|Internet-Draft||CDDL for CSVs||June 2023|
|Bormann & Birkholz||Expires 25 December 2023||[Page]|
- Network Working Group
- Intended Status:
- Standards Track
Using CDDL for CSVs
The Concise Data Definition Language (CDDL), standardized in RFC 8610, is defined to provide data models for data shaped like JSON or CBOR.¶
Another representation format that is quote popular is the CSV (Comma-Separated Values) file as defined by RFC 4180.¶
The present document shows a way how to use CDDL to provide a data model for CSV files.¶
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The present document shows how to use CDDL to provide a data model for CSV files.¶
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.¶
csv = [?header, *record] header = [+header-field] record = [+field] header-field = text field = text¶
Note that the elements of this data model describe the interpretation of the data after processing and removal of lexical structure such as newlines, commas, escape characters, and quotation marks.¶
For the purposes of a specific application, the data model level structure of each field may be described in a more elaborate way, e.g., as a number. CDDL currently does not have a way to express the transformation from the text string in the CSV field to the number that this text string represents at the application data model level; the usage of anything but "text" for a field therefore MUST be accompanied by an instruction how to perform the translation. As a preferred choice, the JSON representation of the data model item, if it exists, MAY be chosen by that instruction.¶
Since the CSV media type text/csv defaults to using the US-ASCII
character set (i.e., [STD80]; see Section 3 of [RFC4180]), many uses of CSV will need to specify the media type
(Note that CDDL can describe text information that is in UTF-8 form,
which includes US-ASCII as that is a subset of UTF-8.
If a different form that is not a subset of UTF-8 is really still
needed, some rules for conversion will need to be defined by the
The media type parameter
header MAY be used to
indicate the presence or absence of a header line; if it is not given,
the grammar MUST NOT be ambiguous about the presence of a header
(i.e., it MUST be either mandatory or absent).¶
Note that the ABNF [STD68] in [RFC4180] does not quite handle the case that
charset is not
For the purposes of the present specification, the ABNF is understood
to allow all characters from the
charset except %x22 and %x2C in
For the purposes of the present specification, the ABNF rule
CRLF = [CR] LF¶
; header = absent SID-File = [meta-record, ?description-record, *dependency-record, *range-record, *item-record] meta-record = ["ietf-sid-file", module-name: text, module-revision: empty / text, sid-file-revision: empty / text, sid-file-status: empty / "unpublished" / "published"] description-record = ["description", description: empty / text] dependency-record = ["dependency", module-name: text, module-revision: text] range-record = ["range", entry-point: uint, size: uint] item-record = [; "item", -- useful to elide for bulk of file sid: uint ( namespace: "module" / "identity" / "feature" identifier: yang-identifier // namespace: "data" identifier: schema-node-path ) status: empty / "stable" / "unstable" / "obsolete"] yang-identifier = text .abnf ("yang-identifier" .det id-abnf) schema-node-path = text .abnf ("schema-node-path" .det id-abnf) id-abnf = ' schema-node-path = "/" QID *( "/" OQID) yang-identifier = ID QID = ID ":" ID OQID = ID [":" ID] ID = I *C I = "_" / %x41-5a / %x61-7a C = I / %x30-39 / "-" / "." ' empty = ""¶
This CDDL data model assumes that the text strings representing the
sid are converted to uint.
(Note that, due to the way YANG-JSON [RFC7951] defines the
uint64 data items, these actually are text strings
in JSON, which in CSV is indistinguishable from numbers.
However, the CDDL model for the CSV files will be more useful if it
takes into account typical CSV applications that automatically convert
integer-like text strings into numbers.)¶
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
- Shafranovich, Y., "Common Format and MIME Type for Comma-Separated Values (CSV) Files", RFC 4180, DOI 10.17487/RFC4180, , <https://www.rfc-editor.org/rfc/rfc4180>.
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
- Birkholz, H., Vigano, C., and C. Bormann, "Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, , <https://www.rfc-editor.org/rfc/rfc8610>.
- Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC5234, , <https://www.rfc-editor.org/rfc/rfc5234>.
- Veillette, M., Pelov, A., Petrov, I., Bormann, C., and M. Richardson, "YANG Schema Item iDentifier (YANG SID)", Work in Progress, Internet-Draft, draft-ietf-core-sid-20, , <https://datatracker.ietf.org/doc/html/draft-ietf-core-sid-20>.
- Lhotka, L., "JSON Encoding of Data Modeled with YANG", RFC 7951, DOI 10.17487/RFC7951, , <https://www.rfc-editor.org/rfc/rfc7951>.
- Watsen, K., Auerswald, E., Farrel, A., and Q. Wu, "Handling Long Lines in Content of Internet-Drafts and RFCs", RFC 8792, DOI 10.17487/RFC8792, , <https://www.rfc-editor.org/rfc/rfc8792>.
