Rails model's to_param sometimes not calling - ruby-on-rails

I working on project using Rails 4.1.6 now. And I have strange problem. Method to_param for my models (Product, Category) sometimes not calling. I use it for SEO-friendly urls.
Here is my to_param method for Category model:
def to_param
puts 'I am in Category to_param'
"#{id}-#{title.to_slug.normalize.to_s}"
end
I use puts for find out is this method working or no. So, when my urls looks good (/categories/39-средства-дезинфекции) I can see the string 'I am in Category to_param' on my server console. This is correct case and all it's great.
But sometimes I have urls like /categories/39 for the same objects. When I look into console for this case, I don't see any prints from my to_param method form Category model.
These two cases I have on the same pages, same views and using the same helpers for category url (category_path).
Most complicated for this situation is that I can't reproduce this bug and don't see any regularity. For the same objects I have correct urls most of times, but sometimes it's not. If I restart rails server and refresh browser with clear cache – problem may out and urls will be correct again.
During my debug and research I found source code for base class. But I can't see there any reasons for the situation described above.
def to_param(method_name = nil)
if method_name.nil?
super()
else
define_method :to_param do
if (default = super()) &&
(result = send(method_name).to_s).present? &&
(param = result.squish.truncate(20, separator: /\s/, omission: nil).parameterize).present?
"#{default}-#{param}"
else
default
end
end
end
end
Also I can tell that this problem was appear, when I used FriendlyID before, using regex for clear and build slugs, and now for babosa gem. So, I think the problem is my to_param sometimes not calling for my model.

So, I found the reason of this behaviour. Now it's resolved!
The reason was I have redefined to_param for Product and Category in my ActiveAdmin files:
before_filter do
Product.class_eval do
def to_param
puts "I am in admin Product to_param"
id.to_s
end
end
Category.class_eval do
def to_param
puts "I am in admin Category to_param"
id.to_s
end
end
end
So, when I was log in Admin panel and go to Product page – "bug" will appear on front-end views.
So, I need to remove Product.class_eval and Category.class_eval blocks from my admin classes.

Related

Rails force to_param to return something even when not persisted

I need to handle a particular case of generating email views with URLs constructed from non-persisted data.
Example : assume my user can create posts, and that triggers a post creation notification email, I'd like to send the user an example of fake post creation. For this, I am using a FactoryGirl.build(:post) and passing this to my PostMailer.notify_of_creation(#post)
In everyday Rails life, we use the route url_helpers by passing as argument the model itself, and the route generator will automatically convert the model into its ID to be used for the route URL generation (in article_path(#article), the routes helper converts #article into #article.id for constructing the /articles/:id URL.
I believe it is the same in ActiveRecord, but anyways in Mongoid, this conversion fails if the model is not persisted (and this is somewhat nice as it prevents the generation of URLs that may not correspond to actual data)
So in my specific case, URL generation crashes as the model is not persisted:
<%= post_url(#post_not_persisted) %>
crashes with
ActionView::Template::Error: No route matches {:action=>"show", :controller=>"posts", :post_id=>#<Post _id: 59b3ea2aaba9cf202d4eecb6 ...
Is there a way I can bypass this limitation only in a very specific scope ? Otherwise I could replace all my resource_path(#model) by resource_path(#model.id.to_s) or better #model.class.name but this doesn't feel like the right situation...
EDIT :
The main problem is
Foo.new.to_param # => nil
# whereas
Foo.new.id.to_s # => "59b528e8aba9cf74ce5d06c0"
I need to force to_param to return the ID (or something else) even if the model is not persisted. Right now I'm looking at refinements to see if I can use a scoped monkeypatch but if you have better ideas please be my guest :-)
module ForceToParamToUseIdRefinement
refine Foo do
def to_param
self.class.name + 'ID'
end
end
end
However I seem to have a small scope problem when using my refinement, as this doesn't bubble up as expected to url_helpers. It works fine when using te refinement in the console though (Foo.new.to_param # => 59b528e8aba9cf74ce5d06c0)
I found a way using dynamic method override. I don't really like it but it gets the job done. I am basically monkeypatching the instances I use during my tests.
To make it easier, I have created a class method example_model_accessor that basically behaves like attr_accessor excepts that the setter patches the #to_param method of the object
def example_model_accessor(model_name)
attr_reader model_name
define_method(:"#{model_name}=") do |instance|
def instance.to_param
self.class.name + 'ID'
end
instance_variable_set(:"##{model_name}", instance)
end
end
Then in my code I can just use
class Testing
example_model_accessor :message
def generate_view_with_unpersisted_data
self.message = FactoryGirl.build(:message)
MessageMailer.created(message).deliver_now
end
end
# views/message_mailer/created.html.erb
...
<%= message_path(#message) %> <!-- Will work now and output "/messages/MessageID" ! -->

