unleash-client-delphi

Requirements

• Delphi 10.3 or higher

Using the unleash client for Delphi

This library was developed with the interfaces of the NodeJS client in mind.

Initialization

var
  Unleash: IUnleash;
  Config: TUnleashConfig;
begin
  Config.Default;
  Config.url := 'http://127.0.0.1:4242/';
  Config.appName := 'my-app-name';
  Config.instanceId := 'my-unique-instance-id';
  Config.prefixFilter := 'app.'; // optional
  Config.apiKey := 'user.production.12ab34cd56ef57ab89cd'; // optional

  Unleash := TUnleash.Create;
  Unleash.Initialize(Config);
end;

Example

if Unleash.IsEnabled('app.ToggleX') then
begin
  // Feature implementation ...
end;

Unleash context

var
  Context: TUnleashContext;
begin
  Context.userId := '123';
  Context.remoteAddress := '127.0.0.1';

  if Unleash.IsEnabled('app.ToggleX', Context) then
  begin
    // Feature implementation ...
  end;
end;

Default context

A slight difference with the NodeJS client, in this version we can also setup the default context so it doesn't have to be passed to IsEnabled all the time.

var
  Context: TUnleashContext;
begin
  Context.userId := '123';
  Context.remoteAddress := '127.0.0.1';

  Unleash.SetDefaultContext(Context);

  if Unleash.IsEnabled('app.ToggleX') then
  begin
    // Feature implementation ...
  end;
end;

Supported strategies

• DefaultStrategy
• UserIdStrategy
• GradualRolloutUserIdStrategy
• GradualRolloutRandomStrategy
• RemoteAddressStrategy

Differences with the nodejs client

• The DefaultContext is always used when no context is supplied to the IsEnabled function.
• There's no refresh rate of fetching features from the server, but you can implement your own timer or thread that may call Unleash.Refresh;
• There's no default backup option that allows for offline features, but you can implement your own through Unleash.GetLatestFeaturesJson and Config.initialFeaturesJson := LastKnownOrDefaultFeaturesJson;
• The default If-Modified behaviour causes an internal IDE Exception because of the 403 status-code when calling Unleash.Refresh, you can choose to disable If-Modified by setting Config.noETag := False;, although this is not recommended.
• The nodejs client supports custom headers to send along with the requests (and thus the Authorization header), we offer a simple apiKey setting.
• Metrics have not been implemented yet.