profileTwitterPullerFn.cs

#r "Newtonsoft.Json"

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

public static async Task<object> Run(HttpRequestMessage req, TraceWriter log)
{
    string TwitterKey = "";
    string TwitterSecret = "";
    
    log.Verbose($"Webhook was triggered!");

    string jsonContent = await req.Content.ReadAsStringAsync();
    dynamic data = JsonConvert.DeserializeObject(jsonContent);

    if (data.id == null || data.handle == null)
    {
        return req.CreateResponse(HttpStatusCode.BadRequest, new {
            error = "Please pass the user ID and Twitter handle properties in the input object"
        });
    }

    var bearerToken = await GetBearerToken(TwitterKey, TwitterSecret);

    if (string.IsNullOrEmpty(bearerToken))
    {
        return req.CreateResponse(HttpStatusCode.InternalServerError, new {
            error = "Twitter failed to authenticate application, please check key/secret info and restart function."
        });
    }

    // Added count=5 to help cut back on memory usage
    string timelineUrl = "https://api.twitter.com/1.1/statuses/user_timeline.json?screen_name=" + data.handle + "&count=5";
    var timelineJson = await CallApi(timelineUrl, bearerToken);

    if (string.IsNullOrEmpty(timelineJson))
    {
        return req.CreateResponse(HttpStatusCode.InternalServerError, new {
            error = "User not found on Twitter or failed to make call to Twitter."
        });
    }

    JArray timeline = JArray.Parse(timelineJson);
    List<string> latestTweets = new List<string>();

    for (int i = 0; i < timeline.Count() && i < 5; ++i)
    {
        JObject tweet = JObject.Parse(timeline[i].ToString());
        latestTweets.Add(tweet["text"].ToString());
    }

    // TODO: Add code to save to db through API or other mechanism

    return req.CreateResponse(HttpStatusCode.OK, new {
        UserID = data.id,
        Tweets = JsonConvert.SerializeObject(latestTweets)
    });
}

public static async Task<string> GetBearerToken(string Key, string Secret)
{
    string key = Uri.EscapeDataString(Key);
    string secret = Uri.EscapeDataString(Secret);

    byte[] encBytes = Encoding.UTF8.GetBytes(key + ":" + secret);
    string encoded = Convert.ToBase64String(encBytes);

    HttpClient client = new HttpClient();
    client.BaseAddress = new Uri("https://api.twitter.com/oauth2/token");
    client.DefaultRequestHeaders.Add("Authorization", "Basic " + encoded);
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
    client.DefaultRequestHeaders.AcceptCharset.Add(new StringWithQualityHeaderValue("UFT-8"));

    Dictionary<string, string> body = new Dictionary<string, string>();
    body.Add("grant_type", "client_credentials");
    HttpContent bodyContent = new FormUrlEncodedContent(body);

    HttpResponseMessage respMsg = await client.PostAsync("https://api.twitter.com/oauth2/token", bodyContent);

    if (respMsg.IsSuccessStatusCode)
    {
        var response = await respMsg.Content.ReadAsStringAsync();
        dynamic json = JsonConvert.DeserializeObject(response);

        return json.access_token;
    }

    return null;
}

public static async Task<string> CallApi(string Url, string BearerToken)
{
    HttpClient client = new HttpClient();
    client.DefaultRequestHeaders.Add("Authorization", "Bearer " + BearerToken);
    HttpResponseMessage respMsg = await client.GetAsync(Url);

    if (respMsg.IsSuccessStatusCode)
    {
        return await respMsg.Content.ReadAsStringAsync();
    }

    return null;
}