feat: replace openapi hashing system with /version

Apparently I didn't use my brain cells and rely on the /version
endpoint that Headscale has exposed since 0.26 (our lowest supported
version). Switching to that significantly simplifies the API surface.

app/server/headscale/api/capabilities.ts

@@ -0,0 +1,55 @@
+// MARK: Headscale Capabilities
+//
+// Behavioural facts about the connected Headscale server, derived
+// once from `ServerVersion` at boot. Capabilities are named for *what
+// changed* — not for the version number it changed in — so a reader
+// who has never seen Headscale can tell what each flag controls
+// without consulting a release note.
+//
+// Add a capability here when you find yourself reaching for a raw
+// version comparison in endpoint or route code. Adding a capability
+// is also the right answer when a new Headscale release changes wire
+// format or removes an endpoint.
+
+import { gte, type ServerVersion } from "./server-version";
+
+export interface Capabilities {
+  /**
+   * Pre-auth keys have stable IDs. `GET /api/v1/preauthkey` (no
+   * user filter) returns every key in the system, and
+   * `POST /api/v1/preauthkey/expire` takes `{ id }` instead of
+   * `{ user, key }`. Tag-only pre-auth keys (no owning user) are
+   * supported. Introduced in 0.28.0.
+   */
+  readonly preAuthKeysHaveStableIds: boolean;
+
+  /**
+   * Node tags are a flat `tags: string[]` field on the wire.
+   * Pre-0.28 returned `forcedTags` / `validTags` / `invalidTags`
+   * that the client had to union itself. Introduced in 0.28.0.
+   */
+  readonly nodeTagsAreFlat: boolean;
+
+  /**
+   * A node's owning user is immutable after creation;
+   * `POST /api/v1/node/{id}/user` no longer reassigns. Effective in
+   * 0.28.0+.
+   */
+  readonly nodeOwnerIsImmutable: boolean;
+
+  /**
+   * Policy parse errors use the modern `parsing HuJSON:` /
+   * `parsing policy from bytes:` prefixes. Pre-0.27 emitted
+   * `parsing hujson` / `unmarshalling policy`. Introduced in 0.27.0.
+   */
+  readonly policyErrorsUseModernFormat: boolean;
+}
+
+export function capabilitiesFor(version: ServerVersion): Capabilities {
+  return {
+    preAuthKeysHaveStableIds: gte(version, "0.28.0"),
+    nodeTagsAreFlat: gte(version, "0.28.0"),
+    nodeOwnerIsImmutable: gte(version, "0.28.0"),
+    policyErrorsUseModernFormat: gte(version, "0.27.0"),
+  };
+}

app/server/headscale/api/endpoints/api-keys.ts

@@ -1,20 +0,0 @@
-import type { Key } from "~/types";
-
-import { defineApiEndpoints } from "../factory";
-
-export interface ApiKeyEndpoints {
-  /**
-   * Retrieves all API keys from the Headscale instance.
-   *
-   * @returns An array of `Key` objects representing the API keys.
-   */
-  getApiKeys(): Promise<Key[]>;
-}
-
-export default defineApiEndpoints<ApiKeyEndpoints>((client, apiKey) => ({
-  getApiKeys: async () => {
-    const { apiKeys } = await client.apiFetch<{ apiKeys: Key[] }>("GET", "v1/apikey", apiKey);
-
-    return apiKeys;
-  },
-}));

app/server/headscale/api/endpoints/index.ts

@@ -1,75 +0,0 @@
-import {
-  composeEndpoints,
-  defineApiEndpoints,
-  type ExtractApiEndpoints,
-  type UnionToIntersection,
-} from "../factory";
-import type { HeadscaleApiInterface } from "../index";
-import apiKeyEndpoints from "./api-keys";
-import nodeEndpoints from "./nodes";
-import policyEndpoints from "./policy";
-import preAuthKeyEndpoints from "./pre-auth-keys";
-import userEndpoints from "./users";
-
-interface HealthcheckEndpoint {
-  /**
-   * Checks if the Headscale instance is healthy.
-   *
-   * @returns A boolean indicating if the instance is healthy.
-   */
-  isHealthy(): Promise<boolean>;
-}
-
-const healthcheckEndpoint = defineApiEndpoints<HealthcheckEndpoint>((client, apiKey) => ({
-  isHealthy: async () => {
-    try {
-      const res = await client.rawFetch("/health", {
-        method: "GET",
-        headers: {
-          // This doesn't really matter
-          Authorization: `Bearer ${apiKey}`,
-        },
-      });
-
-      return res.statusCode === 200;
-    } catch {
-      return false;
-    }
-  },
-}));
-
-/**
- * A constant list of all endpoint groups.
- * Add new endpoint groups here.
- */
-export const endpointSets = [
-  apiKeyEndpoints,
-  healthcheckEndpoint,
-  nodeEndpoints,
-  policyEndpoints,
-  preAuthKeyEndpoints,
-  userEndpoints,
-] as const;
-
-/**
- * All of the available API methods when interacting with Headscale's API.
- * We have wrapped each operation with nice methods and parameters to make it
- * easier to do integration testing by spinning up an actual Headscale instance
- * and calling these methods against it.
- *
- * We also have the benefit of supporting multiple Headscale versions by
- * passing in different internal implementations based on the OpenAPI spec.
- */
-export type RuntimeApiClient = UnionToIntersection<
-  ExtractApiEndpoints<(typeof endpointSets)[number]>
->;
-
-/**
- * Composes all endpoint groups into a single runtime API client.
- *
- * @param client - The client helpers for making API requests.
- * @param apiKey - The API key for authentication.
- * @returns A fully composed runtime API client.
- */
-export default (client: HeadscaleApiInterface["clientHelpers"], apiKey: string) =>
-  composeEndpoints(endpointSets, client, apiKey);

