Quoting arwed <af@bbp.biz>:
This works, but I am sure there is a better way todo this:
# GET /posts/1/edit
def edit
@post = Post.find(params[:id])
# Find user galleries that have not been used in posts yet
usergalleries = Array.new
@post.user.galleries.each do |pug|
usergalleries << pug.id
end
userpostgalleries = Array.new
@post.user.posts.each do |pup|
userpostgalleries << pup.gallery_id
end
aug = usergalleries - userpostgalleries
@availableusergalleries = @post.user.galleries.find
(:all, :conditions => { :id => aug })
end
Any ideas?
# @post = Post.find(params[:id])
@post = Post.find(params[:id], :include => {:user => [:galleries, :posts]})
# One database call instead of many. I think this is correct form, but
# have no easy way to test it.
# # Find user galleries that have not been used in posts yet
# usergalleries = Array.new
# @post.user.galleries.each do |pug|
# usergalleries << pug.id
# end
user_galleries = @post.user.galleries.map{|pug| pug[:id]}
# I find pug[:id] more reliable than pug.id; the latter in some contexts is
# interpreted as the Object id, instead of the primary key/ID from the
# database and a deprecation warning is given.
# userpostgalleries = Array.new
# @post.user.posts.each do |pup|
# userpostgalleries << pup.gallery_id
# end
user_post_galleries = @post.user.posts.map{|pup| pup.gallery_id}
aug = usergalleries - userpostgalleries
# @availableusergalleries = @post.user.galleries.find(:all, :conditions =>
{ :id => aug })
@availableusergalleries = @post.user.galleries.find(aug)
# ActiveRecord.find will take an array of IDs.
Another way that takes less memory (if speed is of more concern, benchmark
both):
aug = @post.user.galleries.map{|pug| pug[:id]}
@post.user.posts.each{|pup| aug.delete(pup.gallery_id)}
@availableusergalleries = Gallery.find(aug)
HTH,
Jeffrey
