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Getting IP address geolocation info with Delphi

9 Comments

ipinfodb.com provides a free service wich let you obtain geolocation info about any ip address. you can access this info parsing the content returned by this page.

the request must be done in this way

http://ipinfodb.com/ip_query.php?timezone=true&ip=204.236.220.71

UPDATE

The above url is not longer valid because to a New APIs are being introduced with API key. you must register in this site to get access to the info.

now you must use a url like this

http://api.ipinfodb.com/v2/ip_query.php?key=&ip=74.125.45.100&timezone=true

and the response look like this

<Response>
<Ip>204.236.220.71</Ip>
<Status>OK</Status>
<CountryCode>US</CountryCode>
<CountryName>United States</CountryName>
<RegionCode>53</RegionCode>
<RegionName>Washington</RegionName>
<City>Seattle</City>
<ZipPostalCode>98144</ZipPostalCode>
<Latitude>47.5839</Latitude>
<Longitude>-122.299</Longitude>
<TimezoneName>America/Los_Angeles</TimezoneName>
<Gmtoffset>-28800</Gmtoffset>
<Isdst>0</Isdst>
</Response>

Now using a TIdHTTP component you can get the result of the request to this page.

uses
  Classes,
  ComObj,
  Variants,
  IdHTTP,

type
 TGeoInfo   = record
  Status        : string;
  CountryCode   : string;
  CountryName   : string;
  RegionCode    : string;
  City          : string;
  ZipPostalCode : string;
  Latitude      : string;
  Longitude     : string;
  TimezoneName  : string;
  Gmtoffset     : string;
  Isdst         : string;
 end;

const
 UrlGeoLookupInfo  ='http://ipinfodb.com/ip_query.php?timezone=true&ip=%s';
 UrlGeoLookupInfo2 ='http://backup.ipinfodb.com/ip_query.php?timezone=true&ip=%s'; //backup server

procedure GetGeoInfo(const IpAddress : string;var GeoInfo :TGeoInfo);
var
  lHTTP  : TIdHTTP;
  lStream: TStringStream;
  XMLDoc : OleVariant;
  ANode  : OleVariant;
begin
  lHTTP   := TIdHTTP.Create(nil);
  lStream := TStringStream.Create;
  try
      try
        lHTTP.Get(Format(UrlGeoLookupInfo,[IpAddress]), lStream); //get the request
      except
        lHTTP.Get(Format(UrlGeoLookupInfo2,[IpAddress]), lStream); //if something is wrong try using the backup server.
      end;
      lStream.Seek(0,0);
      XMLDoc := CreateOleObject('Msxml2.DOMDocument.6.0');
      XMLDoc.async := false;
      XMLDoc.LoadXML(lStream.ReadString(lStream.Size));
      XMLDoc.setProperty('SelectionLanguage','XPath');//use XPath to parse the xml result
      ANode:=XMLDoc.selectSingleNode('/Response/Status');
      if not VarIsNull(ANode) then GeoInfo.Status:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/CountryCode');
      if not VarIsNull(ANode) then GeoInfo.CountryCode:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/CountryName');
      if not VarIsNull(ANode) then GeoInfo.CountryName:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/RegionCode');
      if not VarIsNull(ANode) then GeoInfo.RegionCode:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/City');
      if not VarIsNull(ANode) then GeoInfo.City:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/ZipPostalCode');
      if not VarIsNull(ANode) then GeoInfo.ZipPostalCode:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/Latitude');
      if not VarIsNull(ANode) then GeoInfo.Latitude:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/Longitude');
      if not VarIsNull(ANode) then GeoInfo.Longitude:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/TimezoneName');
      if not VarIsNull(ANode) then GeoInfo.TimezoneName:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/Gmtoffset');
      if not VarIsNull(ANode) then GeoInfo.Gmtoffset:=ANode.Text;
      ANode:=XMLDoc.selectSingleNode('/Response/Isdst');
      if not VarIsNull(ANode) then GeoInfo.Isdst:=ANode.Text;
  finally
    lHTTP.Free;
    lStream.Free;
  end;
end;

Author: Rodrigo

Just another Delphi guy.

9 thoughts on “Getting IP address geolocation info with Delphi

  1. Good to know!
    Is it accurate? I guess I’ll have to try with my blog’s comments without a proper flag to see if it finds them …

  2. Thanks for the useful article and site link Rodrigo. Unfortunately, the code you posted will only work for a couple of days (until Nov 15). The site is moving to a new API that requires an API key and registration.

    Best regards.

  3. Why the double-slash (//) descendant operator search in stead of the single-slash (/) search prefix at the beginning of your XPath queries?

    You know for sure that the Ip will be at /Response/Ip, so why have it search through the whole document using //Response/Ip ?

    BTW: http://chris.photobooks.com/xml is a nice on-line way of checking your XPath queries.

    BTW2: Nice list of XPath patterns: http://www.brainbell.com/tutors/XML/XML_Book_B/Basic_XPath_Patterns.htm

    –jeroen

    Via: http://www.tizag.com/xmlTutorial/xpathdescendant.php

    • Jeroen, thanks for you suggestions, for this particular case both methods works

      using
      ANode:=XMLDoc.selectSingleNode('//Response/Status');
      or
      ANode:=XMLDoc.selectSingleNode('/Response/Status');

      but the correct way is using a single-slash (/). (the code was edited for include you suggestion)

  4. Pingback: Tweets that mention Getting IP address geolocation info with delphi « The Road to Delphi – a Blog About Delphi Programming (mostly) -- Topsy.com

  5. Error when calling upon the procedure??

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