| 1 | import { type Credentials, saveCredentials } from "./credentials"; |
| 2 | import { SignedOut, refresh } from "./oauth"; |
| 3 | import type { Server } from "./server"; |
| 4 | |
| 5 | /** |
| 6 | * Every request the app makes, with its credentials: `api` for the REST |
| 7 | * API (api.g1t.sh), `site` for the site's own JSON routes, which Chat |
| 8 | * lives behind (`/<workspace>/-/chat/api`). Both take |
| 9 | * `Authorization: Bearer g1t_…`. |
| 10 | * |
| 11 | * An OAuth access token is refreshed a minute before it expires, and on a |
| 12 | * 401 once; requests that need a refresh at the same time share it, |
| 13 | * because a refresh token works once. |
| 14 | */ |
| 15 | |
| 16 | export type ErrorCode = |
| 17 | /** Signed out: the session is over and the app returns to sign-in. */ |
| 18 | | "signed_out" |
| 19 | /** |
| 20 | * The site refused the token: an OAuth token, or a personal one without |
| 21 | * "Use the website as you". The API still works; Chat does not. |
| 22 | */ |
| 23 | | "website_refused" |
| 24 | | "not_found" |
| 25 | | "forbidden" |
| 26 | | "offline" |
| 27 | | "failed"; |
| 28 | |
| 29 | export class ApiError extends Error { |
| 30 | constructor( |
| 31 | readonly code: ErrorCode, |
| 32 | message: string, |
| 33 | readonly status = 0, |
| 34 | ) { |
| 35 | super(message); |
| 36 | } |
| 37 | } |
| 38 | |
| 39 | export type Session = { |
| 40 | server: Server; |
| 41 | credentials: Credentials; |
| 42 | /** Told when credentials change (a refresh) or end (signed out). */ |
| 43 | onCredentials: (next: Credentials | null) => void; |
| 44 | }; |
| 45 | |
| 46 | const REFRESH_EARLY_MS = 60_000; |
| 47 | |
| 48 | export class Client { |
| 49 | private refreshing: Promise<Credentials> | null = null; |
| 50 | |
| 51 | constructor(private session: Session) {} |
| 52 | |
| 53 | get server(): Server { |
| 54 | return this.session.server; |
| 55 | } |
| 56 | |
| 57 | get credentials(): Credentials { |
| 58 | return this.session.credentials; |
| 59 | } |
| 60 | |
| 61 | /** A REST API call: `client.api<Repo[]>("/repos")`. */ |
| 62 | api<T>(path: string, init?: RequestInit): Promise<T> { |
| 63 | return this.json<T>(this.session.server.api + path, init, "api"); |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * One of the site's JSON routes. They answer `{ ok, value }` or |
| 68 | * `{ ok: false, error }`, the services' own shape, which this unwraps. |
| 69 | */ |
| 70 | async site<T>(path: string, init?: RequestInit): Promise<T> { |
| 71 | const answer = await this.json<{ ok: true; value: T } | { ok: false; error: { code: string; message: string } }>( |
| 72 | this.session.server.site + path, |
| 73 | init, |
| 74 | "site", |
| 75 | ); |
| 76 | if (!answer.ok) { |
| 77 | const code: ErrorCode = answer.error.code === "not_found" ? "not_found" : answer.error.code === "forbidden" ? "forbidden" : "failed"; |
| 78 | throw new ApiError(code, answer.error.message); |
| 79 | } |
| 80 | return answer.value; |
| 81 | } |
| 82 | |
| 83 | /** One of the site's JSON routes that answers in its own shape, such as `/-/notify`. */ |
| 84 | siteRaw<T>(path: string, init?: RequestInit): Promise<T> { |
| 85 | return this.json<T>(this.session.server.site + path, init, "site"); |
| 86 | } |
| 87 | |
| 88 | /** The current access token, refreshed first when it is about to expire. */ |
| 89 | async token(): Promise<string> { |
| 90 | const credentials = this.session.credentials; |
| 91 | if (credentials.kind === "oauth" && credentials.expiresAt - REFRESH_EARLY_MS < Date.now()) { |
| 92 | return (await this.refreshOnce()).accessToken; |
| 93 | } |
| 94 | return credentials.accessToken; |
| 95 | } |
| 96 | |
| 97 | private refreshOnce(): Promise<Credentials> { |
| 98 | const credentials = this.session.credentials; |
| 99 | if (credentials.kind !== "oauth") return Promise.resolve(credentials); |
| 100 | this.refreshing ??= refresh(this.session.server, credentials) |
