/// <summary>
        /// Processes a GetLock request
        /// </summary>
        /// <remarks>
        /// For full documentation on GetLock, see https://wopi.readthedocs.org/projects/wopirest/en/latest/files/GetLock.html
        /// </remarks>
        private async static Task <HttpResponseMessage> GetLock(this HttpContext context, FileModel file)
        {
            // Check for valid lock on file
            if (String.IsNullOrEmpty(file.LockValue))
            {
                // File is not locked...return empty X-WOPI-Lock header
                context.Response.Headers[WopiResponseHeaders.LOCK] = String.Empty;

                // Return success 200
                return(returnStatus(HttpStatusCode.OK, "Success"));
            }
            else if (file.LockExpires != null && file.LockExpires < DateTime.Now)
            {
                // File lock expired, so clear it out
                file.LockValue   = null;
                file.LockExpires = null;
                await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                // File is not locked...return empty X-WOPI-Lock header
                context.Response.Headers[WopiResponseHeaders.LOCK] = String.Empty;

                // Return success 200
                return(returnStatus(HttpStatusCode.OK, "Success"));
            }
            else
            {
                // File has a valid lock, so we need to return it
                context.Response.Headers[WopiResponseHeaders.LOCK] = file.LockValue;

                // Return success 200
                return(returnStatus(HttpStatusCode.OK, "Success"));
            }
        }
        /// <summary>
        /// Processes a Lock request
        /// </summary>
        /// <remarks>
        /// For full documentation on Lock, see https://wopi.readthedocs.org/projects/wopirest/en/latest/files/Lock.html
        /// </remarks>
        private async static Task <HttpResponseMessage> Lock(this HttpContext context, FileModel file)
        {
            // Get the Lock value passed in on the request
            string requestLock = context.Request.Headers[WopiRequestHeaders.LOCK];

            // Ensure the file isn't already locked or expired
            if (String.IsNullOrEmpty(file.LockValue) ||
                (file.LockExpires != null &&
                 file.LockExpires < DateTime.Now))
            {
                // Update the file with a LockValue and LockExpiration
                file.LockValue   = requestLock;
                file.LockExpires = DateTime.Now.AddMinutes(30);
                await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                // Return success 200
                return(returnStatus(HttpStatusCode.OK, "Success"));
            }
            else if (file.LockValue == requestLock)
            {
                // File lock matches existing lock, so refresh lock by extending expiration
                file.LockExpires = DateTime.Now.AddMinutes(30);
                await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                // Return success 200
                HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
                return(returnStatus(HttpStatusCode.OK, "Success"));
            }
            else
            {
                // The file is locked by someone else...return mismatch
                return(context.returnLockMismatch(file.LockValue, String.Format("File already locked by {0}", file.LockValue)));
            }
        }
        /// <summary>
        /// Processes a PutUserInfo request
        /// </summary>
        /// <remarks>
        /// For full documentation on PutUserInfo, see https://wopi.readthedocs.org/projects/wopirest/en/latest/files/PutUserInfo.html
        /// </remarks>
        private async static Task <HttpResponseMessage> PutUserInfo(this HttpContext context, FileModel file)
        {
            // Set and save the UserInfo on the file
            var stream = context.Request.InputStream;
            var bytes  = new byte[stream.Length];
            await stream.ReadAsync(bytes, 0, (int)stream.Length);

            file.UserInfo = System.Text.Encoding.UTF8.GetString(bytes);

            // Update the file in DocumentDB
            await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

            // Return success
            return(returnStatus(HttpStatusCode.OK, "Success"));
        }
        /// <summary>
        /// Processes a RenameFile request
        /// </summary>
        /// <remarks>
        /// For full documentation on RenameFile, see https://wopi.readthedocs.org/projects/wopirest/en/latest/files/RenameFile.html
        /// </remarks>
        private async static Task <HttpResponseMessage> RenameFile(this HttpContext context, FileModel file)
        {
            // Get the Lock value passed in on the request
            string requestLock = context.Request.Headers[WopiRequestHeaders.LOCK];

            // Make sure the X-WOPI-RequestedName header is included
            if (context.Request.Headers[WopiRequestHeaders.REQUESTED_NAME] != null)
            {
                // Get the new file name
                var newFileName = context.Request.Headers[WopiRequestHeaders.REQUESTED_NAME];

