Show non-json response from API RRS feed

  • Question

  • User-1262787652 posted
    Shopping cart in browser calls API in Apache server to add product to cart using additem. 
    API controller returns 
    BadRequest( new { title="errormessage"} ) 
    in case or error and 
    new { title="Product added successfully to cart"} if OK. 
    In case of server error apache may return 4xx and 5xx codes with text/html content. 
    How to show this response in javascript in borwser ? 
    function addItem(product, quantity) {
        fetch('api/addItemToCart', {
            method: 'POST',
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json'
            body: JSON.stringify({
                product: [product],
                quantity: [quantity]
            .then(response => {
                if (response.ok) {
                    return response.json();
                    json => {
                return null;
            .then((data) => {
                if (data == null)
            .catch(error => alert('addItem error', error));
    If server or proxy is down, Apache returns html content as error message instead of requested json. In this case response.json() fails. 
    How to check for non-json response and show responce body in this case? 
    Code should probably use conditionally response.text() instead of response.json() . ShowMessage() and showErrorMessage() injet text to span in page into bootstrap alert compoment. 
     if (data == null) > return; 
    looks ugly. 
    This is ASP.NET 5 Core MVC application using Apache+Kestrel.

    Wednesday, May 26, 2021 9:21 AM

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