ValidateGraphQLClientAssembliesAsync

Validates every request type a client owns in a set of assemblies against that client's schema, so a query the server no longer accepts fails at startup or in a test instead of on first use. Call it after app.Build().

Signatures

public static Task ValidateGraphQLClientAssembliesAsync(
    this IServiceProvider services,
    params Assembly[] assemblies)
 
public static Task ValidateGraphQLClientAssembliesAsync(
    this IServiceProvider services,
    object serviceKey,
    params Assembly[] assemblies)

Parameter	Type	Required	Description
`services`	`IServiceProvider`	Yes	The built container, usually `app.Services`
`serviceKey`	`object`	Keyed overload	The key the client was registered with by AddKeyedTraxGraphQLClient
`assemblies`	`Assembly[]`	Yes	The assemblies to scan

Returns: a Task that completes when every request has validated.

Which requests are checked

Every concrete class in assemblies that implements IGenericGraphQLClientRequest and belongs to the client:

The unkeyed overload checks the types that carry no [GraphQLClient] mark, against the unkeyed client's schema.
The keyed overload checks the types marked [GraphQLClient(serviceKey)], against the schema of the client registered under that key.

Each type is created with RuntimeHelpers.GetUninitializedObject, without running a constructor, and its Query is validated. A Query must therefore not depend on state a constructor sets. A literal string, an embedded resource (GraphQLResourceRequest) and a TypedRequest all qualify. Validation stops at the first failure.

Exceptions

Exception	When
`GraphQLValidationException`	A query does not validate against the schema, has no operation, or has more than one. `Query` holds the failing text and `Errors` the validator's errors
`GraphQLSchemaIntrospectionException`	The schema could not be loaded (introspection failed, the SDL file is missing or invalid)
`InvalidOperationException`	No request type in `assemblies` belongs to this client, or (keyed overload) no client is registered under `serviceKey`

Finding nothing to validate is refused on purpose: it almost always means a request was left unmarked or marked with a misspelt key, and passing would hide that.

Example

var app = builder.Build();
 
await app.Services.ValidateGraphQLClientAssembliesAsync(typeof(Program).Assembly);
await app.Services.ValidateGraphQLClientAssembliesAsync("billing", typeof(Program).Assembly);
 
app.Run();

In a test, the same call over a container built with UseFileSchema checks every query against the checked-in schema with no server running.

Validating with a custom filter

IGraphQLClientValidator, which every client registers, carries an extension for scanning without the ownership rule:

public static Task ValidateAssembliesAsync(
    this IGraphQLClientValidator validator,
    IEnumerable<Assembly> assemblies,
    CancellationToken cancellationToken = default)
 
public static Task ValidateAssembliesAsync(
    this IGraphQLClientValidator validator,
    IEnumerable<Assembly> assemblies,
    Func<Type, bool>? typeFilter,
    CancellationToken cancellationToken = default)

It validates every request type typeFilter accepts (all of them when null), whatever its [GraphQLClient] mark, and does not fail when it finds none.

Remarks

For host-startup gating, UseStartupValidation on the builder does the same check from a hosted service, so the host refuses to start on a failure.
The validator caches each query text that passes, so validating at startup also warms the cache the executor uses.

Package

dotnet add package Trax.Api.GraphQL.Client