refactor(http-recorder): Redactor + Recorder seams, README (#26636)

packages/http-recorder/src/matching.ts

@@ -1,5 +1,6 @@
 import { Option, Schema } from "effect"
-import type { RequestSnapshot } from "./schema"
+import { REDACTED, secretFindings } from "./redaction"
+import type { HttpInteraction, RequestSnapshot } from "./schema"
 
 const JsonValue = Schema.fromJsonString(Schema.Unknown)
 export const decodeJson = Schema.decodeUnknownOption(JsonValue)
@@ -34,3 +35,90 @@ export const canonicalSnapshot = (snapshot: RequestSnapshot): string =>
 
 export const defaultMatcher: RequestMatcher = (incoming, recorded) =>
   canonicalSnapshot(incoming) === canonicalSnapshot(recorded)
+
+const safeText = (value: unknown) => {
+  if (value === undefined) return "undefined"
+  if (secretFindings(value).length > 0) return JSON.stringify(REDACTED)
+  const text = JSON.stringify(value)
+  if (!text) return String(value)
+  return text.length > 300 ? `${text.slice(0, 300)}...` : text
+}
+
+const jsonBody = (body: string) => Option.getOrUndefined(decodeJson(body))
+
+const valueDiffs = (expected: unknown, received: unknown, base = "$", limit = 8): ReadonlyArray<string> => {
+  if (Object.is(expected, received)) return []
+  if (isRecord(expected) && isRecord(received)) {
+    return [...new Set([...Object.keys(expected), ...Object.keys(received)])]
+      .toSorted()
+      .flatMap((key) => valueDiffs(expected[key], received[key], `${base}.${key}`, limit))
+      .slice(0, limit)
+  }
+  if (Array.isArray(expected) && Array.isArray(received)) {
+    return Array.from({ length: Math.max(expected.length, received.length) }, (_, index) => index)
+      .flatMap((index) => valueDiffs(expected[index], received[index], `${base}[${index}]`, limit))
+      .slice(0, limit)
+  }
+  return [`${base} expected ${safeText(expected)}, received ${safeText(received)}`]
+}
+
+const headerDiffs = (expected: Record<string, string>, received: Record<string, string>) =>
+  [...new Set([...Object.keys(expected), ...Object.keys(received)])].toSorted().flatMap((key) => {
+    if (expected[key] === received[key]) return []
+    if (expected[key] === undefined) return [`  ${key} unexpected ${safeText(received[key])}`]
+    if (received[key] === undefined) return [`  ${key} missing expected ${safeText(expected[key])}`]
+    return [`  ${key} expected ${safeText(expected[key])}, received ${safeText(received[key])}`]
+  })
+
+export const requestDiff = (expected: RequestSnapshot, received: RequestSnapshot): ReadonlyArray<string> => {
+  const lines: string[] = []
+  if (expected.method !== received.method) {
+    lines.push("method:", `  expected ${expected.method}, received ${received.method}`)
+  }
+  if (expected.url !== received.url) {
+    lines.push("url:", `  expected ${expected.url}`, `  received ${received.url}`)
+  }
+  const headers = headerDiffs(expected.headers, received.headers)
+  if (headers.length > 0) lines.push("headers:", ...headers.slice(0, 8))
+  const expectedBody = jsonBody(expected.body)
+  const receivedBody = jsonBody(received.body)
+  const body =
+    expectedBody !== undefined && receivedBody !== undefined
+      ? valueDiffs(expectedBody, receivedBody).map((line) => `  ${line}`)
+      : expected.body === received.body
+        ? []
+        : [`  expected ${safeText(expected.body)}, received ${safeText(received.body)}`]
+  if (body.length > 0) lines.push("body:", ...body)
+  return lines
+}
+
+export const mismatchDetail = (interactions: ReadonlyArray<HttpInteraction>, incoming: RequestSnapshot): string => {
+  if (interactions.length === 0) return "cassette has no recorded HTTP interactions"
+  const ranked = interactions
+    .map((interaction, index) => ({ index, lines: requestDiff(interaction.request, incoming) }))
+    .toSorted((a, b) => a.lines.length - b.lines.length || a.index - b.index)
+  const best = ranked[0]
+  return ["no recorded interaction matched", `closest interaction: #${best.index + 1}`, ...best.lines].join("\n")
+}
+
+export const selectMatch = (
+  interactions: ReadonlyArray<HttpInteraction>,
+  incoming: RequestSnapshot,
+  match: RequestMatcher,
+): { readonly interaction: HttpInteraction | undefined; readonly detail: string } => {
+  const interaction = interactions.find((candidate) => match(incoming, candidate.request))
+  return { interaction, detail: interaction ? "" : mismatchDetail(interactions, incoming) }
+}
+
+export const selectSequential = (
+  interactions: ReadonlyArray<HttpInteraction>,
+  incoming: RequestSnapshot,
+  match: RequestMatcher,
+  index: number,
+): { readonly interaction: HttpInteraction | undefined; readonly detail: string } => {
+  const interaction = interactions[index]
+  if (!interaction) return { interaction, detail: `interaction ${index + 1} of ${interactions.length} not recorded` }
+  if (!match(incoming, interaction.request))
+    return { interaction: undefined, detail: requestDiff(interaction.request, incoming).join("\n") }
+  return { interaction, detail: "" }
+}