- Cerf, V., "ASCII format for network interchange", STD 80, RFC 20, DOI 10.17487/RFC0020, , <https://www.rfc-editor.org/rfc/rfc20>.
This appendix shows the CSV file that is automatically generated from Appendix A of [I-D.ietf-core-sid]. (Note that plaintext-based RFCs are limited to 72 columns; therefore five long lines in the CSV file have been folded as defined in [RFC8792].)¶
=============== NOTE: '\' line wrapping per RFC 8792 ================ ietf-sid-file,ietf-system,2014-08-06,, description,Example sid file dependency,ietf-yang-types,2013-07-15 dependency,ietf-inet-types,2013-07-15 dependency,ietf-netconf-acm,2018-02-14 dependency,iana-crypt-hash,2014-08-06 range,1700,100 1700,module,ietf-system, 1701,identity,authentication-method, 1702,identity,local-users, 1703,identity,radius, 1704,identity,radius-authentication-type, 1705,identity,radius-chap, 1706,identity,radius-pap, 1707,feature,authentication, 1708,feature,dns-udp-tcp-port, 1709,feature,local-users, 1710,feature,ntp, 1711,feature,ntp-udp-port, 1712,feature,radius, 1713,feature,radius-authentication, 1714,feature,timezone-name, 1715,data,/ietf-system:set-current-datetime, 1716,data,/ietf-system:set-current-datetime/current-datetime, 1717,data,/ietf-system:system, 1718,data,/ietf-system:system-restart, 1719,data,/ietf-system:system-shutdown, 1720,data,/ietf-system:system-state, 1721,data,/ietf-system:system-state/clock, 1722,data,/ietf-system:system-state/clock/boot-datetime, 1723,data,/ietf-system:system-state/clock/current-datetime, 1724,data,/ietf-system:system-state/platform, 1725,data,/ietf-system:system-state/platform/machine, 1726,data,/ietf-system:system-state/platform/os-name, 1727,data,/ietf-system:system-state/platform/os-release, 1728,data,/ietf-system:system-state/platform/os-version, 1729,data,/ietf-system:system/authentication, 1730,data,/ietf-system:system/authentication/user, 1731,data,/ietf-system:system/authentication/user-authentication-\ order, 1732,data,/ietf-system:system/authentication/user/authorized-key, 1733,data,/ietf-system:system/authentication/user/authorized-key/\ algorithm, 1734,data,/ietf-system:system/authentication/user/authorized-key/key\ -data, 1735,data,/ietf-system:system/authentication/user/authorized-key/\ name, 1736,data,/ietf-system:system/authentication/user/name, 1737,data,/ietf-system:system/authentication/user/password, 1738,data,/ietf-system:system/clock, 1739,data,/ietf-system:system/clock/timezone-name, 1740,data,/ietf-system:system/clock/timezone-utc-offset, 1741,data,/ietf-system:system/contact, 1742,data,/ietf-system:system/dns-resolver, 1743,data,/ietf-system:system/dns-resolver/options, 1744,data,/ietf-system:system/dns-resolver/options/attempts, 1745,data,/ietf-system:system/dns-resolver/options/timeout, 1746,data,/ietf-system:system/dns-resolver/search, 1747,data,/ietf-system:system/dns-resolver/server, 1748,data,/ietf-system:system/dns-resolver/server/name, 1749,data,/ietf-system:system/dns-resolver/server/udp-and-tcp, 1750,data,/ietf-system:system/dns-resolver/server/udp-and-tcp/\ address, 1751,data,/ietf-system:system/dns-resolver/server/udp-and-tcp/port, 1752,data,/ietf-system:system/hostname, 1753,data,/ietf-system:system/location, 1754,data,/ietf-system:system/ntp, 1755,data,/ietf-system:system/ntp/enabled, 1756,data,/ietf-system:system/ntp/server, 1757,data,/ietf-system:system/ntp/server/association-type, 1758,data,/ietf-system:system/ntp/server/iburst, 1759,data,/ietf-system:system/ntp/server/name, 1760,data,/ietf-system:system/ntp/server/prefer, 1761,data,/ietf-system:system/ntp/server/udp, 1762,data,/ietf-system:system/ntp/server/udp/address, 1763,data,/ietf-system:system/ntp/server/udp/port, 1764,data,/ietf-system:system/radius, 1765,data,/ietf-system:system/radius/options, 1766,data,/ietf-system:system/radius/options/attempts, 1767,data,/ietf-system:system/radius/options/timeout, 1768,data,/ietf-system:system/radius/server, 1769,data,/ietf-system:system/radius/server/authentication-type, 1770,data,/ietf-system:system/radius/server/name, 1771,data,/ietf-system:system/radius/server/udp, 1772,data,/ietf-system:system/radius/server/udp/address, 1773,data,/ietf-system:system/radius/server/udp/authentication-port, 1774,data,/ietf-system:system/radius/server/udp/shared-secret,¶