123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103
import { computeHash, hmacSign, splitBy } from "../shared/util.ts";import { SessionImpl } from "./session.ts";import type { ConnInfo, Context, HTMLRewriterHandlers, Session, SessionOptions } from "./types.ts";
export const NEXT = Symbol();export const CUSTOM_HTML_REWRITER = Symbol();
export type ContextInit = {  req: Request;  connInfo: ConnInfo;  sessionOptions?: SessionOptions;};
/** create a context object */export function createContext(next: () => Promise<Response> | Response, init: ContextInit): Context {  let cookies: Map<string, string> | null = null;  let session: Session<Record<string, unknown>> | null = null;  const customHtmlRewriter: [string, HTMLRewriterHandlers][] = [];  const extension = {};  const ctx: Context = {    connInfo: init.connInfo,    params: {},    cookies: {      get(name: string) {        if (!cookies) {          cookies = new Map<string, string>();          const cookieHeader = init.req.headers.get("Cookie");          if (cookieHeader) {            for (const cookie of cookieHeader.split(";")) {              const [key, value] = splitBy(cookie, "=");              cookies.set(key.trim(), value);            }          }        }        return cookies.get(name);      },    },    // deno-lint-ignore ban-ts-comment    // @ts-ignore    async getSession(): Promise<Session<Record<string, unknown>>> {      if (session) {        return session;      }
      const { sessionOptions } = init;      const cookieName = sessionOptions?.cookie?.name ?? "session";      const secret = sessionOptions?.secret ?? "-";      let sid = ctx.cookies.get(cookieName);      let skipInit = false;      if (sid) {        const [rid, signature] = splitBy(sid, ".");        if (!signature || signature !== await hmacSign(rid, secret, "SHA-256")) {          sid = undefined;        }      }      if (!sid) {        const rid = await computeHash("SHA-1", crypto.randomUUID());        sid = rid + "." + hmacSign(rid, secret);        skipInit = true;      }
      const sessionImpl = new SessionImpl<Record<string, unknown>>(sid, sessionOptions);      session = sessionImpl;      if (!skipInit) {        await sessionImpl.init();      }      return session;    },    htmlRewriter: {      on: (selector: string, handlers: HTMLRewriterHandlers) => {        customHtmlRewriter.push([selector, handlers]);      },    },    next,  };  return new Proxy(Object.create({}), {    get(_target, prop) {      if (prop === CUSTOM_HTML_REWRITER) {        return customHtmlRewriter;      }      if (Reflect.has(ctx, prop)) {        return Reflect.get(ctx, prop);      }      return Reflect.get(extension, prop);    },    set(_target, prop, value) {      if (prop === NEXT) {        Reflect.set(ctx, "next", value);      }      if (!Reflect.has(ctx, prop)) {        return Reflect.set(extension, prop, value);      }      return false;    },    deleteProperty(_target, prop) {      if (!Reflect.has(ctx, prop)) {        return Reflect.deleteProperty(extension, prop);      }      return false;    },  });}