| 101 | .then(async (next) => { |
| 102 | this.session = { ...this.session, credentials: next }; |
| 103 | await saveCredentials(next); |
| 104 | this.session.onCredentials(next); |
| 105 | return next; |
| 106 | }) |
| 107 | .catch((error) => { |
| 108 | if (error instanceof SignedOut) this.session.onCredentials(null); |
| 109 | throw error instanceof SignedOut ? new ApiError("signed_out", error.message, 401) : error; |
| 110 | }) |
| 111 | .finally(() => { |
| 112 | this.refreshing = null; |
| 113 | }); |
| 114 | return this.refreshing; |
| 115 | } |
| 116 | |
| 117 | private async json<T>(url: string, init: RequestInit | undefined, target: "api" | "site", retried = false): Promise<T> { |
| 118 | const token = await this.token(); |
| 119 | let response: Response; |
| 120 | try { |
| 121 | response = await fetch(url, { |
| 122 | ...init, |
| 123 | headers: { |
| 124 | accept: "application/json", |
| 125 | ...(init?.body ? { "content-type": "application/json" } : {}), |
| 126 | ...init?.headers, |
| 127 | authorization: `Bearer ${token}`, |
| 128 | }, |
| 129 | }); |
| 130 | } catch { |
| 131 | throw new ApiError("offline", "Could not reach g1t. Check your connection."); |
| 132 | } |
| 133 | if (response.status === 401) { |
| 134 | // An expired or revoked OAuth token gets one refresh; the site refusing |
| 135 | // a token it will never take is not that. |
| 136 | const refusedBySite = target === "site" && (await this.siteRefusesToken(response)); |
| 137 | if (refusedBySite) { |
| 138 | throw new ApiError( |
| 139 | "website_refused", |
| 140 | this.session.credentials.kind === "oauth" |
| 141 | ? "Chat is not open to the app's sign-in on this g1t yet. Sign in with an access token that can use the website, from You → Sign in another way." |
| 142 | : "This access token cannot use the website. Turn on “Use the website as you” for it in Settings → Access tokens.", |
| 143 | 401, |
| 144 | ); |
| 145 | } |
| 146 | if (!retried && this.session.credentials.kind === "oauth") { |
| 147 | await this.refreshOnce(); |
| 148 | return this.json<T>(url, init, target, true); |
| 149 | } |
| 150 | this.session.onCredentials(null); |
| 151 | throw new ApiError("signed_out", "You were signed out. Sign in again.", 401); |
| 152 | } |
| 153 | if (response.status === 404) throw new ApiError("not_found", "Not found.", 404); |
| 154 | if (response.status === 403) throw new ApiError("forbidden", await messageOf(response, "You do not have access to this."), 403); |
| 155 | if (!response.ok) throw new ApiError("failed", await messageOf(response, `g1t answered ${response.status}.`), response.status); |
| 156 | return (await response.json()) as T; |
| 157 | } |
| 158 | |
| 159 | /** |
| 160 | * Whether a 401 from the site is it refusing the token itself (its |
| 161 | * `WWW-Authenticate` names `invalid_token`; apps/web lib/website-token.ts). |
| 162 | * The token may still be good for the API: check before signing out. |
| 163 | */ |
| 164 | private async siteRefusesToken(response: Response): Promise<boolean> { |
| 165 | if (!/invalid_token/.test(response.headers.get("www-authenticate") ?? "")) return false; |
| 166 | try { |
| 167 | const check = await fetch(`${this.session.server.api}/user`, { |
| 168 | headers: { authorization: `Bearer ${this.session.credentials.accessToken}` }, |
| 169 | }); |
| 170 | return check.ok; |
| 171 | } catch { |
| 172 | return false; |
| 173 | } |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | async function messageOf(response: Response, fallback: string): Promise<string> { |
| 178 | try { |
| 179 | const body = (await response.clone().json()) as { message?: string; error?: { message?: string }; error_description?: string }; |
| 180 | return body.message ?? body.error?.message ?? body.error_description ?? fallback; |
| 181 | } catch { |
| 182 | const text = await response.text().catch(() => ""); |
| 183 | return text.trim().slice(0, 300) || fallback; |
| 184 | } |
| 185 | } |