NpgsqlGraphQL 0.0.1-preview

NpgsqlGraphQL

Tiny .NET client and GraphQL.NET transport adapter experiment for PostgreSQL's pg_graphql extension.

This package does not implement a GraphQL schema generator or EF Core provider. PostgreSQL's pg_graphql extension owns schema reflection and execution. This library only calls graphql.resolve(...) through Npgsql and plugs that execution into GraphQL.NET's ASP.NET Core transport.

Usage

await using var client = new NpgsqlGraphqlClient(connectionString);

await client.EnsureExtensionAsync();

var json = await client.ResolveAsync(
    """
    query Blogs($first: Int!) {
      blogCollection(first: $first) {
        edges {
          node {
            id
            title
          }
        }
      }
    }
    """,
    new { first = 10 });

ASP.NET Core

using Npgsql.GraphQL;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddNpgsqlGraphQL(
    "Host=localhost;Port=5432;Database=postgres;Username=pgAdmin;Password=123456");

var app = builder.Build();

app.MapNpgsqlGraphQL("/graphql");

app.Run();

With PostgreSQL session settings for RLS or multi-tenancy:

builder.Services.AddNpgsqlGraphQL(options =>
{
    options.ConnectionString = builder.Configuration.GetConnectionString("Postgres");
    options.SetSessionSetting("app.source", "graphql");
    options.MapClaimToSessionSetting("app.user_id", "sub");
});

app.MapNpgsqlGraphQL("/graphql", options =>
{
    options.CsrfProtectionEnabled = false;
});

Request:

POST /graphql
Content-Type: application/json

{
  "query": "query { blogCollection(first: 10) { edges { node { id title } } } }"
}

Frontend clients

The endpoint is a normal GraphQL HTTP endpoint, so frontend applications can use standard clients:

• React: Apollo Client, urql, Relay, or plain fetch.
• Vue: Vue Apollo or any framework-agnostic GraphQL client.
• TypeScript: GraphQL Code Generator can generate typed operations from schema/query documents.

The frontend still writes GraphQL operations, but they are usually colocated in .graphql files or gql tags and can be type-generated instead of hand-parsed.

Notes

• Requires PostgreSQL with the pg_graphql extension installed.
• EnsureExtensionAsync runs create extension if not exists pg_graphql;.
• Query execution is delegated to graphql.resolve.
• The ASP.NET Core endpoint uses GraphQL.NET's HTTP transport and serializers.
• NpgsqlGraphqlDocumentExecuter implements GraphQL.NET's IDocumentExecuter<ISchema> and delegates execution to PostgreSQL.
• No .NET GraphQL schema is required; the ExecutionOptions.Schema value is ignored because schema reflection lives in PostgreSQL.
• PostgreSQL session settings are applied inside a transaction with set_config(..., true).
• PostgreSQL GraphQL error extensions.code is mapped to GraphQL.NET's ExecutionError.Code.
• When GraphQL.NET enables execution metrics, the response includes an extensions.npgsql.durationMs value.