Encode a file’s contents as Base64 text

Summary

The base64 macro reads a file and returns its contents encoded as a Base64 string. This is useful for embedding binary content or file data directly in text-based configuration files.

Syntax 

${base64;<file>[;fileSizeLimit]}

Parameters

  • file - Path to the file to encode (relative to the project directory)
  • fileSizeLimit (optional) - Maximum file size in bytes (default: 100,000 bytes)

Behavior

  • Reads the entire file into memory
  • Encodes the file contents as Base64
  • Enforces a size limit to prevent memory issues with large files
  • Throws an exception if the file exceeds the size limit
  • File path is resolved relative to the current project directory

Examples

Encode a small binary file:

${base64;resources/icon.png}

Encode with custom size limit (1MB):

${base64;data/config.bin;1000000}

Embed a certificate in a property:

certificate.data=${base64;certs/ca-cert.pem}

Use Cases

  • Embedding small binary resources in manifest files
  • Including certificates or keys in configuration
  • Encoding binary data for transmission in text formats
  • Creating data URIs for embedded content
  • Storing binary configuration data in properties files

Notes

  • Default size limit is 100,000 bytes to prevent memory exhaustion
  • For large files, consider referencing the file path instead of embedding
  • The encoded output will be approximately 33% larger than the original file

See test cases in MacroTestsForDocsExamples.java