Apply a schema validation against an HTTP request with JSON body

Question

    [HttpPost]
    [Authorize("PublicCreateOrder")]
    public async Task<ActionResult> CreateOrder(CancellationToken cancellationToken)
    {
        var watch = System.Diagnostics.Stopwatch.StartNew();
        //--------------> Performance measure Start <------------ FROM THIS POINT
        StreamReader requestReader = new StreamReader(Request.Body);
        JObject jsonRequest;
        try
        {
            jsonRequest = JObject.Parse(await requestReader.ReadToEndAsync());
        }
        catch (Exception ex)
        {
            return BadRequest("Please send a metadata has the type of JSON.");
        }
        var filePath = System.IO.Path.GetDirectoryName(Assembly.GetEntryAssembly().Location) + "\\OrderSchema.json";
        using (StreamReader fileReader = new StreamReader(filePath))
        {
            JSchema jsonSchema = JSchema.Parse(await fileReader.ReadToEndAsync());
            IList<ValidationError> errors;
            if (!jsonRequest.IsValid(jsonSchema, out errors))
            {
                List<ValidationError> newErrors = new List<ValidationError>();
                new List<ValidationError>(errors).ForEach(error =>
                {
                    if (error.ChildErrors.Count > 0)
                        newErrors.AddRange(error.ChildErrors);
                    else
                        newErrors.Add(error);
                });
                var errorsItems = errors.Select(error => new GetSchemaValidationResponse
                {
                    Message = error.Message,
                    ErrorType = error.ErrorType.ToString(),
                    LineNumber = error.LineNumber,
                    LinePosition = error.LinePosition,
                    Path = error.Path                       
                }).ToList();
                watch.Stop();
                var elapsedMs = watch.ElapsedMilliseconds;
                //--------------> Performance measure Finish<------------ TO THIS POINT
                return BadRequest(errorsItems);
            }
        }
        CreateOrderRequest request = JsonConvert.DeserializeObject<CreateOrderRequest>(jsonRequest.ToString());

In this code block i apply a json schema validation against an http request with json body. But because of this validation will perform against every request maybe it will cause a performance issues. For now, this code block took under 2ms but i want to improve the performance. Do you have any idea?

And also if you have an advice about code quality, i would be glad to know it.

Answer 1

Useless Copying

You're creating a lot of lists for no reasons. No need to copy one list to another just to iterate over it.

Separation of Concerns

The schema validation code pollutes the controller method. It's much better placed in a custom model binder or Filter

Answer 2

It is not a full review, just a quick observation: Rather than loading and parsing the schema each and every time when this method is being called you should do it only once, if the schema is not changing while the application is running.

You can do it eagerly inside the static constructor for example or lazily via the Lazy<T> type.