Converting RSS feed to different formats using FeedBurner services

So, why should anyone bother converting RSS feed format? The answer is that RSS feeds can have various formats: RSS 1.0, RSS 2.0, Atom 0.3, Atom 1.0, etc. RSS reader has to know these formats and display the feed normally as if its format is the same for all feeds.

At present I’m using SharpReader as my primary RSS reading tool and there is one thing that I’m annoyed with – its memory consumption. I have smth around 180 feeds in my feed list. After SharpReader refreshes them all, its memory consumption rises to more then 200 Mb. It is not appropriate for me.

Recently I've obtained link that lead me to the download page of Internet Explorer 7 Beta3.
Though there was Beta2 out there already for quite long, I didn’t want to bother myself with “raw” product, especially if it is Internet Explorer :8-).

However, now it is Beta3 and I thought why not? Installation was okay. Then I exported RSS feeds from SharpReader into OPML file and imported it into IE.
Import was also fine, feeds hierarchy was preserved, what I really appreciate.

I’ll omit describing some inconveniences with feeds browsing I experienced with IE, and focus myself on the issue that can explain the title of this post :8-).

IE 7 Beta3 supports only several RSS formats!!! I was surprised. Namely, IE doesn’t have support for RDF format.

So, if RDF is not supported I have to convert it to something that is supported, for example RSS 2.0. How to resolve? FeedBurner comes to rescue!

Here are the steps do obtain converted feed:
1) go to http://www.feedburner.com
2) if you have an account there - sign in, if not – register and sign in
3) burn a feed. Put in the url of the feed that has unsupported format
4) after feed is burnt, go to main page, select it and then select “Optimize” tab
5) then select “Convert Format Burner”. This option will let you select appropriate RSS format. Choose “Save” and that’s it, you can use new feed url instead of the old one.

Example of such converted feed is
RDF: http://www.ixbt.com/export/articles.rdf
RSS 2.0: http://feeds.feedburner.com/Ixbt

Microsoft Robotics Studio

Nowadays, robots become more and more popular. Asian countries: South Korea and Japan are the leaders in the robotics.

Recently, member of Windows Mobile team blogged about creation of a robot that works under Windows Mobile ( http://www.wimobot.com ).

Microsoft, recently announced its Microsoft Robotics Studio.

Things get, more and more interesting :8-)

Deferred custom actions with WiX

Definition of Deferred Custom Actions

The installer does not execute a deferred execution custom action at the time the installation sequence is processed. Instead the installer writes the custom action into the installation script.


Custom actions that set properties, feature states, component states, or target directories, or that schedule system operations by inserting rows into sequence tables, can in many cases use immediate execution safely. However, custom actions that change the system directly, or call another system service, must be deferred to the time when the installation script is executed.

Purpose of deferred Custom Actions

The purpose of a deferred execution custom action is to delay the execution of a system change to the time when the installation script is executed. This differs from a regular custom action, or a standard action, in which the installer executes the action immediately upon encountering it in a sequence table or in the form with tag.


<Publish Event="DoAction" Value="CustomActionName">
<![CDATA[1]]>
</Publish>

How to define deferred custom action in WiX

Deferred custom action is defined in the following way:


<CustomAction Id="MyAction" Return="check" Execute="deferred"
BinaryKey="CustomActionsLibrary" DllEntry="_MyAction@4"
HideTarget="yes"/>


Lets describe the sample above:
- Execute=“deferred” – means that custom action with Id “MyAction” will execute in deferred mode ( in-script ).
- DllEntry="_MyAction@4" – the name of the function to be called, when installer executes generated install script.
- HideTarget="yes" - for security reasons, you may transfer confidential info to your custom action, this attribute notifies installer not to log parameters passed to custom action.

How to Transfer Properties to Deferred Custom Action

Because the installation script can be executed outside of the installation session in which it was written, the session may no longer exist during execution of the installation script. This means that the original session handle and property data set during the installation sequence is not available to a deferred execution custom action. Deferred custom actions that call dynamic-link libraries (DLLs) pass a handle which can only be used to obtain a very limited amount of information.


Properties that can be retrieved during in-script execution are:

- CustomActionData - value at time custom action is processed in sequence table. The “CustomActionData” property is only available to deferred execution custom actions. Immediate custom actions do not have access to this property.
- ProductCode - unique code for the product, a GUID string.
- UserSID - set by the installer to the user's security identifier (SID).


If other property data is required by the deferred execution custom action, then their values must be stored in the installation script. This can be done by using a second custom action.
In order to write the value of a property into the installation script for use during a deferred execution custom action we have to do the following:


- Insert a small custom action into the installation sequence that sets the property of interest to a property having the same name as the deferred execution custom action. For example, if Id for the deferred execution custom action is "MyAction" set a property named "MyAction" to the property X which you need to retrieve. You must set the "MyAction" property in the installation sequence before the "MyAction" custom action.


Although any type of custom action can set the context data, the simplest method is to use a property assignment custom action.


At the time when the installation sequence is processed, the installer will write the value of property X into the execution script as the value of the property CustomActionData.


Lets illustrate the above said with WiX sample.


At first we define custom action that will assign CustomActionData property.


<Property Id=”SOME_PUBLIC_PROPERTY”>
<![CDATA[Hello, from deferred CA]]>
</Property>


<CustomAction Id="MyAction.SetProperty" Return="check"
Property="MyAction" Value="[SOME_PUBLIC_PROPERTY]">
</CustomAction>


Then we put above defined custom action into execution sequence along with “MyAction” deferred custom action


<InstallExecuteSequence>
<Custom Action="MyAction.SetProperty" After="ValidateProductID"/>
<Custom Action="MyAction" After="MyAction.SetProperty"/>
</InstallExecuteSequence>


Our custom action will reside in DLL. Below is the sample where we retrieve “SOME_PUBLIC_PROPERTY”, during deferred (in-script) installer execution.


<Binary Id='CustomActionsLibrary'
SourceFile='Binary\CustomActionsLibrary.dll' />


#include <windows.h>
#include <msi.h>
#include <msiquery.h>
#include <tchar.h>


#pragma comment(linker, "/EXPORT:MyAction=_MyAction@4")

extern "C" UINT __stdcall MyAction (MSIHANDLE hInstall)

{

TCHAR szActionData[MAX_PATH] = {0};

MsiGetProperty (hInstall, "CustomActionData",
szActionData,sizeof(szActionData));

::MessageBox(NULL, szActionData, _T(“Deferred Custom Action”),
MB_OK | MB_ICONINFORMATION);

return ERROR_SUCCESS;

}


If there is need to transfer multiple properties into deferred custom action, “CustomActionData” property may contain value pairs e.g. PropertyName=PropertyValue with some separator symbol ( ; ).