Add Kratos public-API fetch client (todo §4); createKratosPublic(): self-service flow init/get/submit, whoami, session→JWT tokenize

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2026-06-17 17:15:50 +02:00
parent fcf042fa66
commit 898dc7f2cf
4 changed files with 252 additions and 1 deletions

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src/kratos-public.test.ts Normal file
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// Kratos public-API client (§4): typed fetch wrappers over Ory Kratos' public endpoints.
// Guards the request contracts (URLs, JSON-accept, cookie relay) and the result mapping
// (200/401/4xx, validation-flow vs success, tokenized JWT). Live wiring is verified by the
// flow pages (§4); these catch contract drift with a mock fetch.
import { test } from "node:test";
import assert from "node:assert/strict";
import { createKratosPublic, KratosError } from "./kratos-public.ts";
const BASE = "http://kratos:4433";
function res(status: number, body?: unknown, setCookie: string[] = []): Response {
const headers = new Headers();
if (body !== undefined) headers.set("content-type", "application/json");
for (const c of setCookie) headers.append("set-cookie", c);
return new Response(body === undefined ? null : JSON.stringify(body), { status, headers });
}
// Records each call so a test can assert URL/method/headers/body.
function recorder(handler: (url: string, init: RequestInit | undefined) => Response) {
const calls: { body: string | undefined; headers: Headers; method: string; url: string }[] = [];
const fetchImpl = (async (input: unknown, init?: RequestInit) => {
calls.push({
body: init?.body as string | undefined,
headers: new Headers(init?.headers),
method: init?.method ?? "GET",
url: String(input),
});
return handler(String(input), init);
}) as typeof fetch;
return { calls, fetchImpl };
}
test("initBrowserFlow gets /self-service/<type>/browser as JSON, relays Set-Cookie, forwards return_to", async () => {
const flow = { id: "f1", ui: { action: `${BASE}/self-service/login?flow=f1`, method: "POST", nodes: [] } };
const { calls, fetchImpl } = recorder(() => res(200, flow, ["csrf_token=abc; Path=/; HttpOnly"]));
const out = await createKratosPublic({ baseUrl: BASE, fetchImpl }).initBrowserFlow("login", { returnTo: "http://app/after" });
assert.deepEqual(out.flow, flow);
assert.deepEqual(out.setCookie, ["csrf_token=abc; Path=/; HttpOnly"]);
assert.match(calls[0]!.url, /\/self-service\/login\/browser\?return_to=http%3A%2F%2Fapp%2Fafter$/);
assert.equal(calls[0]!.headers.get("accept"), "application/json");
});
test("getFlow fetches the flow by id forwarding the browser cookie", async () => {
const flow = { id: "f2", ui: { action: "x", method: "POST", nodes: [] } };
const { calls, fetchImpl } = recorder(() => res(200, flow));
const out = await createKratosPublic({ baseUrl: BASE, fetchImpl }).getFlow("registration", "f2", { cookie: "csrf_token=abc" });
assert.deepEqual(out, flow);
assert.match(calls[0]!.url, /\/self-service\/registration\/flows\?id=f2$/);
assert.equal(calls[0]!.headers.get("cookie"), "csrf_token=abc");
});
test("getFlow throws a KratosError carrying the status when the flow is gone (410)", async () => {
const { fetchImpl } = recorder(() => res(410, { error: { id: "self_service_flow_expired" } }));
await assert.rejects(
createKratosPublic({ baseUrl: BASE, fetchImpl }).getFlow("login", "old"),
(e: unknown) => e instanceof KratosError && e.status === 410,
);
});
test("submitFlow POSTs urlencoded to the action and reports success + relays Set-Cookie", async () => {
