Examples

API screens

Clinic staff register pets and read the pet directory through the clinic API.

Each API request and each API response is a screen with kind = "api". The request screen sends the command. The response screen shows the read model. Both screens name the endpoint in api_endpoint. Spec v0.7.0 added the kind attribute.

state_change state_view

The rendered canvas

Generated with emhcl diagram examples/api-screens.em.hcl. Use the chapter picker to choose a chapter, then the view switcher for its Model, Compact, and Storming views. Context Map covers the whole model. Click a slice to view its scenarios.

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The source

Source file: examples/api-screens.em.hcl.

# Clinic staff register pets through a client program that calls the clinic # API, and read the pet directory through the same API. Each API request and # each API response is a screen with kind = "api". board { workflows = [ workflow.register_pet, workflow.pet_directory, ] } actor "clinic_staff" { title = "Clinic Staff" auth_required = true } bounded_context "clinic" { title = "Clinic" aggregate "pet" { title = "Pet" } field_type "pet_id" { type = "UUID" id_attribute = true } field_type "pet_name" { type = "String" } event "pet_registered" { title = "Pet Registered" aggregate = aggregate.pet field "pet_id" { type = field_type.clinic.pet_id } field "name" { type = field_type.clinic.pet_name } } } state_change "register_pet" { title = "Register Pet" screen "register_pet_request" { kind = "api" api_endpoint = "POST /pets" actor = actor.clinic_staff to = [command.register_pet] field "name" { type = field_type.clinic.pet_name } } command "register_pet" { title = "Register Pet" aggregate = aggregate.clinic.pet to = [event.clinic.pet_registered] field "pet_id" { type = field_type.clinic.pet_id generated = true } field "name" { type = field_type.clinic.pet_name } } scenario "pet_is_registered" { when { command = command.register_pet } then { event = event.clinic.pet_registered } } } state_view "pet_directory" { title = "Pet Directory" readmodel "pets" { question = "Which pets does the clinic know?" from = [event.clinic.pet_registered] to = [screen.pets_response] field "pet_id" { type = field_type.clinic.pet_id } field "name" { type = field_type.clinic.pet_name } } screen "pets_response" { kind = "api" api_endpoint = "GET /pets" actor = actor.clinic_staff field "pet_id" { type = field_type.clinic.pet_id } field "name" { type = field_type.clinic.pet_name } } scenario "registered_pet_is_listed" { given { event = event.clinic.pet_registered } then { readmodel = readmodel.pets } } }