{"schemaVersion":"mappls.journey-workshop.v1","slug":"navigation-session","journeySlug":"navigation-session","title":"Build Recoverable navigation session","summary":"An eight-lab, source-bounded workshop for the complete navigation session lifecycle: exact commands and events, durable records, replay, concurrency, unknown outcomes, hostile fixtures, a maintained capstone, and production exit evidence.","duration":"2 hr 10 min","level":"Advanced","productSlug":"routes-navigation","stateModel":"hybrid","aggregate":"navigation session","actorCount":4,"stateCount":6,"transitionCount":6,"eventCount":6,"sourceGuideSlugs":["mappls-android-sdk","mappls-ios-sdk","mappls-react-native-sdk","mapmyindia-maps-vectorsdk-android","mapmyindia-maps-vectorsdk-ios"],"contractSlugs":[],"relatedTutorialSlugs":[],"sample":{"slug":"trip-planner","name":"Weekend Trip Planner","downloadPath":"/downloads/trip-planner.zip","checksumPath":"/downloads/trip-planner.zip.sha256","verifiedTestCount":8,"runCommand":"npm test --workspace @mappls-example/trip-planner"},"labs":[{"slug":"model-lifecycle","title":"Model the lifecycle before the UI","duration":"15 min","objective":"Turn the navigation session blueprint into an explicit aggregate boundary owned by the application.","build":["draft: Origin, destination, stops, vehicle profile, and constraints are incomplete or editable.","preview: Alternatives and trade-offs are visible but guidance and sensor use have not started.","navigating: Guidance owns an active route and consumes position, progress, traffic, and user commands.","rerouting: The active route is temporarily superseded by a recalculation caused by deviation, traffic, or destination change.","arrived: Arrival policy passed and the application is waiting for confirmation or final trip actions.","ended: Sensors, audio, observers, foreground services, and SDK session resources are released."],"prove":["Every persisted state exists in the reviewed blueprint.","Terminal states reject ordinary forward commands.","Recovery text is operational guidance, not another hidden state."]},{"slug":"command-event-contract","title":"Implement every command and event pair","duration":"20 min","objective":"Make intent, actor authority, allowed source state, committed state, and emitted fact reviewable together.","build":["calculate_route by Navigation application: draft | preview → preview; emit route.calculated.","start_guidance by Driver: preview → navigating; emit navigation.started.","request_reroute by Navigation application: navigating | rerouting → rerouting; emit reroute.requested.","accept_reroute by Mappls navigation SDK: rerouting → navigating; emit route.updated.","confirm_arrival by Navigation application: navigating → arrived; emit navigation.arrived.","end_session by Driver: preview | navigating | rerouting | arrived → ended; emit navigation.ended."],"prove":["calculate_route resolves to navigation-session-route-calculated without claiming a provider webhook payload.","start_guidance resolves to navigation-session-navigation-started without claiming a provider webhook payload.","request_reroute resolves to navigation-session-reroute-requested without claiming a provider webhook payload.","accept_reroute resolves to navigation-session-route-updated without claiming a provider webhook payload.","confirm_arrival resolves to navigation-session-navigation-arrived without claiming a provider webhook payload.","end_session resolves to navigation-session-navigation-ended without claiming a provider webhook payload."]},{"slug":"durable-records","title":"Persist restart-safe records","duration":"15 min","objective":"Separate business identity, provider evidence, command receipts, immutable facts, audit, and downstream delivery.","build":["Route intent: Portable origin, stops, profile, constraints, and version. Keys: intentId, version, waypoints, profile, constraints.","Session checkpoint: Minimal recoverable progress without persisting unsafe SDK internals. Keys: sessionId, intentVersion, routeId, legIndex, lastPositionTime.","Navigation trace: Privacy-bounded operational and quality evidence. Keys: sessionId, eventType, occurredAt, routeVersion, quality."],"prove":["Process restart restores the same aggregate version and command result.","Opaque SDK or native UI objects are not durable records.","Provider evidence and application decisions remain distinguishable."]},{"slug":"concurrency-replay","title":"Make concurrency and replay deterministic","duration":"15 min","objective":"Apply optimistic expected versions and aggregate-scoped idempotency before executing effects.","build":["Only one guidance session owns foreground navigation resources at a time.","Every route result is applied only to the intent version that requested it.","The last valid route remains available while a reroute is pending.","Arrival requires an explicit distance, speed, dwell, and stop policy.","End releases every observer, sensor, audio, and service resource exactly once in effect."],"prove":["An exact replay returns the first result without another event or version.","A reused key with different intent conflicts.","A stale expected version changes no durable truth."]