graphql-language-service-server

graphql-language-service-server

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Server process backing the GraphQL Language Service.

GraphQL Language Service Server provides an interface for building GraphQL language services for IDEs.

Partial support for Microsoft's Language Server Protocol is in place, with more to come in the future.

Supported features include:

• Diagnostics (GraphQL syntax linting/validations) (spec-compliant)
• Autocomplete suggestions (spec-compliant)
• Hyperlink to fragment definitions and named types (type, input, enum) definitions (spec-compliant)
• Outline view support for queries
• Support for gql graphql and other template tags inside javascript, typescript, jsx, ts, vue and svelte files, and an interface to allow custom parsing of all files.

Installation and Usage

Dependencies

• An LSP compatible client with its own file watcher, that sends watch notifications to the server, such as vscode, nvim, or sublime-lsp.
• Node.js ^18.18.0 || >=20.9.0 or later is required.
• (for now) a graphql config file is required

Installation

npm install graphql-language-service-server
# or
yarn add graphql-language-service-server

We also provide a CLI interface to this server, see graphql-language-service-cli

Usage

Initialize the GraphQL Language Server with the startServer function:

import { startServer } from 'graphql-language-service-server';

await startServer({
  method: 'node',
});

If you are developing a service or extension, this is the LSP language server you want to run.

When developing vscode extensions, just the above is enough to get started for your extension's ServerOptions.run.module, for example.

startServer function takes the following parameters:

Parameter	Required	Description
port	true when method is socket, false otherwise	port for the LSP server to run on
method	false	socket, streams, or node (ipc)
config	false	custom graphql-config instance from loadConfig (see example above)
configDir	false	the directory where graphql-config is found
extensions	false	array of functions to transform the graphql-config and add extensions dynamically
parser	false	Customize all file parsing by overriding the default parseDocument function
fileExtensions	false. defaults to ['.js', '.ts', '.tsx, '.jsx']	Customize file extensions used by the default LSP parser

GraphQL configuration file

You must provide a graphql config file

Check out graphql-config to learn the many ways you can define your graphql config

.graphqlrc or .graphqlrc.yml/yaml or graphql.config.yml

schema: 'packages/api/src/schema.graphql'
documents: 'packages/app/src/components/**/*.{tsx,ts}'
extensions:
  endpoints:
    example:
      url: 'http://localhost:8000'
  customExtension:
    foo: true

.graphqlrc or .graphqlrc.json or graphql.config.json

{
  "schema": "https://localhost:8000"
}

graphql.config.js or .graphqlrc.js

module.exports = { schema: 'https://localhost:8000' };

custom startServer

use graphql config loadConfig for further customization:

import { loadConfig } from 'graphql-config'; // 3.0.0 or later!

// with required params
const config = await loadConfig();

await startServer({
  method: 'node',
  // or instead of configName, an exact path (relative from rootDir or absolute)

  // deprecated for: loadConfigOptions.rootDir. root directory for graphql config file(s), or for relative resolution for exact `filePath`. default process.cwd()
  // configDir: '',
  loadConfigOptions: {
    // any of the options for graphql-config@3 `loadConfig()`
    schema: await config.getSchema(),
    // rootDir is same as `configDir` before, the path where the graphql config file would be found by cosmic-config
    rootDir: 'config/',
    // or - the relative or absolute path to your file
    filePath: 'exact/path/to/config.js', // (also supports yml, json, ts, toml)
    // myPlatform.config.js/json/yaml works now!
    configName: 'myPlatform',
  },
});

Custom graphql-config features

The graphql-config features we support are:

module.exports = {
  extensions: {
    // add customDirectives (legacy). you can now provide multiple schema pointers to config.schema/project.schema, including inline strings. same with scalars or any SDL type that you'd like to append to the schema
    customDirectives: ['@myExampleDirective'],
    // a function that returns an array of validation rules, ala https://github.com/graphql/graphql-js/tree/main/src/validation/rules
    // note that this file will be loaded by the vscode runtime, so the node version and other factors will come into play
    customValidationRules: require('./config/customValidationRules'),
    languageService: {
      // this is enabled by default if non-local files are specified in the project `schema`
      // NOTE: this will disable all definition lookup for local SDL files
      cacheSchemaFileForLookup: true,
      // undefined by default which has the same effect as `true`, set to `false` if you are already using // `graphql-eslint` or some other tool for validating graphql in your IDE. Must be explicitly `false` to disable this feature, not just "falsy"
      enableValidation: true,
      // (experimental) enhanced auto expansion of graphql leaf fields and arguments
      fillLeafsOnComplete: true,
      // instead of jumping directly to the SDL file, you can override definition peek/jump results to point to different files or locations
      // (for example, source files for your schema in any language!)
      // based on Relay vscode's pathToLocateCommand
      // see LocateCommand type!
      locateCommand(projectName, typePath, info) {
        // pass more info, such as GraphQLType with the ast node. info.project is also available if you need it
        const { path, range } = ourLookupUtility(
          projectName,
          typePath,
          info.type.node,
        );
        return { uri: path, range }; // range.start.line/range.end.character/etc, base 1
        // you can also return relay LSP style
        // return '/path/to/file.py:20:23'; // (range: 20:1 )
        // return '/path/to/file.py'; // (range: 1:1 1:1)
      },
    },
  },
};

or for multi-project workspaces:

