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Migrated client to use fetch-cookie to keep session alive while keepi…
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…ng track of changing cookies
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@kartikk221
kartikk221 committed Sep 27, 2022
1 parent fc7832c commit 93d6ad5
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Showing 2 changed files with 58 additions and 58 deletions.
114 changes: 57 additions & 57 deletions src/blackboard/client.js
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import fetch from 'node-fetch';
import makeFetchCookie from 'fetch-cookie';
import * as whenTime from 'when-time';
import * as cheero from 'cheerio';
import { EventEmitter } from 'events';
Expand All @@ -18,6 +19,8 @@ export const RegisteredClients = new Map();

// This class will act as an API client for each user
export class BlackboardClient extends EventEmitter {
#fetch;
#cookie_jar;
#keep_alive;
#base = BLACKBOARD_URL_BASE;
#user_agent = DEFAULT_USER_AGENT;
Expand All @@ -39,6 +42,12 @@ export class BlackboardClient extends EventEmitter {
constructor() {
// Initialize the EventEmitter class
super(...arguments);

// Create a new cookie jar
this.#cookie_jar = new makeFetchCookie.toughCookie.CookieJar();

// Create a new fetch instance with the cookie jar
this.#fetch = makeFetchCookie(fetch, this.#cookie_jar);
}

/**
Expand All @@ -51,6 +60,20 @@ export class BlackboardClient extends EventEmitter {
if (this.#client.cookies === null) throw new Error('NO_CLIENT');
}

/**
* Returns the most recent cookies for this client.
*
* @private
* @returns {Promise<String>}
*/
async _get_cookies() {
// Retrieve the cookies from the cookie jar
const cookies = await this.#cookie_jar.getCookies(this.#base);

// Return the cookies as a string
return cookies.map((cookie) => `${cookie.key}=${cookie.value}`).join('; ');
}

/**
* Sets the user agent to use for all requests.
* @param {String} user_agent
Expand All @@ -74,46 +97,36 @@ export class BlackboardClient extends EventEmitter {
// Fill the client cookies with an empty string if it is null
client.cookies = client.cookies || '';

// Convert the cookies into a jar object
const jar = {};
client.cookies
.split(';')
.filter((cookie) => cookie.trim().length > 0)
.forEach((cookie) => {
const [key, value] = cookie.split('=');
if (key) jar[key.trim()] = value.trim();
// If this is not a ping import, parse the string cookies into the cookie jar
if (!client.ping)
client.cookies.split(';').forEach((cookie) => {
const [key, value = ''] = cookie.split('=');
if (key) this.#cookie_jar.setCookie(`${key}=${value}`, this.#base);
});

// Parse the response as text HTML
const text = await with_retries(retries, delay, async () => {
// Make the fetch request to the Blackboard homepage
const response = await fetch(this.#base, {
method: 'GET',
headers: {
'user-agent': this.#user_agent,
cookie: client.cookies,
},
});
// Attempt to safely parse the user name to validate the cookies session
let is_logged_in = false;
try {
// Parse the response as text HTML
const text = await with_retries(retries, delay, async () => {
// Make the fetch request to the Blackboard homepage
const response = await this.#fetch(this.#base, {
method: 'GET',
headers: {
'user-agent': this.#user_agent,
},
});

// Ensure the response status is 200
if (response.status !== 200) throw new Error('Invalid response status code.');
// Ensure the response status is 200
if (response.status !== 200) throw new Error('Invalid response status code.');

// Retrieve the set-cookie header
const set_cookie = response.headers.get('set-cookie');
if (set_cookie)
set_cookie.split(', ').forEach((raw) => {
const cookie = raw.split('; ')[0];
const [key, value] = cookie.split('=');
jar[key.trim()] = value.trim();
});
// Ensure the response url is the Blackboard homepage
if (!response.url.startsWith(this.#base)) throw new Error('Invalid response URL.');

// Return the response
return await response.text();
});
// Return the response
return await response.text();
});

// Attempt to safely parse the user name to validate the cookies session
let is_logged_in = false;
try {
// Cache the cheerio HTML DOM object
const $ = cheero.load(text);

