Neo4j Ruby - Practical Neo4j - page 230

Listing 10-29. The follow Route and follow service Method
# follow a user & return the updated list of users being followed
get '/follow/:username' do
content_type :json
json :following => follow(neo,request.cookies[graphstoryUserAuthKey],params[:username])
end
# the follow method in the User class
def follow(neo,currentusername,username)
cypher = " MATCH (user1:User {username:{cu}} ), (user2:User {username:{u}} ) " +
" CREATE UNIQUE user1-[:FOLLOWS]->user2 " +
" WITH user1" +
" MATCH (user1)-[f:FOLLOWS]->(users)" +
" RETURN users.firstname as firstname, users.lastname as lastname, "+
" users.username as username " +
" ORDER BY users.username"
results=neo.execute_query(cypher, {:cu => currentusername, :u => username} )
results["data"].map {|row| Hash[*results["columns"].zip(row).flatten] }
end
The unfollow feature for the FOLLOWS relationships uses a nearly identical application flow as follows feature. In
the unfollow method, shown in Listing 10-30, the controller passes in two arguments—the current username and
username to be unfollowed. As with the follow method, once the operation is completed, the next part of the query
then runs a MATCH on the users being followed to return the full list of followers ordered by the username.
Listing 10-30. The unfollow Route and unfollow service Method
# unfollow a user & return the updated list of users being followed
get '/unfollow/:username' do
content_type :json
json :following => unfollow(neo,request.cookies[graphstoryUserAuthKey],params[:username])
end
# the unfollow method in the User class
def unfollow(neo,currentusername,username)
cypher = "MATCH (user1:User {username:{cu}} )-[f:FOLLOWS]->(user2:User {username:{u}} ) " +
" DELETE f " +
" WITH user1" +
" MATCH (user1)-[f:FOLLOWS]->(users)" +
" RETURN users.firstname as firstname, users.lastname as lastname, "+
" users.username as username " +
" ORDER BY users.username"
results=neo.execute_query(cypher, {:cu => currentusername, :u => username} )
results["data"].map {|row| Hash[*results["columns"].zip(row).flatten] }
end