Introducing shelltwit

Some time ago I talked about a command line twitter client I was developing. Today I can proudly say it is finished… for now
And I decided to upload the code to Codeplex GitHub for a few reasons. First of all it uses xAuth with .net with no extra library. Some may be asking “why would you want to do that if there are hundreds of libraries out there?”… well yeah but… no I don’t have an answer for that… I guess I just wanted to give it a try.
Also, while developing this tool I encountered some problems that some people does not ever find, specially people from English speaking countries. The problem appears when you want to twit say… “Peñarol Campeón!”. It took me a little while to discover the right encoding and as I said before, there’s not much written about it. (For more info take a look here)
And finally I wanted to share the code in case some soul out there wanted to give me a hand with the rest of the API. So far this tool only updates the status, but I’m also building a library (cleverly called shelltwitlib) where I’m intending to add every twitter API method.
As a bonus, if you use the shelltwitlib (since it works with xAuth) you’ll be able to have your tool displayed on your status like in the picture shown below.

Want more? Bit.ly integration is also available

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Encoding strings for the twitter API

Some time ago, I started to work on shelltwit a command line twitter updater (it only updates your status), but I didn’t want to use any existing library because I wanted to learn how to work directly to twitter API.

I looked around for some examples, the Twitter API doc is not well updated or complete, so it is not easy to start coding right away, you need to read a lot first (I hate when that happens). I found a good sample from Shannon Whitley called Twitter xAuth with .net. I started up with that code but I found an issue with international characters, like á, é or ñ, which kept me from posting about #Peñarol. So I started to hunt the bug, looked around online, went to the Twitter API user group and found out that there are a lot of issues with international characters. I found people form Brazil, Russia and Japan complaining about it. Apparently most libraries were written by english speaking developers so very few encounter the issue.

Now I can happily say that found the issue so I thought about posting the solution here.

Encoded strings (your twitter status) must be made to UTF8 according to RFC3986 and there’s no native .net function that does that, so after some researching I came up with an algorithm that does exactly that. So I hope it helps some one else.

static string UNRESERVED_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~";

//http://en.wikipedia.org/wiki/Percent-encoding
//http://www.w3schools.com/tags/ref_urlencode.asp see 'Try It Yourself' to see if this function is encoding well
//This should be encoded according to RFC3986 http://tools.ietf.org/html/rfc3986
//I could not find any native .net function to achieve this
/// <summary>
/// Encodes a string according to RFC 3986
/// </summary>
/// <param name="value">string to encode</param>
/// <returns></returns>
public static string EncodeString(string value)
{
    StringBuilder sb = new StringBuilder();
    foreach (char c in value)
    {
        if (UNRESERVED_CHARS.IndexOf(c) != -1)
            sb.Append(c);
        else
        {
            byte[] encoded = Encoding.UTF8.GetBytes(new char[] { c });
            for (int i = 0; i < encoded.Length; i++)
            {
                sb.Append('%');
                sb.Append(encoded[i].ToString("X2"));
            }
        }
    }
    return sb.ToString();
}

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