PolyMPR/routes/login.tsx

import { Handlers } from "$fresh/server.ts";
import { State } from "$root/routes/_middleware.ts";
import { parse, type RegularTagNode } from "@melvdouc/xml-parser";
import {
  CasContent,
  CasResponse,
  CasTagNode,
  LoginJWT,
} from "$root/defaults/interfaces.ts";
import { createJwt } from "@popov/jwt";
import { setCookie } from "$std/http/cookie.ts";
import { getKey } from "$root/routes/_middleware.ts";

const CAS = "https://ident.univ-amu.fr/cas";

function getTag(tag: CasTagNode): [string, string] {
  return [
    tag.tagName.replace("cas:", ""),
    tag.children[0].value,
  ];
}

function createUserJWT(casResponse: CasResponse): Promise<string> {
  const nodes = casResponse.children[1].children.map(getTag);
  const fullUserInfos: Record<string, string | string[]> = {};

  nodes.forEach(([key, value]: [string, string]) => {
    if (typeof fullUserInfos[key] == "string") {
      fullUserInfos[key] = [fullUserInfos[key]];
    }

    if (Array.isArray(fullUserInfos[key])) {
      fullUserInfos[key].push(value);
    } else {
      fullUserInfos[key] = value;
    }
  });

  const now = Math.floor(Date.now() / 1000);
  const oneHour = 60 * 60;

  const payload: LoginJWT = {
    iss: "PolyMPR",
    iat: now,
    exp: now + oneHour,
    aud: "PolyMPR",
    user: fullUserInfos as unknown as CasContent,
  };

  const key = getKey(fullUserInfos.uid as string);
  return createJwt(payload, key);
}

// deno-lint-ignore no-explicit-any
export const handler: Handlers<any, State> = {
  async GET(request, context) {
    const url = new URL(request.url);
    const ticket = url.searchParams.get("ticket");
    const service = `${context.url.origin}/login`;

    if (ticket) {
      const response = await fetch(
        `${CAS}/serviceValidate?service=${service}&ticket=${ticket}`,
      );
      const body = parse(await response.text()) as [RegularTagNode];
      const casResponse = body[0].children[0] as CasResponse;

      if (casResponse.tagName != "cas:authenticationSuccess") {
        return new Response(null, {
          status: 302,
          headers: {
            Location: `${CAS}/login?service=${service}`,
          },
        });
      }

      const headers = new Headers();

      setCookie(headers, {
        name: "sessionToken",
        value: await createUserJWT(casResponse),
      });
      headers.set("Location", "/apps");

      return new Response(null, {
        status: 302,
        headers,
      });
    }

    if (context.state.isAuthenticated) {
      return new Response(null, {
        status: 302,
        headers: {
          Location: "/apps",
        },
      });
    } else {
      return new Response(null, {
        status: 302,
        headers: {
          Location: `${CAS}/login?service=${service}`,
        },
      });
    }
  },
};