Question

I m using Google s DistanceMatrix API from a VB.net desktop app using HttpWebRequest. I pass it a URL containing two locations (Expressed as Longitude and Latitude) and it gives me driving distances in miles and minutes using real streets. (Actually meters and seconds but I convert it.)

It works great from my desktop. The most significant part of my code is below. But I m not a web / internet / networking guy, and I m doing this by example. So far I don t have to know how it works and I m cool with that.

THE PROBLEM: Google says they have usage limits. Personally I don t approach those limits but my app may be distributed to many, and if a lot of others use it, together we will. In fact some users might go over the limits from a single workstation. I am willing to pay for extra usage if needed, but I don t know if I would be required to do so in this situation.

THE QUESTION: I ve looked thoroughly, (or at least I think I have) and as far as I can see Google doesn t document exactly how they monitor usage in this scenario. The documentation seems to assume it will always be used from a web server, and there are some references in the documentation that it can t be used from certain domains. But this is a windows forms app, so is it really "by domain"? What domain? Is it the service provider s domain? Or is it by IP Address? And importantly, will each user be counted separately in this situation or will it be somehow tied to the app itself wherever it may reside?

如果我看上去.子,就医。但是,在这方面是否有任何帮助?

我的法典的相关职能如下,也在此为本文提供谷歌文件页。

http://code.google.com/apis/maps/documentation/distancematrix/

Public Function GetHTML(ByVal URL As String, Optional ByVal UserName As String = "", Optional ByVal Password As String = "") As String
    Try
        Dim reader As StreamReader
        Dim Request As HttpWebRequest = HttpWebRequest.Create(URL)
         The following line empowers some downloads to work.
        If UserName <> "" Then
            Request.Credentials = New NetworkCredential(UserName, Password)
        End If
        Request.AllowAutoRedirect = True
        Request.CookieContainer = CookieJar
        Dim Response As HttpWebResponse = Request.GetResponse()
        reader = New StreamReader(Response.GetResponseStream())
        Response.Close()
        Return reader.ReadToEnd()
    Catch
        Return ""
    End Try
End Function

Answer 1

The usage limits described in the documentation would have no identifying information from your application (just look at the http call you are issuing to Google), so the limits would be enforced on a per-user basis. Perhaps if you contact Google s sales team they can provide more information about how to address your use case with the potential for users to need higher limits.

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