rnr-mcp-server
Version:
A Model Context Protocol (MCP) server for React Native Reusables components, providing AI assistants with access to component source code, demos, and metadata for React Native development.
271 lines (270 loc) • 12 kB
JavaScript
/**
* Request handler setup for the Model Context Protocol (MCP) server.
*
* This file configures how the server responds to various MCP requests by setting up
* handlers for resources, resource templates, tools, and prompts.
*
* Updated for MCP SDK 1.16.0 with improved error handling and request processing.
*/
import { CallToolRequestSchema, ListResourcesRequestSchema, ListResourceTemplatesRequestSchema, ReadResourceRequestSchema, ListToolsRequestSchema, GetPromptRequestSchema, ListPromptsRequestSchema } from "@modelcontextprotocol/sdk/types.js";
import { resourceHandlers, resources } from "./resources.js";
import { promptHandlers, prompts } from "./prompts.js";
import { toolHandlers } from "./tools/index.js";
import { getResourceTemplate, resourceTemplates, } from "./resource-templates.js";
import { z } from "zod";
import { validateAndSanitizeParams } from './utils/validation.js';
import { circuitBreakers } from './utils/circuit-breaker.js';
import { logError, logInfo } from './utils/logger.js';
// Define basic component schemas here for tool validation
const componentSchema = { componentName: z.string() };
const searchSchema = { query: z.string() };
const themesSchema = { query: z.string().optional() };
const blocksSchema = {
query: z.string().optional(),
category: z.string().optional()
};
/**
* Wrapper function to handle requests with simple error handling
*/
async function handleRequest(method, params, handler) {
try {
// Validate and sanitize input parameters
const validatedParams = validateAndSanitizeParams(method, params);
// Execute the handler with circuit breaker protection for external calls
const result = await circuitBreakers.external.execute(() => handler(validatedParams));
return result;
}
catch (error) {
logError(`Error in ${method}`, error);
throw error;
}
}
/**
* Sets up all request handlers for the MCP server
* Following MCP SDK 1.16.0 best practices for handler registration
* @param server - The MCP server instance
*/
export const setupHandlers = (server) => {
logInfo('Setting up request handlers...');
// List available resources when clients request them
server.setRequestHandler(ListResourcesRequestSchema, async (request) => {
return await handleRequest('list_resources', request.params, async () => ({ resources }));
});
// Resource Templates
server.setRequestHandler(ListResourceTemplatesRequestSchema, async (request) => {
return await handleRequest('list_resource_templates', request.params, async () => ({ resourceTemplates }));
});
// List available tools
server.setRequestHandler(ListToolsRequestSchema, async (request) => {
return await handleRequest('list_tools', request.params, async () => {
// Return the tools that are registered with the server
const registeredTools = [
{
name: 'get_component',
description: 'Get the source code for a specific React Native Reusables component',
inputSchema: {
type: 'object',
properties: {
componentName: {
type: 'string',
description: 'Name of the React Native Reusables component (e.g., "accordion", "button")',
},
},
required: ['componentName'],
},
},
{
name: 'get_component_demo',
description: 'Get demo code illustrating how a React Native Reusables component should be used',
inputSchema: {
type: 'object',
properties: {
componentName: {
type: 'string',
description: 'Name of the React Native Reusables component (e.g., "accordion", "button")',
},
},
required: ['componentName'],
},
},
{
name: 'list_components',
description: 'Get all available React Native Reusables components',
inputSchema: {
type: 'object',
properties: {},
},
},
{
name: 'get_component_metadata',
description: 'Get metadata for a specific React Native Reusables component',
inputSchema: {
type: 'object',
properties: {
componentName: {
type: 'string',
description: 'Name of the React Native Reusables component (e.g., "accordion", "button")',
},
},
required: ['componentName'],
},
},
{
name: 'get_directory_structure',
description: 'Get the directory structure of the React Native Reusables repository',
inputSchema: {
type: 'object',
properties: {
path: {
type: 'string',
description: 'Path within the repository (default: packages/ui/src)',
},
owner: {
type: 'string',
description: 'Repository owner (default: "mrzachnugent")',
},
repo: {
type: 'string',
description: 'Repository name (default: "react-native-reusables")',
},
branch: {
type: 'string',
description: 'Branch name (default: "main")',
},
},
},
},
{
name: 'get_block',
description: 'Get source code for a specific React Native Reusables block (e.g., calendar-01, dashboard-01)',
inputSchema: {
type: 'object',
properties: {
blockName: {
type: 'string',
description: 'Name of the block (e.g., "calendar-01", "dashboard-01", "login-02")',
},
includeComponents: {
type: 'boolean',
description: 'Whether to include component files for complex blocks (default: true)',
},
},
required: ['blockName'],
},
},
{
name: 'list_blocks',
description: 'Get all available React Native Reusables blocks with categorization',
inputSchema: {
type: 'object',
properties: {
category: {
type: 'string',
description: 'Filter by category (calendar, dashboard, login, sidebar, products)',
},
},
},
},
];
return { tools: registeredTools };
});
});
// Return resource content when clients request it
server.setRequestHandler(ReadResourceRequestSchema, async (request) => {
return await handleRequest('read_resource', request.params, async (validatedParams) => {
const { uri } = validatedParams;
// Check if this is a static resource
const resourceHandler = resourceHandlers[uri];
if (resourceHandler) {
const result = await Promise.resolve(resourceHandler());
return {
contentType: result.contentType,
contents: [{
uri: uri,
text: result.content
}]
};
}
// Check if this is a generated resource from a template
const resourceTemplateHandler = getResourceTemplate(uri);
if (resourceTemplateHandler) {
const result = await Promise.resolve(resourceTemplateHandler());
return {
contentType: result.contentType,
contents: [{
uri: uri,
text: result.content
}]
};
}
throw new Error(`Resource not found: ${uri}`);
});
});
// List available prompts
server.setRequestHandler(ListPromptsRequestSchema, async (request) => {
return await handleRequest('list_prompts', request.params, async () => ({ prompts: Object.values(prompts) }));
});
// Get specific prompt content with optional arguments
server.setRequestHandler(GetPromptRequestSchema, async (request) => {
return await handleRequest('get_prompt', request.params, async (validatedParams) => {
const { name, arguments: args } = validatedParams;
const promptHandler = promptHandlers[name];
if (!promptHandler) {
throw new Error(`Prompt not found: ${name}`);
}
return promptHandler(args);
});
});
// Tool request Handler - executes the requested tool with provided parameters
server.setRequestHandler(CallToolRequestSchema, async (request) => {
return await handleRequest('call_tool', request.params, async (validatedParams) => {
const { name, arguments: params } = validatedParams;
if (!name || typeof name !== 'string') {
throw new Error("Tool name is required");
}
const handler = toolHandlers[name];
if (!handler) {
throw new Error(`Tool not found: ${name}`);
}
// Execute handler with circuit breaker protection
const result = await circuitBreakers.external.execute(() => Promise.resolve(handler(params || {})));
return result;
});
});
// Add global error handler
server.onerror = (error) => {
logError('MCP server error', error);
};
logInfo('Handlers setup complete');
};
/**
* Get Zod schema for tool validation if available
* Following MCP SDK 1.16.0 best practices for schema validation
* @param toolName Name of the tool
* @returns Zod schema or undefined
*/
function getToolSchema(toolName) {
try {
switch (toolName) {
case 'get_component':
case 'get_component_details':
return z.object(componentSchema);
case 'get_examples':
return z.object(componentSchema);
case 'get_usage':
return z.object(componentSchema);
case 'search_components':
return z.object(searchSchema);
case 'get_themes':
return z.object(themesSchema);
case 'get_blocks':
return z.object(blocksSchema);
default:
return undefined;
}
}
catch (error) {
logError('Schema error', error);
return undefined;
}
}