jwtaccess.js 5.88 KB
"use strict";
/**
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
Object.defineProperty(exports, "__esModule", { value: true });
const jws = require("jws");
const LRU = require("lru-cache");
const messages = require("../messages");
const DEFAULT_HEADER = {
    alg: 'RS256',
    typ: 'JWT',
};
class JWTAccess {
    /**
     * JWTAccess service account credentials.
     *
     * Create a new access token by using the credential to create a new JWT token
     * that's recognized as the access token.
     *
     * @param email the service account email address.
     * @param key the private key that will be used to sign the token.
     * @param keyId the ID of the private key used to sign the token.
     */
    constructor(email, key, keyId) {
        this.cache = new LRU({ max: 500, maxAge: 60 * 60 * 1000 });
        this.email = email;
        this.key = key;
        this.keyId = keyId;
    }
    /**
     * Indicates whether the credential requires scopes to be created by calling
     * createdScoped before use.
     * @deprecated
     * @return always false
     */
    createScopedRequired() {
        // JWT Header authentication does not use scopes.
        messages.warn(messages.JWT_ACCESS_CREATE_SCOPED_DEPRECATED);
        return false;
    }
    /**
     * Get a non-expired access token, after refreshing if necessary.
     *
     * @param authURI The URI being authorized.
     * @param additionalClaims An object with a set of additional claims to
     * include in the payload.
     * @deprecated Please use `getRequestHeaders` instead.
     * @returns An object that includes the authorization header.
     */
    getRequestMetadata(url, additionalClaims) {
        messages.warn(messages.JWT_ACCESS_GET_REQUEST_METADATA_DEPRECATED);
        return { headers: this.getRequestHeaders(url, additionalClaims) };
    }
    /**
     * Get a non-expired access token, after refreshing if necessary.
     *
     * @param url The URI being authorized.
     * @param additionalClaims An object with a set of additional claims to
     * include in the payload.
     * @returns An object that includes the authorization header.
     */
    getRequestHeaders(url, additionalClaims) {
        const cachedToken = this.cache.get(url);
        if (cachedToken) {
            return cachedToken;
        }
        const iat = Math.floor(new Date().getTime() / 1000);
        const exp = iat + 3600; // 3600 seconds = 1 hour
        // The payload used for signed JWT headers has:
        // iss == sub == <client email>
        // aud == <the authorization uri>
        const defaultClaims = {
            iss: this.email,
            sub: this.email,
            aud: url,
            exp,
            iat,
        };
        // if additionalClaims are provided, ensure they do not collide with
        // other required claims.
        if (additionalClaims) {
            for (const claim in defaultClaims) {
                if (additionalClaims[claim]) {
                    throw new Error(`The '${claim}' property is not allowed when passing additionalClaims. This claim is included in the JWT by default.`);
                }
            }
        }
        const header = this.keyId
            ? Object.assign(Object.assign({}, DEFAULT_HEADER), { kid: this.keyId }) : DEFAULT_HEADER;
        const payload = Object.assign(defaultClaims, additionalClaims);
        // Sign the jwt and add it to the cache
        const signedJWT = jws.sign({ header, payload, secret: this.key });
        const headers = { Authorization: `Bearer ${signedJWT}` };
        this.cache.set(url, headers);
        return headers;
    }
    /**
     * Create a JWTAccess credentials instance using the given input options.
     * @param json The input object.
     */
    fromJSON(json) {
        if (!json) {
            throw new Error('Must pass in a JSON object containing the service account auth settings.');
        }
        if (!json.client_email) {
            throw new Error('The incoming JSON object does not contain a client_email field');
        }
        if (!json.private_key) {
            throw new Error('The incoming JSON object does not contain a private_key field');
        }
        // Extract the relevant information from the json key file.
        this.email = json.client_email;
        this.key = json.private_key;
        this.keyId = json.private_key_id;
        this.projectId = json.project_id;
    }
    fromStream(inputStream, callback) {
        if (callback) {
            this.fromStreamAsync(inputStream).then(r => callback(), callback);
        }
        else {
            return this.fromStreamAsync(inputStream);
        }
    }
    fromStreamAsync(inputStream) {
        return new Promise((resolve, reject) => {
            if (!inputStream) {
                reject(new Error('Must pass in a stream containing the service account auth settings.'));
            }
            let s = '';
            inputStream
                .setEncoding('utf8')
                .on('data', chunk => (s += chunk))
                .on('error', reject)
                .on('end', () => {
                try {
                    const data = JSON.parse(s);
                    this.fromJSON(data);
                    resolve();
                }
                catch (err) {
                    reject(err);
                }
            });
        });
    }
}
exports.JWTAccess = JWTAccess;
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