Posting attachments with Facebook Graph API using iPhone SDK

问题

I've been trying desperately to publish a message with an attachment to the current user's wall using Facebook's Graph API. I've been successful at publishing a POST object with an image but once I start getting into attachments, it won't work. It's as if it is not recognizing that property.

Here is my code sample:

NSDictionary* attachment = [NSDictionary dictionaryWithObjectsAndKeys:
                            @"ATT NAME", @"name",
                            @"http://my.web.com", @"href",
                            @"ATT CAPTION", @"caption",
                            @"ATT DESC", @"description",
                            [NSDictionary dictionaryWithObjectsAndKeys:
                             @"property 1", @"PROP1",
                             @"property 2", @"PROP2",
                             nil], @"properties"
                            nil];

NSString *attachmentStr = [jsonWriter stringWithObject:attachment];

NSMutableDictionary* params = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                               @"post", @"type",
                               @"MY MESSAGE", @"message",
                               attachmentStr, @"attachment",
                               nil];

[_facebook requestWithGraphPath:@"me/feed" andParams:params andHttpMethod:@"POST" andDelegate:self];

This will publish "MY MESSAGE" but nothing else. The reason why I truly need this attachment is because of the "properties" element.

Thanks so much in advance!

Edit: I just wanted to clarify that if I use the following dictionary for my params instead of the one above, it works perfectly fine. My issue is that I need to use the "properties" property of the "attachment" object for formatting purposes. Here is the dictionary:

NSMutableDictionary* params = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                               @"post", @"type",
                               @"http://my.web.com/pic.png", @"picture",
                               @"http://my.web.com", @"link",
                               postName, @"name",
                               postCaption, @"caption",
                               postDescription, @"description",
                               postMessage, @"message",
                               nil];

回答1:

OK, I found how to send properties together with my stream post. I discovered it by taking a look at the html in the actual Facebook Wall page. Turns out, the parameters for the POST object are considered the attachment so the only thing to be done is add the "properties" property directly to the POST parameters like this:

NSDictionary *properties = [NSDictionary dictionaryWithObjectsAndKeys:
                            @"property 1", @"PROP1",
                            @"property 2", @"PROP2",
                            nil];

NSString *propStr = [jsonWriter stringWithObject:properties];


NSMutableDictionary* params = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                           @"post", @"type",
                           @"http://my.web.com/pic.png", @"picture",
                           @"http://my.web.com", @"link",
                           postName, @"name",
                           postCaption, @"caption",
                           postDescription, @"description",
                           postMessage, @"message",
                           propStr, @"properties",
                           nil];

[_facebook requestWithGraphPath:@"me/feed" andParams:params andHttpMethod:@"POST" andDelegate:self];

And voila! It worked!