caccl-lti
Version:
LTI launch validator for IMS-LTI standard launches.
124 lines • 6.97 kB
JavaScript
;
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
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function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __generator = (this && this.__generator) || function (thisArg, body) {
var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
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function verb(n) { return function (v) { return step([n, v]); }; }
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};
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
var oauth_signature_1 = __importDefault(require("oauth-signature"));
var fast_clone_1 = __importDefault(require("fast-clone"));
var NONCE_LIFESPAN_SEC_1 = __importDefault(require("./shared/constants/NONCE_LIFESPAN_SEC"));
/**
* Checks if an LTI launch request is valid. Throws an error if invalid
* @author Gabe Abrams
* @param opts object containing all arguments
* @param opts.req Express request object to verify
* @param opts.consumerSecret an LTI consumer secret to use for signature
* signing
* @param opts.store a nonce store to use for keeping track of used nonces
* @param opts.startTimestamp time when store was created
*/
var validateLaunch = function (opts) { return __awaiter(void 0, void 0, void 0, function () {
var req, consumerSecret, store, startTimestamp, nonce, timestamp, secDiff, prevNonceOccurrence, originalURL, urlNoQuery, path, url, body, generatedSignature;
var _a, _b, _c;
return __generator(this, function (_d) {
switch (_d.label) {
case 0:
req = opts.req, consumerSecret = opts.consumerSecret, store = opts.store, startTimestamp = opts.startTimestamp;
/*----------------------------------------*/
/* Parse request */
/*----------------------------------------*/
// Nonce
if (!((_a = req.body) === null || _a === void 0 ? void 0 : _a.oauth_nonce)) {
throw new Error('no nonce included');
}
nonce = String(req.body.oauth_nonce);
// Timestamp
if (!((_b = req.body) === null || _b === void 0 ? void 0 : _b.oauth_timestamp)
|| Number.isNaN(Number.parseFloat(req.body.oauth_timestamp))) {
throw new Error('no valid timestamp included');
}
timestamp = (Number.parseFloat(req.body.oauth_timestamp)
* 1000);
// Signature
if (!((_c = req.body) === null || _c === void 0 ? void 0 : _c.oauth_signature)) {
throw new Error('no signature included');
}
/*----------------------------------------*/
/* Check Nonce */
/*----------------------------------------*/
// Check if from before start
if (timestamp <= startTimestamp) {
throw new Error('nonce too old');
}
secDiff = Math.abs(Date.now() - timestamp) / 1000;
if (secDiff > (NONCE_LIFESPAN_SEC_1.default - 5)) {
// Expired!
throw new Error('nonce expired');
}
return [4 /*yield*/, store.set(nonce, { timestamp: timestamp })];
case 1:
prevNonceOccurrence = _d.sent();
if (prevNonceOccurrence) {
// Nonce was already used
throw new Error('nonce already used');
}
originalURL = (req.originalUrl || req.url);
if (!originalURL) {
// No url: cannot sign the request
throw new Error('no URL to use in signature');
}
urlNoQuery = originalURL.split('?')[0].split('#')[0];
path = (urlNoQuery
// Remove protocol
.replace("".concat(req.protocol, "://"), '')
// Remove host
.replace(req.hostname, ''));
url = "https://".concat(req.headers.host).concat(path);
body = (0, fast_clone_1.default)(req.body);
delete body.oauth_signature;
generatedSignature = decodeURIComponent(oauth_signature_1.default.generate(req.method, url, body, consumerSecret));
// Check the signature
if (generatedSignature !== req.body.oauth_signature) {
throw new Error('invalid signature');
}
return [2 /*return*/];
}
});
}); };
exports.default = validateLaunch;
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