app/server/headscale/api/endpoints/nodes.ts

@@ -1,171 +0,0 @@
-import type { Machine } from "~/types";
-
-import type { HeadscaleApiInterface } from "..";
-import { defineApiEndpoints } from "../factory";
-
-interface RawMachine extends Omit<Machine, "tags"> {
-  tags?: string[];
-  forcedTags?: string[];
-  validTags?: string[];
-  invalidTags?: string[];
-}
-
-/**
- * Normalizes the tags of a RawMachine based on the Headscale version.
- *
- * @param client The Headscale API client helper.
- * @param node The RawMachine object to normalize.
- * @returns A Machine object with normalized tags.
- */
-function normalizeTags(client: HeadscaleApiInterface["clientHelpers"], node: RawMachine): Machine {
-  if (client.isAtleast("0.28.0")) {
-    return { ...node, tags: node.tags ?? [] } as Machine;
-  }
-
-  const tags = Array.from(new Set([...(node.forcedTags ?? []), ...(node.validTags ?? [])]));
-
-  return { ...node, tags } as Machine;
-}
-
-export interface NodeEndpoints {
-  /**
-   * Retrieves all nodes (machines) from the Headscale instance.
-   *
-   * @returns An array of `Machine` objects representing the nodes.
-   */
-  getNodes(): Promise<Machine[]>;
-
-  /**
-   * Retrieves a specific node (machine) by its ID.
-   *
-   * @param id The ID of the node to retrieve.
-   * @returns A `Machine` object representing the node.
-   */
-  getNode(id: string): Promise<Machine>;
-
-  /**
-   * Deletes a specific node (machine) by its ID.
-   *
-   * @param id The ID of the node to delete.
-   */
-  deleteNode(id: string): Promise<void>;
-
-  /**
-   * Registers a new node (machine) with the given user and key.
-   *
-   * @param user The user to associate with the node.
-   * @param key The registration key for the node.
-   * @returns A `Machine` object representing the newly registered node.
-   */
-  registerNode(user: string, key: string): Promise<Machine>;
-
-  /**
-   * Approves routes for a specific node (machine) by its ID.
-   *
-   * @param id The ID of the node.
-   * @param routes An array of routes to approve for the node.
-   */
-  approveNodeRoutes(id: string, routes: string[]): Promise<void>;
-
-  /**
-   * Expires a specific node (machine) by its ID.
-   *
-   * @param id The ID of the node to expire.
-   */
-  expireNode(id: string): Promise<void>;
-
-  /**
-   * Renames a specific node (machine) by its ID.
-   *
-   * @param id The ID of the node to rename.
-   * @param newName The new name for the node.
-   */
-  renameNode(id: string, newName: string): Promise<void>;
-
-  /**
-   * Sets tags for a specific node (machine) by its ID.
-   *
-   * @param id The ID of the node.
-   * @param tags An array of tags to set for the node.
-   */
-  setNodeTags(id: string, tags: string[]): Promise<void>;
-
-  /**
-   * Sets the user for a specific node (machine) by its ID.
-   *
-   * @param id The ID of the node.
-   * @param user The user to set for the node.
-   */
-  setNodeUser(id: string, user: string): Promise<void>;
-}
-
-export default defineApiEndpoints<NodeEndpoints>((client, apiKey) => ({
-  getNodes: async () => {
-    const { nodes } = await client.apiFetch<{ nodes: RawMachine[] }>("GET", "v1/node", apiKey);
-    return nodes.map((node) => normalizeTags(client, node));
-  },
-
-  getNode: async (nodeId) => {
-    const { node } = await client.apiFetch<{ node: RawMachine }>(
-      "GET",
-      `v1/node/${nodeId}`,
-      apiKey,
-    );
-
-    return normalizeTags(client, node);
-  },
-
-  deleteNode: async (nodeId) => {
-    await client.apiFetch<void>("DELETE", `v1/node/${nodeId}`, apiKey);
-  },
-
-  registerNode: async (user, key) => {
-    const qp = new URLSearchParams();
-    qp.append("user", user);
-    qp.append("key", key);
-    const { node } = await client.apiFetch<{ node: RawMachine }>(
-      "POST",
-      `v1/node/register?${qp.toString()}`,
-      apiKey,
-      {
-        user,
-        key,
-      },
-    );
-
-    return normalizeTags(client, node);
-  },
-
-  approveNodeRoutes: async (nodeId, routes) => {
-    await client.apiFetch<void>("POST", `v1/node/${nodeId}/approve_routes`, apiKey, { routes });
-  },
-
-  expireNode: async (nodeId) => {
-    await client.apiFetch<void>("POST", `v1/node/${nodeId}/expire`, apiKey);
-  },
-
-  renameNode: async (nodeId, newName) => {
-    await client.apiFetch<void>(
-      "POST",
-      `v1/node/${nodeId}/rename/${encodeURIComponent(newName)}`,
-      apiKey,
-    );
-  },
-
-  setNodeTags: async (nodeId, tags) => {
-    await client.apiFetch<void>("POST", `v1/node/${nodeId}/tags`, apiKey, {
-      tags,
-    });
-  },
-
-  setNodeUser: async (nodeId, user) => {
-    // Headscale 0.28.0 got rid of node reassignment to users
-    if (client.isAtleast("0.28.0")) {
-      return;
-    }
-
-    await client.apiFetch<void>("POST", `v1/node/${nodeId}/user`, apiKey, {
-      user,
-    });
-  },
-}));

app/server/headscale/api/endpoints/policy.ts

@@ -1,41 +0,0 @@
-import { defineApiEndpoints } from "../factory";
-
-export interface PolicyEndpoints {
-  /**
-   * Retrieves the current ACL policy from the Headscale instance.
-   *
-   * @returns The ACL policy as a string and the date it was last updated.
-   */
-  getPolicy(): Promise<{ policy: string; updatedAt: Date | null }>;
-
-  /**
-   * Sets the ACL policy for the Headscale instance.
-   *
-   * @param policy The ACL policy as a string.
-   * @returns The updated ACL policy as a string and the date it was last updated.
-   */
-  setPolicy(policy: string): Promise<{ policy: string; updatedAt: Date }>;
-}
-
-export default defineApiEndpoints<PolicyEndpoints>((client, apiKey) => ({
-  getPolicy: async () => {
-    const { policy, updatedAt } = await client.apiFetch<{
-      policy: string;
-      updatedAt: string;
-    }>("GET", "v1/policy", apiKey);
-
-    return {
-      policy,
-      updatedAt: updatedAt !== null ? new Date(updatedAt) : null,
-    };
-  },
-
-  setPolicy: async (policy) => {
-    const { policy: newPolicy, updatedAt } = await client.apiFetch<{
-      policy: string;
-      updatedAt: string;
-    }>("PUT", "v1/policy", apiKey, { policy });
-
-    return { policy: newPolicy, updatedAt: new Date(updatedAt) };
-  },
-}));

app/server/headscale/api/endpoints/pre-auth-keys.ts

@@ -1,93 +0,0 @@
-import type { PreAuthKey } from "~/types";
-
-import { defineApiEndpoints } from "../factory";
-
-export interface PreAuthKeyEndpoints {
-  /**
-   * List all pre-auth keys. Requires Headscale 0.28+.
-   */
-  getAllPreAuthKeys(): Promise<PreAuthKey[]>;
-
-  /**
-   * Retrieves all pre-authentication keys for a specific user.
-   *
-   * @param user The user to retrieve pre-authentication keys for.
-   * @returns An array of `PreAuthKey` objects representing the pre-authentication keys.
-   */
-  getPreAuthKeys(user: string): Promise<PreAuthKey[]>;
-
-  /**
-   * Creates a new pre-authentication key.
-   * User can be null for tag-only keys (requires Headscale 0.28+).
-   */
-  createPreAuthKey(
-    user: string | null,
-    ephemeral: boolean,
-    reusable: boolean,
-    expiration: Date | null,
-    aclTags: string[] | null,
-  ): Promise<PreAuthKey>;
-
-  /**
-   * Expires a specific pre-authentication key for a user.
-   *
-   * @param user The user associated with the pre-authentication key.
-   * @param key The pre-authentication key to expire.
-   */
-  expirePreAuthKey(user: string, key: PreAuthKey): Promise<void>;
-}
-
-export default defineApiEndpoints<PreAuthKeyEndpoints>((client, apiKey) => ({
-  getAllPreAuthKeys: async () => {
-    const { preAuthKeys } = await client.apiFetch<{
-      preAuthKeys: PreAuthKey[];
-    }>("GET", "v1/preauthkey", apiKey, {});
-
-    return preAuthKeys;
-  },
-
-  getPreAuthKeys: async (user) => {
-    const { preAuthKeys } = await client.apiFetch<{
-      preAuthKeys: PreAuthKey[];
-    }>("GET", "v1/preauthkey", apiKey, { user });
-
-    return preAuthKeys;
-  },
-
-  createPreAuthKey: async (user, ephemeral, reusable, expiration, aclTags) => {
-    const body: Record<string, unknown> = {
-      ephemeral,
-      reusable,
-      expiration: expiration ? expiration.toISOString() : null,
-    };
-
-    if (user) {
-      body.user = user;
-    }
-
-    if (aclTags && aclTags.length > 0) {
-      body.aclTags = aclTags;
-    }
-
-    const { preAuthKey } = await client.apiFetch<{
-      preAuthKey: PreAuthKey;
-    }>("POST", "v1/preauthkey", apiKey, body);
-
-    return preAuthKey;
-  },
-
-  expirePreAuthKey: async (user, key) => {
-    if (client.isAtleast("0.28.0")) {
-      await client.apiFetch<void>("POST", "v1/preauthkey/expire", apiKey, {
-        id: key.id,
-      });
-
-      return;
-    }
-
-    await client.apiFetch<void>("POST", "v1/preauthkey/expire", apiKey, {
-      user,
-      key: key.key,
-    });
-  },
-}));

