adastra_app/docs/decisions/0004-http-interceptors-pipeline.md

ADR 0004: HTTP Interceptors Pipeline

Date: 2026-04-26 Status: Accepted

Context

Every API call requires the same three cross-cutting concerns:

1. Prepend the API base URL so services don't hard-code it.
2. Attach the JWT bearer token when one exists.
3. Unwrap error responses into a consistent shape.

Handling these ad hoc in each service would duplicate logic and couple services to environment details.

Decision

Three functional interceptors are chained in order in app.config.ts:

1. apiInterceptor — prepends environment.apiBaseUrl to every outgoing request URL. Consequence: all services call relative paths (e.g. /skydive/jumps), never absolute URLs.
2. tokenInterceptor — attaches Authorization: Token <jwt> when a token exists in JwtService.
3. errorInterceptor — unwraps err.error from HttpErrorResponse and rethrows, so subscribers receive the API error payload directly.

Consequences

• Positive: Services are environment-agnostic. Swapping the API base URL requires changing only environment.ts.
• Positive: Auth header injection is transparent to all services.
• Positive: Error handling is uniform across the application.
• Constraint: Services must always use relative paths starting with /. Absolute URLs would get the base URL prepended, breaking them.