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12 Session 4: Introducing the Windows Vista APIs Windows RSS Platform Overview As part of the RSS support in Microsoft Internet Explorer® 7, users can discover and subscribe to RSS feeds within the browser. When the user subscribes to a feed, the feed is added to the Common Feed List, which is a collection of Really Simple Syndication (RSS) feeds that is available for other applications to use in addition to or instead of their own list. The Microsoft Windows RSS Platform is an application programming interface (API) that enables applications to access and manipulate the Common Feed List. You can use the Windows RSS Platform in your applications to: • Subscribe to new feeds and enumerate existing subscriptions. • Easily access properties of feeds (channels), feed items, and enclosures. • Manage and organize feeds into folders. • Listen for and respond to feed and feed folder events. • Check the status of the background Feed Download Engine or modify settings. • Normalize the Extensible Markup Language (XML) source of a feed. Session 4: Introducing the Windows Vista APIs 13 Windows RSS platform components include: • The Common Feed List. A shared hierarchical representation of all the feeds to which the current user is subscribed. • The Feed Store. The central location in Windows of your RSS feeds. • The Feed Download Engine. The background process that merges new feed items and enclosures into the Feed Store. The Feed Download Engine automatically downloads the feed items from the source URL specified in the feed. These downloads can occur on a schedule or as requested by the user. The value of the Interval property and TTL (time to live) element of the feed determine how often the feed is downloaded. 14 Session 4: Introducing the Windows Vista APIs Managing Subscriptions by Using the Common Feed List The Common Feed List is a shared hierarchical representation of all the feeds to which the current user is subscribed. The Common Feed List resembles a hierarchical file system with folders and feeds. You can use the Microsoft Windows RSS Platform APIs to manage the common feed list. To do this, you will use the following objects and interfaces: • FeedsManager. The top-level object in the Windows RSS Platform is the FeedsManager object. To create the object for scripting, reference the Microsoft.FeedsManager library. • FeedFolder. The IFeedFolder interface contains properties and methods for accessing feeds contained within the folder in addition to properties and methods for accessing subfolders. The root folder of the Common Feed List is accessed through the FeedsManager.RootFolder property, which returns an object of type IFeedFolder. • Feed. The IFeed interface exposes the required and optional elements of an RSS feed. To subscribe to a feed, you must assign it to a folder by calling FeedFolder.CreateFeed(name,url). Session 4: Introducing the Windows Vista APIs 15 • FeedItem. Individual items in a feed are represented by FeedItem objects. Depending on the type of feed, these items are aggregated as news items that are merged into the feed or as list items that replace the contents of the previous list. Additional RSS 2.0 item elements, such as GUID and source, are available in the XML source document of the feed. • FeedEnclosure. The IFeedEnclosure interface provides access to the optional media file attachment that may be associated with each feed item. The following table lists the methods and properties that are used to traverse and manipulate the Common Feed List hierarchy. Object.Method Description FeedsManager.RootFolder Returns top-level system feed folder FeedFolder.Subfolders Returns collection of subfolders FeedsManager.GetFolder(path) Returns specific folder by path FeedFolder.GetSubfolder(name) Returns specific subfolder FeedFolder.CreateSubfolder(name) Creates and returns new subfolder FeedFolder.Delete Deletes folder, including its subfolders and feeds FeedsManager.GetFeed(path) Returns specific feed by feed list path FeedFolder.GetFeedByUrl(url) Returns specific feed, if subscribed, by URL FeedFolder.GetFeed(name) Returns specific feed by name FeedFolder.Feeds Returns collection of feeds FeedFolder.CreateFeed(name,url) Creates feed in folder and subscribes to it FeedsManager.DeleteFeed(path) Deletes the feed Feed.Delete Deletes the feed 16 Session 4: Introducing the Windows Vista APIs Implementing Feed and Folder Events The Microsoft Windows RSS Platform includes a rich eventing subsystem that developers can use to build applications that will listen for and respond to feed and folder events. To do this, the developer must configure the applications to register for events on folders and on feeds. To register