Add support for base64 encoded credentials

[sam-at-luther]

Summary

This PR adds support for base64 encoded credentials passed as environment variables, enabling better containerized deployments without file system dependencies.

Changes

Added Environment Variables

• ****: Base64 encoded OAuth client credentials (gcp-oauth.keys.json)
• ****: Base64 encoded user OAuth tokens (.gdrive-server-credentials.json)

Implementation

• Added decodeBase64Json() helper function to decode and parse base64 JSON strings
• Updated loadCredentialsAndRunServer() to check for base64 env vars before falling back to file paths
• Maintains full backwards compatibility with existing file-based approach

Documentation

• Added comprehensive section in README about base64 credential usage
• Included examples for generating base64 encoded credentials
• Documented environment variable priority order

Benefits

1. Better containerized deployments: No file system dependencies
2. Simplified secrets management: Credentials can be injected as env vars from secret stores
3. Consistent with Google Sheets connector: Aligns with the base64 pattern used in mcp-server-google-sheets
4. Backwards compatible: Existing deployments continue to work without changes

Testing

✅ Build successful
✅ TypeScript compilation passed
✅ Backwards compatible with existing file-based credentials

Environment Variable Priority

OAuth Client Credentials:

1. (base64 encoded)
2. (file path)
3. Default: credentials/gcp-oauth.keys.json

User Credentials:

1. (base64 encoded)
2. (file path)
3. Default: credentials/.gdrive-server-credentials.json

Example Usage

# Generate base64 encoded credentials
base64 < credentials/gcp-oauth.keys.json | tr -d '\n'
base64 < credentials/.gdrive-server-credentials.json | tr -d '\n'

# Use in environment
export OAUTH_CREDENTIALS_JSON_B64="ewogICJpbnN0YWxsZWQi..."
export GDRIVE_CREDENTIALS_JSON_B64="ewogICJhY2Nlc3NfdG9rZW4i..."
node dist/index.js

Related

• Part of a broader effort to support base64 credentials across all MCP connectors
• Similar to: Add support for CREDENTIALS_JSON_B64 and TOKEN_JSON_B64 environment variables mcp-server-google-sheets#2