Consuming Web API secured with JWT authentication from ASP.NET Core MVC application

Question

I would like to understand how to consume an ASP.NET Core Web API secured with JWT token authentication from the an ASP.NET Core MVC web application - thanks.

Searched a couple of articles but all are consuming through Postman and externally passing JWT tokens

Answer 1

For example, we have a method like this in the MVC controller and we can use it to generate a correct jwt token.

private string generateJwt() {
     var securityKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_config["Jwt:Key"]));
     var credentials = new SigningCredentials(securityKey, SecurityAlgorithms.HmacSha256);

     var claims = new[] {
                new Claim(JwtRegisteredClaimNames.Sub, "user_name"),
                new Claim(JwtRegisteredClaimNames.Email, "user_email"),
                new Claim(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString()),
                new Claim("role","admin"),
                new Claim(ClaimTypes.NameIdentifier,"admin")
            };

     var token = new JwtSecurityToken(_config["Jwt:Issuer"],
                _config["Jwt:Issuer"],
                claims,
                expires: DateTime.Now.AddMinutes(120),
                signingCredentials: credentials);

     return new JwtSecurityTokenHandler().WriteToken(token);
}

Then we need to add the token into the request header to when we send a http request. Following the official document, we need to add HttpClient in Program.cs: builder.Services.AddHttpClient(); then we can call the api with code like this:

private readonly IHttpClientFactory _httpClientFactory;

public HelloController(IHttpClientFactory httpClientFactory)
{
      _httpClientFactory = httpClientFactory;
}

public async Task<string> GetAsync() {
      var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get,"https://localhost:7212/WeatherForecast")
      {
           Headers =
           {
               { HeaderNames.Authorization, "Bearer "+ accessToken}
           }
      };

      var httpClient = _httpClientFactory.CreateClient();
      var response = await httpClient.SendAsync(httpRequestMessage);
      var res = "";
      if (response.StatusCode == HttpStatusCode.OK)
      {
           res = await response.Content.ReadAsStringAsync();
      }
      return "hello" + res ;
}