How to refactor and unit test this method.

[HttpPost]
[Consumes(MediaTypeNames.Application.Json)]        [ProducesResponseType(StatusCodes.Status201Created)]       [ProducesResponseType(StatusCodes.Status400BadRequest)]
public IActionResult Post([FromBody] BlogRequest blogModel)
{
            try
            {
                if (ModelState.IsValid)
                {
                    var userId = User.Claims.Where(x => x.Type == "uid").FirstOrDefault()?.Value;
                    if(userId == null) return BadRequest(ModelState);   
                    var blog = _mapper.Map<Blog>(blogModel);
                    blog.UserId = userId;
                    _unitOfWork.BlogRepository.Add(blog);
                    _unitOfWork.save();
                    return Created("~api/blogs", blogModel);
                }
            }
            catch (Exception ex)
            {
                ModelState.AddModelError("AddBlog", ex.Message);
            }
            return BadRequest(ModelState);
        }