Network Working Group M. Rankin Internet-Draft 16 September 2024 Intended status: Informational Expires: 20 March 2025 Common Format and Media Type for Control-Character-Separated Values (CCSV) Files draft-rankin-ccsv-02 Abstract This document establishes the format used for Control-Character- Separated Values (CCSV) files and registers the associated MIME type "text/ccsv". About This Document This note is to be removed before publishing as an RFC. The latest revision of this draft can be found at https://oldgrognard.github.io/ccsv-id/draft-rankin-ccsv.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-rankin-ccsv/. Source for this draft and an issue tracker can be found at https://github.com/oldgrognard/ccsv-id. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 20 March 2025. Rankin Expires 20 March 2025 [Page 1] Internet-Draft CCSV September 2024 Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 2.1. Definition of the CCSV format . . . . . . . . . . . . . . 3 2.1.1. Formatting Rules . . . . . . . . . . . . . . . . . . 3 3. Encoding Considerations . . . . . . . . . . . . . . . . . . . 4 3.1. Why UTF-8? . . . . . . . . . . . . . . . . . . . . . . . 4 3.1.1. Compatibility . . . . . . . . . . . . . . . . . . . . 4 3.1.2. Internationalization . . . . . . . . . . . . . . . . 4 3.1.3. Efficiency . . . . . . . . . . . . . . . . . . . . . 4 3.1.4. Standardization . . . . . . . . . . . . . . . . . . . 4 3.1.5. Future-Proofing . . . . . . . . . . . . . . . . . . . 5 4. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. Interoperability Considerations . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. Normative References . . . . . . . . . . . . . . . . . . . . 6 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction A CCSV (Control-Character-Separated Values file) is a file format that enables moving data between spreadsheets, statistical analysis programs, databases, and any other program that works with rectangular data. It is very similar to (CSV) Comma-Separated Values files [RFC4180], (TSV) Tab-Separated Values files, and their derivatives. Unlike those file types, the CCSV minimizes usage ambiguity by having non-printable characters as delimiters. The two delimiter characters may not appear in the document's text, making the practice of escaping certain characters or adding additional delimiters for certain strings unnecessary. This document seeks to define the format of Control Character Separated Values (CCSV) files and formally register the "text/ccsv" Media Type for CCSV in Rankin Expires 20 March 2025 [Page 2] Internet-Draft CCSV September 2024 accordance with [RFC6838]. 2. Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2.1. Definition of the CCSV format In order for a file to be a CCSV, it MUST adhere to the following formatting rules: 2.1.1. Formatting Rules 1. The file MUST use UTF-8 encoding. Since US-ASCII is a subset of UTF-8, programs may create CCSV files with that encoding. A consuming program may not be able to interpret all characters if it only works with US-ASCII and SHOULD work with UTF-8 if the source is unknown. 2. The file MUST NOT begin with a Byte Order Mark (U+FEFF). 3. A CCSV MUST begin with a header. The header consists of the names of the columns separated with US (U+001F) entities. 4. A Unit Separator US (U+001F) is used between each field in a record. Note that carriage returns and line feeds are not part of the delimiter and are valid characters in the body of a field. 5. A Record Separator RS (U+001E) is used between each record in the file including the header. 6. A Record Separator RS (U+001E) MAY appear as the last entity of the last record but is NOT RECOMMENDED. 7. The header and each record, if any, MUST contain the same number of US (U+001F) entities. Consequently, the header and every record will have the same number of fields. 8. Empty fields are represented by consecutive delimiters. 9. The US (U+001F) entity and the RS (U+001E) entity MUST NOT appear in the body of a field. The ABNF grammar [STD68] appears as follows: Rankin Expires 20 March 2025 [Page 3] Internet-Draft CCSV September 2024 file = header RS *(record RS) [record] header = name *( US name ) record = field *( US field ) name = field field = *VCHAR VCHAR = %x00-1D / %x20-D7FF / %xE000-10FFFF ; all characters except the designated delimiters and surrogates RS = %x1E ; record separator US = %x1F ; unit separator 3. Encoding Considerations CCSV files MUST be encoded using UTF-8 [RFC3629]. Implementations MUST NOT add a byte order mark (U+FEFF) to the beginning of the file or networked-transmitted text. 3.1. Why UTF-8? 3.1.1. Compatibility UTF-8 is widely supported across different platforms, operating systems, and languages. This ensures that CCSV files can be opened and read correctly regardless of the environment they are used in. 3.1.2. Internationalization UTF-8 supports a vast range of characters from various languages, including those that use non-Latin scripts. This is crucial for data that might include international names, addresses, or other text in multiple languages, ensuring that all characters are preserved and displayed correctly. 3.1.3. Efficiency UTF-8 is a variable-width encoding scheme that uses 1 to 4 bytes for each character. It is efficient for encoding text that is primarily in English, as it uses only one byte for the most common characters, but can still accommodate characters from other languages when needed. 3.1.4. Standardization By requiring UTF-8, the CCSV format ensures a standard way of encoding text, which simplifies processing, parsing, and exchanging files. It helps in avoiding the complexities and potential errors that can arise from dealing with multiple encodings. Rankin Expires 20 March 2025 [Page 4] Internet-Draft CCSV September 2024 3.1.5. Future-Proofing As the internet and technologies continue to evolve, UTF-8 remains a robust and forward-compatible choice, ensuring that CCSV files remain accessible and usable in the long term 4. Security Considerations CCSV files alone are considered relatively harmless as there is no additional prescribed processing. However, the file may be parsed and further processed by the recipient. To the extent that a receiving application executes arbitrary system level commands from strings contained in a CCSV file, they may be at risk. 5. Interoperability Considerations Adherence to the Formatting Rules Section 2.1.1 and the Encoding Considerations Section 3 ensures a high level of interoperability. 6. IANA Considerations This section provides the media-type registration application (as per [RFC6838]). Type name: text Subtype name: ccsv Required parameters: N/A Optional parameters: N/A Encoding considerations: See Section 3 Security considerations: See Section 4 Interoperability considerations: See Section 5 Published specification: TBD Applications that use this media type: Databases, spreadsheets, statistical programs, and data conversion utilities Fragment identifier considerations: N/A Additional information: Rankin Expires 20 March 2025 [Page 5] Internet-Draft CCSV September 2024 Deprecated alias names for this type: N/A Magic number(s): N/A File extension(s): CCSV Macintosh file type code(s): TEXT Person & email address to contact for further information: Mike Rankin 2108 Independence Dr Chambersburg, PA 17201 USA mrankin@icf.com Intended usage: COMMON Restrictions on usage: N/A Author/Change controller: Mike Rankin Provisional registration? 7. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 2003, . [RFC4180] Shafranovich, Y., "Common Format and MIME Type for Comma- Separated Values (CSV) Files", RFC 4180, DOI 10.17487/RFC4180, October 2005, . [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type Specifications and Registration Procedures", BCP 13, RFC 6838, DOI 10.17487/RFC6838, January 2013, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Rankin Expires 20 March 2025 [Page 6] Internet-Draft CCSV September 2024 [STD68] Internet Standard 68, . At the time of writing, this STD comprises the following: Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC5234, January 2008, . Acknowledgments TODO acknowledge. Author's Address Mike Rankin Email: mrankin@oldgrognard.pub Rankin Expires 20 March 2025 [Page 7]