app/server/headscale/api/endpoints/users.ts

@@ -1,87 +0,0 @@
-import type { User } from "~/types";
-
-import { defineApiEndpoints } from "../factory";
-
-export interface UserEndpoints {
-  /**
-   * Retrieves users from the Headscale instance, optionally filtering by ID, name, or email.
-   *
-   * @param id Optional ID of the user to retrieve.
-   * @param name Optional name of the user to retrieve.
-   * @param email Optional email of the user to retrieve.
-   * @returns An array of `User` objects representing the users.
-   */
-  getUsers(id?: string, name?: string, email?: string): Promise<User[]>;
-
-  /**
-   * Creates a new user in the Headscale instance.
-   *
-   * @param username The username of the new user.
-   * @param email Optional email of the new user.
-   * @param displayName Optional display name of the new user.
-   * @param pictureUrl Optional picture URL of the new user.
-   * @returns A `User` object representing the newly created user.
-   */
-  createUser(
-    username: string,
-    email?: string,
-    displayName?: string,
-    pictureUrl?: string,
-  ): Promise<User>;
-
-  /**
-   * Deletes a specific user by its ID.
-   *
-   * @param id The ID of the user to delete.
-   */
-  deleteUser(id: string): Promise<void>;
-
-  /**
-   * Renames a specific user by its ID.
-   *
-   * @param id The ID of the user to rename.
-   * @param newName The new name for the user.
-   */
-  renameUser(id: string, newName: string): Promise<void>;
-}
-
-export default defineApiEndpoints<UserEndpoints>((client, apiKey) => ({
-  getUsers: async (id, name, email) => {
-    const moreThanOneFilter = [id, name, email].filter((v) => v !== undefined).length > 1;
-
-    if (moreThanOneFilter) {
-      throw new Error("Only one of id, name, or email filters can be provided");
-    }
-
-    const { users } = await client.apiFetch<{ users: User[] }>("GET", "v1/user", apiKey, {
-      id,
-      name,
-      email,
-    });
-
-    return users;
-  },
-
-  createUser: async (username, email, displayName, pictureUrl) => {
-    const { user } = await client.apiFetch<{ user: User }>("POST", "v1/user", apiKey, {
-      name: username,
-      email,
-      displayName,
-      pictureUrl,
-    });
-
-    return user;
-  },
-
-  deleteUser: async (id) => {
-    await client.apiFetch<void>("DELETE", `v1/user/${id}`, apiKey);
-  },
-
-  renameUser: async (oldId, newName) => {
-    await client.apiFetch<void>(
-      "POST",
-      `v1/user/${oldId}/rename/${encodeURIComponent(newName)}`,
-      apiKey,
-    );
-  },
-}));

app/server/headscale/api/factory.ts

@@ -1,38 +0,0 @@
-import type { HeadscaleApiInterface } from "../api";
-
-/**
- * Creates a strongly-typed group factory for a given endpoint interface.
- *
- * Example:
- *   export const apiKeyGroup = defineGroup<ApiKeyEndpoints>({...})
- */
-
-export interface EndpointFactory<T extends object> {
-  __type?: T;
-  (client: HeadscaleApiInterface["clientHelpers"], apiKey: string): T;
-}
-
-export function defineApiEndpoints<T extends object>(
-  factories: (client: HeadscaleApiInterface["clientHelpers"], apiKey: string) => T,
-): EndpointFactory<T> {
-  return factories;
-}
-
-export type ExtractApiEndpoints<F> = F extends EndpointFactory<infer T> ? T : never;
-export type UnionToIntersection<U> = (U extends any ? (k: U) => void : never) extends (
-  k: infer I,
-) => void
-  ? I
-  : never;
-
-/**
- * Compose multiple endpoint sets into a single typed runtime client
- */
-export function composeEndpoints<T extends readonly EndpointFactory<any>[]>(
-  factories: T,
-  clientHelpers: any,
-  apiKey: string,
-): UnionToIntersection<ExtractApiEndpoints<T[number]>> {
-  const instances = factories.map((f) => f(clientHelpers, apiKey));
-  return Object.assign({}, ...instances) as any;
-}

app/server/headscale/api/hasher.ts

@@ -1,51 +0,0 @@
-import { createHash } from "node:crypto";
-
-import { dereference } from "@readme/openapi-parser";
-import { OpenAPIV2 } from "openapi-types";
-
-/**
- * A map of operation IDs to their hashes.
- */
-export interface DocumentHash {
-  [operationId: string]: string;
-}
-
-/**
- * Given an OpenAPI v2 document, generate a map of operations with hashes.
- * This gives us deterministic identifers to determine the version of Headscale
- * that is being used at runtime.
- *
- * @param doc The OpenAPI v2 document to hash.
- * @returns A map of operation IDs to their hashes.
- */
-export async function hashOpenApiDocument(doc: OpenAPIV2.Document): Promise<DocumentHash> {
-  const spec = await dereference(doc);
-  const hashes: DocumentHash = {};
-  const seen = new Set<string>();
-
-  for (const [path, item] of Object.entries(spec.paths)) {
-    for (const [method, operation] of Object.entries(item)) {
-      if (typeof operation !== "object") {
-        continue;
-      }
-
-      const { parameters, responses } = operation as OpenAPIV2.OperationObject;
-      const raw = JSON.stringify(
-        {
-          path,
-          method: method.toUpperCase(),
-          parameters,
-          responses,
-        },
-        Object.keys({ path, method, parameters, responses }).sort(),
-      );
-
-      const hash = createHash("md5").update(raw).digest("hex").slice(0, 16);
-      const final = seen.has(hash) ? `${hash}_${seen.size}` : hash;
-      seen.add(final);
-      hashes[`${method.toUpperCase()} ${path}`] = final;
-    }
-  }
-
-  return hashes;
-}

app/server/headscale/api/index.ts

@@ -1,328 +1,92 @@
-import { createHash } from "node:crypto";
-import { readFile } from "node:fs/promises";
-
-import { dereference } from "@readme/openapi-parser";
-import type { OpenAPIV2 } from "openapi-types";
-import { data } from "react-router";
-import { Agent, type Dispatcher, request } from "undici";
+// MARK: Headscale API
+//
+// The public entry point for talking to a Headscale server. Boot
+// detects the server version via `GET /version` (unauthenticated,
+// available since Headscale 0.26.0), derives a typed `Capabilities`
+// object, and returns a `Headscale` value that constructs
+// authenticated `HeadscaleClient`s on demand.
 