for these events, the application calls the GetWatcher method on the folder or feed, specifying the scope and mask. The interface returned by GetWatcher is an IConnectionPointContainer, which the application uses to register its implementation of the event sink interface. Defining the event scope When registering for events on a folder, the application can specify a value from the FEEDS_EVENTS_SCOPE enumeration that indicates which of the events will be fired. The following options are available: • FES_SELF_ONLY. Raise events for this folder and its feeds. • FES_SELF_AND_CHILDREN_ONLY. Raise events for this folder and its feeds and for its direct subfolders and their feeds. • FES_ALL. Raise events for this folder and its feeds and all subfolders recursively and their feeds. Session 4: Introducing the Windows Vista APIs 17 Defining the event mask To limit which events are raised, applications can specify the FEEDS_EVENTS_MASK. This mask determines which events will be raised by the Windows RSS Platform. The following options are available: • FEM_FOLDEREVENTS. Raise folder events only (added, deleted, renamed, moved). • FEM_FEEDEVENTS. Raise feed events only (added, deleted, renamed, moved). As an example, the following code shows how to subscribe to the FeedItemCountChanged event: // Declaration of FeedList objects FeedsManager fm = new FeedsManager(); IFeedFolder rootFolder = (IFeedFolder)fm.RootFolder; IFeedFolderEvents_Event fw; fw = (IFeedFolderEvents_Event)rootFolder.GetWatcher( FEEDS_EVENTS_SCOPE.FES_ALL, FEEDS_EVENTS_MASK.FEM_FEEDEVENTS); fw.FeedItemCountChanged += new IFeedFolderEvents_FeedItemCountChangedEventHandler(fw_FeedItemCountChanged); The following table lists some of the folder events that are available. Event Description Mask FolderAdded(path) A subfolder was added. FEM_FOLDEREVENTS FolderDeleted(path) A subfolder was deleted. FEM_FOLDEREVENTS FolderItemCountChanged(path,count, unread) The number of items (aggregated) or the number of unread items (aggregated) changed. FEM_FOLDEREVENTS FeedAdded(path) A feed was added. FEM_FEEDEVENTS The following table lists some of the feed events that are available. Event Description Mask FeedDeleted(path) A feed was deleted. FEM_FEEDEVENTS FeedUrlChanged(path) The URL of a feed changed. FEM_FEEDEVENTS FeedDownloading(path) A feed has started downloading. FEM_FEEDEVENTS FeedDownloadCompleted(path,error) A feed has completed downloading (success or error). FEM_FEEDEVENTS FeedItemCountChanged(path,count, unread) The number of items or the number of unread items changed. FEM_FEEDEVENTS Error An error has occurred in the eventing subsystem. N/A 18 Session 4: Introducing the Windows Vista APIs Demonstration 1: Building an RSS Reader In this demonstration, you will see how you can build an RSS reader by using the Microsoft Windows RSS Platform. Key Point The key point of this demonstration is: • You can write an RSS reader application that uses the Windows Vista APIs to read and manipulate RSS feeds. Session 4: Introducing the Windows Vista APIs 19 Querying the Windows Search Engine Introduction One of the important new features in Windows Vista is the new search functionality. You can configure Windows Search to index all of the important content sources on your computer and then search that index to locate relevant documents and other content very quickly. By using the Windows Vista APIs, you can integrate this search capability into any application you write. Objectives After completing this section, you will be able to: • Describe how the property system works for Windows Search. • Describe how to query the Windows Search system by using the OLEDB provider. 20 Session 4: Introducing the Windows Vista APIs Windows Search Property System Overview The goal of the Windows Search system is to return the most precise results possible. The properties assigned to documents and other content are at the heart of the Windows Search system. Properties allow searches to return more precise results by ensuring that all search results meet the properties specified in the search. For example, properties such as file author, creation date, and size may be important criteria when searching for a file. The results returned by a search will also include properties. Some applications may simply provide path to the actual item in the search result, but in most cases, the search also displays the properties for all items returned in the search. The user can then use these properties to quickly identify which item in the search result to look at first. Properties are identified in two ways in Window Vista: • Canonical name. In SQL-style searches, the canonical name is used. This is a text name for the property. System-defined properties all