How to read the raw json post body before hitting the controller in dot net c#?

Question

I need to implement a [HttpPost] web api with same route/uri, but more than 10 different combinations of parameters in json body. In which some parameters are null in some case but required in another case. As I am migrating an already deployed project to dot net 6, I don't have the freedom to modify api routes.

I have planned to execute this requirement by reading entire json raw body data in a model binder, deserialize it and setting it to different model classes before hitting the controller. I assume that this method also helps me with model state validations, so that I need not perform any manual validations in controller or service.

Already existing code in java (Maven Web App Controller):

@PostMapping(produces = HttpUtilities.APPLICATION_JSON_UTF8_VALUE, consumes = HttpUtilities.APPLICATION_JSON_UTF8_VALUE)
public ResponseEntity<HashMap<String, Object>> postForApproving(@RequestBody HashMap<String, Object> record,
        HttpServletRequest request) {

    RequestStore requestStore = (RequestStore) request.getAttribute("requestStore");

    logger.info("postForApproving({})", requestStore.toString());

    AuthorizationService.checkApiRole(requestStore, "postForApproving_" + entity_name, "Staff-Management");

    HashMap<String, Object> respBody = getService().postForApproving(requestStore, record);

    return new ResponseEntity<HashMap<String, Object>>(respBody, HttpUtilities.getResponseHeaders(requestStore),
            HttpStatus.CREATED);
}

And in the service the 'action' parameter in the request record is checked in else-if conditions and corresponding repository method is called for each situation.

Welcome to StackOverflow! Could you please share with us your already existing code that you want to migrate to .NET 6? — Peter Csala, Jul 30 '22 at 07:55

score 3 · Accepted Answer · answered Aug 01 '22 at 10:04

Custom Model Binder:

public class GetModelBindingContext : IModelBinder
{
    public async Task BindModelAsync(ModelBindingContext bindingContext)
    {
        string json;
        using (var reader = new StreamReader(bindingContext.ActionContext.HttpContext.Request.Body, Encoding.UTF8))
            json = await reader.ReadToEndAsync();

        bindingContext.Result = ModelBindingResult.Success(json);
    }
}

Api Controller:

[ApiController]
public class ApproverDataController : ControllerBase
{
    private readonly IApproverDataService _myService;
    private readonly IModelBinder _modelBinder;

    public MyController(IMyService myService)
    {
        _myService = myService;
    }

    [Route("rest/prd/v1/post_data/body")]
    [HttpPost]
    public async Task<IActionResult> PostForAction([FromBody][ModelBinder(BinderType = typeof(GetModelBindingContext))] string json)
    {
        dynamic requestBody = JsonConvert.DeserializeObject(json);
        return Ok("Success!");
    }
}

How to read the raw json post body before hitting the controller in dot net c#?

1 Answers1