 import log from "~/utils/log";
 
-import endpointSets, { RuntimeApiClient } from "./endpoints";
-import { undiciToFriendlyError } from "./error";
-import { HeadscaleAPIError, isApiError } from "./error-client";
-import { detectApiVersion, isAtLeast, type Version } from "./version";
+import { type Capabilities, capabilitiesFor } from "./capabilities";
+import { type ApiKeyApi, makeApiKeyApi } from "./resources/api-keys";
+import { makeNodeApi, type NodeApi } from "./resources/nodes";
+import { makePolicyApi, type PolicyApi } from "./resources/policy";
+import { makePreAuthKeyApi, type PreAuthKeyApi } from "./resources/pre-auth-keys";
+import { makeUserApi, type UserApi } from "./resources/users";
+import { formatServerVersion, parseServerVersion, type ServerVersion } from "./server-version";
+import { createTransport, type Transport } from "./transport";
 
-/**
- * A low-level composed interface for interacting with the Headscale API.
- * This interface provides direct access to the underlying Undici agent
- * and methods for making API requests.
- *
- * It is also responsible for handling OpenAPI spec polling and hashing to
- * determine the implementations of API methods when requested for use.
- */
-export interface HeadscaleApiInterface {
-  /**
-   * The underlying Undici agent used for making requests.
-   */
-  undiciAgent: Agent;
-
-  /**
-   * The base URL of the Headscale API.
-   */
-  baseUrl: string;
-
-  /**
-   * The OpenAPI hashes retrieved from the Headscale instance at runtime.
-   * This is used to determine which implementations of API methods to use.
-   */
-  openapiHashes: Record<string, string> | null;
-
-  /**
-   * The detected API version of the connected Headscale instance.
-   */
-  apiVersion: Version;
-
-  /**
-   * Retrieves a runtime API client for the given API key.
-   *
-   * @param apiKey The API key to use for authentication.
-   * @returns A `RuntimeApiClient` instance for interacting with the API.
-   */
-  getRuntimeClient(apiKey: string): RuntimeApiClient;
-
-  /**
-   * A set of helper methods made available to API method implementations.
-   * The idea is to make interacting with the API easier by providing
-   * common functionality that can be reused across multiple methods.
-   */
-  clientHelpers: {
-    /**
-     * Checks if the connected Headscale instance's API version
-     * is at least the specified version.
-     *
-     * @param version The version to check against.
-     * @returns `true` if the API version is at least the specified version, `false` otherwise.
-     */
-    isAtleast(version: Version): boolean;
-
-    /**
-     * Makes a raw fetch request to the Headscale API via the Undici agent.
-     * This method is used internally by API method implementations
-     * to make requests to the Headscale API.
-     *
-     * @param path The API path to request.
-     * @param options Optional request options.
-     * @returns A promise that resolves to the response data.
-     */
-    rawFetch(
-      path: string,
-      options?: Partial<Dispatcher.RequestOptions>,
-    ): Promise<Dispatcher.ResponseData>;
-
-    /**
-     * Makes a typed API fetch request to the Headscale API.
-     * This method is used internally by API method implementations
-     * to make requests to the Headscale API and parse the response.
-     *
-     * @param method The HTTP method to use.
-     * @param apiPath The API path to request.
-     * @param apiKey The API key to use for authentication.
-     * @param bodyOrQuery Optional body or query parameters.
-     * @returns A promise that resolves to the typed response data.
-     */
-    apiFetch<T>(
-      method: "GET" | "POST" | "PUT" | "DELETE" | "PATCH",
-      apiPath: `v1/${string}`,
-      apiKey: string,
-      bodyOrQuery?: Record<string, unknown>,
-    ): Promise<T>;
-  };
+export interface Headscale {
+  readonly version: ServerVersion;
+  readonly capabilities: Capabilities;
+  /** True if the Headscale server's `/health` endpoint returns 200. */
+  health(): Promise<boolean>;
+  /** Build an API client bound to a specific Headscale API key. */
+  client(apiKey: string): HeadscaleClient;
+  /** Stop background work and close the underlying HTTP agent. */
+  dispose(): Promise<void>;
 }
 
-/**
- * Creates a new Headscale API client interface.
- *
- * @param baseUrl The base URL of the Headscale API.
- * @param certPath Optional path to a custom TLS certificate for secure connections.
- * @returns A promise that resolves to a `HeadscaleApiClient` instance.
- */
-export async function createHeadscaleInterface(
-  baseUrl: string,
-  certPath?: string,
-): Promise<HeadscaleApiInterface> {
-  const undiciAgent = await createUndiciAgent(certPath);
-  let openapiHashes: Record<string, string> | null = null;
-  let apiVersion: Version;
-
-  const rawFetch = async (
-    url: string,
-    options?: Partial<Dispatcher.RequestOptions>,
-  ): Promise<Dispatcher.ResponseData> => {
-    const method = options?.method ?? "GET";
-    log.debug("api", "%s %s", method, url);
-
-    try {
-      const res = await request(new URL(url, baseUrl), {
-        dispatcher: undiciAgent,
-        headers: {
-          ...options?.headers,
-          Accept: "application/json",
-          "User-Agent": `Headplane/${__VERSION__}`,
-        },
-
-        body: options?.body,
-        method,
-      });
-
-      return res;
-    } catch (error) {
-      const errorBody = undiciToFriendlyError(error, `${method} ${url}`);
-      throw data(errorBody, {
-        status: 502,
-        statusText: "Bad Gateway",
-      });
-    }
-  };
-
-  const apiFetch = async <T>(
-    method: "GET" | "POST" | "PUT" | "DELETE" | "PATCH",
-    apiPath: `v1/${string}`,
-    apiKey: string,
-    bodyOrQuery?: Record<string, unknown>,
-  ): Promise<T> => {
-    let url = `/api/${apiPath}`;
-    const options: Partial<Dispatcher.RequestOptions> = {
-      method: method,
-      headers: {
-        Authorization: `Bearer ${apiKey}`,
-      },
-    };
-
-    if (bodyOrQuery) {
-      if (method === "GET" || method === "DELETE") {
-        const params = new URLSearchParams();
-        for (const [key, value] of Object.entries(bodyOrQuery)) {
-          if (value !== undefined) {
-            params.append(key, String(value));
-          }
-        }
-
-        if ([...params.keys()].length > 0) {
-          url += `?${params.toString()}`;
-        }
-      } else {
-        options.body = JSON.stringify(bodyOrQuery);
-        options.headers = {
-          ...options.headers,
-          "Content-Type": "application/json",
-        };
-      }
-    }
-
-    const res = await rawFetch(url, options);
-    if (res.statusCode >= 400) {
-      log.debug("api", "%s %s failed with status %d", method, apiPath, res.statusCode);
-      const rawData = await res.body.text();
-      const jsonData = (() => {
-        try {
-          return JSON.parse(rawData) as Record<string, unknown>;
-        } catch {
-          return null;
-        }
-      })();
-
-      throw data(
-        {
-          requestUrl: `${method} ${apiPath}`,
-          statusCode: res.statusCode,
-          rawData,
-          data: jsonData,
-        } satisfies HeadscaleAPIError,
-        { status: 502, statusText: "Bad Gateway" },
-      );
-    }
-
-    return res.body.json() as Promise<T>;
-  };
-
+export interface HeadscaleClient {
+  nodes: NodeApi;
+  users: UserApi;
+  policy: PolicyApi;
+  preAuthKeys: PreAuthKeyApi;
+  apiKeys: ApiKeyApi;
   /**
-   * Polls the OpenAPI spec endpoint and generates operation hashes.
-   * This is used to determine which implementations of API methods to use.
-   *
-   * @returns A promise that resolves to the OpenAPI operation hashes.
+   * Convenience passthrough to `Headscale.health()`. Headscale's
+   * `/health` endpoint is unauthenticated so callers that already
+   * have a client (loaders/actions) don't need to also reach for
+   * the top-level `Headscale` value.
    */
-  async function fetchAndHashOpenapi(): Promise<Record<string, string> | null> {
-    try {
-      const res = await rawFetch("/swagger/v1/openapiv2.json");
-      if (res.statusCode !== 200) {
-        log.error("api", "Failed to fetch OpenAPI spec: %d", res.statusCode);
-        return null;
-      }
+  isHealthy(): Promise<boolean>;
+}
 
