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HTTP API

The Workflows4s HTTP API exposes comprehensive information about workflows, including:

  • inspecting workflow definitions
  • inspecting and searching workflow instances
  • interacting with instances through signals

It is available through the following modules:

"org.business4s" %% "workflows4s-web-api-shared" % "0.4.0" // Endpoint definitions and models
"org.business4s" %% "workflows4s-web-api-server" % "0.4.0" // Server implementation

See Getting Started for an example usage.

Workflow Entries​

To expose its functionality, the API relies on WorkflowEntry, a helper that enriches a WorkflowRuntime with additional information required to serve the API.

It consists of the following elements:

  • Workflow runtime - grants access to instances
  • Name and description - used for display purposes
  • State encoder - renders the current instance state to JSON for display
  • Signal support - for each signal, provides a request JSON Schema (so a form can be rendered generically in the UI) and codecs to deserialize the request and serialize the response, enabling exchanging them with the client
warning

The current API for SignalSupport is not type-safe and might change in the future.

WorkflowSearch is an interface for searching workflow instances and is intended to be implemented by workflow registries.

Currently, only an in-memory implementation is provided; other implementations may come later. Contributions of reusable implementations are welcome.

Compatibility guarantees​

warning

The API is experimental and no compatibility guarantees are provided. We recommend using the API via the Tapir definitions, consuming it from Scala.js, and ensuring the client and server versions match.