set to the value 200 if the function succeeded and to the error code if the function failed. The
describes the status of the function, it's set to 'OK' if the function succeeded and to the error description if the function failed.
The rest of the XML data is defined based on the function.
![]( "jmp Logo")
You have the option to use one of two domains, http://bit.ly and http://j.mp (new,) both offer you the same functionality and the same flexibility, however, the first counts to 20 characters while the other counts to only 18. (The domain can be set in the shortening function in the argument domain.)
Keep in mind that the code just after the domain name (e.g. bnPuEX of http://bit.ly/bnPuEX) is called Hash and it is exactly 6 characters (case-sensitive.)
There're two types of hash, each short URL has many hashes:
- User Hash:
That hash of the URL generated for a given user shortened the URL. That means that a long URL might have more than one user hash equals to the number of users shortened that URL. (More than one hash means more than one short URL.)
- Global Hash:
A hash that is shared by all users for the same short URL.
Thus, a short URL has only one global hash, but it might have more than one user hash (for each user shortened the same long URL.)
You cannot think about making thousands of function calls every hour, access to the API is limited for each user on an hourly base. Limits are very sufficient for your application, but it's going not to be sufficient if you are willing to spam the service or to drop it!
Function Explanation
Now we are going to talk about each function and how you can call it.
First, get your API key that will be used to authenticate your calls to the API. If you need to bother yourself and to clog your application use the demo API user bitlyapidemo that have the API key R_0da49e0a9118ff35f52f629d2d71bf07.
Shortening Function
The first function we are going to talk about today is the shortening function, shorten. This function has the following address http://api.bit.ly/v3/shorten (as you expected) and is used to shorten long URLs. Besides main arguments key, apiKey, and format, it takes two more:
- longUrl:
The long URL to be shortened.
- domain:
Optional. The preferred domain, bit.ly or j.mp.
You can get hands on this function and try it simply by navigating to the results of the following URL:
http://api.bit.ly/v3/shorten?login=bitlyapidemo&apiKey=R_0da49e0a9118ff35f52f629d2d71bf07 &format=txt&longUrl=http://JustLikeAMagic.com
This call simply tries to shorten the URL http://JustLikeAMagic.com by using credentials of the demo API user (substitute the current information with your own.) The format is set to plain text.
You can also use change the format to XML and get output like this:
<?xml version="1.0" encoding="utf-8"?>
<response>
<status_code>200</status_code>
<status_txt>OK</status_txt>
<data>
<url>http://bit.ly/bO9TgE</url>
<hash>bO9TgE</hash>
<global_hash>9gSDEU</global_hash>
<long_url>http://JustLikeAMagic.com</long_url>
<new_hash>0</new_hash>
</data>
</response>
Notice that the status code is 200 that means that everything went 'OK'. Notice that we have 5 elements:
- url:
The long URL generated.
- hash:
The user hash string.
- global_hash:
The globally shared hash. Can be used to browse to the URL too, it would be counted in the global statistics but not in user's.
- long_url:
The original URL.
- new_hash:
Equals to 1 if this is the first time that URL being shortened (using the bit.ly service of course,) or 0 otherwise.
Now, let's code! The following function accepts a long URL and user API credentials and tries to shorten the URL using our shortening function.
Don't forget to add using statements to namespaces System.IO, System.Net, and System.Xml to that code and to the other code demonstrated in this article.
// C#
string Shorten(string url, string login, string key, bool xml)
{ url = Uri.EscapeUriString(url);
string reqUri =
String.Format("http://api.bit.ly/v3/shorten?" + "login={0}&apiKey={1}&format={2}&longUrl={3}", login, key, xml ? "xml" : "txt", url);
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(reqUri);
req.Timeout = 10000; // 10 seconds
// if the function fails and format==txt throws an exception
Stream stm = req.GetResponse().GetResponseStream();
if (xml)
{ XmlDocument doc = new XmlDocument();
doc.Load(stm);
// error checking for xml
if (doc["response"]["status_code"].InnerText != "200")
throw new WebException(doc["response"]["status_txt"].InnerText);
return doc["response"]["data"]["url"].InnerText;
}
else // Text
using (StreamReader reader = new StreamReader(stm))
return reader.ReadLine();
}
Take notice of the mechanism used to check for errors.