},{"slug":"effects-reconciliation","title":"Control effects and unknown outcomes","duration":"15 min","objective":"Commit outbox intent atomically, execute effects outside the transaction, and reconcile ambiguous results.","build":["Application process is killed: detect with A persisted active checkpoint exists without a live runtime owner. Recover with Recreate resources, validate destination intent, recalculate if stale, and ask before resuming guidance.","GNSS quality degrades: detect with Accuracy, age, speed consistency, or map-matching confidence crosses policy. Recover with Surface degraded positioning, use supported dead-reckoning inputs, and avoid false reroutes.","Reroute response arrives after destination changed: detect with Response intent version is older than the active intent. Recover with Discard it and keep the latest calculation; never apply by arrival order alone.","Network disappears: detect with Online route, traffic, or search dependency fails while local guidance remains active. Recover with Keep last valid guidance, expose freshness, and use entitled offline capability when available."],"prove":["A timeout remains an unknown outcome until identity-based reconciliation completes.","Retries are bounded and preserve the original business and command identities.","Dead-letter or manual review retains the entire attempt history."]},{"slug":"hostile-scenarios","title":"Run all hostile fixture scenarios","duration":"15 min","objective":"Exercise the success path plus replay, concurrency, state, and response-loss failures without an account.","build":["Complete journey: Commit the shortest reviewed success path to the journey-specific operating target.","Idempotent replay: Repeat one command identity and prove that version, event identity, and side effects do not duplicate.","Stale version: Reject a command based on an outdated aggregate version without changing durable truth.","Invalid transition: Reject a known command when the current state does not permit it.","Unknown outcome recovery: Reconcile after a lost response, then replay the original command identity safely."],"prove":["All fixture checks pass for all five scenarios.","Rejected commands emit no event and do not increment version.","The fixture makes zero provider calls and exposes no write tool."]},{"slug":"maintained-capstone","title":"Trace the Weekend Trip Planner capstone","duration":"20 min","objective":"Follow the maintained source through domain rules, adapter seam, repository transaction, HTTP boundary, UI evidence, and restart test.","build":["Run the app's declared test suite (8 tests).","Run fixture mode without a credential.","Inspect audit and outbox evidence after each transition.","Restart the process and continue the same aggregate."],"prove":["The downloadable archive checksum verifies before execution.","The capstone covers the journey target without inventing provider completion.","Browser and HTTP surfaces report the same durable version."]},{"slug":"production-exit","title":"Qualify the real integration boundary","duration":"15 min","objective":"Replace only reviewed adapter seams and collect independent production evidence without weakening application invariants.","build":["Route calculation latency and alternative selection","Position age, accuracy, and map-matching confidence","Reroute cause, time, cancellation, and supersession","Guidance session starts without matching cleanup","Arrival false-positive and manual-override rate","Crash/restart recovery outcome"],"prove":["Exact product entitlement and regional behavior are validated separately.","Provider contract tests cover success, rejection, throttling, timeout, and unknown outcome.","Security, privacy, operations, rollback, and product owners approve exact evidence.","Fixture completion is never presented as provider or production completion."]}],"codeSamples":[{"language":"typescript","label":"TypeScript aggregate boundary","code":"type State = \"draft\" | \"preview\" | \"navigating\" | \"rerouting\" | \"arrived\" | \"ended\";\ntype CommandName = \"calculate_route\" | \"start_guidance\" | \"request_reroute\" | \"accept_reroute\" | \"confirm_arrival\" | \"end_session\";\n\ntype Command = {\n  name: CommandName;\n  aggregateId: string;\n  expectedVersion: number;\n  idempotencyKey: string;\n};\n\nconst transitions = {\n  \"calculate_route\": { from: [\"draft\", \"preview\"], to: \"preview\", event: \"route.calculated\" },\n  \"start_guidance\": { from: [\"preview\"], to: \"navigating\", event: \"navigation.started\" },\n  \"request_reroute\": { from: [\"navigating\", \"rerouting\"], to: \"rerouting\", event: \"reroute.requested\" },\n  \"accept_reroute\": { from: [\"rerouting\"], to: \"navigating\", event: \"route.updated\" },\n  \"confirm_arrival\": { from: [\"navigating\"], to: \"arrived\", event: \"navigation.arrived\" },\n  \"end_session\": { from: [\"preview\", \"navigating\", \"rerouting\", \"arrived\"], to: \"ended\", event: \"navigation.ended\" },\n} as const;\n\nexport function decide(current: { state: State | null; version: number }, command: Command) {\n  const rule = transitions[command.name];\n  if (command.expectedVersion !