Rails: How to set the page title to URL (Routes)

I develop my Rails app on the Cloud9.
What I'd like to do is to set a part of title to the URL such as stackoverflow.
(e.g. example.com/part-of-tile-here)
Although I found the similar questions, I don't understand what I should do because some of them are old posts, links in the answer are not found.
(e.g. Adding title to rails route)
I will not use Gem as yet.
It would be appreciated if you could give me any hint.
Generally, Ho Man is right but there are a few caveats to the proposed solution.
First of all, you should override the to_param method as well so it actually uses the slug:
# app/models/page.rb
def to_param
slug
end
# ... which allows you to do this in views/controllers:
page_path(#page)
# instead of
page_path(#page.slug)
Second, you should use find_by!(slug: params[:id]) to 1) be up to date (find_by_xxx was deprecated in Rails 4.0 and removed from Rails 4.1) and 2) to replicate the behavior of find and raise an ActiveRecord::RecordNotFound error in case no post can be found for the given slug.
Third, I suggest to always keep the slug up to date and include the ID like so:
# app/models/page.rb
before_validation :set_slug
def to_param
"#{id}-#{slug}"
end
private
def set_slug
self.slug = title.parameterize
end
# ... which allows you to use the regular ActiveRecord find again because it just looks at the ID in this case:
#post = Post.find(params[:id]) # even if params[:id] is something like 1-an-example-post
If you care about search engine results, you should then also include the canonical URL in the <head> section and/or redirect with a 301 status in the controller to avoid duplicate content which search engines generally don't like:
# in the view
<%= tag(:link, rel: :canonical, href: page_url(#page)) %>
# and/or in the controller:
redirect_to(post_url(#post), status: 301) and return unless params[:id] == #post.to_param
Hope that helps.
Have a look at this Railscast which is roughly what you want.
tl;dr
You'll want to save a slug which is a parameterized title, delimited by - when you save the page. (In a before_validation or before_save)
For example, "Random Title Of Page" will get random-title-of-page generated as it's slug.
before_validation :generate_slug
def generate_slug
self.slug ||= title.parameterize
end
In the page controller, you'll need to enable searching by slug.
def show
#page = Page.find_by_slug(params[:id])
end

Is there a way to prevent serialized attributes in rails from getting updated even if there are not changes?

