Class: A2A::Server

Inherits:
Object
  • Object
show all
Defined in:
lib/a2a/server.rb,
lib/a2a/server/env.rb,
lib/a2a/server/triage.rb,
lib/a2a/server/sse/stream.rb,
lib/a2a/server/well_known.rb,
lib/a2a/server/bindings/grpc.rb,
lib/a2a/server/bindings/rest.rb,
lib/a2a/server/sse/rest_stream.rb,
lib/a2a/server/sse/event_parser.rb,
lib/a2a/server/bindings/json_rpc.rb,
lib/a2a/server/sse/json_rpc_stream.rb,
lib/a2a/server/middleware/fetch_task.rb,
lib/a2a/server/middleware/sse_stream.rb,
lib/a2a/server/middleware/extract_message.rb,
lib/a2a/server/middleware/limit_history_length.rb,
lib/a2a/server/middleware/limit_pagination_size.rb

Overview

Rack application that exposes an A2A-compliant agent server.

Composes a single linear middleware stack. Each middleware checks the request path and either handles the request or passes it downstream:

Env                 → injects shared context into the env
WellKnown           → serves /.well-known/agent-card.json
Bindings::Grpc      → /grpc (reserved) → 501 Not Implemented
Bindings::Rest      → /rest (HTTP+JSON/REST)
Bindings::JsonRpc   → everything else (JSON-RPC 2.0)
SSEStream           → offers env["a2a.stream"] to the agent
Triage              → resolves the target operation
ExtractMessage      → sets env["a2a.message"] when a message is present
LimitHistoryLength  → sets env["a2a.history_length"]
LimitPaginationSize → sets env["a2a.page_size"]
Agent               → the terminal app (your block)

The block is the terminal rack app — it is executed at the end of the stack, wrapped in the A2A::Agent error boundary. Usage (A2A.agent is a shorthand for this):

app = A2A::Server.new(agent_card: { "name" => "My Agent", ... }) do |env|
case env["a2a.operation"]
in "SendMessage"
  A2A::Protocol::JsonSchema["Send Message Response"].new({})
end
end

run app

Defined Under Namespace

Modules: Bindings, Middleware, SSE Classes: Env, Triage, WellKnown

Instance Method Summary collapse

Constructor Details

#initialize(agent_card: {}, history_length: 100, page_size: 100, &block) ⇒ Server

Returns a new instance of Server.

Raises:

  • (ArgumentError) 


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# File 'lib/a2a/server.rb', line 42

def initialize(agent_card: {}, history_length: 100, page_size: 100, &block)
  raise ArgumentError, "Server requires a block" unless block

  @agent_card     = agent_card
  @agent          = Agent.new(&block)
  @history_length = history_length
  @page_size      = page_size
  @app            = build_app
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/a2a/server.rb', line 52

def call(env)
  @app.call(env)
end