Expanding Function
The next function we have is the function that is used to expand a URL, i.e., to get the long URL from the short one. Obviously, this function is called expand and it accepts the short URL shortUrl besides the three main arguments.
Likewise, calling this function generate a data based on the function format, txt, xml, or json. The following XML data is generated when the function is called while the format is set to xml:
<?xml version="1.0" encoding="utf-8" ?>
<response>
<status_code>200</status_code>
<status_txt>OK</status_txt>
<data>
<entry>
<short_url>http://bit.ly/bnPuEX</short_url>
<long_url>http://justlikeamagic.com</long_url>
<user_hash>bnPuEX</user_hash>
<global_hash>bdE96m</global_hash>
</entry>
</data>
</response>
Now you can see the two hashes, user_hash and global_hash, and the two lend the user to your page (although the access is counted differently.)
Now, let's code! The following function retrieves the long URL from the short one:
// C#
string Expand(string url, string login, string key, bool xml)
{ url = Uri.EscapeUriString(url);
string reqUri =
String.Format("http://api.bit.ly/v3/expand?" + "login={0}&apiKey={1}&format={2}&shortUrl={3}", login, key, xml ? "xml" : "txt", url);
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(reqUri);
req.Timeout = 10000; // 10 seconds
// if the function fails and format==txt throws an exception
Stream stm = req.GetResponse().GetResponseStream();
if (xml)
{ XmlDocument doc = new XmlDocument();
doc.Load(stm);
// error checking for xml
if (doc["response"]["status_code"].InnerText != "200")
throw new WebException(doc["response"]["status_txt"].InnerText);
return doc["response"]["data"]["entry"]["long_url"].InnerText;
}
else // Text
using (StreamReader reader = new StreamReader(stm))
return reader.ReadLine();
}
Validation Function
The function validate is used to check if another username and API key pair is valid. For this function to work, you should use valid API credentials to check for the other credentials if they are valid or not. Therefore, you are going to use two additional arguments for the additional credentials, x_login and x_apiKey.
This function doesn't support plain text format. If XML was used, the function returns data like the following:
<?xml version="1.0" encoding="UTF-8"?>
<response>
<status_code>200</status_code>
<status_txt>OK</status_txt>
<data>
<valid>0</valid>
</data>
</response>
The valid element is set to 1 if the credentials were OK or 0 otherwise.
And this is our C# function that validates user API credentials:
// C#
string Validate(string login, string key, string xLogin, string xKey, bool xml)
{ string reqUri =
String.Format("http://api.bit.ly/v3/validate?" + "login={0}&apiKey={1}&x_login={4}&x_key={5}&format={2}" + login, key, xLogin, xKey, xml ? "xml" : "txt");
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(reqUri);
req.Timeout = 10000; // 10 seconds
// if the function fails and format==txt throws an exception
Stream stm = req.GetResponse().GetResponseStream();
if (xml)
{ XmlDocument doc = new XmlDocument();
doc.Load(stm);
// error checking for xml
if (doc["response"]["status_code"].InnerText != "200")
throw new WebException(doc["response"]["status_txt"].InnerText);
return int.Parse(doc["response"]["data"]["valid"]) == 1 ? true : false;
}
else // Text
using (StreamReader reader = new StreamReader(stm))
return int.Parse(reader.ReadLine()) == 1 ? true : false;
}
Stats Function
This function is used to get stats about the short URL; the stats are represented in two values, user clicks and global clicks. User clicks value is the number of access times made to that user link. Global clicks value is the number of access times made from all short URLs (from all users) refer to the same address (almost like user hashes and global hash.)
