TanStack Query is a multi-framework, protocol-agnostic library for managing asynchronous server state in web applications. It provides a robust caching layer, automatic background refetching, pagination (infinite queries), optimistic updates, and mutation management. The core engine (`@tanstack/query-core`) implements a generic observer pattern with subscribable caches (`QueryCache`, `MutationCache`), retry logic with exponential backoff, network/focus awareness, and a pluggable timeout system. Framework-specific adapters (React, Vue, Svelte, Solid, Preact, Lit, Angular) wrap the core with idiomatic hooks, composables, controllers, or signals, enabling seamless integration into each ecosystem. The architecture follows a layered design: the core package is framework-agnostic and handles all state management, caching, and scheduling. Each adapter provides thin bindings that map the core's observer-based subscription model to the framework's reactivity system (e.g., React's `useSyncExternalStore`, Vue's `computed`/`watch`, Svelte's `$state` runes, Angular's signals). Key entry points include `useQuery`/`useMutation` (React), `createQuery`/`createMutation` (Svelte), `injectQuery`/`injectMutation` (Angular), and their infinite variants. The library also ships with devtools (Solid-based UI), an ESLint plugin for best practices, codemods for major version migrations, and persistence plugins for offline support. Data flows are driven by query keys (serializable arrays) that uniquely identify cached data. Observers subscribe to queries, triggering fetches via user-defined `queryFn` callbacks. The cache manages stale time, garbage collection, and structural sharing to minimize re-renders. Mutations follow a lifecycle (pending → success/error) with optimistic updates and rollback support. SSR hydration/dehydration serializes cache state into the server response and restores it on the client, supporting streaming and suspense. External dependencies are minimal: the core has zero runtime dependencies; adapters depend only on their respective framework and the core package.
fselect is a Rust command-line tool that enables searching the filesystem using SQL-like queries. It parses a SELECT-FROM-WHERE-GROUP BY-HAVING-ORDER BY-LIMIT syntax, traverses directories, and extracts rich metadata from files including size, timestamps, permissions, media information (EXIF, audio/video dimensions, duration), cryptographic hashes, MIME types, extended attributes, ACLs, git status, and more. The tool supports aggregation functions, subqueries (both FROM-subselects and correlated IN/EXISTS), and multiple output formats (tabular, CSV, JSON, HTML). It can accelerate searches via external indexes (Everything on Windows, plocate on Linux) and includes an interactive REPL mode. The architecture is a single binary with clean separation of concerns: lexer/parser for query processing, a searcher module for filesystem traversal and expression evaluation, utilities for metadata extraction, and pluggable output formatters.
Whois is a Go library and command-line tool for performing WHOIS queries on domain names, IP addresses (IPv4 and IPv6), and ASNs. The library handles the complexity of WHOIS referral chains, server-specific quirks (such as those for ARIN and GoDaddy), and provides configurable options for timeout, dialer (for proxy support), and referral control. The CLI tool provides a user-friendly interface for querying WHOIS information and optionally outputting parsed JSON results using the whois-parser package. The project is actively maintained with regular commits, CI/CD workflows, and versioned releases.
AutoFilterer is a .NET library that automatically generates LINQ expressions from Data Transfer Objects (DTOs) for filtering, sorting, and pagination on IQueryable collections. It is designed to be compatible with OpenAPI 3.0 specifications, unlike oData or GraphQL. The core architecture revolves around filter DTOs that inherit from FilterBase or its derivatives (PaginationFilterBase, OrderableFilterBase). Properties in these DTOs are decorated with attributes (e.g., StringFilterOptions, OperatorComparison, CompareTo) or use special types (StringFilter, OperatorFilter<T>, Range<T>) to define filtering rules. The library builds expression trees at runtime and applies them via the ApplyFilter extension method. It also provides a Swagger integration package (AutoFilterer.Swagger) to expose filter parameters in Swagger UI, and a source generator (AutoFilterer.Generators) to automatically create filter DTOs from entity classes. The codebase is well-structured with clear separation of concerns: abstractions (IFilter, IFilterableType), attributes, types, extensions, and a dynamic filter variant. It includes comprehensive unit tests, benchmark tests, and a sandbox application demonstrating usage with a Northwind database. The library targets netstandard2.0, netstandard2.1, and net9.0, making it broadly compatible. While the core library is mature and actively maintained, some ancillary packages (e.g., Swagger integration) use slightly outdated dependencies (Swashbuckle 5.x), and the documentation has some TODO sections. Overall, it is a solid, reusable filtering framework with high craftsmanship in expression tree manipulation.