Skip to main content

EML Format (Email)

Description​

EML (Email) format represents a single email message in RFC 822 format. EML files contain email headers and body content, and may include attachments. Each EML file typically represents one email message.

File Extensions​

  • .eml - Email message files

Implementation Details​

Reading​

The EML implementation:

  • Uses Python's built-in email module
  • Parses RFC 822 email format
  • Extracts email headers (From, To, Subject, Date, etc.)
  • Handles email body (text and HTML)
  • Extracts attachments
  • Converts email to dictionary

Writing​

Writing support:

  • Builds an RFC 822 message from header fields (from, to, subject, …)
  • Uses body or body_text as the message content

Key Features​

  • Email format: Single email message format
  • Header extraction: Extracts all email headers
  • Body handling: Handles text and HTML body
  • Attachment support: Extracts attachment information
  • Date parsing: Parses email dates

Usage​

from iterable import open_iterable

# Basic reading
with open_iterable('message.eml') as source:
    for email in source:
        print(email)  # Contains email headers and body

# Writing
with open_iterable('output.eml', mode='w') as dest:
    dest.write({
        'from': 'a@example.com',
        'to': 'b@example.com',
        'subject': 'Hello',
        'body': 'Message text',
    })

Parameters​

  • encoding (str): File encoding (default: utf8)

Limitations​

  1. Single message: Each file typically contains one email
  2. Email focus: Designed for email data, not general data
  3. Complex structure: Email structure can be complex with multipart content

Compression Support​

EML files can be compressed with all supported codecs:

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

Use Cases​

  • Email processing: Processing individual email messages
  • Email archiving: Archiving email messages
  • Email analysis: Analyzing email content
  • Data migration: Migrating email data

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.
  • MBOX - Mailbox format (multiple emails)
  • MHTML - Web archive format