public async get()

in packages/storage/src/providers/AWSS3Provider.ts [360:486]
121 lines of code
20 McCabe index (conditional complexity)

	public async get<T extends S3ProviderGetConfig & StorageOptions>(
		key: string,
		config?: T
	): Promise<S3ProviderGetOuput<T>>;
	public async get(
		key: string,
		config?: S3ProviderGetConfig
	): Promise<string | GetObjectCommandOutput> {
		const credentialsOK = await this._ensureCredentials();
		if (!credentialsOK || !this._isWithCredentials(this._config)) {
			throw new Error(StorageErrorStrings.NO_CREDENTIALS);
		}
		const opt = Object.assign({}, this._config, config);
		const {
			bucket,
			download,
			cacheControl,
			contentDisposition,
			contentEncoding,
			contentLanguage,
			contentType,
			expires,
			track,
			SSECustomerAlgorithm,
			SSECustomerKey,
			SSECustomerKeyMD5,
			progressCallback,
		} = opt;
		const prefix = this._prefix(opt);
		const final_key = prefix + key;
		const emitter = new events.EventEmitter();
		const s3 = this._createNewS3Client(opt, emitter);
		logger.debug('get ' + key + ' from ' + final_key);

		const params: GetObjectCommandInput = {
			Bucket: bucket,
			Key: final_key,
		};

		// See: https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/S3.html#getObject-property
		if (cacheControl) params.ResponseCacheControl = cacheControl;
		if (contentDisposition)
			params.ResponseContentDisposition = contentDisposition;
		if (contentEncoding) params.ResponseContentEncoding = contentEncoding;
		if (contentLanguage) params.ResponseContentLanguage = contentLanguage;
		if (contentType) params.ResponseContentType = contentType;
		if (SSECustomerAlgorithm) {
			params.SSECustomerAlgorithm = SSECustomerAlgorithm;
		}
		if (SSECustomerKey) {
			params.SSECustomerKey = SSECustomerKey;
		}
		if (SSECustomerKeyMD5) {
			params.SSECustomerKeyMD5 = SSECustomerKeyMD5;
		}

		if (download === true) {
			const getObjectCommand = new GetObjectCommand(params);
			try {
				if (progressCallback) {
					if (typeof progressCallback === 'function') {
						emitter.on(SEND_DOWNLOAD_PROGRESS_EVENT, progress => {
							progressCallback(progress);
						});
					} else {
						logger.warn(
							'progressCallback should be a function, not a ' +
								typeof progressCallback
						);
					}
				}
				const response = await s3.send(getObjectCommand);
				emitter.removeAllListeners(SEND_DOWNLOAD_PROGRESS_EVENT);
				dispatchStorageEvent(
					track,
					'download',
					{ method: 'get', result: 'success' },
					{
						fileSize: Number(response.Body['size'] || response.Body['length']),
					},
					`Download success for ${key}`
				);
				return response;
			} catch (error) {
				dispatchStorageEvent(
					track,
					'download',
					{
						method: 'get',
						result: 'failed',
					},
					null,
					`Download failed with ${error.message}`
				);
				throw error;
			}
		}

		try {
			const signer = new S3RequestPresigner({ ...s3.config });
			const request = await createRequest(s3, new GetObjectCommand(params));
			// Default is 15 mins as defined in V2 AWS SDK
			const url = formatUrl(
				await signer.presign(request, {
					expiresIn: expires || DEFAULT_PRESIGN_EXPIRATION,
				})
			);
			dispatchStorageEvent(
				track,
				'getSignedUrl',
				{ method: 'get', result: 'success' },
				null,
				`Signed URL: ${url}`
			);
			return url;
		} catch (error) {
			logger.warn('get signed url error', error);
			dispatchStorageEvent(
				track,
				'getSignedUrl',
				{ method: 'get', result: 'failed' },
				null,
				`Could not get a signed URL for ${key}`
			);
			throw error;
		}
	}