                // Ensure the file isn't locked
                if (String.IsNullOrEmpty(file.LockValue) ||
                    (file.LockExpires != null &&
                     file.LockExpires < DateTime.Now))
                {
                    // Update the file with a LockValue and LockExpiration
                    file.LockValue    = requestLock;
                    file.LockExpires  = DateTime.Now.AddMinutes(30);
                    file.BaseFileName = newFileName;
                    await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                    // Return success 200
                    return(returnStatus(HttpStatusCode.OK, "Success"));
                }
                else if (file.LockValue == requestLock)
                {
                    // File lock matches existing lock, so we can change the name
                    file.LockExpires  = DateTime.Now.AddMinutes(30);
                    file.BaseFileName = newFileName;
                    await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                    // Return success 200
                    HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
                    return(returnStatus(HttpStatusCode.OK, "Success"));
                }
                else
                {
                    // The file is locked by someone else...return mismatch
                    return(context.returnLockMismatch(file.LockValue, String.Format("File locked by {0}", file.LockValue)));
                }
            }
            else
            {
                // X-WOPI-RequestedName header wasn't included
                return(returnStatus(HttpStatusCode.BadRequest, "X-WOPI-RequestedName header wasn't included in request"));
            }
        }
        /// <summary>
        /// Processes a UnlockAndRelock request
        /// </summary>
        /// <remarks>
        /// For full documentation on UnlockAndRelock, see https://wopi.readthedocs.org/projects/wopirest/en/latest/files/UnlockAndRelock.html
        /// </remarks>
        private async static Task <HttpResponseMessage> UnlockAndRelock(this HttpContext context, FileModel file)
        {
            // Get the Lock and OldLock values passed in on the request
            string requestLock    = context.Request.Headers[WopiRequestHeaders.LOCK];
            string requestOldLock = context.Request.Headers[WopiRequestHeaders.OLD_LOCK];

            // Ensure the file has a valid lock
            if (String.IsNullOrEmpty(file.LockValue))
            {
                // File isn't locked...pass empty Lock in mismatch response
                return(context.returnLockMismatch(String.Empty, "File isn't locked"));
            }
            else if (file.LockExpires != null && file.LockExpires < DateTime.Now)
            {
                // File lock expired, so clear it out
                file.LockValue   = null;
                file.LockExpires = null;
                await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                // File isn't locked...pass empty Lock in mismatch response
                return(context.returnLockMismatch(String.Empty, "File isn't locked"));
            }
            else if (requestOldLock != file.LockValue)
            {
                // File lock mismatch...pass Lock in mismatch response
                return(context.returnLockMismatch(file.LockValue, "Lock mismatch"));
            }
            else
            {
                // Update the file with a LockValue and LockExpiration
                file.LockValue   = requestLock;
                file.LockExpires = DateTime.Now.AddMinutes(30);
                await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                // Return success 200
                return(returnStatus(HttpStatusCode.OK, "Success"));
            }
        }
        /// <summary>
        /// Processes a PutFile request
        /// </summary>
        /// <remarks>
        /// For full documentation on PutFile, see https://wopi.readthedocs.org/projects/wopirest/en/latest/files/PutFile.html
        /// </remarks>
        private async static Task <HttpResponseMessage> PutFile(this HttpContext context, FileModel file)
        {
            // Get the Lock value passed in on the request
            string requestLock = context.Request.Headers[WopiRequestHeaders.LOCK];

            // Ensure the file has a valid lock
            if (String.IsNullOrEmpty(file.LockValue))
            {
                // If the file is 0 bytes, this is document creation
                if (context.Request.InputStream.Length == 0)
                {
                    // Update the file in blob storage
                    var bytes = new byte[context.Request.InputStream.Length];
                    context.Request.InputStream.Read(bytes, 0, bytes.Length);
                    file.Size = bytes.Length;
                    await AzureStorageUtil.UploadFile(file.id.ToString(), file.Container, bytes);

                    // Update version
                    file.Version++;
                    await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                    // Return success 200
                    return(returnStatus(HttpStatusCode.OK, "Success"));
                }
                else
                {
                    // File isn't locked...pass empty Lock in mismatch response
                    return(context.returnLockMismatch(String.Empty, "File isn't locked"));
                }
            }
            else if (file.LockExpires != null && file.LockExpires < DateTime.Now)
            {
                // File lock expired, so clear it out
                file.LockValue   = null;
                file.LockExpires = null;
                await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                // File isn't locked...pass empty Lock in mismatch response
                return(context.returnLockMismatch(String.Empty, "File isn't locked"));
            }
            else if (requestLock != file.LockValue)
            {
                // File lock mismatch...pass Lock in mismatch response
                return(context.returnLockMismatch(file.LockValue, "Lock mismatch"));
            }
            else
            {
                // Update the file in blob storage
                var bytes = new byte[context.Request.InputStream.Length];
                context.Request.InputStream.Read(bytes, 0, bytes.Length);
                file.Size = bytes.Length;
                await AzureStorageUtil.UploadFile(file.id.ToString(), file.Container, bytes);

                // Update version
                file.Version++;
                await DocumentRepository <FileModel> .UpdateItemAsync("Files", file.id.ToString(), (FileModel)file);

                // Return success 200
                return(returnStatus(HttpStatusCode.OK, "Success"));
            }
        }