Flickr Pipes / Discuss

alto maltés says:

Using this application, you may list your contacts with whom you have a specific (mutual) relationship. For example, you may want to see who of your friends has marked you as a friend, or rather who of your contacts does not list you as a contact, etc.

Run the application.

The first time, you will have to grant “read” permission to the application. This permission may be revoked at any time.




Technical info

This Pipe makes authenticated calls to the Flickr API. By following the login link, a user is presented with the Flickr sign-in prompt. Just the first time, the user will be asked to grant “read” permissions to the Pipe. Once the user is signed into Flickr and grants the permission, he is redirected to the Pipe. Flickr passes a frob as a parameter to the Pipe.

The Pipe calls www.flickr.com/services/api/flickr.auth.getToken.html to convert the frob into a token, which it then uses to fetch the calling user's contact list by calling www.flickr.com/services/api/flickr.contacts.getList.html. The list is filtered so that only contacts with whom the user has a specific forward relationship are allowed to flow through.

However the response of flickr.contacts.getList does not contain information about the reverse relationship of a user with a contact. This information is obtained by making an authenticated call to www.flickr.com/services/api/flickr.people.getInfo.html for every contact, using the same authentication token generated earlier. The list is then filtered so that only contacts with whom the user has a specific reverse relationship are allowed to flow through.

The calls to flickr.auth.getToken, flickr.contacts.getList and flickr.people.getInfo must be signed. Signing a request involves adding an api_sig parameter to its URL. The computation of this parameter's value necessitates the computation of an MD5 hash. Since such a function is not provided natively by Yahoo! Pipes, the computation is delegated to a YQL script implementing this function.

This Pipe also implements a primitive form of “error handling”. If the call to flickr.auth.getToken fails (typically due to an expired frob), the user is presented with a single item that links to the login page. Following this link will generate a “fresh” frob, and re-run the Pipe.


Originally posted at 9:46AM, 8 July 2007 PDT (permalink)
alto maltés edited this topic 19 months ago.