The function only accepts the short URL, shortUrl, besides the three main arguments. The data returned from the function is almost like this (in XML):
<?xml version="1.0" encoding="utf-8" ?>
<response>
<status_code>200</status_code>
<data>
<clicks>
<short_url>http://bit.ly/bnPuEX</short_url>
<global_hash>bdE96m</global_hash>
<user_clicks>0</user_clicks>
<user_hash>bnPuEX</user_hash>
<global_clicks>0</global_clicks>
</clicks>
</data>
<status_txt>OK</status_txt>
</response>
The following C# function is used to retrieve number of access times for the current user and for all users:
// C#
int GetClicks(string url, string login, string key, out int globalClicks)
{ url = Uri.EscapeUriString(url);
string reqUri =
String.Format("http://api.bit.ly/v3/clicks?" + "login={0}&apiKey={1}&shortUrl={2}&format=xml" + login, key, url);
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(reqUri);
req.Timeout = 10000; // 10 seconds
Stream stm = req.GetResponse().GetResponseStream();
XmlDocument doc = new XmlDocument();
doc.Load(stm);
// error checking for xml
if (doc["response"]["status_code"].InnerText != "200")
throw new WebException(doc["response"]["status_txt"].InnerText);
XmlElement el = doc["response"]["data"]["clicks"];
globalClicks = int.Parse(el["global_clicks"].InnerText);
return int.Parse(el["user_clicks"].InnerText);
}
Lookup Function
This function is used with long URLs to check whether they have been shortened before, and if so, the function returns the short URLs.
If the long URL was found in service database, XML data like this is returned:
<?xml version="1.0" encoding="utf-8" ?>
<response>
<status_code>200</status_code>
<status_txt>OK</status_txt>
<data>
<lookup>
<url>http://JustLikeAMagic.com</url>
<short_url>http://bit.ly/9gSDEU</short_url>
<global_hash>9gSDEU</global_hash>
</lookup>
</data>
</response>
Otherwise, you get another form of XML data:
// C# Code
string GetInfo(string url, string login, string key, out string createdBy)
{ url = Uri.EscapeUriString(url);
string reqUri =
String.Format("http://api.bit.ly/v3/info?" + "login={0}&apiKey={1}&shortUrl={2}&format=xml" + login, key, url);
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(reqUri);
req.Timeout = 10000; // 10 seconds
Stream stm = req.GetResponse().GetResponseStream();
XmlDocument doc = new XmlDocument();
doc.Load(stm);
// error checking for xml
if (doc["response"]["status_code"].InnerText != "200")
throw new WebException(doc["response"]["status_txt"].InnerText);
XmlElement el = doc["response"]["data"]["info"];
createdBy = el["created_by"].InnerText;
return el["title"].InnerText;
}
Authentication Function
This is the last function today, the authenticate function. This function is used to check whether a username and a password are valid. Although this function and the validation function work the same way, there's a big difference. The validation function checks for API credentials, the username and the API key, while this function checks for login information, the username and the password. Another big difference is that this function is currently access-restricted and you cannot use it before asking for permission from [email protected].
This function accepts two addition parameters, the username x_login and the password x_password.
This function is called in a very specific way. You add arguments in the body of your request. In addition, the request is made by the method POST.
If the function succeeded you get the API key for that user. For example:
<?xml version="1.0" encoding="UTF-8"?>
<response>
<status_code>200</status_code>
<data>
<authenticate>
<username>bitlyapidemo</username>
<successful>1</successful>
<api_key>R_0da49e0a9118ff35f52f629d2d71bf07</api_key>
</authenticate>
</data>
<status_txt>OK</status_txt>
</response>
Otherwise, the successful element is set to 0 and no other information is available:
<?xml version="1.0" encoding="UTF-8"?>
<response>
<status_code>200</status_code>
<data>
<authenticate>
<successful>0</successful>
</authenticate>
</data>
<status_txt>OK</status_txt>
</response>
The next C# function tries to authenticate a given user and retrieve his API key (Notice how to set information in the body of the request):
// C#
string Authenticate(string login, string key, string xLogin, string xPassword)
{ string reqUri = "http://api.bit.ly/v3/authenticate";
string body =
string.Format("login={0}&apiKey={1}&x_login={2}" + "&x_password={3}&format=xml", login, key, xLogin,xPassword);
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(reqUri);
req.Timeout = 10000;
req.Method = "POST";
StreamWriter writer = new StreamWriter(req.GetRequestStream());
writer.WriteLine(body);
Stream stm = req.GetResponse().GetResponseStream();
XmlDocument doc = new XmlDocument();
doc.Load(stm);
// error checking for xml
if (doc["response"]["status_code"].InnerText != "200")
throw new WebException(doc["response"]["status_txt"].InnerText);
XmlElement el = doc["response"]["data"]["authenticate"];
if (el["successful"].InnerText == "1")
return el["api_key"].InnerText;
else
return null;
}
Sample
Download the sample code
here.
Where to go next
Read more about URL shortening services
here.