Commit graph inspector/clients/web/src/utils/uriTemplate.ts
Author SHA1 Message Date
cliffhall
9caac43da4 fix: accept only well-formed UTF-8 sequences, and validate before previewing
Addresses Copilot's round-18 review on #2035. Two suppressed comments, both
holes in my own recent fixes rather than in the original code.

1. Round 16's grouping keyed off the length-announcing lead byte alone, so
   it accepted sequences RFC 3629 forbids -- and the comment claiming they
   fell back to per-triplet counting was simply wrong. Measured on 05bbfe50:

     x{+v:1}  "%C0%80x"        =>  "x%C0%80"        overlong
              "%E0%80%80x"     =>  "x%E0%80%80"     overlong
              "%ED%A0%80x"     =>  "x%ED%A0%80"     UTF-16 surrogate
              "%F4%90%80%80x"  =>  "x%F4%90%80%80"  past U+10FFFF

   The lead-byte ranges are now the well-formed ones -- C2-DF, E0 only with
   A0-BF, ED only with 80-9F, F0 only with 90-BF, F4 only with 80-8F -- so
   each of the above falls back to one triplet, which is what the fallback
   was always documented to do. The legal boundary cases (%E0%A0%80,
   %ED%9F%BF, %F4%8F%BF%BF) are tested alongside, so tightening the ranges
   cannot quietly start splitting valid characters.

2. The preview never ran the read's template validation. It expands
   expression by expression, so `x://{a}}/{b}` with both fields filled
   previewed `x://1}/2` -- a URI whose stray `}` makes every read refuse.

   Validation moved into an exported `templateError` that both callers
   consult, so they cannot drift. It subsumes the narrower rule round 12
   added here ("leave the invalid part standing"), which still let the REST
   of such a template expand: the refusal is per template, not per
   expression, so the preview now shows the template verbatim -- literals
   unencoded included, since half-normalizing an unreadable template invents
   a string the server never published. Two existing tests asserted the
   weaker behavior and now assert this one.

npm run ci passes.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-17 01:40:50 -04:00
cliffhall
7d9410cbe0 fix: keep a pct-encoded UTF-8 sequence whole, and bound the preview too
Addresses Copilot's round-16 review on #2035. Two suppressed comments, both
real, and both refinements of fixes from the previous two rounds rather than
defects in the original code.

1. Round 11 settled on "a pct-encoded triplet counts as one character", but
   a multi-octet character spans several triplets -- `%C3%A9` is one `é`.
   Measured on a3dd8563:

     x{+v:1}  v = "%C3%A9x"  =>  "x%C3"   a lone lead byte, decoding to nothing

   `prefixUnits` now recognizes a well-formed pct-encoded UTF-8 sequence from
   its lead byte (RFC 3629: C2-DF two octets, E0-EF three, F0-F4 four;
   continuations 80-BF), longest alternative first so a four-octet sequence
   is not read as a two-octet one followed by loose triplets.

   A malformed sequence -- a lead byte with too few continuations, or a stray
   continuation -- matches no sequence alternative and falls back to
   per-triplet counting. That is the conservative direction: it counts as
   MORE units, so truncation keeps less rather than emitting octets that
   were never in the value.

2. Round 14's per-value ceiling only covered the read. The panel calls
   `previewUriTemplate` on every keystroke, and that path expands expression
   by expression, so it reached the allocation-heavy encoders with the same
   oversized value -- submission refused while the UI froze on the paste
   anyway. Both paths now share one exported `valueLengthError`, checked
   before any encoding happens.

npm run ci passes.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-17 01:13:17 -04:00
cliffhall
1c595e96ee fix: dedupe a repeated name in a group, and name every unmet requirement
Addresses Copilot's round-13 review on #2035. Two suppressed comments, both
real, both in the required-group work from round 7 rather than in the recent
preview rework.

1. `{a,a}` is ONE requirement named twice, but `requiredGroups` stored it as
   a two-name group, so everything downstream read it as "either of these
   will do". The TUI was left with a form it could not submit: its
   `length === 1` test marked `a` optional while ResourceTestModal's guard
   still refused a blank. The web panel offered the useless hint
   "Any one of: a, a". Names are now deduplicated within the expression --
   expansion still emits both occurrences (`x://{a,a}` -> `x://1,1`), which
   RFC 6570 requires.

2. The per-field hint used `find`, so a variable in several shared groups
   advertised only the first. With `{a,b}{b,c}{a,c}`, filling `b` satisfies
   the first two and every visible hint then looks met while Read Resource
   stays disabled on the unmet `{a,c}` -- a requirement with nothing on
   screen pointing at it.

