Implementation Strategy

To monitor processing progress in ASP.NET MVC applications, we ipmlement a polling mechanism using JavaScript to periodically query server-side status updates. Below are the implementation details.

Front end Implementation

The JavaScript function timedCount() sends AJAX requests at regular intervals to fetch the latest progress information:

var pollTimer;
function timedCount() {
    $.ajax({
        type: 'GET',
        url: '../../TMS.Service/OrderImport/GetImportProcess?cacheKey=' + sessionKey,
        dataType: 'json',
        success: function (response) {
            if (response.status) {
                $('#statusDisplay').html(
                    "<label>Current Progress:</label>" +
                    "<span style="color:red;font-size: large;">" + response.message + "</span>"
                );
            }
        }
    });
    pollTimer = setTimeout(timedCount, 2000);
}

A unique session identifier is generated using a GUID generator function:

var sessionKey = "";

function generateGUID() {
    function randomHex() {
        return ((1 + Math.random()) * 0x10000 | 0).toString(16).substring(1);
    }
    return (randomHex() + randomHex() + "-" + randomHex() + "-" + 
            randomHex() + "-" + randomHex() + "-" + randomHex() + 
            randomHex() + randomHex());
}

Backend Implementation

The controller action handles progress queries via HTTP GET requests:

[HttpGet]
public ActionResult GetImportProcess(string cacheKey = null)
{
    try
    {
        var result = new OrderImportHandler().GetProcessingStatus(cacheKey);
        return new ResponseWrapper { 
            status = !string.IsNullOrEmpty(result), 
            message = result 
        };
    }
    catch (Exception ex)
    {
        return new ResponseWrapper { 
            status = false, 
            message = $"<br></br>Failed to retrieve progress: {ex.Message}!" 
        };
    }
}

Cache Management

Progress information is stored in server-side cache using a helper class:

CacheManager.SetCacheStatus(MSG_CACHE_KEY, "Preparing to submit data to system");

The cache utility class provides methods for status tracking:

public class CacheManager
{
    public static object GetCacheValue(string key)
    {
        return HttpRuntime.Cache.Get(key);
    }

    public static void SetCacheStatus(string key, object value)
    {
        var cache = HttpRuntime.Cache;
        if (cache != null && value != null)
        {
            cache.Insert(key, value);
        }
    }

    public static void SetCacheWithExpiration(string key, object value, int seconds = 2)
    {
        if (value == null) return;
        var cache = HttpRuntime.Cache;
        cache.Insert(key, value, null, DateTime.Now.AddSeconds(seconds), TimeSpan.Zero, 
                   CacheItemPriority.High, null);
    }

    public static void ClearCache(string key)
    {
        HttpRuntime.Cache.Remove(key);
    }

    public static void ClearAllCaches()
    {
        var cache = HttpRuntime.Cache;
        var enumerator = cache.GetEnumerator();
        while (enumerator.MoveNext())
        {
            cache.Remove(enumerator.Key.ToString());
        }
    }
}