Blazor WebAssembly FetchData Will Not Work On SQL Server

Question

I am developing a Blazor WebAssembly app. I am targeting .NET 5.0, publishing to a folder via VS 2019. My web server is IIS 8 on Windows Server 2012 R2. If it matters, the app will only be accessible within our corporate intranet.

The current status of the app is that it has the default counter and weather forecasting, although I have changed the weather forecasting to query an SQL database. This weather forecast querying is done via HTTP requests as shown in this Youtube tutorial (with some relevant code included below). I have added a second set of data for querying, also performed via HTTP requests.

My problem is that I can fetch the data (and do CRUD on it) just fine when I launch the app from within VS 2019 and the SQL server is hosted on that same development workstation. However, when I publish out to IIS, I run into problems.

Specifically, if the SQL Server is on my development workstation, I get the exception "Response status code does not indicate success: 404 (Not Found)." Looking to the Network part of the Console, I see a 404 on http://[my IIS server's network-accessible name]:5001/api/weatherforecast. That particular page loads just fine when launching from VS 2019 on my development machine.

One of my thoughts is that it might be an issue with the authentication for SQL Server Express. When pointed at my local workstation, it was using Windows Authentication, via the following connection string:

"Default": "Data Source = [my development workstation's name]; Initial Catalog = blazorTest; Integrated Security = True; MultipleActiveResultSets = True"

To test this, I set up SQL Server Express 2012 on the virtual server (with mixed mode authentication), and changed the connection string to:

"Data Source=[virtual server's name]; Initial Catalog=blazorTest; User Id=sa; Password=[super-secure password]"

Now, I get a different error when attempting to access the weather forecasts, specifically:

"Failed to load resource: the server responded with a status of 400 ()"

Oddly, this appears to be an uncaught exception and not a Console.Writeline(ex.Message) like I was seeing before. The uncaught exception references /api/weatherforecast.

Here is the code for the weather forecast API (CART is the name of the application):

using CART.Server.Data_Access_Layer;
using CART.Shared;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace CART.Server.Controllers
{
[ApiController]
[Route("api/[controller]")]
public class WeatherForecastController : ControllerBase
{
    private readonly ILogger _logger;
    private readonly WeatherDbContext _context;

    public WeatherForecastController(ILogger logger, WeatherDbContext context)
    {
        _logger = logger;
        _context = context;
    }

    [HttpGet]
    public async Task Get()
    {            
        try
        {
            List forecasts = await _context.Forecasts.ToListAsync();
            return Ok(forecasts);
        }

        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

        return BadRequest();
    }

    [HttpGet]
    [Route("{id}")]
    public async Task GetById(int id)
    {
        try
        {
            WeatherForecast forecast = await _context.Forecasts.Where(f => f.Id == id).FirstOrDefaultAsync();
            return Ok(forecast);
        }

        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

        return BadRequest();
        
    }

    [HttpPost]
    public async Task Create([FromBody] WeatherForecast forecast)
    {
        try
        {
            _context.Forecasts.Add(forecast);
            await _context.SaveChangesAsync();
            return Ok(forecast);
        }

        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

        return BadRequest();            
    }

    [HttpPut]
    [Route("{id}")]
    public async Task Update(int id, WeatherForecast updatedForecast)
    {
        try
        {
            _context.Forecasts.Update(updatedForecast);
            await _context.SaveChangesAsync();

            return Ok(updatedForecast);
        }

        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

        return BadRequest();            
    }

    [HttpDelete]
    [Route("{id}")]
    public async Task Delete(int id)
    {
        try
        {
            WeatherForecast forecast = await _context.Forecasts.Where(f => f.Id == id).FirstOrDefaultAsync();
            _context.Forecasts.Remove(forecast);
            await _context.SaveChangesAsync();
            return Ok(forecast);
        }
        
        catch (Exception ex) 
        {
            Console.WriteLine(ex.Message); 
        }

        return BadRequest();
    }
}
}

So, it appears to me that none of the tries are throwing exceptions (as I'd see a Console.WriteLine(ex.message) in such a case), but yet the return within the try is not being reached. Instead the return BadRequest is being reached, and that's causing its own exception in other code. But how can that be? I suspect I'm misunderstanding something here.

And just as importantly, what do I need to change / investigate in order to get this working?

ETA: It turns out the SQL Server on the virtual server was not configured to allow remote connections. Following this link's answers I was able to get the basic SQL fetching of data to work again within Visual Studio where it talked with a remote SQL Server. However, when I publish to the virtual server I continue to get "Response status code does not indicate success: 404 (Not Found). Further, the URL of http://[virtual server name]:5001/api/weatherforecast gets a 404.

Blazor WebAssembly FetchData Will Not Work On SQL Server

Answers (1)

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