I am trying to filter the results of an user search in my app to only show users who are NOT friends. My friends table has 3 columns; f1 (userid of person who sent request), f2 (userid of friend who received request), and confirmed (boolean of true or false). As you can see, #usersfiltered is the result of the search. Then the definition of the current user's friend is established. Then I am trying to remove the friends from the search results. This does not seem to be working but should be pretty straight forward. I've tried delete (not good) and destroy.
def index
#THIS IS THE SEARCH RESULT
#usersfiltered = User.where("first_name LIKE?", "%#{params[:first_name]}%" )
#THIS IS DEFINING ROWS ON THE FRIEND TABLE THAT BELONG TO CURRENT USER
#confirmedfriends = Friend.where(:confirmed => true)
friendsapproved = #confirmedfriends.where(:f2 => current_user.id)
friendsrequestedapproved = #confirmedfriends.where(:f1 => current_user.id)
#GOING THROUGH SEARCH RESULTS
#usersfiltered.each do |usersfiltered|
if friendsapproved.present?
friendsapproved.each do |fa|
if usersfiltered.id == fa.f1
#NEED TO REMOVE THIS FROM RESULTS HERE SOMEHOW
usersfiltered.remove
end
end
end
#SAME LOGIC
if friendsrequestedapproved.present?
friendsrequestedapproved.each do |fra|
if usersfiltered.id == fra.f2
usersfiltered.remove
end
end
end
end
end
I would flip it around the other way. Take the logic that is loop-invariant out of the loop, which gives a good first-order simplification:
approved_ids = []
approved_ids = friendsapproved.map { |fa| fa.f1 } if friendsapproved.present?
approved_ids += friendsrequestedapproved.map { |fra| fra.f2 } if friendsrequestedapproved.present?
approved_ids.uniq! # (May not be needed)
#usersfiltered.delete_if { |user| approved_ids.include? user.id }
This could probably be simplified further if friendsapproved and friendsrequestedapproved have been created separately strictly for the purpose of the deletions. You could generate a single friendsapproval list consisting of both and avoid unioning id sets above.
While I agree that there may be better ways to implement what you're doing, I think the specific problem you're facing is that in Rails 4, the where method returns an ActiveRecord::Relation not an Array. While you can use each on a Relation, you cannot in general perform array operations.
However, you can convert a Relation to an Array with the to_a method as in:
#usersfiltered = User.where("first_name LIKE?", "%#{params[:first_name]}%" ).to_a
This would then allow you to do the following within your loop:
usersfiltered.delete(fa)
Related
So I have app that has political candidates.
When a new political candidate is entered, I want to enter a notification into the notifications table for every user that's state is equal to the state of the new candidate being entered.
Ultimately, I want to enter in records to the notification table for every single user where that condition is met.
I know I'm way off, but here's where I'm at now. I'm trying to loop through each user and then enter this record when that condition is true.
def create
#candidate = Candidate.new(candidate_params)
if #candidate.save
User.each do |u|
if Candidate.state == User.state
#notification = Notification.new(:message => 'Message', :user_id => U.id)
#notification.save
else
end
end
else
render('new')
end
end
The candidate is created with this code, but the notifications aren't working. Basically I have two users where their state equals "Arizona" and I would expect if I create a new candidate where the state is "Arizona" that I should get two record into notifications, one with each user ID.
I think you got a bit mixed up between classes and instances. Here's the relevant bit:
#candidate = Candidate.new(candidate_params)
...
User.each do |u|
if Candidate.state == User.state
...
end
end
In your code Candidate is a class, and #candidate holds the recently created instance of a Candidate. Likewise, User is a class and u holds a User instance (on each loop iteration). Your comparison should actually use the instances rather than the classes:
if #candidate.state == u.state
Having sorted that, it's worth noting that your code has a couple of other errors -- User.each won't work. You need to specify a selector to get a list of User objects to loop through. One way would be to call User.all.each (which looking at your code is probably what you were trying). That pulls all User objects. But, since users can be from anywhere, if you do that you will cycle through a lot of users you don't need to.
Since all you need is users whose state matches the new candidate, you can use the where() method to pre-filter the list you are looping through. That way you don't need the if at all.
#candidate = Candidate.new(candidate_params)
...
User.where(state: #candidate.state).each do |u|
#notification = Notification.new(message: 'Message', user: u)
#notification.save
end
The other problem in your code is in the line to create a notification. You use U.id but the loop variable is lower case u. As an added tip, you don't need to set the object ID specifically. If you just pass the User object (as in the code above), Rails is smart enough to figure out the rest.
