db-mcp-tool

Implementation Reference

• src/index.ts:53-71 (handler)

  Inline handler for the !pg tool that initializes a PostgreSQL DatabaseService and connects to the database.

  async (args: { connection: DatabaseConnectionConfig }) => {
    try {
      const config: DatabaseConfig = {
        type: 'postgres',
        connection: args.connection
      };
      dbService = new DatabaseService(config);
      await dbService.connect();
      return {
        content: [{ type: "text", text: "Successfully connected to PostgreSQL database!" }],
      };
    } catch (error: unknown) {
      const errorMessage = error instanceof Error ? error.message : 'Unknown error';
      return {
        content: [{ type: "text", text: `PostgreSQL connection error: ${errorMessage}` }],
        isError: true,
      };
    }
  }

• src/index.ts:50-72 (registration)

  Registration of the !pg tool on the MCP server with its schema and handler function.

  server.tool(
    "!pg",
    postgresConnectionSchema,
    async (args: { connection: DatabaseConnectionConfig }) => {
      try {
        const config: DatabaseConfig = {
          type: 'postgres',
          connection: args.connection
        };
        dbService = new DatabaseService(config);
        await dbService.connect();
        return {
          content: [{ type: "text", text: "Successfully connected to PostgreSQL database!" }],
        };
      } catch (error: unknown) {
        const errorMessage = error instanceof Error ? error.message : 'Unknown error';
        return {
          content: [{ type: "text", text: `PostgreSQL connection error: ${errorMessage}` }],
          isError: true,
        };
      }
    }
  );

• src/index.ts:22-30 (schema)

  Zod schema defining input parameters for PostgreSQL connection.

  const postgresConnectionSchema = {
    connection: z.object({
      host: z.string(),
      port: z.number().optional(),
      database: z.string(),
      user: z.string(),
      password: z.string(),
    }),
  };

• src/services/database.ts:16-35 (helper)

  DatabaseService.connect() method implementation, specifically the PostgreSQL connection logic (lines 18-22).

  async connect(): Promise<void> {
      switch (this.config.type) {
          case 'postgres': {
              const config = this.config.connection as any;
              this.postgresClient = new pg.Client(config);
              await this.postgresClient.connect();
              break;
          }
          case 'mysql': {
              const config = this.config.connection as any;
              this.mysqlConnection = await mysql.createConnection(config);
              break;
          }
          case 'firestore': {
              const config = this.config.connection as any;
              this.firestoreClient = new Firestore(config);
              break;
          }
      }
  }

• src/types/database.ts:3-13 (schema)

  TypeScript interface for database connection config used by !pg schema.

  export interface DatabaseConnectionConfig {
      // PostgreSQL ve MySQL için
      host?: string;
      port?: number;
      database?: string;
      user?: string;
      password?: string;
      // Firestore için
      projectId?: string;
      keyFilename?: string;
  }