== current.version) throw new Error(\"version_conflict\");\n  if (!rule.from.includes(current.state as never)) throw new Error(\"invalid_transition\");\n  return {\n    state: rule.to as State,\n    version: current.version + 1,\n    event: rule.event,\n    idempotencyKey: command.idempotencyKey,\n  };\n}\n\n// Persist the result, immutable event, audit row, and outbox intent atomically.\n// Store the first result by idempotencyKey before executing another effect."},{"language":"sql","label":"SQL durability skeleton","code":"CREATE TABLE journey_navigation_session (\n  aggregate_id text PRIMARY KEY,\n  state text NOT NULL,\n  version bigint NOT NULL CHECK (version > 0),\n  updated_at timestamptz NOT NULL DEFAULT now()\n);\n\nCREATE TABLE journey_navigation_session_commands (\n  aggregate_id text NOT NULL REFERENCES journey_navigation_session(aggregate_id),\n  idempotency_key text NOT NULL,\n  request_hash text NOT NULL CHECK (length(request_hash) = 64),\n  committed_version bigint NOT NULL,\n  result_json jsonb NOT NULL,\n  PRIMARY KEY (aggregate_id, idempotency_key)\n);\n\nCREATE TABLE journey_navigation_session_outbox (\n  event_id text PRIMARY KEY,\n  aggregate_id text NOT NULL,\n  aggregate_version bigint NOT NULL,\n  event_type text NOT NULL,\n  payload jsonb NOT NULL,\n  published_at timestamptz\n);\n\n-- In one transaction: lock aggregate, compare version, decide, append audit/event,\n-- insert the outbox row, and remember the exact command result."},{"language":"curl","label":"Complete fixture journey","code":"curl --request POST 'https://developer.mappls.com/api/journey-simulator' \\\n+  --header 'content-type: application/json' \\\n+  --data '{\"journey\":\"navigation-session\",\"scenario\":\"complete-journey\"}'"},{"language":"curl","label":"Unknown-outcome drill","code":"curl --request POST 'https://developer.mappls.com/api/journey-simulator' \\\n+  --header 'content-type: application/json' \\\n+  --data '{\"journey\":\"navigation-session\",\"scenario\":\"unknown-outcome\"}'\n\n# Reconcile navigationsession identity and the original idempotency key.\n# Never mint a replacement key merely because the response was lost."},{"language":"json","label":"First command envelope","code":"{\n  \"command\": \"calculate_route\",\n  \"aggregateId\": \"fixture-navigation-session-001\",\n  \"expectedVersion\": 1,\n  \"idempotencyKey\": \"cmd_navigation-session_001\",\n  \"evidenceBoundary\": \"application-owned-workshop\"\n}"}],"simulationScenarios":[{"slug":"complete-journey","title":"Complete journey","outcome":"Commit the shortest reviewed success path to the journey-specific operating target.","href":"/tools/journey-lab?journey=navigation-session&scenario=complete-journey#lab"},{"slug":"idempotent-replay","title":"Idempotent replay","outcome":"Repeat one command identity and prove that version, event identity, and side effects do not duplicate.","href":"/tools/journey-lab?journey=navigation-session&scenario=idempotent-replay#lab"},{"slug":"stale-version","title":"Stale version","outcome":"Reject a command based on an outdated aggregate version without changing durable truth.","href":"/tools/journey-lab?journey=navigation-session&scenario=stale-version#lab"},{"slug":"invalid-transition","title":"Invalid transition","outcome":"Reject a known command when the current state does not permit it.","href":"/tools/journey-lab?journey=navigation-session&scenario=invalid-transition#lab"},{"slug":"unknown-outcome","title":"Unknown outcome recovery","outcome":"Reconcile after a lost response, then replay the original command identity safely.","href":"/tools/journey-lab?journey=navigation-session&scenario=unknown-outcome#lab"}],"acceptance":["All 6 reviewed transitions are implemented with actor and source-state checks.","All 6 application event identities are immutable and versioned.","Exact replay, idempotency conflict, stale version, invalid transition, and unknown outcome are tested.","Aggregate, event, audit, command result, and outbox intent commit atomically.","The Weekend Trip Planner capstone passes 8 declared tests after archive checksum verification.","Provider entitlement, payload, callback, completion, and production behavior remain independently evidenced."],"sourceBoundary":["The journey blueprint and application event contracts are implementation guidance, not Mappls provider payload specifications.","Only linked normalized contracts and source guides may define provider request syntax; empty evidence is never backfilled.","The simulator and maintained capstone operate in explicit fixture mode and make no entitlement claim.","Credentials, precise production payloads, opaque native objects, and provider secrets stay outside workshop inputs and durable examples."],"releaseBoundary":"Workshop completion proves an application-owned reliability design only. Production still requires issued entitlement, exact adapter contract tests, regional and quota validation, security/privacy review, operational drills, and independent release approval.","websitePath":"/journeys/navigation-session/workshop","apiPath":"/api/journey-workshops?journey=navigation-session","providerCalls":0,"writesExposed":false}