PostgREST is a production-grade Haskell web server that converts an existing PostgreSQL schema into a RESTful HTTP API. At startup it introspects PostgreSQL system catalogs to build a schema cache of tables, views, relationships, routines, and media handlers. Each request is parsed into an internal AST (ApiRequest), planned against the schema cache (Plan), compiled to parameterized SQL (QueryBuilder), and executed through the vendored Hasql PostgreSQL driver. The server supports full CRUD, RPC calls, resource embedding via foreign keys, filtering, ordering, pagination, JWT authentication, OpenAPI generation, and custom PostgreSQL-defined media types. Authorization is delegated to the database: PostgREST connects as an authenticator role that does SET ROLE to the JWT-specified role, so row-level security, grants, and triggers are enforced by PostgreSQL. The system runs as a single Haskell binary with lifecycle management, SIGUSR2/config reload through LISTEN/NOTIFY, a separate admin server exposing /live, /ready, /metrics, and schema cache dumps, and metrics via Prometheus. Build and packaging is Nix-based with static linking, Docker images, and cabal/stack support. CI runs integration suites against multiple PostgreSQL versions and includes load, memory, observability, and replica tests. Maintenance is active, with frequent releases and broad production use. The codebase demonstrates a clean separation between HTTP parsing, query planning, SQL generation, and database access. It is one of the few Haskell projects at this scale with deep PostgreSQL binary-protocol integration. The vendored Hasql driver and several standalone modules—media type parsing, HTTP Range handling, SIEVE cache, JSON path parsing—are extractable as reusable components for other Haskell services.
NocoDB is an open-source no-code database platform that provides a spreadsheet-like interface for managing relational databases. It supports multiple view types (grid, form, calendar, kanban, gallery, map, timeline, gantt), rich field types (formula, rollup, lookup, links, attachments, AI prompt), and automations via webhooks and scripts. The architecture is a full-stack monorepo: a NestJS backend with REST APIs (v1–v3), a Vue 3/Nuxt frontend with a custom canvas-based grid renderer, and a shared SDK (`nocodb-sdk`) for types, column helpers, and API client. Key entry points include the server bootstrap (`Noco.ts`), the Nuxt app, and the SDK. Data flows involve Knex-based query building with dialect-specific field handlers, caching via Redis, real-time updates via Socket.io, and background job processing via Bull. External dependencies include PostgreSQL, MySQL, SQLite, MSSQL, Oracle, Redis, and various storage/notification plugins. The codebase demonstrates high craftsmanship with reusable patterns such as column helpers, field handlers, builder generators, caching abstractions, and composables, though it contains many CE stubs for enterprise features and a large migration history.
Hasura GraphQL Engine is an open-source, metadata-driven GraphQL server that provides instant, real-time GraphQL APIs over multiple databases (PostgreSQL, MSSQL, BigQuery, CockroachDB, Citus, and custom sources via Data Connectors). The repository is a large monorepo containing a Rust-based v3 engine, a Go CLI for project management (migrations, metadata, seeds), a React/TypeScript admin console, and community boilerplates for authentication, event triggers, and remote schemas. The system exposes a single GraphQL endpoint that supports queries, mutations, subscriptions, streaming subscriptions, event triggers, cron triggers, remote joins, actions, and Apollo Federation. It relies on external databases, webhook endpoints for auth and event handling, and optionally OpenTelemetry collectors for observability. The architecture is modular: the v3 engine handles metadata resolution, GraphQL schema generation, and execution planning; the CLI manages project lifecycle; and the console provides a GUI for configuration. The codebase is actively maintained with frequent releases, but shows signs of technical drift due to legacy frontend code (Redux vs React Query), dual version support (v2/v3), and multiple programming languages (Rust, Go, TypeScript, Haskell, Python).