-      const body = await res.body.json();
-      const spec = await dereference(body as OpenAPIV2.Document);
-      const hashes = generateSpecHashes(spec);
-      log.debug("api", "OpenAPI hashes updated (%d endpoints)", Object.keys(hashes).length);
-      return hashes;
-    } catch (error) {
-      if (isApiError(error)) {
-        log.debug("api", "Failed to fetch OpenAPI spec: %d", error.statusCode);
-      }
+export interface CreateHeadscaleOptions {
+  url: string;
+  certPath?: string;
+}
 
-      return null;
-    }
+export async function createHeadscale(opts: CreateHeadscaleOptions): Promise<Headscale> {
+  const transport = await createTransport({ url: opts.url, certPath: opts.certPath });
+
+  const versionInfo = await transport.getPublic<{ version: string }>("/version");
+  const version = parseServerVersion(versionInfo.version);
+  const capabilities = capabilitiesFor(version);
+
+  if (version.unknown) {
+    log.warn(
+      "api",
+      "Could not parse Headscale version %s, assuming newest known capabilities",
+      versionInfo.version,
+    );
+  } else {
+    log.info("api", "Connected to Headscale %s", formatServerVersion(version));
   }
 
-  const isAtleast = (version: Version): boolean => {
-    return isAtLeast(apiVersion, version);
-  };
-
-  openapiHashes = await fetchAndHashOpenapi();
-  apiVersion = detectApiVersion(openapiHashes);
-
-  setInterval(async () => {
-    const hashes = await fetchAndHashOpenapi();
-    if (hashes) {
-      openapiHashes = hashes;
-      apiVersion = detectApiVersion(openapiHashes);
-    }
-  }, 60_000); // every 60 seconds
+  return makeHeadscale(transport, version, capabilities);
+}
 
+function makeHeadscale(
+  transport: Transport,
+  version: ServerVersion,
+  capabilities: Capabilities,
+): Headscale {
   return {
-    undiciAgent,
-    baseUrl,
-    openapiHashes,
-    apiVersion,
-    getRuntimeClient: (apiKey: string) => {
-      return endpointSets(
-        {
-          rawFetch,
-          apiFetch,
-          isAtleast,
-        },
-        apiKey,
-      );
-    },
-    clientHelpers: {
-      rawFetch,
-      apiFetch,
-      isAtleast,
+    version,
+    capabilities,
+    health: () => transport.health(),
+    client(apiKey) {
+      return {
+        nodes: makeNodeApi(transport, capabilities, apiKey),
+        users: makeUserApi(transport, capabilities, apiKey),
+        policy: makePolicyApi(transport, capabilities, apiKey),
+        preAuthKeys: makePreAuthKeyApi(transport, capabilities, apiKey),
+        apiKeys: makeApiKeyApi(transport, capabilities, apiKey),
+        isHealthy: () => transport.health(),
+      };
     },
+    dispose: () => transport.dispose(),
   };
 }
-
-/**
- * Creates a new Undici agent for making HTTP requests.
- *
- * @param certPath Optional path to a custom TLS certificate for secure connections.
- * @returns A promise that resolves to an `Agent` instance.
- */
-async function createUndiciAgent(certPath?: string): Promise<Agent> {
-  if (!certPath) {
-    return new Agent();
-  }
-
-  try {
-    log.debug("config", "Loading certificate from %s", certPath);
-    const data = await readFile(certPath, "utf8");
-
-    log.info("config", "Using certificate from %s", certPath);
-    return new Agent({ connect: { ca: data.trim() } });
-  } catch (error) {
-    log.error("config", "Failed to load Headscale TLS cert: %s", error);
-    log.debug("config", "Error Details: %o", error);
-    return new Agent();
-  }
-}
-
-function generateSpecHashes(spec: OpenAPIV2.Document) {
-  const hashes: Record<string, string> = {};
-  const seen = new Set<string>();
-
-  for (const [path, item] of Object.entries(spec.paths)) {
-    for (const [method, operation] of Object.entries(item)) {
-      if (typeof operation !== "object") {
-        continue;
-      }
-
-      const { parameters, responses } = operation as OpenAPIV2.OperationObject;
-      const raw = JSON.stringify(
-        {
-          path,
-          method: method.toUpperCase(),
-          parameters,
-          responses,
-        },
-        Object.keys({ path, method, parameters, responses }).sort(),
-      );
-
-      const hash = createHash("md5").update(raw).digest("hex").slice(0, 16);
-      const final = seen.has(hash) ? `${hash}_${seen.size}` : hash;
-      seen.add(final);
-      hashes[`${method.toUpperCase()} ${path}`] = final;
-    }
-  }
-
-  return hashes;
-}

app/server/headscale/api/resources/api-keys.ts

@@ -0,0 +1,25 @@
+import type { Key } from "~/types";
+
+import type { Capabilities } from "../capabilities";
+import type { Transport } from "../transport";
+
+export interface ApiKeyApi {
+  list(): Promise<Key[]>;
+}
+
+export function makeApiKeyApi(
+  transport: Transport,
+  _capabilities: Capabilities,
+  apiKey: string,
+): ApiKeyApi {
+  return {
+    list: async () => {
+      const { apiKeys } = await transport.request<{ apiKeys: Key[] }>({
+        method: "GET",
+        path: "v1/apikey",
+        apiKey,
+      });
+      return apiKeys;
+    },
+  };
+}