This is probably one of the things that all new users find out about Rails sooner or later. I just realized that rails is updating all fields with the serialize keyword, without checking if anything really changed inside. In a way that is the sensible thing to do for the generic framework.
But is there a way to override this behavior? If I can keep track of whether the values in a serialized fields have changed or not, is there a way to prevent it from being pushed in the update statement? I tried using "update_attributes" and limiting the hash to the fields of interest, but rails still updates all the serialized fields.
Suggestions?
Here is a similar solution for Rails 3.1.3.
From: https://sites.google.com/site/wangsnotes/ruby/ror/z00---topics/fail-to-partial-update-with-serialized-data
Put the following code in config/initializers/
ActiveRecord::Base.class_eval do
class_attribute :no_serialize_update
self.no_serialize_update = false
end
ActiveRecord::AttributeMethods::Dirty.class_eval do
def update(*)
if partial_updates?
if self.no_serialize_update
super(changed)
else
super(changed | (attributes.keys & self.class.serialized_attributes.keys))
end
else
super
end
end
end
Yes, that was bugging me too. This is what I did for Rails 2.3.14 (or lower):
# config/initializers/nopupdateserialize.rb
module ActiveRecord
class Base
class_attribute :no_serialize_update
self.no_serialize_update = false
end
end
module ActiveRecord2
module Dirty
def self.included(receiver)
receiver.alias_method_chain :update, :dirty2
end
private
def update_with_dirty2
if partial_updates?
if self.no_serialize_update
update_without_dirty(changed)
else
update_without_dirty(changed | (attributes.keys & self.class.serialized_attributes.keys))
end
else
update_without_dirty
end
end
end
end
ActiveRecord::Base.send :include, ActiveRecord2::Dirty
Then in your controller use:
model_item.no_serialize_update = true
model_item.update_attributes(params[:model_item])
model_item.increment!(:hits)
model_item.update_attribute(:nonserializedfield => "update me")
etc.
Or define it in your model if you do not expect any changes to the serialized field once created (but update_attribute(:serialized_field => "update me" still works!)
class Model < ActiveRecord::Base
serialize :serialized_field
def no_serialize_update
true
end
end
I ran into this problem today and ended up hacking my own serializer together with a getter and setter. First I renamed the field to #{column}_raw and then used the following code in the model (for the media attribute in my case).
require 'json'
...
def media=(media)
self.media_raw = JSON.dump(media)
end
def media
JSON.parse(media_raw) if media_raw.present?
end
Now partial updates work great for me, and the field is only updated when the data is actually changed.
The problem with Joris' answer is that it hooks into the alias_method_chain chain, disabling all the chains done after (like update_with_callbacks which accounts for the problems of triggers not being called). I'll try to make a diagram to make it easier to understand.
You may start with a chain like this
update -> update_with_foo -> update_with_bar -> update_with_baz
Notice that update_without_foo points to update_with_bar and update_without_bar to update_with_baz
Since you can't directly modify update_with_bar per the inner workings of alias_method_chain you might try to hook into the chain by adding a new link (bar2) and calling update_without_bar, so:
alias_method_chain :update, :bar2
Unfortunately, this will get you the following chain:
update -> update_with_bar2 -> update_with_baz
So update_with_foo is gone!
So, knowing that alias_method_chain won't let you redefine _with methods my solution so far has been to redefine update_without_dirty and do the attribute selection there.
Not quite a solution but a good workaround in many cases for me was simply to move the serialized column(s) to an associated model - often this actually was a good fit semantically anyway.
There is also discussions in https://github.com/rails/rails/issues/8328.

Add http(s) to URL if it's not there?

