gogrlx/nats-server
1
0
Fork 0
mirror of https://github.com/gogrlx/nats-server.git synced 2026-04-02 03:38:42 -07:00
Code Issues Packages Projects Releases Wiki Activity

Header ADR clarifications (#1528)

Browse Source 
* clarifications on the ADR. Go is non-standard, and it's formatting
rules, create formatting dependencies that are not part of the spec.
Also added simplified guidance of allowed characters to help those
having to implement it.

* clarified that http.Header in go internally uses textproto.MIMEHeader.

[ci skip]
This commit is contained in:
Alberto Ricart
2020-09-05 19:06:55 -05:00
committed by GitHub
parent 9c210284a4
commit 92e00f2a40
1 changed files with 11 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
doc/adr/0004-nats-headers.md
View File

@@ -18,7 +18,17 @@ The salient points of the HTTP header specification are:
- The specification may allow any number of strange things like comments/tokens etc.
- The keys can repeat.
The reference NATS Go client uses the `http.Header` infrastructure for serializing NATS headers. Other language clients may not be able to reuse header serialization infrastructure outside of the context of an HTTP request. Furthermore, the implementation of the native header library may diverge from the Go `http.Header` while still being standard.
More specifically from [rfc822](https://www.ietf.org/rfc/rfc822.txt) Section 3.1.2:
> Once a field has been unfolded, it may be viewed as being composed of a field-name followed by a colon (":"), followed by a field-body, and terminated by a carriage-return/line-feed.
> The field-name must be composed of printable ASCII characters (i.e., characters that have values between 33. and 126., decimal, except colon). The field-body may be composed of any ASCII characters, except CR or LF. (While CR and/or LF may be present in the actual text, they are removed by the action of unfolding the field.)
The reference NATS Go client uses the `http.Header` which internally uses `textproto.MIMEHeader` infrastructure for serializing NATS headers. Other language clients may not be able to reuse header serialization infrastructure outside of the context of an HTTP request. Furthermore, the implementation of the native header library may diverge from the Go `http.Header` while still being standard.
For example, the Go `http.Header` library, performs the following formatting which while not part of the spec, as header field names are case-insensitive, become a requirement in NATS header fields:
- First character in a header field is capitalized if in the range of [a-z]
- First characters following a dash (`-`) are capitalized if in the range of [a-z]
_If a client doesn't serialize field names as above, it is possible that the server may ignore them._
NATS Headers: