PLGoogleReader

Introduction

PLGoogleReader is an iOS library of Google Reader. Since now, google reader has not announced offical API. The implementation is based on the reverse-engineering result shared by pyrfeed. For login, PLGoogleReader use gtm-auth to implement the oauth authetication.

Add PLGoogleReader to your project

Step1. Add frameworks used by PLGoogleReader

1. Open Xcode
2. Select the project file
3. Select a target
4. Select Build Phases tab
5. Open Link Binary with Libraries
6. Add SystemConfiguration.framework and Security.framework

Step2. Add all sources for libraries used by PLGoogleReader

Copy all files in /Enternals to your project

Step3. Copy the PLGoogleReader source

Copy all the files in the /PLGoogleReader to your project.

How to use.

Actually, you can easilty look into the example files to know how to use this library. Here, I briefly describe the usage of PLGoogleReader.

1. GoogleReader.h - The only header file you need to include.
2. PLGoogleReader - The main class of PLGoogleReader. We use it to signin, get the subscription object, and send a GoogleReader request.
3. PLGRRequest - The request object is inspried by the facebook-ios-sdk. All the PLGoogleReader request would return a request object. we can cancel the request if necessary.
4. PLSubscription - This is a high level class to perform multiple request to Google Reader and build up the subscription list.
5. PLSubscriptionItem - Represent an entry of the subscripition list. An entry can be a tag, label, or feed.

Get a PLGoogleReader object

Simplily call +[PLGoogleReader defaultGoogleReader] to get the google reader instance.

PLGoogleReader* googleReader = [PLGoogleReader defaultGoogleReader];

Sign in

For signin, we use the gtm-oauth to implement the oauth. In this library, there has been an easy-to-use view controller GTMOAuthViewControllerTouch to provide the signin web ui. The only thing PLGoogleReader does is just return the GTMOAuthViewControllerTouch view controller back to caller.

UIViewController* viewController = [googleReader viewControllerForSignIn:self];    
[self.navigationController pushViewController:viewController animated:YES];        

And in your view controller class, also remember to implement the PLGoogleReaderSignInDelegate protocol to receive the signin result.

Subscription list

The subscription list is implemented by the class PLGRSubscription. It is a placeholder to preserve the result of the following google reader API.

• http://www.google.com/reader/api/0/subscription/list - A list of all the subscribed feed.
• http://www.google.com/reader/api/0/tag/list - A list of all the user defined or system defined tags.
• http://www.google.com/reader/api/0/preference/stream/list - The sorting for tags.
• http://www.google.com/reader/api/0/unread-count - The unread count for tags.

To get a instance, just

PLGRSubscription* subscription = [googleReader subscription];

After getting this instance, you may need to load the subscription

[subscription reload:self];

In this piece of code, it would reload the subscription list, and set the delegate to self. Once complete, you can get the subscription list by

NSArray* subscriptionList = [subscription subscriptionList];
for(PLGRSubscriptionItem* item in subscriptionList)
{
	NSLog(@"the subscribed item is %@", item.streamid];
}

or get the tag list by

NSArray* tagList = [subscription tagList];	

or get the sorted subscription list of root directory.

NSArray* sortedList = [subscription sortedListForTag:nil];

or get the sorted subscription list of specified tag

NSArray* sortedList = [subscription sortedListForTag:@"/user/-/label/mylabel"];

Usually, we may have a tree UI to show the subscription list (just like the bottom-left list in the offical google reader website). All you need to do is interate the items in root directory and put the item.streamid as argument of -[PLGRSubscription sortedListForTag:].

Get the feed data

Get the stream data

PLGRSubscriptionItem* item = ...;
[googleReader requestWithStreamContents:item.streamid
         	                 withParams:nil
					       withDelegate:self];	// delegate of type PLGRRequestDelegate

On complete, parse the JSON

- (void)request:(PLGRRequest*)request didLoad:(NSData*)data
{        			
	NSString* result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];        
	id resultData = [result JSONValue];
	// parse the json daa.
}

Mark as read or mark all as read.

We have not implemented a high level API for this requirement. But you can use -[PLGoogleReader requestWithAPIPath:withParams:withHttpMethod:withDelegate] to archive it though.

External Libraries

• json-framework - json parser
• gtm-oauth - use it for oauth implemention
• gtm - use the NSString+HTML addition.

Reference

The project reference the following articles.

• http://code.google.com/p/pyrfeed/wiki/GoogleReaderAPI
• http://blog.martindoms.com/2009/08/15/using-the-google-reader-api-part-1/
• http://blog.martindoms.com/2009/10/16/using-the-google-reader-api-part-2/
• http://blog.martindoms.com/2010/01/20/using-the-google-reader-api-part-3/

License

PLGoogleReader is under LGPL license.

Contact me

If you encounter any problem, feel free to mail me. [email protected]