method before the first access to the storage takes place.

procedure SetBucket(const Bucket: string);

If the Firebase URL is not yet known when the config class is created, this URL can still be provided with the following method before the first access to the RealTimeDB takes place.

procedure SetFirebaseURL(const FirebaseURL: string);

Before the first use of functions, you can define the region of the Firebase Function Server in case you do not use servers in Iowa.

procedure SetServerRegion(const ServerRegion: string);

The following server locations are predefined in constants:

const
  cRegionUSCent1 = 'us-central1';             // Iowa
  cRegionUSEast1 = 'us-east1';                // South Carolina
  cRegionUSEast4 = 'us-east4';                // Nothern Virginia
  cRegionUSWest2 = 'us-west2';                // Los Angeles
  cRegionUSWest3 = 'us-west3';                // Salt Lake City
  cRegionUSWest4 = 'us-west4';                // Las Vegas
  cRegionUSNoEa1 = 'northamerica-northeast1'; // Montreal
  cRegionUSSoEa1 = 'southamerica-east1';      // Sao Paulo
  cRegionEUWest1 = 'europe-west1';            // Belgium
  cRegionEUWest2 = 'europe-west2';            // London
  cRegionEUWest3 = 'europe-west3';            // Frankfurt
  cRegionEUWest6 = 'europe-west6';            // Zürich
  cRegionEUCent2 = 'europe-central2';         // Warsaw
  cRegionAUSoEa1 = 'australia-southeast1';    // Sydney
  cRegionASEast1 = 'asia-east1';              // Taiwan
  cRegionASEast2 = 'asia-east2';              // Hong Kong
  cRegionASNoEa1 = 'asia-northeast1';         // Tokyo
  cRegionASNoEa2 = 'asia-northeast2';         // Osaka
  cRegionASSout1 = 'asia-south1';             // Mumbai
  cRegionASSoEa1 = 'asia-southeast1';         // Singapore
  cRegionASSoEa2 = 'asia-southeast2';         // Jakarta
  cRegionASSoEa3 = 'asia-southeast3';         // Seoul

The first constructor requires all secrets of the Firebase project as ApiKey and ProjectID and when using the Storage and the storage Bucket and accessing the Firebase RT-DB the FirebaseURL as parameters.

constructor Create(const GoogleServicesFile: string); overload;

The second constructor parses the google-services.json file that shall be loaded from the Firebase Console after adding an App to the project settings. If you need to configure another server region than the default one (us-central1) for Firebase Function call SetServerRegion as this information is unfortunately not in the service file.

The following class function returns the library version number.

class function TFirebaseConfiguration.GetLibVersionInfo: string;

The following class function returns the library license information.

class function TFirebaseConfiguration.GetLibLicenseInfo: string;

Helper Classes

The unit FB4D.Helpers offers important helper functions in different classes and class helpers.

Class TFirebaseHelpers

Class TFirestorePath

Class Helper TJSONHelpers

Class Helper TQueryParamsHelper

Interfaces for Firebase Authentication

In most applications, you will not call any other Firebase services until you have received an authentication token using the Firebase Authentication Service. For a quick and dirty application (e.g. RTDB_SimpleReadWrite of the FB4D Sample Projects), you can also use a service without such an authentication token. In this case, however, you must disable all access rules for Firebase.

Interface IFirebaseAuthentication

Interface IFirebaseUser

Interface ITokenJWT

Another good source of inspiration is the GUI Pattern to integrate a self-registration workflow for e-mail and password authorization.

Interfaces for Real-Time Database

The Firebase Real-Time Database is a NoSQL cloud database for store and synchronize data between multiple client applications. The data is stored as a large JSON tree. Applications can register an event handler to monitor all changes in and under a JSON node.

Interface IRealTimeDB

Interface IFirebaseEvent

Interfaces for Firestore Database

The Firestore Database is newer than the Realtime Database and better scalable and more flexible. It allows queries comparable to SQL databases. The Firestore offers the possibility to listen to changes in documents and collections without polling the database.

Interface IFirestoreDatabase

Interface IStructuredQuery

Interface IQueryFilter

Interface IFirestoreDocument

Interface IFirestoreDocuments

Interface for Firebase Storage

The Firebase Storage stores any kind of files in a directory structure. For more information about the Firebase Storage read first the Google Cloud Storage Documentation.

Interface IFirebaseStorage

Interface IStorageObject