// graphql.config.ts
export default {
  projects: {
    myProject: {
      schema: [
        // internally in `graphql-config`, an attempt will be made to combine these schemas into one in-memory schema to use for validation, lookup, etc
        'http://localhost:8080',
        './my-project/schema.graphql',
        './my-project/schema.ts',
        '@customDirective(arg: String!)',
        'scalar CustomScalar',
      ],
      // project specific defaults
      extensions: {
        languageService: {
          cacheSchemaFileForLookup: true,
          enableValidation: false,
        },
      },
    },
    anotherProject: {
      schema: {
        'http://localhost:8081': {
          customHeaders: { Authorization: 'Bearer example' },
        },
      },
    },
  },
  // global defaults for all projects
  extensions: {
    languageService: {
      cacheSchemaFileForLookup: false,
      enableValidation: true,
    },
  },
};

You can specify any of these settings globally as above, or per project. Read the graphql-config docs to learn more about this!

For secrets (headers, urls, etc), you can import dotenv() and set a base path as you wish in your graphql-config file to pre-load process.env variables.

Troubleshooting notes

• you may need to manually restart the language server for some of these configurations to take effect
• graphql-config's multi-project support is not related to multi-root workspaces in vscode - in fact, each workspace can have multiple graphql config projects, which is what makes multi-root workspaces tricky to support. coming soon!

Workspace Configuration

The LSP Server reads config by sending workspace/configuration method when it initializes.

Note: We still do not support LSP multi-root workspaces but will tackle this very soon!

Many LSP clients beyond vscode offer ways to set these configurations, such as via initializationOptions in nvim.coc. The options are mostly designed to configure graphql-config's load parameters, the only thing we can't configure with graphql config. The final option can be set in graphql-config as well

Parameter	Default	Description
graphql-config.load.baseDir	workspace root or process.cwd()	the path where graphql config looks for config files
graphql-config.load.filePath	null	exact filepath of the config file.
graphql-config.load.configName	graphql	config name prefix instead of graphql
graphql-config.load.legacy	true	backwards compatibility with graphql-config@2
graphql-config.dotEnvPath	null	backwards compatibility with graphql-config@2
vscode-graphql.cacheSchemaFileForLookup	true if schema contains non-sdl files or urls	generate an SDL file based on your graphql-config schema configuration for schema definition lookup and other features. enabled by default when your schema config are urls or introspection json, or if you have any non-local SDL files in schema

all the graphql-config.load.* configuration values come from static loadConfig() options in graphql config.

(more coming soon!)

Architectural Overview

GraphQL Language Service currently communicates via Stream transport with the IDE server. GraphQL server will receive/send RPC messages to perform language service features, while caching the necessary GraphQL artifacts such as fragment definitions, GraphQL schemas etc. More about the server interface and RPC message format below.

The IDE server should launch a separate GraphQL server with its own child process for each .graphqlrc.yml file the IDE finds (using the nearest ancestor directory relative to the file currently being edited):

./application

  ./productA
    .graphqlrc.yml
    ProductAQuery.graphql
    ProductASchema.graphql

  ./productB
    .graphqlrc.yml
    ProductBQuery.graphql
    ProductBSchema.graphql

A separate GraphQL server should be instantiated for ProductA and ProductB, each with its own .graphqlrc.yml file, as illustrated in the directory structure above.

The IDE server should manage the lifecycle of the GraphQL server. Ideally, the IDE server should spawn a child process for each of the GraphQL Language Service processes necessary, and gracefully exit the processes as the IDE closes. In case of errors or a sudden halt the GraphQL Language Service will close as the stream from the IDE closes.

Server Interface

GraphQL Language Server uses JSON-RPC to communicate with the IDE servers. Microsoft's language server currently supports two communication transports: Stream (stdio) and IPC. For IPC transport, the reference guide to be used for development is the language server protocol documentation.

For each transport, there is a slight difference in JSON message format, especially in how the methods to be invoked are defined - below are the currently supported methods for each transport (will be updated as progress is made):

	Stream	IPC
Diagnostics	getDiagnostics	textDocument/publishDiagnostics
Autocompletion	getAutocompleteSuggestions	textDocument/completion
Outline	getOutline	textDocument/outline
Document Symbols	getDocumentSymbols	textDocument/symbols
Workspace Symbols	getWorkspaceSymbols	workspace/symbols
Go-to definition	getDefinition	textDocument/definition
Workspace Definition	getWorkspaceDefinition	workspace/definition
File Events	Not supported yet	didOpen/didClose/didSave/didChange events