   Fields now hint every shared group they sit in. That alone is not enough,
   because no per-field hint can say WHICH group is still outstanding, so
   the form states it directly: "Still needed: a or c", built from the same
   `unmetRequiredGroups` the submit gate uses, so the message and the button
   cannot disagree. `hasRequiredValues` is no longer called here -- the
   panel derives both from the one list.

npm run ci passes.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-17 00:33:52 -04:00
cliffhall
6a345ae77c fix: keep the URI preview from throwing or promising an unsendable URI
Addresses Copilot's round-12 review on #2035. Both halves are regressions
from my own round-10 rework, which replaced "expand a rewritten template
through the lenient expandUriTemplate" with a part-by-part assembly and so
lost two properties that implementation had for free. Reproduced on
c6fb6271:

  previewUriTemplate("x://{v}",  { v: "\ud800" })  =>  throws URIError
  previewUriTemplate("x://{a,}", { a: "1" })       =>  "x://1"

The first is the worse one: the preview runs during render, so an escaping
throw unmounts the whole panel rather than disabling its button -- and an
unpaired surrogate is real input, since `encodeURIComponent` raises URIError
on one and a paste can deliver it. The panel already reports that case
properly through `tryExpandUriTemplate`; the display path now degrades to
the raw template instead of taking the panel down with it.

The second promised a URI the user could never send: `{a,}` is an invalid
template whose submission is refused, but `a` survives into the
expression's varspecs, so filling it previewed `x://1`. An invalid
expression is now left standing as written, which is what the rest of the
panel already says about it.

Tests for both, plus one asserting the valid expressions around an invalid
one still preview.

npm run ci passes.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-17 00:22:09 -04:00
cliffhall
2e06b369f4 fix: encode literals per RFC 6570 3.1, and label the varname tolerance
Addresses Copilot's round-10 review on #2035. One inline comment, one
suppressed; both real.

1. Literals were copied through verbatim, but RFC 6570 3.1 requires them
   pct-encoded on expansion -- the conformance case `café/{var}` expands to
   `caf%C3%A9/value`. Measured on ef3f5e74 it produced `café/value`, raw
   UTF-8 in the path; since this module replaced the SDK's expander for both
   clients, nothing else was going to encode it. (The pinned SDK does not
   either -- it returns `café/value` too -- so this is a gap we inherited
   rather than introduced.)

   `encodeLiteral` keeps reserved delimiters (a literal's `/`, `?` and `#`
   are structure) and existing pct-triplets, and encodes the rest. A BRACE
   passes through: it can only reach a literal from a malformed template,
   where an unclosed `{` becomes trailing text, and `%7B` would leave a
   string resembling neither the template nor anything the server can match.

   This is also what removed the preview's placeholder machinery. No token
   can survive a round trip now that literals are encoded, so the preview
   assembles part by part instead -- `encodeLiteral` for literal runs,
   `expandTemplateExpression` for filled expressions, `part.source` for the
   rest. Both halves still come from the shared expander, so the preview
   cannot promise a URI that submitting would not send, and the question of
   what token could never collide with a server-supplied template is gone.

2. On the varname set I took the structural point rather than the
   conclusion. `VARCHAR` is RFC-exact again; `-` and `~` moved into a
   separately named `TOLERATED_VARCHAR` tier, and a name needing it parses
   with `conforming: false`, surfaced on `TemplateVariable`.

   So the grammar in the code says what the RFC says and the tolerance is
   explicit and separately tested -- but the Inspector still expands
   `{default-graph-uri}`, because real servers publish hyphenated names and
   the SDK's matcher round-trips them. Refusing to read a resource that
   demonstrably works is a worse failure for a debugging tool than expanding
   a name the conformance suite would reject. A caller wanting RFC-exact
   behavior refuses on the flag rather than re-deriving the grammar.

npm run ci passes.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-16 23:44:45 -04:00
cliffhall
6acaff70ca fix: honor a defined-but-empty value, and announce the expansion error
Addresses Copilot's round-8 review on #2035 (one inline comment, one
suppressed). Both real.

1. RFC 6570 distinguishes an UNDEFINED variable, which omits its whole
   expression, from one defined as the empty string, which expands. The
   expander was calling `definedValues` on the way in, collapsing the two --
   so `x{?q}` with `{ q: "" }` gave `x` instead of `x?q=`, and there was no
   way for any caller, `readResourceFromTemplate` included, to request
   either that or `x;q`. Key presence is now honored, including §3.2.7's
   rule that the matrix operator drops the `=` for an empty value (`x{;q}`
   -> `x;q`, while `?`/`&` keep it).

   Dropping blanks is a FORM concern, so it moved to the two form
   boundaries: the web panel seeds every declared variable with "" and the
   TUI's ink-form returns "" for every untouched field, so neither can tell
   "never touched" from "deliberately empty" -- but that is a fact about a
   text input, not about the template, and it has no business deciding what
   a template means for every other caller.

   Six unit tests and one integration test encoded the old collapse and now
   assert the corrected meaning. The prototype-collision cases get stronger
   rather than weaker: a blank `{?toString}` expands to `?toString=` -- its
   OWN empty value -- where the original bug expanded the inherited
   function's body.

