This series is about a promotion game we built to support our iPhone apps.
You can play the game here – it is “early stage” but you can really win! I already told about the background of this series in my first post. And I handled some parts of the infrastructure in the second part.
Now lets focus on the game itself. Again – the primary goal is to spread information about iPhone software.
And we decided to use twitter as carrier for this.
I already played around with twitter before. http://manniat.pp-p.net/TwitterSL/Default.aspx
But this was nothing more than a proof of concept – I didn’t even put content on that page.
Anyhow – the first thing I did was to take a look a the twitter guidelines for “competition games” – yes there is a guideline for this.
Anyhow – I found that what I need was not covered by my previous work.
So I looked around a bit and stumbled into linq2twitter by Joe Mayo.
First of all I love Linq – next it looks as if this project is under active development (some others I found seem more or less to be “frozen”).
Anyhow – I gave it a try – and my first thoughts – there is something missing.
OK – I found something on how to send a direct message – but it looked “a bit strange”:
But (reading the manual sometimes helps) it turned out that almost everything is available using a Linq query.
Snippet created with CBEnhancer
from A in m_twcContext.Status where A.Type == StatusType.Mentions
&& A.Count == nSearchCount orderby A.StatusID descending select A
This query for an example searches for tweets where your account is mentioned. Since I want to get only a certain number of entries I say A.Count==nSearchCount.
m_twcContext is the “main token” which holds you account info and other things. Simply use it to make your queries. The “strange” thing I wrote about before is that you give twitter API parameters as “conditions” in your Linq statement.
But – after some experience with it you will learn the same as I did: that’s the correct way to do this.
And by the way – sometimes I was confused by my own code. The reason? I had to look twice to find out if I query my SQL Server or twitter 
So once again thank you Joe Mayo for sharing this great work.
And last not least a snippet which shows how easy it is to get a list of Mentions.
For those not familiar with the twitter API – you get max 200 entries per call – so if you get exactly 200 entries you have to check if more entries exist. The following code fills a list handling this paging in a simple manner.
Snippet created with CBEnhancer List<
Status> lRet =
new List<
Status>();
int nSearchCount = 200;
int nPage = 2;
//this is the first number for the second call :) lTmpErg = (
from A
in m_twcContext.Status
where A.Type ==
StatusType.Mentions && A.Count == nSearchCount
orderby A.StatusID
descending select A).ToList();
while(lTmpErg.Count() == nSearchCount) {
//maybe more exists lRet.AddRange(lTmpErg);
lTmpErg = (
from A
in m_twcContext.Status
where A.Type ==
StatusType.Mentions && A.Count == nSearchCount && A.Page == nPage
orderby A.StatusID
descending select A).ToList();
nPage++;
}
if(lTmpErg.Count() > 0) {
lRet.AddRange(lTmpErg);
}
Sending a direct message is also very simple:
Snippet created with CBEnhancer public bool SendDirectMessage(
string strUser,
string strMessage) {
try {
if(!m_twAuth.IsAuthorized) {
m_twAuth.SignOn();
}
m_twcContext.NewDirectMessage(strUser, strMessage);
return (
true);
}
catch {
return (
false);
}
}
With this I’ll finish the part about the twitter access.
In the next part I’ll talk about the rest of the infrastructure – primarily about WCF and Caching.
Stay tuned
Manfred
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