Introduction

MRX SDK is a set of small, focused .NET libraries built around a single idea: an API and its clients should agree on a well-structured, machine-readable error contract, and the plumbing that keeps them in sync should be automatic rather than hand-written.

The problem

ASP.NET Core's default model validation reports errors as flat, human-readable messages keyed by model binding path (e.g. "Address.Street"). This is fine for logging, but it's awkward for clients that want to:

  • Map an error back to a specific form field reliably, including when the field's name collides across binding sources (route, query, body).
  • Distinguish "the value at this JSON path is invalid" from "an unrelated exception occurred while binding".
  • Read a machine-readable error code, not just a free-text message, so the UI can localize or branch on it.

The pieces

  • MRX.Core replaces the default ASP.NET Core IObjectModelValidator with one that re-keys validation errors into consistent, camelCase-by-default JSON paths and converts them into CodedError instances — a (Code, Description) pair — under a stable errors extension on the ProblemDetails response. See Disambiguation for how it resolves colliding keys across binding sources.
  • MRX.Core.Common holds the types shared between server and client (CodedError, well-known feature names), with no dependency on the ASP.NET Core shared framework, so it can be referenced from Blazor WebAssembly projects too.
  • MRX.UI.ErrorsAutoWiring is the client-side counterpart: it reads the errors extension off an HTTP response and, using MRX.Json and MRX.Json.Reflection to walk each JSON path back onto your bound request models, populates a Blazor EditContext's validation messages automatically — no manual mapping between error keys and form fields.
  • MRX.FeatureDiscovery lets a client ask, for a given route and HTTP method, which MRX features (such as disambiguation) are active on that endpoint, so clients don't have to guess or hardcode assumptions about server behavior.
  • MRX.Json, MRX.Json.Reflection, MRX.Parsing, and MRX.Parsing.Reflection are the lower-level building blocks (JSON Path parsing/walking, reflection-based property access and type conversion) that the higher-level packages are built on. They're usable standalone if you only need JSON Path matching or generic parsing.

Limitations

Only body, query, URL path and header binding sources are currently supported.

Continue to Getting Started to wire these up in a project.

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