const { calls, fetchImpl } = recorder(() => res(200, { session: { active: true } }, ["plainpages_session=s; Path=/"]));
const out = await createKratosPublic({ baseUrl: BASE, fetchImpl })
.submitFlow(`${BASE}/self-service/login?flow=f`, { body: "identifier=a&password=b", cookie: "csrf_token=abc" });
assert.equal(out.ok, true);
assert.equal(out.status, 200);
assert.deepEqual(out.setCookie, ["plainpages_session=s; Path=/"]);
assert.equal(calls[0]!.method, "POST");
assert.equal(calls[0]!.headers.get("content-type"), "application/x-www-form-urlencoded");
assert.equal(calls[0]!.body, "identifier=a&password=b");
});
test("submitFlow returns the re-rendered flow (no throw) on a 400 validation error", async () => {
const flow = { id: "f", ui: { action: "x", messages: [{ id: 4000006, text: "invalid credentials", type: "error" }], method: "POST", nodes: [] } };
const { fetchImpl } = recorder(() => res(400, flow));
const out = await createKratosPublic({ baseUrl: BASE, fetchImpl }).submitFlow(`${BASE}/x`, { body: "x=1" });
assert.equal(out.ok, false);
assert.equal(out.status, 400);
assert.deepEqual(out.body, flow);
});
test("submitFlow surfaces the redirect target — Location header or a 422 redirect_browser_to body", async () => {
const k = (handler: () => Response) => createKratosPublic({ baseUrl: BASE, fetchImpl: recorder(handler).fetchImpl });
const viaHeader = await k(() => new Response(null, { headers: new Headers({ location: "http://app/" }), status: 303 }))
.submitFlow(`${BASE}/x`, { body: "x=1" });
assert.equal(viaHeader.location, "http://app/");
const viaBody = await k(() => res(422, { redirect_browser_to: "http://app/login?flow=next" }))
.submitFlow(`${BASE}/x`, { body: "x=1" });
assert.equal(viaBody.location, "http://app/login?flow=next");
});
test("whoami returns the session on 200 (cookie forwarded) and null on 401", async () => {
const session = { active: true, identity: { id: "u1", traits: { email: "a@b" } } };
const { calls, fetchImpl } = recorder((url) => (url.endsWith("/sessions/whoami") ? res(200, session) : res(401)));
const k = createKratosPublic({ baseUrl: BASE, fetchImpl });
assert.deepEqual(await k.whoami({ cookie: "plainpages_session=s" }), session);
assert.equal(calls[0]!.headers.get("cookie"), "plainpages_session=s");
assert.equal(await createKratosPublic({ baseUrl: BASE, fetchImpl: (async () => res(401)) as typeof fetch }).whoami(), null);
});
test("whoami?tokenize_as mints a session JWT via the tokenizer template", async () => {
const session = { active: true, identity: { id: "u1" }, tokenized: "header.payload.sig" };
const { calls, fetchImpl } = recorder(() => res(200, session));
const out = await createKratosPublic({ baseUrl: BASE, fetchImpl }).whoami({ cookie: "plainpages_session=s", tokenizeAs: "plainpages" });
assert.equal(out?.tokenized, "header.payload.sig");
assert.match(calls[0]!.url, /\/sessions\/whoami\?tokenize_as=plainpages$/);
});
test("whoami throws on an unexpected upstream error", async () => {
const { fetchImpl } = recorder(() => res(500, { error: "boom" }));
await assert.rejects(createKratosPublic({ baseUrl: BASE, fetchImpl }).whoami(), KratosError);
});

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// Kratos public-API client (todo §4): typed `fetch` wrappers over Ory Kratos' public
// endpoints — self-service flow init/get/submit, session `whoami`, and the session→JWT
// tokenizer (`whoami?tokenize_as`). Built-in `fetch` only, no SDK dep (AGENTS.md). The
// themed flow pages and login completion (§4) build on this; rendering flow `ui.nodes`
// and mapping field errors is the renderer's job (§4), so we keep those types loose.
