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MessagePack Format

Description​

MessagePack is an efficient binary serialization format that's like JSON but faster and more compact. It's designed for efficient data exchange between systems and is widely used in distributed systems and APIs.

File Extensions​

  • .msgpack - MessagePack files
  • .mp - MessagePack files (alias)

Implementation Details​

Reading​

The MessagePack implementation:

  • Uses msgpack library for unpacking
  • Reads MessagePack data sequentially
  • Converts MessagePack data to Python objects
  • Supports streaming for large files

Writing​

Writing support:

  • Packs Python objects to MessagePack format
  • Writes binary data sequentially
  • Handles nested structures

Key Features​

  • Binary format: More compact than JSON
  • Fast serialization: Optimized for speed
  • Nested data: Supports complex nested structures
  • Type preservation: Maintains data types
  • Streaming: Can process large files efficiently

Usage​

from iterable import open_iterable

# Basic reading
with open_iterable('data.msgpack') as source:
    for row in source:
        print(row)

# Writing
with open_iterable('output.msgpack', mode='w') as dest:
    dest.write({'name': 'John', 'age': 30})

Parameters​

No specific parameters required.

Limitations​

  1. msgpack dependency: Requires msgpack package
  2. Binary format: Not human-readable
  3. File structure: Expects sequential MessagePack objects
  4. Type limitations: Some Python types may not serialize perfectly

Compression Support​

MessagePack files can be compressed with all supported codecs:

  • GZip (.msgpack.gz)
  • BZip2 (.msgpack.bz2)
  • LZMA (.msgpack.xz)
  • LZ4 (.msgpack.lz4)
  • ZIP (.msgpack.zip)
  • Brotli (.msgpack.br)
  • ZStandard (.msgpack.zst)

Use Cases​

  • API communication: Efficient data exchange
  • Distributed systems: Fast serialization for microservices
  • Caching: Compact storage format
  • Data pipelines: Efficient intermediate format

Error Handling​

  • Missing dependency: optional libraries raise ImportError with an install hint (pip install 'iterabledata[<extra>]' when an extra exists).
  • Write mode: read-only formats raise WriteNotSupportedError or ValueError when opened with mode="w".
  • Bad or unsupported input: may raise ValueError, OSError, or library-specific errors.
  • See Troubleshooting for decoding, detection, and engine issues.
  • JSON - Text-based format
  • BSON - MongoDB's binary format
  • CBOR - Another binary format