2. The expansion error is now `role="alert"`. It can appear while typing (a
   pasted value that cannot be encoded), and plain text is not announced, so
   a screen-reader user met a disabled Read Resource with no stated reason.

npm run ci passes.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-16 23:08:30 -04:00
cliffhall
1ad3edd96d fix: refuse a template that cannot expand, instead of reading the raw one
Ports the two behaviors PR #2033 (the parallel attempt at #1919, now closed
as a duplicate) got right and this branch did not.

1. An expression declaring no variable is a malformed template, not one
   with a member to skip. RFC 6570 requires at least one varspec per
   expression and admits no empty member, so `{}`, `{,}`, `{a,}`, `{?}`
   and `{*}` (an explode modifier is not a name) now make the template
   invalid. Skipping them was the more dangerous reading: `x://{}`
   expanded to `x://` while the form rendered no inputs, so its
   "everything required is filled" check was vacuously true and it
   submitted a URI that is not the template the server published.

2. The read is withheld when expansion fails. `expandUriTemplate`'s
   raw-template fallback exists for the preview, which runs during render
   -- but the submit path used it too, so an invalid template was read
   with its braces intact and the server answered with a confusing "not
   found" for a defect that is not the user's. `tryExpandUriTemplate`
   returns the URI or the reason as a value the caller cannot mistake for
   one; the panel gates Read Resource on it and prints the reason.
   This also covers a value that cannot be encoded -- an unpaired
   surrogate has no UTF-8 encoding, so `encodeURIComponent` throws
   `URIError` on it, and a text input can hold one via paste.

`requiredGroups` now skips an expression naming no variable: an empty
group can never be satisfied, so it would gate the form a second time on
a condition nothing can meet, and the "any one of" hint built from it
would name no fields. The accurate reason is the malformed template,
which the expansion gate reports.

npm run ci passes.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-16 22:32:27 -04:00
cliffhall
1939136eff fix: read template variables as own properties only
Addresses Copilot's round-6 review on #2035.

`toString`, `constructor`, `valueOf` and `__proto__` are all valid RFC
6570 variable names -- `varname` allows ALPHA / DIGIT / `_` / pct-encoded
-- and every lookup here was a bare `values[name]`, which finds
`Object.prototype`'s member for each of them. Measured: `({})["toString"]
!== undefined` is true with typeof "function", and `({}["constructor"] ??
"").length` is 1.

So a *blank* `{?toString}` field read as supplied and expanded a function
body into the URI instead of omitting the expression, and
`hasRequiredValues([["constructor"]], {})` returned true because
`Object.length` is 1 -- a required group satisfied by nothing.

All reads now go through an own-property `readValue`, and the web
preview's filled-check uses `Object.hasOwn`. `expandExpression` carries
the value through its filter rather than re-reading it afterwards, so the
"is it defined" test and the read cannot disagree and nothing needs a
non-null assertion.

The remaining six findings were documentation drifting behind the code,
which matters here because the comments are the argument for why this
module exists:

- The web helper still described the SDK's second-`?`-to-`&` rewrite as
  something the preview relies on. That was removed last round.
- Three places still named the CLI as a consumer. It has no template form
  and passes an already-expanded `--uri` to `readResource`.
- The PR description still described the superseded architecture
  (expansion delegated to the SDK), i.e. the opposite of what now ships.

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-16 22:02:39 -04:00
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
cliffhall
83658db2dd fix(web): expand resource templates per RFC 6570
The Resources screen discovered and substituted template variables with a
bare `/\{(\w+)\}/g` regex, which is wrong two ways: it cannot see an
expression carrying an operator, so `foobar://events{?topic}` rendered no
input at all; and it splices the raw value in, so a `/`, `?`, `#`, `%`,
space or non-ASCII character in a simple `{topic}` landed unencoded and
changed the URI's structure -- `foo/bar` produced an extra path segment
that a conforming matcher rejects with `-32602 Resource not found`.

Delegate expansion to the SDK's `UriTemplate`, the same implementation
`InspectorClient.readResourceFromTemplate` (and so the TUI) already
expands through, so the two clients cannot disagree about what a template
means. The new `utils/uriTemplate` supplies only what that class does
not: which variables to render an input for, which of them a read cannot
proceed without, and a partially-expanded preview.

Required-ness follows the operator. Under `?`, `&`, `.` or `/` the whole
expression is omitted when the variable is undefined, so those fields are
marked Optional and reading with them blank is a legitimate request for
the unfiltered resource; under `""`, `+` or `#` the variable sits mid-URI,
so it stays required. Blank fields are dropped before expanding so an
untouched optional field reads as undefined rather than as the empty
string, which would expand to a valueless `?topic=`.

Adds the `rfc6570_templates` preset and a `rfc6570-templates-http.json`
showcase server serving the two templates from the issue.

Closes #1919

Signed-off-by: cliffhall <cliff@futurescale.com>
2026-08-16 18:31:35 -04:00