Merge pull request #5992 from wandonye/Fix#5410

added getS3FileUrl, fixed #5410

packages/rocketchat-file-upload/package.js

@@ -39,6 +39,7 @@ Package.onUse(function(api) {
 	api.addFiles('server/config/configFileUploadGridFS.js', 'server');
 
 	api.addFiles('server/methods/sendFileMessage.js', 'server');
+	api.addFiles('server/methods/getS3FileUrl.js', 'server');
 
 	api.addFiles('server/startup/settings.js', 'server');
 

packages/rocketchat-file-upload/server/methods/getS3FileUrl.js

+const crypto = Npm.require('crypto');
+let protectedFiles, S3accessKey, S3secretKey, S3expiryTimeSpan;
+
+RocketChat.settings.get('FileUpload_ProtectFiles', function(key, value) {
+	protectedFiles = value;
+});
+
+RocketChat.settings.get('FileUpload_S3_AWSAccessKeyId', function(key, value) {
+	S3accessKey = value;
+});
+
+RocketChat.settings.get('FileUpload_S3_AWSSecretAccessKey', function(key, value) {
+	S3secretKey = value;
+});
+
+RocketChat.settings.get('FileUpload_S3_URLExpiryTimeSpan', function(key, value) {
+	S3expiryTimeSpan = value;
+});
+
+Meteor.methods({
+	getS3FileUrl(fileId) {
+		if (protectedFiles && !Meteor.userId()) {
+			throw new Meteor.Error('error-invalid-user', 'Invalid user', { method: 'sendFileMessage' });
+		}
+		const file = RocketChat.models.Uploads.findOneById(fileId);
+		const resourceURL = '/' + file.s3.bucket + '/' + file.s3.path + file._id;
+		const expires = parseInt(new Date().getTime() / 1000) + Math.max(5, S3expiryTimeSpan);
+		const StringToSign = 'GET\n\n\n' + expires +'\n'+resourceURL;
+		const signature = crypto.createHmac('sha1', S3secretKey).update(new Buffer(StringToSign, 'utf-8')).digest('base64');
+		return {
+			url:file.url + '?AWSAccessKeyId='+encodeURIComponent(S3accessKey)+'&Expires='+expires+'&Signature='+encodeURIComponent(signature)
+		};
+	}
+});