start with the term System. For example, the following are valid canonical names: • System.Author • System.Photo.FNumber • System.Music.Artist Session 4: Introducing the Windows Vista APIs 21 Companies could devise their own application-specific canonical names by using a format such as CompanyName.GroupName.PropertyName. The first GroupName value can be anything, but it would typically be the name of an application or a suite of applications. • PROPERTYKEY. The second way of identifying a property is through a unique binary identifier. This is the usual way of identifying the properties in an application when working with the search and property shell API. This option is often more convenient to work with because it uses a fixed-size binary structure rather than a string. You can also use structures like the following to map between the PROPERTYKEY binary format and the canonical name: struct PROPERTYKEY { GUID fmtid; DWORD propid; }; [...]... used by developers when creating applications This session described: • The new API features available in Windows Vista • How to develop an RSS reader by using the Windows Vista API • How to query Windows Search by using the Windows Vista API 26 Session 4: Introducing the Windows Vista APIs Next Steps Access the Vista Bridge sample library to view managed wrappers the new Vista APIs: • http://windowssdk.msdn.microsoft.com/en-us/library/ms756482.aspx... an application that can use the Windows Search engine to locate information on the computer • You can configure the search to look for files with specific properties, and you can configure how the result set is ordered Session 4: Introducing the Windows Vista APIs 25 Session Summary In addition to providing support for the new features in NET Framework 3.0, Windows Vista also provides many enhanced... systemindex scope() WHERE \"System.Size\" > 102 4"; OleDbCommand cmd = new OleDbCommand(sqlCommand, conn); using (OleDbDataReader reader = cmd.ExecuteReader()) { while (reader.Read()) { … } } conn.Close(); } 23 24 Session 4: Introducing the Windows Vista APIs Demonstration 2: Querying the Windows Search Engine In this demonstration, you will see how you can query the Windows Search engine by using the OLE... http://windowssdk.msdn.microsoft.com/en-us/library/ms756482.aspx Session 4: Introducing the Windows Vista APIs Questions and Answers 27 28 Session 4: Introducing the Windows Vista APIs Clinic Evaluation Your evaluation of this product will help Microsoft understand the quality of your learning experience Please work with your training provider to access the product evaluation form Microsoft will keep your answers to this survey private...22 Session 4: Introducing the Windows Vista APIs Querying Windows Search by Using the OLEDB Provider One of the easiest ways to query the Windows Search system is to use the OLE DB provider To use the OLE DB provider, you will write a series of SQL-like SELECT statements that use the... Microsoft OLE DB Provider for Microsoft Search is called Search.CollatorDSO.1 You can use the following connection string when instantiating the OleDBConnection object: "provider=Search.CollatorDSO.1;EXTENDED PROPERTIES=\"Application =Windows\ "" This code is included in the following code snippet: string indexerConnString = "provider=Search.CollatorDSO.1;EXTENDED PROPERTIES=\"Application =Windows\ ""; using (OleDbConnection... can specify only a single index that can be queried You can precede SYSTEMINDEX SCOPE() with a machine name to execute a query against the local index of a remote machine Session 4: Introducing the Windows Vista APIs • WHERE The optional WHERE clause supports a number of predicates • Simple predicates: Literal value comparisons (,=) and LIKE • Full-text predicates: CONTAINS and FREETEXT • Search depth... statement includes the following elements: • SELECT The represents a list of one or more comma-separated column names in which the columns correspond to properties defined in the new Windows Vista property system Property names must be enclosed in double quotation marks (due to the period used in the naming convention) SELECT * is not supported, so you will need to specify at least one . query Windows Search by using the Windows Vista API. 26 Session 4: Introducing the Windows Vista APIs Next Steps Access the Vista Bridge sample library to view managed wrappers the new Vista. property system works for Windows Search. • Describe how to query the Windows Search system by using the OLEDB provider. 20 Session 4: Introducing the Windows Vista APIs Windows Search Property. Session 4: Introducing the Windows Vista APIs Implementing Feed and Folder Events The Microsoft Windows RSS Platform includes a rich eventing subsystem that developers can use to build