As I had some troubles finding out how to show some of my own Flickr photos on this site using the Flickr API and Ruby on Rails I thought it would be useful to write it down in a small tutorial.
STEP 1: Finding a library: rFlickr
Flickr lists 3 possible Ruby frameworks for their API. After trying flickr.rb (no longer available) and not being able to login I decided to switch to rFlickr as it seems the most popular one. I didn't look at the last one: flickr-ruby.
Start with installing the rFlickr library. You may need to uninstall a previous library if you installed another one earlier.
STEP 2: Get a Flickr API key
Flickr doesn't use the username/password combination as most other API's do. An application can ask for permissions which the user has to grant. A token is returned when this is done allowing the application to connect the next time so we'll only have to do this once. Apply for a key at the Flickr website and remember the key and the shared secret. I use a “Web Application” key as I want to use it for my blog.
STEP 3: Get a Flickr token
Start your development environment:
Next load the newly installed rFlickr module and ask for a Flickr frob using the API key and shared secret you got earlier.
This will return a URL you need to copy & paste in your browser to allow the application to read, write and delete your photos. If you don't need all this permissions your can add the ‘perms’ parameter for a less greedy permissions. Use the following if you only need read access to the photos:
Allow the application to access your photos when you open the URL. You can request the forb we need and make sure to to keep it for now.
Now we'll need a token. The token is more permanent as the frob but we need the forb to get one. Finally cache the token:
STEP 4: Give me my photos!
Now it's time to do something more useful with the token. What about showing the thumbnails of the 6 last added photos? We'll need your NSID which is the strange number in your Flickr URL that looks like 26227936@N00.
Look, you now have an array with the last 6 posted public photos and their ID. Good luck!