Google Map Direction Api在本地工作正常，但在服务器上部署后无法正常工作

Question

I am trying to get direction details between a source and destination by calling Google Map API XML in a web service using c#. When I try to call below function locally, it works fine. But when I deploy my code on the server, for some locations, it does not give direction details. The local System where I try is Win2K8 R2 and the web server is Win2K3. Here is my Code

 public List<DirectionSteps> getDistance(string sourceLat, string sourceLong, string destLat, string destLong)
    {
    var requestUrl = String.Format("http://maps.google.com/maps/api/directions/xml?origin=" + sourceLat + "," + sourceLong + "&destination=" + destLat + "," + destLong + "&sensor=false&units=metric");
    try
    {
        var client = new WebClient();
        var result = client.DownloadString(requestUrl);
        //return ParseDirectionResults(result);
        var directionStepsList = new List<DirectionSteps>();
        var xmlDoc = new System.Xml.XmlDocument { InnerXml = result };
        if (xmlDoc.HasChildNodes)
        {
            var directionsResponseNode = xmlDoc.SelectSingleNode("DirectionsResponse");
            if (directionsResponseNode != null)
            {
                var statusNode = directionsResponseNode.SelectSingleNode("status");
                if (statusNode != null && statusNode.InnerText.Equals("OK"))
                {
                    var legs = directionsResponseNode.SelectNodes("route/leg");

                    foreach (System.Xml.XmlNode leg in legs)
                    {
                        //int stepCount = 1;
                        var stepNodes = leg.SelectNodes("step");
                        var steps = new List<DirectionStep>();

                        foreach (System.Xml.XmlNode stepNode in stepNodes)
                        {
                            var directionStep = new DirectionStep();
                            directionStep.Index = stepCount++;
                            directionStep.Distance = stepNode.SelectSingleNode("distance/text").InnerText;
                            directionStep.Duration = stepNode.SelectSingleNode("duration/text").InnerText;

                            directionStep.Description = Regex.Replace(stepNode.SelectSingleNode("html_instructions").InnerText, "<[^<]+?>", "");
                            steps.Add(directionStep);
                        }

                        var directionSteps = new DirectionSteps();
                        //directionSteps.OriginAddress = leg.SelectSingleNode("start_address").InnerText;
                        //directionSteps.DestinationAddress = leg.SelectSingleNode("end_address").InnerText;
                        directionSteps.TotalDistance = leg.SelectSingleNode("distance/text").InnerText;
                        directionSteps.TotalDuration = leg.SelectSingleNode("duration/text").InnerText;
                        directionSteps.Steps = steps;
                        directionStepsList.Add(directionSteps);
                    }
                }
            }
        }
        return directionStepsList;
    }
    catch (Exception ex)
    {
        throw ex; 
    }

    }

Answer 1

After reading many posts and google usage policy, it turns out that Google does not allow such automated queries from FQDN or any public server. I was making around 15-20 direction request which was blocked after around 10 requests. I had to change my logic and implemented the same function in mobile device and called the google maps directions api from mobile and it works perfectly !! It seems that google is not blocking such requests when they come from mobile devices. But you never know when they change it back.

Answer 2

You can use Google maps api http://maps.googleapis.com/maps/api/directions/

Instaructions here: https://developers.google.com/maps/documentation/directions/

Limits:

2,500 directions requests per day.

Google Maps API for Business customers have higher limits:

100,000 directions requests per day.

23 waypoints allowed in each request.