MCP Fetch

import { GraphQLClient, gql } from "graphql-request" import { getIntrospectionQuery, buildClientSchema, printSchema } from "graphql" import { schemaCache } from "./index" // Get schema with caching export async function getSchema( endpoint: string, headers: Record<string, string>, useCache: boolean, cacheTTL: number ): Promise<any> { const cacheKey = `${endpoint}:${JSON.stringify(headers)}` // Check cache if (useCache) { const cached = schemaCache.get(cacheKey) if (cached && Date.now() - cached.timestamp < cacheTTL) { return cached.schema } } // Fetch schema const client = new GraphQLClient(endpoint, { headers }) const introspectionQuery = getIntrospectionQuery() const result = await client.request(gql`${introspectionQuery}`) // The result should already be in the correct format for buildClientSchema // Cache the entire result schemaCache.set(cacheKey, { schema: result, timestamp: Date.now(), }) return result } // Handle full schema request export function handleFullSchema(schema: any): string { const schemaSDL = printSchema(schema) return JSON.stringify({ success: true, schemaSDL, stats: { totalTypes: schema.getTypeMap ? Object.keys(schema.getTypeMap()).length : 0, } }, null, 2) } // Handle list operations request export function handleListOperations(schema: any): string { const queryType = schema.getQueryType() const mutationType = schema.getMutationType() const subscriptionType = schema.getSubscriptionType() const operations = { queries: queryType ? Object.keys(queryType.getFields()) : [], mutations: mutationType ? Object.keys(mutationType.getFields()) : [], subscriptions: subscriptionType ? Object.keys(subscriptionType.getFields()) : [], } // Get detailed info for each operation const detailedOperations = { queries: queryType ? getOperationDetails(queryType) : [], mutations: mutationType ? getOperationDetails(mutationType) : [], subscriptions: subscriptionType ? getOperationDetails(subscriptionType) : [], } return JSON.stringify({ success: true, operations, detailedOperations, stats: { totalQueries: operations.queries.length, totalMutations: operations.mutations.length, totalSubscriptions: operations.subscriptions.length, } }, null, 2) } // Get detailed operation information function getOperationDetails(type: any) { const fields = type.getFields() return Object.entries(fields).map(([name, field]: [string, any]) => ({ name, description: field.description, args: field.args.map((arg: any) => ({ name: arg.name, type: arg.type.toString(), description: arg.description, defaultValue: arg.defaultValue, })), returnType: field.type.toString(), })) } // Handle get type request export function handleGetType(schema: any, typeName: string): string { const type = schema.getType(typeName) if (!type) { return JSON.stringify({ success: false, error: `Type '${typeName}' not found in schema`, }, null, 2) } // Get type details based on type kind let typeDetails: any = { name: type.name, description: type.description, kind: type.constructor.name, } // Add fields for object types if (type.getFields) { const fields = type.getFields() typeDetails.fields = Object.entries(fields).map(([fieldName, field]: [string, any]) => ({ name: fieldName, description: field.description, type: field.type.toString(), args: field.args?.map((arg: any) => ({ name: arg.name, type: arg.type.toString(), description: arg.description, })) || [], })) } // Add values for enum types if (type.getValues) { typeDetails.values = type.getValues().map((value: any) => ({ name: value.name, description: value.description, deprecationReason: value.deprecationReason, })) } // Add possible types for interfaces and unions if (type.getPossibleTypes) { typeDetails.possibleTypes = type.getPossibleTypes().map((t: any) => t.name) } return JSON.stringify({ success: true, type: typeDetails, }, null, 2) } // Main introspection function export async function introspectGraphQL( endpoint: string, headers: Record<string, string> = {}, action: string, typeName?: string, useCache: boolean = true, cacheTTL: number = 300000 ): Promise<string> { try { // Get schema (from cache or fetch) const introspectionData = await getSchema(endpoint, headers, useCache, cacheTTL) // Build schema from introspection result const schema = buildClientSchema(introspectionData) switch (action) { case "full-schema": return handleFullSchema(schema) case "list-operations": return handleListOperations(schema) case "get-type": if (!typeName) { return JSON.stringify({ success: false, error: "typeName is required when action is 'get-type'", }, null, 2) } return handleGetType(schema, typeName) default: return JSON.stringify({ success: false, error: `Unknown action: ${action}`, }, null, 2) } } catch (error) { return JSON.stringify({ success: false, error: error instanceof Error ? error.message : "Unknown error occurred", errorType: error instanceof Error && error.message.includes("Network") ? "NetworkError" : "IntrospectionError", endpoint, }, null, 2) } }