EML — RFC 2231 Continuation Filename With size and creation-date
The conformant answer to non-ASCII filenames: a filename split into three numbered RFC 2231 segments with a charset and a language tag, plus size and creation-date parameters. Parsers commonly handle filename*= but not the numbered continuation form.
From: Meridian Ops <ops@meridiansupply.example>
To: Sam Rivera <sam@meridiansupply.example>
Subject: RFC 2231 continuation filename
Date: Fri, 13 Feb 2026 11:15:00 -0800
Message-ID: <p7-disp-2231@brightside.example>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="=_p7_disp_2231"
--=_p7_disp_2231
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
The attachment's filename is split into three RFC 2231 segments.
--=_p7_disp_2231
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
filename*0*=utf-8'de'Quartalsbericht%20;
filename*1*=Gr%C3%B6%C3%9Fe%20;
filename*2*=SAMPLE.txt;
size=69;
creation-date="Fri, 13 Feb 2026 11:15:00 -0800"
UXVhcnRhbHNiZXJpY2h0IChTQU1QTEUpDQpRMSAyMDI2IHN1cHBseSB2b2x1bWVzLg0KTm8gcmVh
bCBmaWd1cmVzLg0K
--=_p7_disp_2231--
Specifications
- Wave
- p7
- Seed
- 20260807
- Structure
- multipart/mixed
- Parameter Encoding
- RFC 2231
- Filename Segments
- 3
- Charset
- utf-8
- Language
- de
- Decoded Filename
- Quartalsbericht Größe SAMPLE.txt
- Size Param
- 69
- Line Endings
- CRLF (RFC 5322)
Testing contract
Expected to pass- Scenario
- Reassemble an RFC 2231 filename delivered as three numbered, percent-encoded segments carrying charset and language tags.
- Expected result
- The attachment saves as "Quartalsbericht Größe SAMPLE.txt"; the size parameter matches the decoded part length exactly.
What is a .eml file?
An EML file is a single email message stored in the RFC 822 / MIME format — plain-text headers (From, To, Subject, Date, Message-ID) followed by the body, which may be plain text, HTML, or a multipart structure with alternative bodies and file attachments encoded in base64.
How to use this file
Use an example EML to test email header parsing, MIME decoding, HTML-part handling, attachment extraction, and EML-to-other-format conversion.
How to use this file for testing
“EML — RFC 2231 Continuation Filename With size and creation-date” is a deterministic Novus Examples fixture for Email parsing, Encoding detection, Internationalization. Standards-compliant RFC 822 messages — plain, multipart text+HTML, and with an attachment — plus an MBOX mailbox, for testing header parsing, MIME decoding, attachment extraction, and mailbox splitting.
Documented properties for this file: seed 20260807 · de · CRLF (RFC 5322). Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Email fixtures use fixed dates, message IDs, and MIME boundaries so runs are reproducible, and every address is fictional. Test header parsing, MIME decoding, attachment extraction, and EML/MBOX conversion against the documented structure.
Code examples
from email import policy
from email.parser import BytesParser
msg = BytesParser(policy=policy.default).parse(open("disposition-rfc2231-continuation.eml", "rb"))
print(msg["subject"], msg["from"])Related files
- emlEML — UTF-8 Filename AttachmentAn attachment whose filename uses RFC 2231 UTF-8 encoding (résumé) — for MIME filename decoders.
- emlEML — Adjacent Encoded-Words (Separator Must Disappear)A Subject split mid-word across two adjacent encoded-words. RFC 2047 requires the linear whitespace between them to be discarded, so the correct result is one word; a decoder that keeps the space renders a split that reads as a typo.
- emlEML — Encoded-Word Longer Than the 75-Character LimitOne unbroken encoded-word of 148 characters, well past the 75-character ceiling RFC 2047 sets. Real senders emit these, and a decoder should still recover the whole word rather than truncating it at 75 or rejecting the header.
- emlEML — Encoded-Word Subject Folded Over Four LinesA Subject folded across four physical lines, one encoded-word per line, which is the shape RFC 2047 prescribes for long international headers. Because the fold whitespace is discarded on decode, each continuation word carries its own leading space inside the encoded-word — omit that and the subject decodes run-together.
- emlEML — Encoded-Words in Display Names and a FilenameEncoded-words used everywhere they turn up in practice: both display names, the Subject, and — against the spec but very common — inside the quoted filename parameter, where RFC 2231 is the conformant mechanism. A tolerant parser decodes all four.
- emlEML — RFC 2047 Subject Mixing Three CharsetsA single Subject built from three encoded-words in three charsets and two encodings. RFC 2047 allows this, and it is what happens when a subject is quoted through several mail systems, so each word has to be decoded on its own terms.
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