app/server/headscale/api/resources/nodes.ts

@@ -0,0 +1,116 @@
+import type { Machine } from "~/types";
+
+import type { Capabilities } from "../capabilities";
+import type { Transport } from "../transport";
+
+interface RawMachine extends Omit<Machine, "tags"> {
+  tags?: string[];
+  forcedTags?: string[];
+  validTags?: string[];
+  invalidTags?: string[];
+}
+
+export interface NodeApi {
+  list(): Promise<Machine[]>;
+  get(id: string): Promise<Machine>;
+  delete(id: string): Promise<void>;
+  register(user: string, key: string): Promise<Machine>;
+  approveRoutes(id: string, routes: string[]): Promise<void>;
+  expire(id: string): Promise<void>;
+  rename(id: string, newName: string): Promise<void>;
+  setTags(id: string, tags: string[]): Promise<void>;
+  /**
+   * Reassign a node to a different user. Only present when
+   * `capabilities.nodeOwnerIsImmutable` is false (Headscale < 0.28).
+   */
+  reassignUser?: (id: string, user: string) => Promise<void>;
+}
+
+export function makeNodeApi(
+  transport: Transport,
+  capabilities: Capabilities,
+  apiKey: string,
+): NodeApi {
+  function normalize(raw: RawMachine): Machine {
+    if (capabilities.nodeTagsAreFlat) {
+      return { ...raw, tags: raw.tags ?? [] } as Machine;
+    }
+    const tags = Array.from(new Set([...(raw.forcedTags ?? []), ...(raw.validTags ?? [])]));
+    return { ...raw, tags } as Machine;
+  }
+
+  const api: NodeApi = {
+    list: async () => {
+      const { nodes } = await transport.request<{ nodes: RawMachine[] }>({
+        method: "GET",
+        path: "v1/node",
+        apiKey,
+      });
+      return nodes.map(normalize);
+    },
+    get: async (id) => {
+      const { node } = await transport.request<{ node: RawMachine }>({
+        method: "GET",
+        path: `v1/node/${id}`,
+        apiKey,
+      });
+      return normalize(node);
+    },
+    delete: async (id) => {
+      await transport.request({ method: "DELETE", path: `v1/node/${id}`, apiKey });
+    },
+    register: async (user, key) => {
+      // Headscale's node-register endpoint expects the registration
+      // params as both query string and body — preserved as-is.
+      const qp = new URLSearchParams();
+      qp.append("user", user);
+      qp.append("key", key);
+      const { node } = await transport.request<{ node: RawMachine }>({
+        method: "POST",
+        path: `v1/node/register?${qp.toString()}`,
+        apiKey,
+        body: { user, key },
+      });
+      return normalize(node);
+    },
+    approveRoutes: async (id, routes) => {
+      await transport.request({
+        method: "POST",
+        path: `v1/node/${id}/approve_routes`,
+        apiKey,
+        body: { routes },
+      });
+    },
+    expire: async (id) => {
+      await transport.request({ method: "POST", path: `v1/node/${id}/expire`, apiKey });
+    },
+    rename: async (id, newName) => {
+      await transport.request({
+        method: "POST",
+        path: `v1/node/${id}/rename/${encodeURIComponent(newName)}`,
+        apiKey,
+      });
+    },
+    setTags: async (id, tags) => {
+      await transport.request({
+        method: "POST",
+        path: `v1/node/${id}/tags`,
+        apiKey,
+        body: { tags },
+      });
+    },
+  };
+
+  if (!capabilities.nodeOwnerIsImmutable) {
+    api.reassignUser = async (id, user) => {
+      await transport.request({
+        method: "POST",
+        path: `v1/node/${id}/user`,
+        apiKey,
+        body: { user },
+      });
+    };
+  }
+
+  return api;
+}

app/server/headscale/api/resources/policy.ts

@@ -0,0 +1,33 @@
+import type { Capabilities } from "../capabilities";
+import type { Transport } from "../transport";
+
+export interface PolicyApi {
+  get(): Promise<{ policy: string; updatedAt: Date | null }>;
+  set(policy: string): Promise<{ policy: string; updatedAt: Date }>;
+}
+
+export function makePolicyApi(
+  transport: Transport,
+  _capabilities: Capabilities,
+  apiKey: string,
+): PolicyApi {
+  return {
+    get: async () => {
+      const { policy, updatedAt } = await transport.request<{
+        policy: string;
+        updatedAt: string;
+      }>({ method: "GET", path: "v1/policy", apiKey });
+      return {
+        policy,
+        updatedAt: updatedAt !== null ? new Date(updatedAt) : null,
+      };
+    },
+    set: async (policy) => {
+      const { policy: newPolicy, updatedAt } = await transport.request<{
+        policy: string;
+        updatedAt: string;
+      }>({ method: "PUT", path: "v1/policy", apiKey, body: { policy } });
+      return { policy: newPolicy, updatedAt: new Date(updatedAt) };
+    },
+  };
+}

app/server/headscale/api/resources/pre-auth-keys.ts

@@ -0,0 +1,88 @@
+import type { PreAuthKey } from "~/types";
+
+import type { Capabilities } from "../capabilities";
+import type { Transport } from "../transport";
+
+export interface CreatePreAuthKeyOptions {
+  /** Owning user ID, or `null` for tag-only keys (0.28+). */
+  user: string | null;
+  ephemeral: boolean;
+  reusable: boolean;
+  expiration: Date | null;
+  aclTags: string[] | null;
+}
+
+export interface PreAuthKeyApi {
+  /**
+   * List every pre-auth key on the server. Only present when
+   * `capabilities.preAuthKeysHaveStableIds` is true (Headscale 0.28+).
+   * Pre-0.28 callers must use {@link listForUser}.
+   */
+  listAll?: () => Promise<PreAuthKey[]>;
+
+  listForUser(userId: string): Promise<PreAuthKey[]>;
+
+  create(opts: CreatePreAuthKeyOptions): Promise<PreAuthKey>;
+
+  expire(key: PreAuthKey): Promise<void>;
+}
+
+export function makePreAuthKeyApi(
+  transport: Transport,
+  capabilities: Capabilities,
+  apiKey: string,
+): PreAuthKeyApi {
+  const api: PreAuthKeyApi = {
+    listForUser: async (userId) => {
+      const { preAuthKeys } = await transport.request<{
+        preAuthKeys: PreAuthKey[];
+      }>({ method: "GET", path: "v1/preauthkey", apiKey, query: { user: userId } });
+      return preAuthKeys;
+    },
+
+    create: async ({ user, ephemeral, reusable, expiration, aclTags }) => {
+      const body: Record<string, unknown> = {
+        ephemeral,
+        reusable,
+        expiration: expiration ? expiration.toISOString() : null,
+      };
+      if (user) body.user = user;
+      if (aclTags && aclTags.length > 0) body.aclTags = aclTags;
+
+      const { preAuthKey } = await transport.request<{
+        preAuthKey: PreAuthKey;
+      }>({ method: "POST", path: "v1/preauthkey", apiKey, body });
+      return preAuthKey;
+    },
+
+    expire: async (key) => {
+      if (capabilities.preAuthKeysHaveStableIds) {
+        await transport.request({
+          method: "POST",
+          path: "v1/preauthkey/expire",
+          apiKey,
+          body: { id: key.id },
+        });
+        return;
+      }
+      // Pre-0.28: expire takes user + key string.
+      await transport.request({
+        method: "POST",
+        path: "v1/preauthkey/expire",
+        apiKey,
+        body: { user: key.user?.name ?? "", key: key.key },
+      });
+    },
+  };
+
+  if (capabilities.preAuthKeysHaveStableIds) {
+    api.listAll = async () => {
+      const { preAuthKeys } = await transport.request<{
+        preAuthKeys: PreAuthKey[];
+      }>({ method: "GET", path: "v1/preauthkey", apiKey });
+      return preAuthKeys;
+    };
+  }
+
+  return api;
+}

