I'm newvbie in ruby on rails.. I'm having problem with gsub.. I everytime I go to the list of my store page it says "undefined method `gsub' for nil:NilClass"..
here is mycode :
def self.search(search_val, page = 1)
#search_val = search_val.gsub("'", "\\\\'")
search_query = "store_id LIKE '%#{ #search_val }%' OR english_name LIKE '%#{ #search_val }%' OR chinese_name LIKE '%#{ #search_val }%'"
select("jos_store.id, store_id, english_name, chinese_name, store_manager, delivery_area,year, week").joins("LEFT OUTER JOIN (SELECT id as store_replenishment, store, MAX(stock_movement) AS stock_movement FROM jos_store_replenishment GROUP BY store) AS replenishment ON replenishment.store = jos_store.id").joins("LEFT OUTER JOIN jos_stock_movement ON jos_stock_movement.id = replenishment.stock_movement").where(search_query).order("year DESC, week DESC").paginate :page => page, :per_page => 15
end
thanks in advance
A good practice is doing .to_s when you are using string methods.
You can use the & operator on search_val. It allows you to avoid null pointer exceptions without adding additional checks or using to_s to convert a string to a string.
So, you'll have something like this:
#search_val = search_val&.gsub("'", "\\\\'")
You can read more on the safe navigation operator here: http://mitrev.net/ruby/2015/11/13/the-operator-in-ruby/
This means that search_val is in fact nil. You can easily verify this by printing out the value of search_val.
I'm not sure if this is your case, but the same undefined method gsub for nil:NilClass error happened with me after a few rollbacks and migrations.
Then, I restarted the server and works. Maybe this could be the case for some people that reached this topic searching on Google.
Related
We recently upgraded to Rails 4.2 from Rails 4.1 and are seeing problems with using Arel + Activerecord because we're getting this type of error:
ActiveRecord::StatementInvalid: PG::ProtocolViolation: ERROR: bind message supplies 0 parameters, but prepared statement "" requires 8
Here's the code that is breaking:
customers = Customer.arel_table
ne_subquery = ImportLog.where(
importable_type: Customer.to_s,
importable_id: customers['id'],
remote_type: remote_type.to_s.singularize,
destination: 'hello'
).exists.not
first = Customer.where(ne_subquery).where(company_id: #company.id)
second = Customer.joins(:import_logs).merge(
ImportLog.where(
importable_type: Customer.to_s,
importable_id: customers['id'],
remote_type: remote_type.to_s.singularize,
status: 'pending',
destination: 'hello',
remote_id: nil
)
).where(company_id: #company.id)
Customer.from(
customers.create_table_alias(
first.union(second),
Customer.table_name
)
)
We figured out how to solve the first part of the query (running into the same rails bug of not having bindings) by moving the exists.not to be within Customer.where like so:
ne_subquery = ImportLog.where(
importable_type: Customer.to_s,
importable_id: customers['id'],
destination: 'hello'
)
first = Customer.where("NOT (EXISTS (#{ne_subquery.to_sql}))").where(company_id: #company.id)
This seemed to work but we ran into the same issue with this line of code:
first.union(second)
whenever we run this part of the query, the bindings get lost. first and second are both active record objects but as soon as we "union" them, they lose the bindings are become arel objects.
We tried cycling through the query and manually replacing the bindings but couldn't seem to get it working properly. What should we do instead?
EDIT:
We also tried extracting the bind values from first and second, and then manually replacing them in the arel object like so:
union.grep(Arel::Nodes::BindParam).each_with_index do |bp, i|
bv = bind_values[i]
bp.replace(Customer.connection.substitute_at(bv, i))
end
However, it fails because:
NoMethodError: undefined method `replace' for #<Arel::Nodes::BindParam:0x007f8aba6cc248>
This was a solution suggested in the rails github repo.
I know this question is a bit old, but the error sounded familiar. I had some notes and our solution in a repository, so I thought I'd share.
The error we were receiving was:
PG::ProtocolViolation: ERROR: bind message supplies 0 parameters, but
prepared statement "" requires 1
So as you can see, our situation is a bit different. We didn't have 8 bind values. However, our single bind value was still being clobbered. I changed the naming of things to keep it general.
first_level = Blog.all_comments
second_level = Comment.where(comment_id: first_level.select(:id))
third_level = Comment.where(comment_id: second_level.select(:id))
Blog.all_comments is where we have the single bind value. That's the piece we're losing.
union = first_level.union second_level
union2 = Comment.from(
Comment.arel_table.create_table_alias union, :comments
).union third_level
relation = Comment.from(Comment.arel_table.create_table_alias union2, :comments)
We created a union much like you except that we needed to union three different queries.