For performance don't iterate all users, you can search users that match the candidate's state then create notification for each user.
def create
#candidate = Candidate.new(candidate_params)
if #candidate.save
users = User.where(state: #condidate.state)
users.each { |user| #notification = Notification.create(:message => 'Message', :user_id =user.id } if users
else
render 'new'
end
end
I'm trying to extend the functionality of my serverside datatable. I pass some extra filters to my controller / datatable, which I use to filter results. Currently in my model I am testing whether the params are present or not before applying my scopes, but I'm not convinced this is the best way since I will have a lot of if/else scenario's when my list of filters grows. How can I do this the 'rails way'?
if params[:store_id].present? && params[:status].present?
Order.store(params[:store_id]).status(params[:status])
elsif params[:store_id].present? && !params[:status].present?
Order.store(params[:store_id])
elsif !params[:store_id].present? && params[:status].present?
Order.status(params[:status])
else
Order.joins(:store).all
end
ANSWER:
Combined the answers into this working code:
query = Order.all
query = query.store(params[:store_id]) if params[:store_id].present?
query = query.status(params[:status]) if params[:status].present?
query.includes(:store)
You could do it like this:
query = Order
query = query.store(params[:store_id]) if params[:store_id].present?
query = query.status(params[:status]) if params[:status].present?
query = Order.joins(:store) if query == Order
Alternatively, you could also just restructure the status and store scopes to include the condition inside:
scope :by_status, -> status { where(status: status) if status.present? }
Then you can do this instead:
query = Order.store(params[:store_id]).by_status(params[:status])
query = Order.joins(:store) unless (params.keys & [:status, :store_id]).present?
Since relations are chainable, it's often helpful to "build up" your search query. The exact pattern for doing that varies widely, and I'd caution against over-engineering anything, but using plain-old Ruby objects (POROs) to build up a query is common in most of the large Rails codebases I've worked in. In your case, you could probably get away with just simplifying your logic like so:
relation = Order.join(:store)
if params[:store_id]
relation = relation.store(params[:store_id])
end
if params[:status]
relation = relation.status(params[:status])
end
#orders = relation.all
Rails even provides ways to "undo" logic that has been chained previously, in case your needs get particularly complex.
The top answer above worked for me. Here is an example of its' real-life implementation:
lessons = Lesson.joins(:member, :office, :group)
if #member.present?
lessons = lessons.where(member_id: #member)
end
if #office.present?
lessons = lessons.where(office_id: #office)
end
if #group.present?
lessons = lessons.where(group_id: #group)
end
#lessons = lessons.all
I am iterating over all user profiles to get their country. I wish not to include the current user's profile. If I have a total of 10 users, I want only 9 user's country:
# helper function
def method_name
Profile.all.select do |m|
n = m.country.class == String # Because most countries will be nil. A shorter way to not include nil profiles?
return n.reject! {|x| x == current_user.profile.user_id }
end
end
The method above should return all user's profile except for the current user.
The error I got is
undefined method `reject!' for false:FalseClass
The reason? In my views I could:
<%= method_name.map do |p| p.country end %>
Beware of using Profile.all here, because you will potentially use a lot of memory instantiating a profile object for every row in your database.
I think the best way to do this is to create a method within your Profile model, which performs the query, and uses pluck() to return an array containing just the countries you want.
def self.countries_except_for(user)
where.not(user_id: user.id, country: nil).pluck(:country)
end
Now you can just call:
Profile.countries_except(current_user)
To get the array of countries. This approach is much more efficient than looping through as in your question.
The line n = m.country.class == String sets n to true or false, thefore the next line fails, because you try to call reject! {|x| x == current_user.profile.user_id } on that boolean value.
One way to solve the problem might be to fix your code like this:
def method_name
Profile.all.select do |p|
p.country.present? && p != current_user.profile
end
end
Another way - and my preferred one - would be to only load matching record from the database:
def method_name
Profile.where.not(user_id: current_user.id).where.not(country: nil)
end
I have a Rails site that logs simple actions such as when people upvote and downvote information. For every new action, an EventLog is created.
What if the user changes his or her mind? I have an after_create callback that looks for complementary actions and deletes both if it finds a recent pair. For clarity, I mean that if a person upvotes something and soon cancels, both event_logs are deleted. What follows is my callback.