app/server/headscale/api/resources/users.ts

@@ -0,0 +1,66 @@
+import type { User } from "~/types";
+
+import type { Capabilities } from "../capabilities";
+import type { Transport } from "../transport";
+
+export interface CreateUserOptions {
+  name: string;
+  email?: string;
+  displayName?: string;
+  pictureUrl?: string;
+}
+
+export interface ListUsersFilter {
+  id?: string;
+  name?: string;
+  email?: string;
+}
+
+export interface UserApi {
+  list(filter?: ListUsersFilter): Promise<User[]>;
+  create(opts: CreateUserOptions): Promise<User>;
+  delete(id: string): Promise<void>;
+  rename(id: string, newName: string): Promise<void>;
+}
+
+export function makeUserApi(
+  transport: Transport,
+  _capabilities: Capabilities,
+  apiKey: string,
+): UserApi {
+  return {
+    list: async (filter) => {
+      const { id, name, email } = filter ?? {};
+      const moreThanOneFilter = [id, name, email].filter((v) => v !== undefined).length > 1;
+      if (moreThanOneFilter) {
+        throw new Error("Only one of id, name, or email filters can be provided");
+      }
+      const { users } = await transport.request<{ users: User[] }>({
+        method: "GET",
+        path: "v1/user",
+        apiKey,
+        query: { id, name, email },
+      });
+      return users;
+    },
+    create: async ({ name, email, displayName, pictureUrl }) => {
+      const { user } = await transport.request<{ user: User }>({
+        method: "POST",
+        path: "v1/user",
+        apiKey,
+        body: { name, email, displayName, pictureUrl },
+      });
+      return user;
+    },
+    delete: async (id) => {
+      await transport.request({ method: "DELETE", path: `v1/user/${id}`, apiKey });
+    },
+    rename: async (id, newName) => {
+      await transport.request({
+        method: "POST",
+        path: `v1/user/${id}/rename/${encodeURIComponent(newName)}`,
+        apiKey,
+      });
+    },
+  };
+}

app/server/headscale/api/server-version.ts

@@ -0,0 +1,98 @@
+// MARK: ServerVersion
+//
+// Parses the response from Headscale's `GET /version` endpoint into a
+// structured value that capability checks can reason about. The
+// endpoint exists in every Headscale release we support (0.26.0+),
+// returns a plain semver-like string such as `v0.28.0`, `v0.28.0-beta.1`,
+// or `dev` for untagged builds.
+//
+// Comparisons (`gte`) are lenient about prerelease tags by design:
+// `0.28.0-beta.1` is treated as `0.28.0` for capability gating. The
+// behavioural changes that capabilities gate on always land in the
+// first prerelease of a minor version, so a strict semver
+// interpretation would lock prerelease users out of features that
+// their server actually has.
+
+const SEMVER_RE = /^v?(\d+)\.(\d+)\.(\d+)(?:-([0-9A-Za-z.-]+))?(?:\+([0-9A-Za-z.-]+))?$/;
+
+export interface ServerVersion {
+  readonly major: number;
+  readonly minor: number;
+  readonly patch: number;
+  readonly prerelease: string | undefined;
+  readonly build: string | undefined;
+  /** The raw string as reported by Headscale (e.g. `v0.28.0-beta.1`, `dev`). */
+  readonly raw: string;
+  /**
+   * True when the server reported a version we couldn't parse —
+   * typically `dev` for an untagged Headscale build. Capability checks
+   * treat unknown versions as having every known capability so we
+   * exercise the modern code paths against unfamiliar servers rather
+   * than silently falling back to compatibility shims.
+   */
+  readonly unknown: boolean;
+}
+
+export function parseServerVersion(raw: string): ServerVersion {
+  const match = SEMVER_RE.exec(raw.trim());
+  if (!match) {
+    return {
+      major: 0,
+      minor: 0,
+      patch: 0,
+      prerelease: undefined,
+      build: undefined,
+      raw,
+      unknown: true,
+    };
+  }
+  const [, maj, min, pat, pre, build] = match;
+  return {
+    major: Number(maj),
+    minor: Number(min),
+    patch: Number(pat),
+    prerelease: pre,
+    build,
+    raw,
+    unknown: false,
+  };
+}
+
+/** Pretty-print a parsed version for logs (no `v` prefix, includes prerelease). */
+export function formatServerVersion(version: ServerVersion): string {
+  if (version.unknown) return version.raw;
+  const core = `${version.major}.${version.minor}.${version.patch}`;
+  return version.prerelease ? `${core}-${version.prerelease}` : core;
+}
+
+/**
+ * Returns true when `version` is at least `target` (ignoring prerelease
+ * tags — see module-level note). `target` must be a plain semver
+ * string like `0.28.0`. Throws on a malformed target since those come
+ * from static capability tables, not user input.
+ */
+export function gte(version: ServerVersion, target: string): boolean {
+  if (version.unknown) return true;
+  const t = parseTarget(target);
+  if (version.major !== t.major) return version.major > t.major;
+  if (version.minor !== t.minor) return version.minor > t.minor;
+  return version.patch >= t.patch;
+}
+
+interface TargetVersion {
+  major: number;
+  minor: number;
+  patch: number;
+}
+
+function parseTarget(target: string): TargetVersion {
+  const match = SEMVER_RE.exec(target);
+  if (!match) {
+    throw new Error(`Invalid capability target version: ${target}`);
+  }
+  return {
+    major: Number(match[1]),
+    minor: Number(match[2]),
+    patch: Number(match[3]),
+  };
+}