To get the lost bind values at this point, we did a simple assignment. In the end, this is a little simpler of a case than yours. However, it may be helpful.
relation.bind_values = first_level.bind_values
relation
By the way, here's the GitHub issue we found while working on this. It doesn't appear to have any updates since this question was posted though.
I've got a problem in doing some metaprogramming in Ruby / Rails which must be minor, but I can't get the clue.
I wan't to assign values to an active record relation, with my model having attributes:
MyModelClass.p1_id,
.p2_id,
...
.p8_id
SecondModel.position #Integer in (1..8)
I now want to do the following
sms = SecondModel.where(:xyz => 'bla')
sms.each do |sm|
mmc = MyModellClass.first
mmc.#somehow construct method here = sm.id
end
So that somehow this is accomplished
mmc.p1_id = sm.id
mmc.p2_id = sm.id
..
mmc.p8_id = sm.id
To sum up: I want to create that p*n*_id stuff dynamically, but I can't find out, how to tell Ruby, that this should be a method. I tried so far:
mmc.send('p#{sm.position.to_s}_id'.to_sym) = sm.id
But this doesn't work. Any clues?
You were close. Try this:
mmc.send("p#{sm.position.to_s}_id=", sm.id)
Here we call the method with = and pass the value of attribute as the second argument of send
In the process of learning ruby (I have a java background).
I have assignment statements where the value of one hash[:name_field] is being assigned to another. But the value coming from the hash on the right was sometimes blank. This was crashing my code hence i added the ternary logic with .nil ? etc....
I am surprised though that this doesn't work... The error is :
undefined method `nil' for 1133:Fixnum (NoMethodError)
Below is the code:
people_traffic.each do |person|
person_record = DaysTraffic.new
person_record[:name] = person[:name_filed].nil ? 0 : person[:name_filed]
person_record[:age] = person[:age_field].nil ? 0 : person[:age_field]
person_record.save
end
Why am I getting the (NoMethodError) for the nil?
Thank you!
It should be .nil? (with a question mark) not .nil. So in your case, that would be:
person_record[:name] = person[:name_filed].nil? ? 0 : person[:name_filed]
You can actually write this much simpler like so:
person_record[:name] = person[:name_filed] || 0
Because #to_i turns nil into 0, a good way to write something like this is:
person_record[:age] = person[:age_field].to_i
I'm about to lose my mind due to a simple Rails where query. I simply cannot understand why it does work like 10 lines ago and does not after it. I could not figure out what might be causing the problem
#userID = Token.where(:tokenCode => #tokenReceived)
##init.tokenCode=#tokenReceived+"1" #randomize algorithm required!
#init.tokenCode=#codeGenerated=generate_activation_code()
if #userID.nil?
#newToken=Token.new
#newToken.tokenCode=#codeGenerated
else
#tokenToAdd = "12"
#newToken=Token.where(:userID => "1")
#if #newToken.nil?
#newToken.tokenCode="12"
#end
end
##newToken.save
#init.save
When I make a successful JSON request to 'http://localhost:3000/inits.json' it gives me a page with tons of erros but I think the main error among those are:
<h1>
NoMethodError
in InitsController#create
</h1>
<pre>undefined method `tokenCode=' for #<ActiveRecord::Relation:0x007fc43cb40b88></pre>
What could be the reason? Am I writing the where clause all wrong?
Edit: When I activate the if clause it works. I simply believe the #newToken object is null, however it is almost impossible for me to detect why. There is a data in my Token table with userID 1.
When you do:
#newToken=Token.where(:userID => "1")
You get an ActiveRecord::Relation, but you expect an object. So simply replace it with:
#newToken=Token.where(:userID => "1").first
I'm building a conditions hash to run a query but I'm having a problem with one specific case:
conditions2 = ['extract(year from signature_date) = ?', params[:year].to_i] unless params[:year].blank?
conditions[:country_id] = COUNTRIES.select{|c| c.geography_id == params[:geographies]} unless params[:geographies].blank?
conditions[:category_id] = CATEGORY_CHILDREN[params[:categories].to_i] unless params[:categories].blank?
conditions[:country_id] = params[:countries] unless params[:countries].blank?
conditions['extract(year from signature_date)'] = params[:year].to_i unless params[:year].blank?
But the last line breaks everything, as it gets interpreted as follows:
AND ("negotiations"."extract(year from signature_date)" = 2010
Is there a way to avoid that "negotiations"." is prepended to my condition?
thank you,
P.
For something like this, you'll probably have to write your own SQL with find_by_sql. Still wrap it in a method in your model so your model's friends can access it nicely.