export type FlowType = "login" | "recovery" | "registration" | "settings" | "verification";
export interface UiText {
context?: Record<string, unknown>;
id: number;
text: string;
type: string;
}
export interface UiNode {
attributes: Record<string, unknown>;
group: string;
messages: UiText[];
meta: { label?: UiText };
type: string;
}
export interface FlowUi {
action: string; // absolute Kratos URL the browser POSTs the form to (Kratos owns its CSRF)
messages?: UiText[];
method: string;
nodes: UiNode[];
}
export interface Flow {
id: string;
type?: string;
ui: FlowUi;
}
export interface Session {
active?: boolean;
expires_at?: string;
identity?: { id: string; metadata_admin?: unknown; traits?: Record<string, unknown> };
tokenized?: string; // the signed JWT — present only when `tokenize_as` was requested
}
export interface FlowInit {
flow: Flow;
setCookie: string[]; // Kratos' CSRF cookie(s) to relay to the browser
}
export interface FlowSubmission {
body: unknown; // parsed JSON: the re-rendered flow on 400, the success payload on 200
location: string | null; // redirect target (Location header, or a 422 redirect_browser_to)
ok: boolean; // status === 200
setCookie: string[];
status: number;
}
// Carries the HTTP status so a caller can branch — e.g. re-init on an expired flow (404/410).
export class KratosError extends Error {
body: string;
status: number;
constructor(message: string, status: number, body: string) {
super(message);
this.body = body;
this.name = "KratosError";
this.status = status;
}
}
export interface KratosPublic {
getFlow(type: FlowType, id: string, opts?: { cookie?: string }): Promise<Flow>;
initBrowserFlow(type: FlowType, opts?: { cookie?: string; returnTo?: string }): Promise<FlowInit>;
submitFlow(action: string, opts: { body: string; contentType?: string; cookie?: string }): Promise<FlowSubmission>;
whoami(opts?: { cookie?: string; tokenizeAs?: string }): Promise<Session | null>;
}
function isRecord(value: unknown): value is Record<string, unknown> {
return typeof value === "object" && value !== null && !Array.isArray(value);
}
function parseBody(text: string): unknown {
if (!text) return null;
try {
return JSON.parse(text);
} catch {
return text;
}
}
export function createKratosPublic(config: { baseUrl: string; fetchImpl?: typeof fetch }): KratosPublic {
const base = config.baseUrl.replace(/\/+$/, "");
const http = config.fetchImpl ?? fetch;
// Forward the browser cookie + ask for JSON, so Kratos returns the flow/session instead
// of redirecting an API caller.
function headers(cookie?: string): Record<string, string> {
const h: Record<string, string> = { accept: "application/json" };
if (cookie) h["cookie"] = cookie;
return h;
}
return {
async initBrowserFlow(type, opts = {}) {
const url = new URL(`${base}/self-service/${type}/browser`);
if (opts.returnTo) url.searchParams.set("return_to", opts.returnTo);
const res = await http(url, { headers: headers(opts.cookie), redirect: "manual" });
if (res.status !== 200) throw new KratosError(`Kratos init ${type} flow failed (${res.status})`, res.status, await res.text());
return { flow: (await res.json()) as Flow, setCookie: res.headers.getSetCookie() };
},
async getFlow(type, id, opts = {}) {
const url = new URL(`${base}/self-service/${type}/flows`);
url.searchParams.set("id", id);
const res = await http(url, { headers: headers(opts.cookie) });
if (res.status !== 200) throw new KratosError(`Kratos get ${type} flow failed (${res.status})`, res.status, await res.text());
return (await res.json()) as Flow;
},
async submitFlow(action, opts) {
const h = headers(opts.cookie);
h["content-type"] = opts.contentType ?? "application/x-www-form-urlencoded";
// Manual redirect so we can read a 303 Location instead of following it server-side.
const res = await http(action, { body: opts.body, headers: h, method: "POST", redirect: "manual" });
const body = parseBody(await res.text());
const location =
res.headers.get("location") ??
(isRecord(body) && typeof body["redirect_browser_to"] === "string" ? body["redirect_browser_to"] : null);
return { body, location, ok: res.status === 200, setCookie: res.headers.getSetCookie(), status: res.status };
},
async whoami(opts = {}) {
const url = new URL(`${base}/sessions/whoami`);
if (opts.tokenizeAs) url.searchParams.set("tokenize_as", opts.tokenizeAs);
const res = await http(url, { headers: headers(opts.cookie) });
if (res.status === 401) return null; // no/expired session
if (res.status !== 200) throw new KratosError(`Kratos whoami failed (${res.status})`, res.status, await res.text());
return (await res.json()) as Session;
},
};
}