CallGoogleMapsDirectionsAPI.cs

#r "Newtonsoft.Json"

using System;
using System.Net;
using Newtonsoft.Json;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    // parse query parameter
    string lat = req.GetQueryNameValuePairs()
        .FirstOrDefault(q => string.Compare(q.Key, "lat", true) == 0)
        .Value;
    string lng = req.GetQueryNameValuePairs()
        .FirstOrDefault(q => string.Compare(q.Key, "lng", true) == 0)
        .Value;

    // Get request body
    dynamic data = await req.Content.ReadAsAsync<object>();

    // Set name to query string or body data
    lat = lat ?? data?.lat;
    lng = lng ?? data?.lng;

    if(lat == null)
    {
        return req.CreateResponse(HttpStatusCode.BadRequest, "Please pass a lat on the query string or in the request body");
    }

    if(lng == null)
    {
        return req.CreateResponse(HttpStatusCode.BadRequest, "Please pass a lng on the query string or in the request body");
    }

    //Get route info
    using (var client = new HttpClient())
    {
        client.DefaultRequestHeaders.Add("Accept", "application/json");
        var jsonResult = await client.GetStringAsync(string.Format("https://maps.googleapis.com/maps/api/directions/json?origin={0},{1}&destination=Street+Number+City&key=[Put your API key here]", lat, lng));
        dynamic jsonData = JsonConvert.DeserializeObject(jsonResult);

        //Return info
        return req.CreateResponse(HttpStatusCode.OK, new {
            duration = $"{jsonData.routes[0].legs[0].duration.text}",
            distance = $"{jsonData.routes[0].legs[0].distance.text}"});
    }
}