So I'm working on an application that has a feature that generates a list of 100 or so artists that are similar to those in the user's music catalog using the Echo Nest API. Then, a user can supply a certain year, and, based on the similar artists, the application will return a list of albums that were released on that year.
The only problem is that I have no idea how to filter albums based on year. The Echo Nest API doesn't really do much with albums. The Discogs and Last.fm APIs work with albums, and the Discogs API has data about albums' release dates, but there is no way to filter an initial query by release date. For example, if I have the artist Fleet Foxes and I want to filter it by albums released in 2011, there is no option to search for albums by the Fleet Foxes confined to release dates of 2011.
The only option I can really see at this point is iterating over EVERY album an artist has and only adding those albums that meet my specifications. However, this is obviously very heavy on both the APIs and my server, especially considering that many of the artists in the list of 100 similar artists will have no albums that match my criteria and that many artists have well within the range of 100 albums when you take into consideration singles, remixes, etc.
Does anyone see a better way of doing this?
If an API really doesn't have any way to filter by year, then yes, of course you will have to pull down all of the releases and filter them after the fact.
If you think this is a burden on your code and/or their server, you should file a feature request to add the filtering.
However, you should make sure first that they really don't provide such a thing. Most REST APIs separate "fetch" and "search". For example, http://api.example.com/artists/12345/releases may not have any way to filter it, but http://api.example.com/search?type=releases&artist=12345&year=2011 may exist.
Without looking into all of the APIs in detail, a quick check of Discogs' "Run a search query" docs shows that you can include a year criterion in the search (although it looks like maybe you can't actually search by artist ID, just by artist name?).