Best Place to manage shared API calls to 3rd party application inside my asp.net mvc

Question

I am working on an MVC 5 web application. I have the following layers:-

1. Views
2. Controller classes.
3. Repository classes, which are being referenced inside the controller classes.
4. Model classed
5. Entity framework DB context.

now i have the following requirement:-

Inside some action methods I want my application to be sending some API calls (using WebClient()) to 3rd party application.

Where the API calls will almost be the same for all the action methods, except for the Description parameter. Now I can have this shared logic inside my repository class, and reference it from my action methods. But as I know that repository class should not expose or reference WebClient() or similar web classes, as repository should deals with databases and model classes only. So I am not sure what is the best place to manage shared WebClient calls ? so from the action method I only call the shared class and pass the description field ?

For example here is a sample of an action method which directly contain the web client :-

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(Server s)
{
    if (ModelState.IsValid)
    {
        try
        {
            //code goes here....

            XmlDocument doc = new XmlDocument();
            using (var client = new WebClient())
            {
                var query = HttpUtility.ParseQueryString(string.Empty);
                query["username"] = System.Web.Configuration.WebConfigurationManager.AppSettings["ApiUserName"];
                query["password"] = System.Web.Configuration.WebConfigurationManager.AppSettings["ApiPassword"];
                query["assetType"] = controllername;
                query["operation"] = "UpdateAsset";
                query["assetName"] = s.RESOURCENAME;
                query["description"] = s.DESCRIPTION;
                //code goes here
                var url = new UriBuilder(apiurl);
                url.Query = query.ToString();
                try
                {
                    string xml = client.DownloadString(url.ToString());
                    doc.LoadXml(xml);
                    updatestatus = doc.SelectSingleNode("/operation/operationstatus").InnerText;
                }
                catch (WebException ex)
                {
                    ModelState.AddModelError(string.Empty, "Error occurred:" + ex.InnerException.Message);
                }
            }
        }
    }
}

now i do not want to be adding the same WebClient method on multiple action methods,, but rather to have the WebClient() on a shared class, and reference it from the related action methods .

Answer 1

Code sample will help, but overall I think you're on the right track here.

but as i know that repository class should not expose or reference WebClient() or similar web classes, as repository should deals with databases and model classes only

It's not just about databases. My feeling is repositories deal with "data-sources" and external services fall under this. There are no absolute rules about this. What makes sense in your situation?

So I am not sure what is the best place to manage shared WebClient calls ?

I think the repository is fine. Based on your architecture, where else would it fit? You can always add a WebApi piece, but it may not add any value and just serve to complicate things.

so from the action method I only call the shared class and pass the description field ?

Looks like a plan to me. You can also skip the controller/action methods calls and go to the services straight from you views via ajax calls

Answer 2

You can create an Action Filter to manage this API call... so you don't need to polute your action with this code o calls to other classes.

If the description is somehow static in each action, you can even put the description in the decorator itself.

[Httppost]
[ValidateAntiForgeryToken]
[MyApiFilter(Description="theDescription")]
public ActionResult Create(Server s)
{
    //Your action code
}

If you can't place the description in the decorator and need something more dynamic, you can set some parameter inside the action code, to be taken by the filter at runtime.

[Httppost]
[ValidateAntiForgeryToken]
[MyApiFilter]
public ActionResult Create(Server s)
{
    //Your action code

    this.SetAdditionalInfo(myDescription)
}

In your BaseController:

public void SetAdditionalInfo(string description)
{
    this.APICallDescription = description;
}

The base ActionFilterAttribute class has the following methods that you can override:

OnActionExecuting – This method is called before a controller action is executed.

OnActionExecuted – This method is called after a controller action is executed.

OnResultExecuting – This method is called before a controller action result is executed.

OnResultExecuted – This method is called after a controller action result is executed.