400-BadRequest while call rest api of azure Web App - azure

Question

var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-ms-version", "2016-05-31");
var content = new FormUrlEncodedContent(new KeyValuePair<string, string>[]
{
new KeyValuePair<string, string>("api-version", "2016-08-01")
});
content.Headers.ContentType = new MediaTypeHeaderValue("application/xml");
var response = client.PostAsync("https://management.azure.com/subscriptions/SuscriptionID/resourceGroups/Default-Web-SoutheastAsia/providers/Microsoft.Web/sites/MyAppName/stop?", content);
This is how I make a call to Azure WebApp rest api but I am getting statuscode : BadRequest

Answer 1

There are some issues with your code:
You're mixing Azure Service Management API with Azure Resource Manager (ARM) API. API to stop a web app is a Resource Manager API thus you don't need to provide x-ms-version.
You're missing the Authorization header in your request. ARM API requests require an authorization header. Please see this link on how to perform ARM API requests: https://learn.microsoft.com/en-us/rest/api/gettingstarted/.
Based on these, I modified your code:
static async void StopWebApp()
{
var subscriptionId = "<your subscription id>";
var resourceGroupName = "<your resource group name>";
var webAppName = "<your web app name>";
var token = "<bearer token>";
var url = string.Format("https://management.azure.com/subscriptions/{0}/resourceGroups/{1}/providers/Microsoft.Web/sites/{2}/stop?api-version=2016-08-01", subscriptionId, resourceGroupName, webAppName);
var client = new HttpClient();
client.DefaultRequestHeaders.Add("Authorization", "Bearer " + token);
var t = await client.PostAsync(url, null);
var response = t.StatusCode;
Console.WriteLine(t.StatusCode);
}
Please try using this code. Assuming you have acquired proper token, the code should work.