MCP-MongoDB-MySQL-Server

Instructions

Implementation Reference

• src/index.ts:607-660 (handler)

  The primary handler function for the 'connect_db' tool. Parses connection arguments (URL, workspace, or direct params), closes any existing connection, sets the config, ensures connection, and returns success message.

  private async handleConnectDb(args: any) {
    let config: ConnectionConfig | null = null;
  
    // Priority 1: Direct URL
    if (args.url) {
      config = this.parseConnectionUrl(args.url);
    }
    // Priority 2: Workspace config
    else if (args.workspace) {
      this.currentWorkspace = args.workspace;
      config = await this.loadWorkspaceConfig(args.workspace);
    }
    // Priority 3: Individual connection params
    else if (args.host && args.user && args.password && args.database) {
      config = {
        host: args.host,
        user: args.user,
        password: args.password,
        database: args.database
      };
    }
  
    if (!config) {
      throw new McpError(
        ErrorCode.InvalidParams,
        'No valid database configuration provided. Please provide either a URL, workspace path, or connection parameters.'
      );
    }
  
    // Close existing connection if any
    if (this.connection) {
      await this.connection.end();
      this.connection = null;
    }
  
    this.config = config;
  
    try {
      await this.ensureConnection();
      return {
        content: [
          {
            type: 'text',
            text: `Successfully connected to database ${config.database} at ${config.host}`
          }
        ]
      };
    } catch (error) {
      throw new McpError(
        ErrorCode.InternalError,
        `Failed to connect to database: ${getErrorMessage(error)}`
      );
    }
  }

• src/index.ts:211-231 (schema)

  Input schema definition for the 'connect_db' tool, specifying optional properties for URL, workspace, or individual connection parameters.

  inputSchema: {
    type: 'object',
    properties: {
      url: {
        type: 'string',
        description: 'Database URL (mysql://user:pass@host:port/db)',
        optional: true
      },
      workspace: {
        type: 'string',
        description: 'Project workspace path',
        optional: true
      },
      // Keep existing connection params as fallback
      host: { type: 'string', optional: true },
      user: { type: 'string', optional: true },
      password: { type: 'string', optional: true },
      database: { type: 'string', optional: true }
    },
    // No required fields - will try different connection methods
  },

• src/index.ts:208-232 (registration)

  Tool registration in the ListTools response, including name, description, and input schema for 'connect_db'.

  {
    name: 'connect_db',
    description: 'Connect to MySQL database using URL or config',
    inputSchema: {
      type: 'object',
      properties: {
        url: {
          type: 'string',
          description: 'Database URL (mysql://user:pass@host:port/db)',
          optional: true
        },
        workspace: {
          type: 'string',
          description: 'Project workspace path',
          optional: true
        },
        // Keep existing connection params as fallback
        host: { type: 'string', optional: true },
        user: { type: 'string', optional: true },
        password: { type: 'string', optional: true },
        database: { type: 'string', optional: true }
      },
      // No required fields - will try different connection methods
    },
  },

• src/index.ts:537-538 (registration)

  Dispatch registration in the CallToolRequestHandler switch statement, routing 'connect_db' calls to the handleConnectDb method.

  case 'connect_db':
    return await this.handleConnectDb(request.params.arguments);

• src/index.ts:662-688 (helper)

  Helper function to parse MySQL connection URL into config object, used by handleConnectDb.

  private parseConnectionUrl(url: string): ConnectionConfig {
    const parsed = parseUrl(url);
    if (!parsed.host || !parsed.auth) {
      throw new McpError(
        ErrorCode.InvalidParams,
        'Invalid connection URL'
      );
    }
  
    const [user, password] = parsed.auth.split(':');
    const database = parsed.pathname?.slice(1);
  
    if (!database) {
      throw new McpError(
        ErrorCode.InvalidParams,
        'Database name must be specified in URL'
      );
    }
  
    return {
      host: parsed.hostname!,
      user,
      password: password || '',
      database,
      ssl: parsed.protocol === 'mysqls:' ? { rejectUnauthorized: true } : undefined
    };
  }