Expand All @@ -139,14 +152,6 @@ export class BlackboardClient extends EventEmitter {
// Re-schedule all alerts to account for the new imported alerts
this._reschedule_alerts();

// Update the cookies with the new jar
this.#client.cookies = Object.keys(jar)
.map((key) => `${key}=${jar[key]}`)
.join('; ');

// Emit a 'persist' event if the cookies have changed
if (client.cookies !== this.#client.cookies) this.emit('persist');

// Clear the old keep alive interval if it exists
if (this.#keep_alive) clearInterval(this.#keep_alive);

Expand All @@ -156,7 +161,7 @@ export class BlackboardClient extends EventEmitter {
// Perform an import with just the cookies to keep the session alive
let alive = false;
try {
alive = await this.import({ cookies: this.#client.cookies, ping: true });
alive = await this.import({ cookies: await this._get_cookies(), ping: true });
} catch (error) {
console.error(error);
}
Expand All @@ -169,13 +174,15 @@ export class BlackboardClient extends EventEmitter {
// Expire the client if the failure count is greater than the max retries
if (failures >= MAX_KEEP_ALIVE_RETRIES) {
clearInterval(this.#keep_alive);
this.#cookie_jar.removeAllCookies();
this.#client.cookies = null;
this.emit('expired');
}
}
}, 1000 * 60 * 5); // Keep Alive every 5 minutes
} else {
// Clear the cookies value if the user is not logged in
this.#cookie_jar.removeAllCookies();
this.#client.cookies = null;
}
}
Expand All @@ -186,9 +193,12 @@ export class BlackboardClient extends EventEmitter {

/**
* Exports the current client to a JSON object.
* @returns {Client}
* @returns {Promise<Client>}
*/
export() {
async export() {
// Parse and update the client cookies with the current cookie jar
this.#client.cookies = await this._get_cookies();

// Return a shallow copy of the client to allow for the caller to modify the object without affecting the internal client data
return Object.assign({}, this.#client);
}
Expand Down Expand Up @@ -297,11 +307,10 @@ export class BlackboardClient extends EventEmitter {
// Fetch the grades stream viewer POST URL as JSON data
const json = await with_retries(retries, delay, async () => {
// Make fetch request to the Blackboard API endpoint
const response = await fetch(`${this.#base}/webapps/streamViewer/streamViewer`, {
const response = await this.#fetch(`${this.#base}/webapps/streamViewer/streamViewer`, {
method: 'POST',
headers: {
'user-agent': this.#user_agent,
cookie: this.#client.cookies,
accept: 'text/javascript, text/html, application/xml, text/xml, */*',
'content-type': 'application/x-www-form-urlencoded; charset=UTF-8',
pragma: 'no-cache',
Expand Down Expand Up @@ -417,11 +426,10 @@ export class BlackboardClient extends EventEmitter {
// Fetch the raw HTML for the course from the grades URL
const text = await with_retries(retries, delay, async () => {
// Make fetch request to the Blackboard API endpoint
const response = await fetch(`${this.#base}${course.urls.grades}`, {
const response = await this.#fetch(`${this.#base}${course.urls.grades}`, {
method: 'GET',
headers: {
'user-agent': this.#user_agent,
cookie: this.#client.cookies,
},
});

Expand Down Expand Up @@ -654,14 +662,6 @@ export class BlackboardClient extends EventEmitter {
return this.#client.name;
}

/**
* Returns the cookies of the current authenticated user.
* @returns {String}
*/
get cookies() {
return this.#client.cookies;
}

/**
* Returns the user agent used for requests.
* @returns {String}
Expand Down
2 changes: 1 addition & 1 deletion src/blackboard/methods.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -120,7 +120,7 @@ export async function register_client(interaction, cookies) {
export async function store_clients() {
// Convert Map to object of cookies by identifier
const clients = {};
for (const [identifier, client] of RegisteredClients) clients[identifier] = client.export();
for (const [identifier, client] of RegisteredClients) clients[identifier] = await client.export();

// Store all registered clients to the filesystem
await writeFile(process.env['CLIENTS_JSON'], JSON.stringify(clients, null, 2));
Expand Down

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