What is the simplest way to read a long json string (not via query string) from ASP.NET Core minimal Web API MapPost and pass it to ADO.NET as parameters for a stored procedure?

CodePudding user response：

According to your description, I suggest you could try to create a model according to the json and then you could use sql client to call the SP.

More details, you could refer to below codes:

Model:

public class Todo
{
    public string name { get; set; }
    public int id { get; set; }

}

Minimal API

app.MapPost("/todoitems", async (Todo todo) =>
{


    using (SqlConnection con = new SqlConnection("connection string"))
    {
        using (SqlCommand cmd = new SqlCommand("sp_Add_contact", con))
        {
            cmd.CommandType = CommandType.StoredProcedure;

            cmd.Parameters.Add("@FirstName", SqlDbType.VarChar).Value = todo.id;
            cmd.Parameters.Add("@LastName", SqlDbType.VarChar).Value = todo.name;

            con.Open();
            cmd.ExecuteNonQuery();

            return Results.Created($"/todoitems/{todo.id}", todo);
        }
    }
});

You could directly read the json from the httprequest.

More details, you could refer to below codes:

app.MapPost("/", async (HttpRequest request) =>
{
    var person = await request.ReadFromJsonAsync<Person>();

    // ...
});

CodePudding user response：

I tried it 4 different ways with the following results:

json1: success in Postman; error 415 from jQuery no responseText

json2: success in Postman and from jQuery. Works consistently

json3: success in Postman; error 400 from jQuery error Microsoft.AspNetCore.Http.BadHttpRequestException: Failed to read parameter "JsonRec jsonObj" from the request body as JSON.

json4: success in Postman; error 500 from jQuery error System.Text.Json.JsonException: 'j' is an invalid start of a value. Path: $ | LineNumber: 0 | BytePositionInLine: 0.

The code below should be enough to reproduce the errors. All MapPost snippets go in Program.cs of an asp.net core web app/api. The jQuery is called as usual from an html file. You could replace ops.spPostJson with a local stub function. Errors are produced on the client side, before this call.

app.MapPost("/json1", ([FromBody] string jsonStr) =>
{
  return ops.spPostJson("dbo.sp_postJson", jsonStr);
});

app.MapPost("/json2", async (HttpRequest request) =>
{
  string body = "";
  using (StreamReader stream = new StreamReader(request.Body))
  {
    body = await stream.ReadToEndAsync();
  }

  return ops.spPostJson("dbo.sp_postJson", HttpUtility.UrlDecode(body));    
});

for json3 and json4: record JsonRec(object json);

app.MapPost("/json3", async (JsonRec jsonObj) =>
{
  return ops.spPostJson("dbo.sp_postJson", jsonObj.json.ToString());
});

app.MapPost("/json4", async (HttpRequest request) =>
{
  var jsonObj = await request.ReadFromJsonAsync<JsonRec>();
  return ops.spPostJson("dbo.sp_postJson", jsonObj.ToString().Substring(5));
});

The jQuery code (json1 and json2 had contentType: text/plain):

  var jsonObj = { "a": 44, "b": 55 };
  var jsonObjStr = JSON.stringify(jsonObj);
$.ajax({
  url: '/json3',
  type: "POST",
  dataType: "json",
  contentType: "application/json; charset=utf-8",
  data: {
    json: jsonObjStr
  },
  success: function (returnedData, textStatus, jqXhr) {
    console.log('json3 success', returnedData)
  },
  error: function (response, textStatus, jqXhr) {
    console.log('json3 error', response.responseText);
  }
});

It is quite frustrating to go through all that trouble just to read the request body; worse off now than decades ago! Try a C!# equivalent of JSON.stringify or parse. Is that missing the obvious or what?