fileserver

File Server Example

An MCP server that demonstrates resource registration and resource templates.

What This Example Demonstrates

• Resource registration with static URIs
• Resource templates with URI parameters
• Reading directory contents
• Reading specific files
• Security considerations (path traversal prevention)
• Resource read metrics

Resources

1. Examples Directory

• URI: file:///examples
• Description: Lists all examples in the examples directory
• Format: Plain text directory listing

2. Example File (Template)

• URI: file:///examples/{filename}
• Description: Read a specific example's README
• Format: Plain text file content
• Example: file:///examples/hello reads hello/README.md

Running the Example

cd examples/fileserver
go run main.go

Testing with MCP Inspector

mcp-inspector go run main.go

Then use the resource browser to:

1. View file:///examples to see all examples
2. View file:///examples/hello to read the hello example's README

Security Notes

This example includes basic security measures:

• Path traversal prevention
• Restricts access to examples directory only
• Validates filename format

In a production server, you should add:

• More robust URI parsing
• Authentication/authorization
• Rate limiting
• Input validation
• Logging of access attempts

Implementation Details

Resource vs Resource Template

• Resource: Fixed URI, like file:///examples
• Resource Template: Parameterized URI, like file:///examples/{filename}

URI Template Parsing

This example uses a simplified URI parsing approach. For production use, implement proper URI template parsing according to RFC 6570.

Next Steps

• Add write operations (as tools, not resources)
• Support more file types with appropriate MIME types
• Add resource listing capabilities
• Implement proper URI template parsing
• Add authentication

See the main README for more information about building MCP servers.