I'm struggling to get a specific tutorial to work for my application. Can anyone advise me on how to map a general URL to the HTTP methods of an API endpoint that is written in C

I am struggling to retrieve and display data from a C# Web API using Typescript and Angular. As someone new to Typescript, I followed a tutorial to create a service based on this guide: [https://offering.solutions/blog/articles/2016/02/01/consuming-a-rest-api-with-angular-http-service-in-typescript/][1]

The service is consumed within a module called Categories.

However, I am encountering difficulties in getting the response back and rendering it as a table on the Categories page.

In my environments.ts file, I have configured the URL settings like this:

export const environment = {
  production: false,
  server: 'http://localhost:5001/',
  apiUrl: 'api/',
};

Within the service, there is a `get` method defined as follows:

getAll<T>(): Observable<T> {
    return this.http.get<T>(this.actionUrl);
  }

The `this.actionUrl` is constructed using the variables declared in the environment (server and apiUrl).

On the Server side, there is a `GetCategory` method in the Web API that I need to call.

In the CategoriesController.cs:

// GET: api/Categories
        [HttpGet(Name = nameof(GetCategory))]
        public string GetCategory()
        {
            var list = _context.Category.ToList();

            var json = JsonSerializer.Serialize(list);
            return json;
        }

Upon running the application, I encounter the error message:

Failed to load resource: net::ERR_EMPTY_RESPONSE :5001/api/:1

Additionally, the Edge browser console displays:

GET http://localhost:5001/api/ net::ERR_EMPTY_RESPONSE

As a result, the categories page remains empty.

If I manually enter the Web API URL into the browser (https://localhost:5001/api/Categories/), I can successfully receive the JSON response.

My question is how do I map the URL correctly for it to function according to the tutorial I followed?

The technologies I am utilizing include .NET Core 3.1, C#, TypeScript, Angular CLI 8.3.26, and the Angular web template in Visual Studio Community 2019. [1]:

Answer №1

When troubleshooting any issues, one must consider a variety of factors. In my experience, I faced difficulties in setting up my environment properly. A good starting point would be to inspect the JSON serialization parameters within your API.

Personally, I found success using Newtonsoft as opposed to the default JSON serializer. After encountering numerous challenges with integration into my Angular application, I switched to Newtonsoft and saw immediate results.

Below are the configurations for my functional API:

In Startup.cs -> ConfigureServices

It is worth noting that the options.Filters.Add(typeof(AuthorizationFilter)); line may not be applicable to your situation

services.AddControllers(options =>
            {
                options.Filters.Add(typeof(AuthorizationFilter));
            })
            .AddNewtonsoftJson(x => {
                x.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
                x.SerializerSettings.DateTimeZoneHandling = Newtonsoft.Json.DateTimeZoneHandling.Utc;
            });

services.AddMvc(options => options.FormatterMappings.SetMediaTypeMappingForFormat("json", "text/html"))
                    .SetCompatibilityVersion(CompatibilityVersion.Latest);

If the above steps do not resolve your issue, I recommend subscribing to the getAll observable and utilizing console logging to analyze its contents. Additionally, ensure that the properties in your Angular model align with those in your Asp.net API model.

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