PollingWebRequestFunction.cs

using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using System.Collections.Generic;
using System.Linq;
using PollingWebRequest.Classes;
using System.Net.Http.Headers;
using System.Net.Http;

namespace PollingWebRequest
{
    public static class PollingWebRequestFunction
    {
        private static StorageHelper storageHelper = new StorageHelper();
        [StorageAccount("BlobStorageConnectionString")]
        [FunctionName("PollingWebRequestFunction")]
        public static async Task Run([TimerTrigger("0 */5 * * * *")]TimerInfo myTimer, ILogger log)
        {
            storageHelper.InitializeStorageAccount();

            var apiUrl = Utilities.GetEnvironmentVariable("PollUrl");

            HttpClient Client = new HttpClient();

            Client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", Utilities.GetEnvironmentVariable("BearerToken"));

            var result = await Client.GetAsync(apiUrl);

            var requestBody = await result.Content.ReadAsStringAsync();
            var alerts = JsonConvert.DeserializeObject<List<Alert>>(requestBody);
            log.LogInformation($"Initial GET request complete. "+alerts.Count+" alerts found.");

            try
            {

                log.LogInformation($"Updating and looking for duplicated alerts list in Storage.");
                alerts = CheckDuplicatesInStorage(alerts);
                log.LogInformation($"Duplicate check completed. "+alerts.Count+" new alerts identified.");

                if (alerts.Count > 0)
                {
                    var endpoint = Utilities.GetEnvironmentVariable("PostUrl");
                    HttpClient c = new HttpClient();
                    var myContent = JsonConvert.SerializeObject(alerts);
                    var buffer = System.Text.Encoding.UTF8.GetBytes(myContent);
                    var byteContent = new ByteArrayContent(buffer);
                    byteContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
                    var trigger = await c.PostAsync(endpoint, byteContent);
                    Console.WriteLine(JsonConvert.SerializeObject(alerts));
                    log.LogInformation($"Alerts sent!");
                }
            }
            catch (Exception e)
            {
                log.LogInformation(e.ToString());
            }
        }

        static List<Alert> CheckDuplicatesInStorage(List<Alert> alerts)
        {
            List<Alert> filteredAlerts = new List<Alert>();
            var alertsFromStorage = storageHelper.GetListOfAlertsAsync().Result;
            if (alertsFromStorage != null)
            {
                foreach (var alert in alerts)
                {
                    int index = alertsFromStorage.FindIndex(f => string.Equals(f.alert_id, alert.alert_id));
                    if (index < 0)
                    {
                        alertsFromStorage.Add(alert);
                        filteredAlerts.Add(alert);
                    }
                }
                storageHelper.UpdateBlobAsync(JsonConvert.SerializeObject(alertsFromStorage));
            }

            return filteredAlerts;
        }
    }
}