Commit graph inspector/core/mcp/uriTemplate.ts
Author SHA1 Message Date
cliffhall
e7d1246c86 fix(core): scope requiredness to expressions, and encode + / # per RFC 6570
Addresses Copilot's round-3 review on #2035. It again reported "no new
comments" while carrying two suppressed ones; both reproduced.

1. Requiredness could not live on a variable at all. Deduplication kept the
   first occurrence's group, so in `x{?a}{?b}{a,b}` both names ended up
   required with singleton groups and the form demanded both -- while the
   SDK expands that template with only `a` to "x?a=11". Widening the stored
   group would not have been enough either: in `{a,b}{a,c}`, filling `b` and
   `c` satisfies both expressions, which no per-variable flag can express.

   So requiredness is now returned per expression by `requiredGroups`, and
   `hasRequiredValues` asks that each group be satisfied by any one of its
   names. `TemplateVariable.groupNames` is gone rather than left as a field
   that quietly means something narrower than it reads; `required` remains,
   documented as driving the "Optional" marker and nothing else.

2. `encodeURI` is not the allow-reserved encoder `+` and `#` call for. It
   escapes `[` and `]`, which are reserved and must survive, and it escapes
   `%`, so an already-encoded value is double-encoded. Measured:
   "[::1]" -> "%5B::1%5D" and "%2F" -> "%252F". Both corrupt the URI rather
   than merely over-escaping it -- an IPv6 literal or a pre-encoded path
   reaches the server altered, which is the same class of defect #1919 is
   about.

   Added an RFC 6570 3.2.1 encoder that preserves reserved characters and
   existing pct-triplets, splitting on `%XX` so a lone `%` is still encoded
   to `%25`, and matching with the `u` flag so an astral character is
   encoded whole. `+` and `#` expressions are now taken over even for a
   single name, so both expansion paths agree on what those operators mean.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-16 19:35:33 -04:00
cliffhall
25c3ad272e fix(core): support ; and :length, and scope requiredness to the expression
Addresses Copilot's round-2 review on #2035. It reported "no new comments"
but carried three *suppressed* ones; all three reproduced against the
pinned SDK.

1. The `;` path-parameter operator is absent from the SDK's operator list,
   so `{;id}` parsed as a variable literally named ";id" and expanded to
   nothing. Added the operator and its named expansion (`;a=1;b=2`).

2. An RFC 6570 prefix modifier was folded into the variable name: `{id:3}`
   yielded a variable called "id:3" and expanded to nothing. Varspecs are
   now parsed properly and the value truncated before encoding. Truncation
   is by code point, since `String.prototype.slice` counts UTF-16 units and
   would split an astral character into a lone surrogate.

   For both of these the wrong URI is the lesser problem: a form has to
   *name* the variables it asks the user to fill, so the panel was
   rendering fields labelled `;id` and `id:3` that nobody could use.

3. Requiredness was applied per variable, but it is a property of the
   *expression*: RFC 6570 drops undefined names from a multi-name
   expression, so `{a,b}` with only `a` filled expands to `a`'s value --
   the SDK does this too. The panel was refusing input the expander would
   have accepted. `hasRequiredValues` now encodes "any one name in a
   required group suffices", and such a field reads "Any one of: a, b"
   rather than falsely claiming each is mandatory.

Two structural consequences, each pinned by a test:

- Takeover is now per TEMPLATE rather than per expression. Splicing
  corrected fragments into a template the SDK re-expands would leave its
  cross-expression `?`-to-`&` rewrite blind to the fragments already
  resolved.

- Expansion is split into a strict variant that throws and a lenient one
  that returns the raw template. `readResourceFromTemplate` wraps the
  thrown error with the template name -- three pre-existing integration
  tests assert that -- while the form must not throw on a server-supplied
  template, since that would take out the panel on render. The strict
  variant constructs the SDK template unconditionally, because that
  construction is what validates syntax: otherwise `x://{;a}{b,c` would
  take the own-expansion path and its unclosed tail would pass as literal
  text with nothing objecting.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-16 19:17:05 -04:00
cliffhall
409dce37be fix(core): share URI-template expansion and correct the SDK's multi-name branch
Addresses Copilot's review on #2035. All three findings reproduced against
the pinned SDK before acting.

1. `#` was misclassified as required. Measured: `x://a{#frag}` with no
   `frag` expands to exactly `x://a`, a well-formed URI naming a real
   resource -- unlike `{+path}` (`x://a/`) or a simple `{userId}`
   (`file:///users//profile`), which leave an empty path segment. Moved `#`
   into the omittable set; the required cases now assert what the URI
   *becomes* when blank, so the rule is checked rather than asserted.

2. Delegating to the SDK did not actually give RFC 6570 expansion.
   `UriTemplate.expandPart` takes an early `names.length > 1` branch that
   raw-joins values, skipping both `encodeValue` and the operator prefix:
   `x://{a,b}` with `a = "foo/bar"` expands to `x://foo/bar,q` -- the very
   unencoded-slash defect this PR is about -- and `x://a{/p,q}` to
   `x://ax y,z`. Only `?`/`&` are correct, being dispatched earlier.

   Fixing that in the web client alone would have left the TUI and CLI
   wrong, since `readResourceFromTemplate` expands through the same class.
   So parse/classify/expand now live in `core/mcp/uriTemplate.ts` and both
   call sites use it. The correction is surgical: a multi-name non-query
   expression is expanded here and spliced in as literal text before the
   SDK sees the template (safe -- both encoders escape `{`/`}`), while
   every single-name and query expression still goes through the SDK
   untouched. The preview applies the same correction, so it cannot
   promise a URI that submitting would not send.

3. The showcase promised a blank `{?topic}` read that did not work.
   `UriTemplate.match()` compiles `{?topic}` to a *required*
   `\?topic=([^&]+)`, so `match("foobar://events")` returns null and the
   read 404s. A real server exposes the unfiltered collection as its own
   resource; the showcase now registers `foobar://events` so the
   documented step resolves. Verified end to end through the CLI.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-16 18:51:12 -04:00