Queries

The Arc provides comprehensive support for implementing queries in your backend application. Queries are used for retrieving data and are a key component of CQRS (Command Query Responsibility Segregation) architecture, offering powerful features like observability, validation, and flexible parameter handling.

Topics

Topic	Description
Controller based	How to implement queries using controller-based approach.
Model Bound	How to work with model-bound queries for simplified parameter handling.
Use Observable Queries with cURL	How to inspect snapshots, wait for the first payload, stream SSE updates, and emulate long polling from plain HTTP clients.
Observable Query Hub	Composite real-time streaming over a single fixed WebSocket or SSE endpoint.
Query Pipeline	Understanding the query pipeline and how queries are processed.
Read Model Interception	Apply cross-cutting operations (decryption, masking, enrichment) to read models before they are served to clients.
Authorization	How to use authorization attributes for role-based and policy-based authorization.
Validation	How to implement validation for query parameters.

💡 Query Filters: The query pipeline supports filters for cross-cutting concerns like validation and authorization. See the Query Pipeline section for details on built-in filters and creating custom ones. 💡 Frontend Integration: Automatically generate TypeScript proxies for your queries with the Proxy Generation feature.

Overview

Queries in the Arc are designed to be flexible and powerful, supporting both traditional request-response patterns and reactive, observable queries that can provide real-time updates. The framework handles parameter validation, binding, and processing through a comprehensive pipeline that ensures consistent behavior across your application. Query arguments and parameter binding are covered within the controller-based and model-bound topics.