Shorten URLs in Visual Basic using Bit.ly API

I’m currently working on a Twitter client for college that will provide a function to shorten URLs using the Bit.ly API.

It’s actually really simple and easy to use and while my sample interface is written in VB you can use the API with any language. To use the API all you need do is construct a URL like so:

http://api.bit.ly/shorten?version=2.0.1&longUrl=http://www.conorhackett.com&login=[USERNAME]&apiKey=[API_KEY]

You will need to register with Bit.ly to get API key and a username before you can try this. Also, the url you want to shorten must begin with “http://” or else you will get an error. The above URL (with my API key included) will return the following response:

{ “errorCode”: 0, “errorMessage”: “”, “results”: { “http://www.conorhackett.com”: { “hash”: “nzIzC”, “shortKeywordUrl”: “”, “shortUrl”: “http://bit.ly/9SWQS”, “userHash”: “9SWQS” } }, “statusCode”: “OK” }

From this you can extract the shortened URL along with the status of the response among other but they are the only two pieces of information that I used.

Below you’ll find my solution written in VB. The handling of the status messages isn’t the greatest but it works fine. I should really be using regular expressions to validate user input and extract information from the response. It’s late and my regex skills are still a little shaky so i’ll leave that until another day.

    ' NOTE: you must use -> Imports  System.Net

    Public Function getShort(ByVal url As String) As String
        ' New instance of WebClient
        Dim client As WebClient = New WebClient()
        ' if URL doesn't start with http:// then append it to the start
        If url.StartsWith("http://") = False Then
            url = "http://" + url
        End If

        ' Setup command url to be sent to Bit.ly API
        Dim commandUrl As String = "http://api.bit.ly/shorten?version=2.0.1&longUrl=" + url + "&login=[USERNAME]&apiKey=[API_KEY]"
        ' Get raw result string
        Dim result As String = client.DownloadString(commandUrl)

        ' Determine status of repsonse
        ' This needs to be improves but works ok for now.
        If result.IndexOf("""statusCode"": ""OK""") > 0 Then
            ' Get position of the beginning of short URL.
            Dim indexOf As Integer = result.IndexOf("http://bit.ly/")
            result = result.Substring(indexOf, 19)
        End If
        If result.IndexOf("""statusCode"": ""ERROR""") > 0 Then
            ' Throw an exception if response is ERROR.
            Throw New System.Exception("ERROR")
        End If

        Return result
    End Function

Update: This tutorial focuses on getting a JSON formatted response from Bit.ly. This can be changed to XML by adding &format=xml at the end of the request URL. I will post a guide on working with XML in the near future.