app/server/headscale/api/transport.ts

@@ -0,0 +1,191 @@
+// MARK: Headscale Transport
+//
+// Internal HTTP transport for talking to a Headscale server. Owns
+// the Undici agent (and any custom CA), the base URL, error
+// translation, and the distinction between authenticated `/api/v1`
+// calls and unauthenticated public endpoints (`/version`, `/health`).
+//
+// This module is intentionally not exported from the package; all
+// consumers should go through `Headscale` and `HeadscaleClient` in
+// `./index.ts`, never the transport directly.
+
+import { readFile } from "node:fs/promises";
+
+import { data } from "react-router";
+import { Agent, type Dispatcher, request } from "undici";
+
+import log from "~/utils/log";
+
+import { undiciToFriendlyError } from "./error";
+import { type HeadscaleAPIError, isApiError } from "./error-client";
+
+export interface TransportRequest {
+  method: "GET" | "POST" | "PUT" | "DELETE" | "PATCH";
+  /** API path without the `/api/` prefix (e.g. `v1/node`). */
+  path: `v1/${string}`;
+  apiKey: string;
+  /** JSON request body for non-GET/DELETE requests. */
+  body?: Record<string, unknown>;
+  /** Query parameters for GET/DELETE requests. */
+  query?: Record<string, unknown>;
+}
+
+export interface Transport {
+  /**
+   * Send an authenticated JSON request against `/api/{path}`.
+   * Throws a React Router `data()` 502 response on transport errors
+   * and a typed `HeadscaleAPIError` (wrapped in `data()`) on API
+   * errors with statusCode >= 400.
+   */
+  request<T>(opts: TransportRequest): Promise<T>;
+
+  /**
+   * Send an unauthenticated GET against the server root
+   * (e.g. `/version`, `/health`). Returns parsed JSON.
+   */
+  getPublic<T>(path: `/${string}`): Promise<T>;
+
+  /** True if `GET /health` returns 200. Never throws. */
+  health(): Promise<boolean>;
+
+  /** Shut down the underlying Undici agent. */
+  dispose(): Promise<void>;
+}
+
+export interface TransportOptions {
+  url: string;
+  certPath?: string;
+}
+
+export async function createTransport(opts: TransportOptions): Promise<Transport> {
+  const agent = await createUndiciAgent(opts.certPath);
+  const baseUrl = opts.url;
+
+  async function rawRequest(
+    url: string,
+    options: Partial<Dispatcher.RequestOptions> & { method: string },
+  ): Promise<Dispatcher.ResponseData> {
+    log.debug("api", "%s %s", options.method, url);
+    try {
+      return await request(new URL(url, baseUrl), {
+        dispatcher: agent,
+        headers: {
+          ...options.headers,
+          Accept: "application/json",
+          "User-Agent": `Headplane/${__VERSION__}`,
+        },
+        body: options.body,
+        method: options.method,
+      });
+    } catch (error) {
+      const errorBody = undiciToFriendlyError(error, `${options.method} ${url}`);
+      throw data(errorBody, { status: 502, statusText: "Bad Gateway" });
+    }
+  }
+
+  return {
+    async request<T>({ method, path, apiKey, body, query }: TransportRequest): Promise<T> {
+      let url = `/api/${path}`;
+      const options: Partial<Dispatcher.RequestOptions> & { method: string } = {
+        method,
+        headers: { Authorization: `Bearer ${apiKey}` },
+      };
+
+      if (query && (method === "GET" || method === "DELETE")) {
+        const params = new URLSearchParams();
+        for (const [key, value] of Object.entries(query)) {
+          if (value !== undefined) {
+            params.append(key, String(value));
+          }
+        }
+        if ([...params.keys()].length > 0) {
+          url += `?${params.toString()}`;
+        }
+      } else if (body && method !== "GET" && method !== "DELETE") {
+        options.body = JSON.stringify(body);
+        options.headers = { ...options.headers, "Content-Type": "application/json" };
+      }
+
+      const res = await rawRequest(url, options);
+      if (res.statusCode >= 400) {
+        log.debug("api", "%s %s failed with status %d", method, path, res.statusCode);
+        const rawData = await res.body.text();
+        const jsonData = (() => {
+          try {
+            return JSON.parse(rawData) as Record<string, unknown>;
+          } catch {
+            return null;
+          }
+        })();
+
+        throw data(
+          {
+            requestUrl: `${method} ${path}`,
+            statusCode: res.statusCode,
+            rawData,
+            data: jsonData,
+          } satisfies HeadscaleAPIError,
+          { status: 502, statusText: "Bad Gateway" },
+        );
+      }
+
+      return res.body.json() as Promise<T>;
+    },
+
+    async getPublic<T>(path: `/${string}`): Promise<T> {
+      const res = await rawRequest(path, { method: "GET" });
+      if (res.statusCode >= 400) {
+        const rawData = await res.body.text();
+        const jsonData = (() => {
+          try {
+            return JSON.parse(rawData) as Record<string, unknown>;
+          } catch {
+            return null;
+          }
+        })();
+        throw data(
+          {
+            requestUrl: `GET ${path}`,
+            statusCode: res.statusCode,
+            rawData,
+            data: jsonData,
+          } satisfies HeadscaleAPIError,
+          { status: 502, statusText: "Bad Gateway" },
+        );
+      }
+      return res.body.json() as Promise<T>;
+    },
+
+    async health() {
+      try {
+        const res = await rawRequest("/health", { method: "GET" });
+        // Drain the body so the connection can be reused.
+        await res.body.dump();
+        return res.statusCode === 200;
+      } catch (error) {
+        if (isApiError(error)) {
+          log.debug("api", "Health check failed: %d", error.statusCode);
+        }
+        return false;
+      }
+    },
+
+    async dispose() {
+      await agent.close();
+    },
+  };
+}
+
+async function createUndiciAgent(certPath?: string): Promise<Agent> {
+  if (!certPath) return new Agent();
+  try {
+    log.debug("config", "Loading certificate from %s", certPath);
+    const cert = await readFile(certPath, "utf8");
+    log.info("config", "Using certificate from %s", certPath);
+    return new Agent({ connect: { ca: cert.trim() } });
+  } catch (error) {
+    log.error("config", "Failed to load Headscale TLS cert: %s", error);
+    log.debug("config", "Error Details: %o", error);
+    return new Agent();
+  }
+}

app/server/headscale/api/version.ts

@@ -1,86 +0,0 @@
-import canonicals from "~/openapi-canonical-families.json";
-import hashes from "~/openapi-operation-hashes.json";
-import log from "~/utils/log";
-
-/**
- * The known API versions based on operation hashes.
- */
-export type Version = keyof typeof hashes;
-const VERSIONS = Object.keys(hashes) as Version[];
-
-/**
- * Detects the closest matching API version using operation hashes.
- * Falls back to the latest known version and emits a warning if unknown.
- *
- * @param observed - A mapping of operation identifiers to their hashes.
- * @returns The detected API version.
- */
-export function detectApiVersion(observed: Record<string, string> | null): Version {
-  if (!observed) {
-    const latest = VERSIONS.at(-1)!;
-    log.warn("api", "No operation hashes observed, defaulting to version %s", latest);
-    return latest;
-  }
-
-  let bestVersion: Version | null = null;
-  let bestScore = -1;
-
-  for (const [version, known] of Object.entries(hashes) as [Version, Record<string, string>][]) {
-    let score = 0;
-    for (const [op, hash] of Object.entries(observed)) {
-      if (known[op] === hash) score++;
-    }
-    if (score > bestScore) {
-      bestVersion = version;
-      bestScore = score;
-    }
-  }
-
-  if (!bestVersion || bestScore === 0) {
-    const latest = VERSIONS.at(-1)!;
-    log.warn("api", "Could not determine API version, defaulting to %s", latest);
-    return latest;
-  }
-
-  if (bestScore < Object.keys(observed).length) {
-    log.warn(
-      "api",
-      "Partial version match: %d/%d endpoints for version %s",
-      bestScore,
-      Object.keys(observed).length,
-      bestVersion,
-    );
-  }
-
-  const canonical = Object.entries(canonicals).find(([_, family]) =>
-    family.includes(bestVersion),
-  )?.[0] as Version | undefined;
-
-  if (!canonical) {
-    log.warn("api", "Could not canonicalize detected version %s, using as-is", bestVersion);
-
-    return bestVersion;
-  }
-
-  if (canonical !== bestVersion) {
-    log.info(
-      "api",
-      "Canonicalizing detected version %s → %s (same schema)",
-      bestVersion,
-      canonical,
-    );
-  }
-
-  return canonical;
-}
-
-/**
- * Checks if the current version is at least the baseline version.
- *
- * @param current - The current API version.
- * @param baseline - The baseline API version to compare against.
- * @returns True if current is at least baseline, false otherwise.
- */
-export function isAtLeast(current: Version, baseline: Version) {
-  return VERSIONS.indexOf(current) >= VERSIONS.indexOf(baseline);
-}