# Find duplicate events by searching nearly all the fields in the EventLog table
#duplicates = EventLog.where("user_id = ? AND event = ? AND project_id = ? AND ..., ).order("created_at DESC")
if #duplicates.size > 1
#duplicates.limit(2).destroy_all
end
The above code doesn't quite work because if any of the fields happen to be nil, the query returns [].
How can I write this code so it can handle null values, and/or is there a better way of doing this altogether?
If I understood this correctly,
some of the fields can be nil, and you want to find activity logs that have same user_id, same project_id or project id can be nil.
So I guess this query should work for you.
ActivityLog.where(user_id: <some_id> AND activity: <complementary_id> AND :project_id.in => [<some_project_id>, nil] ....)
This way you would get the complementary event logs where user_id is same and project id may or may not be present
class ActivityLog
QUERY_HASH = Proc.new{ {user_id: self.user_id,
activity: complementary_id(self.id),
and so on....
} }
How about:
# event_log.rb
def duplicate_attr_map
{
:user_id,
:project_id
}
end
def duplicates
attribs = duplicate_attr_map.reject_if(&:blank?)
query = attribs.map { |attr| "#{attr} = ?" }.join(' AND ')
values = attribs.map { |attr| self.send(attr) }
EventLog.where(query, *values).order("created_at DESC")
end
def delete_duplicates(n)
duplicates.limit(n).delete_all if duplicates.size > 1
end
# usage:
# EventLog.find(1).delete_duplicates(2)
not tested, could be improved
I have an algorithm that searches through all of my sites users, finding those which share a common property with the user using the algorithm (by going to a certain page). It can find multiple users, each can have multiple shared properties. The algorithm works fine, in terms of finding the matches, but I'm having trouble working out how to store the data so that later I'll be able to use each unit of information. I need to be able to access both the found users, and each of the respective shared properties, so I can't just build a string. This is an example of the output, being run from the perspective of user 1:
user 4
sharedproperty3
sharedproperty6
user 6
sharedproperty6
sharedproperty10
shareproperty11
What do I need to do to be able to store this data, and have access to any bit of it for further manipulation? I was thinking of a hash of a hash, but I can't really wrap my head around it. I'm pretty new to programming, and Ruby in particular. Thanks for reading!
EDIT - Here's the code. I'm fully expecting this to be the most incorrect way to do this, but it's my first try so be gentle :)
So if I'm understanding you guys correctly, instead of adding the interests to a string, I should be creating an array or a hash, adding each interest as I find it, then storing each of these in an array or hash? Thanks so much for the help.
def getMatchedUsers
matched_user_html = nil
combined_properties = nil
online_user_list = User.logged_in.all
shared_interest = false
online_user_list.each do |n| # for every online user
combined_properties = nil
if n.email != current_user.email # that is not the current user
current_user.properties.each do |o| # go through all of the current users properties
n.properties.each do |p| # go through the online users properties
if p.interestname.eql?(o.interestname) # if the online users property matches the current user
shared_interest = true
if combined_properties == nil
combined_properties = o.interestname
else
combined_properties = combined_properties + ", " + o.interestname
end
end
end
if shared_interest == true
matched_user_html = n.actualname + ": " + combined_properties
end
end
end
end
return matched_user_html
render :nothing => true
end
This returns an array of hashes with all users and their corresponding sharedproperties.
class User
def find_matching_users
returning Array.new do |matching_users|
self.logged_in.each do |other_user|
next if current_user == other_user # jump if current_user
# see http://ruby-doc.org/core/classes/Array.html#M002212 for more details on the & opreator
unless (common_properties = current_user.properties & other_user.properties).empty?
matching_users << { :user => other_user, :common_properties => common_properties }
end
end
end
end
end
In your view you can do something like this:
<%- current_user.find_matching_users.each do |matching_user| -%>
<%-# you can acccess the user with matching_user[:user] -%>
<%-# you can acccess the common properties with matching_user[:common_properties] -%>
<%- end -%>
You can use a hash table with the key being the user object and the value being an array of the shared properties . This is assuming that you first need to do a lookup based on the user .
Something like this :
#user_results = { user1 => [sharedproperty3,sharedproperty7] , user2 => [sharedproperty10,sharedproperty11,sharedproperty12]}
You can then acces the values like :
#user_results[user1]
or you can also iterate over all the keys using #user_results.keys