commit 96cf889e6b7bd9e596cbd08849c5351a38eec097
author Jonas Termansen <sortie@google.com> Wed Mar 18 11:36:36 2020 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> Wed Mar 18 11:36:36 2020 +0000
tree a29a9ecf627e32ada602fb0b91247e8a8899736e
parent 5f8802b82faecb77038ea00f96be72632203bae5

[dart:io] Fix HeaderValue parsing, toString(), and support null values.

This is a breaking change. https://github.com/dart-lang/sdk/issues/40709

This change makes the HeaderValue parsing more strict in two invalid
edge cases, supports parameters with null values as a feature, and fixes
toString() so it always produces tokens or quoted-strings valid per RFC
7230 3.2.6.

The empty parameter value without double quotes (which is not allowed by
the standards) is now parsed as the empty string rather than null. E.g.
HeaderValue.parse("v;a=").parameters now gives {"a": ""} rather than
{"a": null}.

Invalid inputs with unbalanced double quotes are now rejected. E.g.
HeaderValue.parse('v;a="b').parameters will now throw a HttpException
instead of giving {"a": "b"}.

The HeaderValue.toString() method now supports parameters with null
values by omitting the value. E.g.:

  HeaderValue("v", {"a": null, "b": "c"}).toString()

now gives

  v; a; b=c

This behavior can be used to implement some features in the Accept and
Sec-WebSocket-Extensions headers.

Likewise the empty value and values using characters outside of RFC 7230
3.2.6 tokens are now correctly implemented by double quoting such values
with escape sequences. E.g.:

  HeaderValue("v",
      {"a": "A", "b": "(B)", "c": "", "d": "ø", "e": "\\\""}).toString()

now gives

   v;a=A;b="(B)";c="";d="ø";e="\\\""

The NNBD migration required making subtle changes to some dart:io
semantics in order to provide a better API. This change backports one of
these semantic changes to the unmigrated SDK so any issues can be
discovered now instead of blocking the future SDK unfork.

Change-Id: Iafc790e03b6290232cac71fe14f995ce0f0b036b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136620
Commit-Queue: Jonas Termansen <sortie@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>