| 1 | import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js' |
| 2 | import { Progress } from '@modelcontextprotocol/sdk/types.js' |
| 3 | import { Logger } from '@nestjs/common' |
| 4 | import { ModuleRef } from '@nestjs/core' |
| 5 | import { Context, McpRequest, SerializableValue } from '../../interfaces' |
| 6 | import { McpRegistryService } from '../mcp-registry.service' |
| 7 | |
| 8 | export abstract class McpHandlerBase { |
| 9 | protected logger: Logger |
| 10 | |
| 11 | constructor( |
| 12 | protected readonly moduleRef: ModuleRef, |
| 13 | protected readonly registry: McpRegistryService, |
| 14 | loggerContext: string, |
| 15 | ) { |
| 16 | this.logger = new Logger(loggerContext) |
| 17 | } |
| 18 | |
| 19 | protected createContext( |
| 20 | mcpServer: McpServer, |
| 21 | mcpRequest: McpRequest, |
| 22 | ): Context { |
| 23 | // handless stateless traffic where notifications and progress are not supported |
| 24 | if (mcpServer.server.transport?.sessionId === undefined) { |
| 25 | return this.createStatelessContext(mcpServer, mcpRequest) |
| 26 | } |
| 27 | |
| 28 | const progressToken = mcpRequest.params?._meta?.progressToken |
| 29 | return { |
| 30 | reportProgress: async (progress: Progress) => { |
| 31 | if (progressToken) { |
| 32 | await mcpServer.server.notification({ |
| 33 | method: 'notifications/progress', |
| 34 | params: { |
| 35 | ...progress, |
| 36 | progressToken, |
| 37 | } as Progress, |
| 38 | }) |
| 39 | } |
| 40 | }, |
| 41 | log: { |
| 42 | debug: (message: string, context?: SerializableValue) => { |
| 43 | void mcpServer.server.sendLoggingMessage({ |
| 44 | level: 'debug', |
| 45 | data: { message, context }, |
| 46 | }) |
| 47 | }, |
| 48 | error: (message: string, context?: SerializableValue) => { |
| 49 | void mcpServer.server.sendLoggingMessage({ |
| 50 | level: 'error', |
| 51 | data: { message, context }, |
| 52 | }) |
| 53 | }, |
| 54 | info: (message: string, context?: SerializableValue) => { |
| 55 | void mcpServer.server.sendLoggingMessage({ |
| 56 | level: 'info', |
| 57 | data: { message, context }, |
| 58 | }) |
| 59 | }, |
| 60 | warn: (message: string, context?: SerializableValue) => { |
| 61 | void mcpServer.server.sendLoggingMessage({ |
| 62 | level: 'warning', |
| 63 | data: { message, context }, |
| 64 | }) |
| 65 | }, |
| 66 | }, |
| 67 | mcpServer, |
| 68 | mcpRequest, |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | protected createStatelessContext( |
| 73 | mcpServer: McpServer, |
| 74 | mcpRequest: McpRequest, |
| 75 | ): Context { |
| 76 | const warn = (fn: string) => { |
| 77 | this.logger.warn(`Stateless context: '${fn}' is not supported.`) |
| 78 | } |
| 79 | return { |
| 80 | reportProgress: async (_progress: Progress) => { |
| 81 | warn('reportProgress not supported in stateless') |
| 82 | }, |
| 83 | log: { |
| 84 | debug: (_message: string, _data?: SerializableValue) => { |
| 85 | warn('server report logging not supported in stateless') |
| 86 | }, |
| 87 | error: (_message: string, _data?: SerializableValue) => { |
| 88 | warn('server report logging not supported in stateless') |
| 89 | }, |
| 90 | info: (_message: string, _data?: SerializableValue) => { |
| 91 | warn('server report logging not supported in stateless') |
| 92 | }, |
| 93 | warn: (_message: string, _data?: SerializableValue) => { |
| 94 | warn('server report logging not supported in stateless') |
| 95 | }, |
| 96 | }, |
| 97 | mcpServer, |
| 98 | mcpRequest, |
| 99 | } |
| 100 | } |
| 101 | } |
| 102 |