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
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.
My website allows users to add text to an image, and displays the result to them via an Ajax.request. Sometimes it works great, but other times the image is incomplete and javascript records the error "Image corrupt or truncated."
How can I make sure the file is completely written before sending the Ajax response back to the browser?
VIEW
new Ajax.Request('<%= url_for(:action => "update_image", :id => #user_image.id) %>?greeting=' + encodeURIComponent(elmgreeting.value), { onSuccess: document.getElementById("card_image").src=card_filename });
MODEL
def create_card
img = Magick::Image.read(self.input_image).first
# ... add the greeting to the image
img.write(self.card_filename)
self.card_width = img.columns
self.card_height = img.rows
self.card_size = img.filesize
end
CONTROLLER
def update_image
#user_image = UserImage.find(params[:id])
#user_image.greeting = params[:greeting]
#user_image.create_card
#user_image.save
render :layout => false
end
[I've also noticed the img.filesize value assigned to the card_size is often inaccurate, leading me to think it's being obtained too early, as well.)
I've tried everything I could find on stackoverflow and elsewhere, but just can't figure it out. Any help greatly appreciated.
FOUND MY PROBLEM: It was the Ajax request. It now works nicely:
new Ajax.Request('<%= url_for(:action => "update_image", :id => #user_image.id) %>?greeting=' + encodeURIComponent(elmgreeting.value), { onComplete:function(request){document.getElementById("card_image").src=card_filename}});
afaik the things you write should be already synchronous, there is probably something else that breaks things. what did your rails server log said? maybe there is an error happens and throws some errors and then your front-side tries to use it as an image source
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.
I am retrieving results from NCBI's online Blast tool with 'net/http' and 'uri'. To do this I have to search through an html page to check if one of the lines is "Status=WAITING" or "Status=READY". When the Blast tool has finished the status will change to ready and results will be posted on the html page.
I have a working version to check the status and then retrieve the information that I need, but it is inefficient and is broken into two methods when I believe that there could be some way to put them into one.
def waitForBlast(rid)
get = Net::HTTP.post_form(URI.parse('http://www.ncbi.nlm.nih.gov/blast/Blast.cgi?'), {:RID => "#{rid}", :CMD => 'Get'})
get.body.each{|line| (waitForBlast(rid) if line.strip == "Status=WAITING") if line[/Status=/]}
end
def returnBlast(rid)
blast_array = Array.new
get = Net::HTTP.post_form(URI.parse('http://www.ncbi.nlm.nih.gov/blast/Blast.cgi?'), {:RID => "#{rid}", :CMD => 'Get'})
get.body.each{|line| blast_array.push(line[/<a href=#\d+>/][/\d+/]) if line[/<a href=#\d+>/]}
return blast_array
end
The first method checks the status and is my main concern because it is recursive. I believe(and correct me if I'm wrong) that designed as is takes too much computing power when all that I need is some way to recheck the results within the same method(adding in a time delay is a bonus). The second method is fine, but I would prefer if it was combined with the first somehow. Any help appreciated.
Take a look at this implementation. This is what he does:
res='http://www.ncbi.nlm.nih.gov/blast/Blast.cgi?CMD=Get&FORMAT_OBJECT=SearchInfo&RID=' + #rid
while status = open(res).read.scan(/Status=(.*?)$/).to_s=='WAITING'
#logger.debug("Status=WAITING")
sleep(3)
end
I think using the string scanner might be a bit more efficient than iterating over every line in the page, but I haven't looked at it's implementation so I may be wrong.
Hi I've this piece of code
class Place < ActiveRecord::Base
def self.find_or_create_by_latlon(lat, lon)
place_id = call_external_webapi
result = Place.where(:place_id => place_id).limit(1)
result = Place.create(:place_id => place_id, ... ) if result.empty? #!
result
end
end
Then I'd like to do in another model or controller
p = Post.new
p.place = Place.find_or_create_by_latlon(XXXXX, YYYYY) # race-condition
p.save
But Place.find_or_create_by_latlon takes too much time to get the data if the action executed is create and sometimes in production p.place is nil.
How can I force to wait for the response before execute p.save ?
thanks for your advices
You're right that this is a race condition and it can often be triggered by people who double click submit buttons on forms. What you might do is loop back if you encounter an error.
result = Place.find_by_place_id(...) ||
Place.create(...) ||
Place.find_by_place_id(...)
There are more elegant ways of doing this, but the basic method is here.
I had to deal with a similar problem. In our backend a user is is created from a token if the user doesn't exist. AFTER a user record is already created, a slow API call gets sent to update the users information.
def self.find_or_create_by_facebook_id(facebook_id)
User.find_by_facebook_id(facebook_id) || User.create(facebook_id: facebook_id)
rescue ActiveRecord::RecordNotUnique => e
User.find_by_facebook_id(facebook_id)
end
def self.find_by_token(token)
facebook_id = get_facebook_id_from_token(token)
user = User.find_or_create_by_facebook_id(facebook_id)
if user.unregistered?
user.update_profile_from_facebook
user.mark_as_registered
user.save
end
return user
end
The step of the strategy is to first remove the slow API call (in my case update_profile_from_facebook) from the create method. Because the operation takes so long, you are significantly increasing the chance of duplicate insert operations when you include the operation as part of the call to create.
The second step is to add a unique constraint to your database column to ensure duplicates aren't created.
The final step is to create a function that will catch the RecordNotUnique exception in the rare case where duplicate insert operations are sent to the database.
This may not be the most elegant solution but it worked for us.
I hit this inside a sidekick job that retries and gets the error repeatedly and eventually clears itself. The best explanation I've found is on a blog post here. The gist is that postgres keeps an internally stored value for incrementing the primary key that gets messed up somehow. This rings true for me because I'm setting the primary key and not just using an incremented value so that's likely how this cropped up. The solution from the comments in the link above appears to be to call ActiveRecord::Base.connection.reset_pk_sequence!(table_name) This cleared up the issue for me.
begin
result = Place.where(:place_id => place_id).limit(1)
result = Place.create(:place_id => place_id, ... ) if result.empty? #!
rescue ActiveRecord::StatementInvalid => error
#save_retry_count = (#save_retry_count || 1)
ActiveRecord::Base.connection.reset_pk_sequence!(:place)
retry if( (#save_retry_count -= 1) >= 0 )
raise error
end