I'm using this regex in my model to validate an URL submitted by the user. I don't want to force the user to type the http part, but would like to add it myself if it's not there.
validates :url, :format => { :with => /^((http|https):\/\/)?[a-z0-9]+([-.]{1}[a-z0-9]+).[a-z]{2,5}(:[0-9]{1,5})?(\/.)?$/ix, :message => " is not valid" }
Any idea how I could do that? I have very little experience with validation and regex..
Use a before filter to add it if it is not there:
before_validation :smart_add_url_protocol
protected
def smart_add_url_protocol
unless url[/\Ahttp:\/\//] || url[/\Ahttps:\/\//]
self.url = "http://#{url}"
end
end
Leave the validation you have in, that way if they make a typo they can correct the protocol.
Don't do this with a regex, use URI.parse to pull it apart and then see if there is a scheme on the URL:
u = URI.parse('/pancakes')
if(!u.scheme)
# prepend http:// and try again
elsif(%w{http https}.include?(u.scheme))
# you're okay
else
# you've been give some other kind of
# URL and might want to complain about it
end
Using the URI library for this also makes it easy to clean up any stray nonsense (such as userinfo) that someone might try to put into a URL.
The accepted answer is quite okay.
But if the field (url) is optional, it may raise an error such as undefined method + for nil class.
The following should resolve that:
def smart_add_url_protocol
if self.url && !url_protocol_present?
self.url = "http://#{self.url}"
end
end
def url_protocol_present?
self.url[/\Ahttp:\/\//] || self.url[/\Ahttps:\/\//]
end
Preface, justification and how it should be done
I hate it when people change model in a before_validation hook. Then when someday it happens that for some reason models need to be persisted with save(validate: false), then some filter that was suppose to be always run on assigned fields does not get run. Sure, having invalid data is usually something you want to avoid, but there would be no need for such option if it wasn't used. Another problem with it is that every time you ask from a model is it valid these modifications also take place. The fact that simply asking if a model is valid may result in the model getting modified is just unexpected, perhaps even unwanted. There for if I'd have to choose a hook I'd go for before_save hook. However, that won't do it for me since we provide preview views for our models and that would break the URIs in the preview view since the hook would never get called. There for, I decided it's best to separate the concept in to a module or concern and provide a nice way for one to apply a "monkey patch" ensuring that changing the fields value always runs through a filter that adds a default protocol if it is missing.
The module
#app/models/helpers/uri_field.rb
module Helpers::URIField
def ensure_valid_protocol_in_uri(field, default_protocol = "http", protocols_matcher="https?")
alias_method "original_#{field}=", "#{field}="
define_method "#{field}=" do |new_uri|
if "#{field}_changed?"
if new_uri.present? and not new_uri =~ /^#{protocols_matcher}:\/\//
new_uri = "#{default_protocol}://#{new_uri}"
end
self.send("original_#{field}=", new_uri)
end
end
end
end
In your model
extend Helpers::URIField
ensure_valid_protocol_in_uri :url
#Should you wish to default to https or support other protocols e.g. ftp, it is
#easy to extend this solution to cover those cases as well
#e.g. with something like this
#ensure_valid_protocol_in_uri :url, "https", "https?|ftp"
As a concern
If for some reason, you'd rather use the Rails Concern pattern it is easy to convert the above module to a concern module (it is used in an exactly similar way, except you use include Concerns::URIField:
#app/models/concerns/uri_field.rb
module Concerns::URIField
extend ActiveSupport::Concern
included do
def self.ensure_valid_protocol_in_uri(field, default_protocol = "http", protocols_matcher="https?")
alias_method "original_#{field}=", "#{field}="
define_method "#{field}=" do |new_uri|
if "#{field}_changed?"
if new_uri.present? and not new_uri =~ /^#{protocols_matcher}:\/\//
new_uri = "#{default_protocol}://#{new_uri}"
end
self.send("original_#{field}=", new_uri)
end
end
end
end
end
P.S. The above approaches were tested with Rails 3 and Mongoid 2.
P.P.S If you find this method redefinition and aliasing too magical you could opt not to override the method, but rather use the virtual field pattern, much like password (virtual, mass assignable) and encrypted_password (gets persisted, non mass assignable) and use a sanitize_url (virtual, mass assignable) and url (gets persisted, non mass assignable).
Based on mu's answer, here's the code I'm using in my model. This runs when :link is saved without the need for model filters. Super is required to call the default save method.
def link=(_link)
u=URI.parse(_link)
if (!u.scheme)
link = "http://" + _link
else
link = _link
end
super(link)
end
Using some of the aforementioned regexps, here is a handy method for overriding the default url on a model (If your ActiveRecord model has an 'url' column, for instance)
def url
_url = read_attribute(:url).try(:downcase)
if(_url.present?)
unless _url[/\Ahttp:\/\//] || _url[/\Ahttps:\/\//]
_url = "http://#{_url}"
end
end
_url
end
I had to do it for multiple columns on the same model.
before_validation :add_url_protocol
def add_url_protocol
[
:facebook_url, :instagram_url, :linkedin_url,
:tiktok_url, :youtube_url, :twitter_url, :twitch_url
].each do |url_method|
url = self.send(url_method)
if url.present? && !(%w{http https}.include?(URI.parse(url).scheme))
self.send("#{url_method.to_s}=", 'https://'.concat(url))
end
end
end
I wouldn't try to do that in the validation, since it's not really part of the validation.
Have the validation optionally check for it; if they screw it up it'll be a validation error, which is good.
Consider using a callback (after_create, after_validation, whatever) to prepend a protocol if there isn't one there already.
(I voted up the other answers; I think they're both better than mine. But here's another option :)

Rails routing-filter, parameters not present

I'm trying to sort out the routing for a multinational web store which only has a presence in certain countries. Each store is different and has a different catalogue of products and there is also a world-wide store for all other countries. I have set up Nginx to prepend the two letter country code from an lookup of the user's IP address so that my Rails app can figure which store to direct the visitor to. I then use Sven Fuch's excellent routing-filter to capture that code, do a lookup against a global SHOPS object and if a match is found then the country code is used, otherwise they get the default (world-wide) store. My routing filter currently looks like this:
module RoutingFilter
class Country < Filter
countries_pattern ||= %r(^/(?i)([a-zA-Z]{2})(?=/|$))
def around_recognize(path, env, &block)
country = "#{extract_segment!(countries_pattern, path)}".upcase
yield(path, env).tap do |params|
params[:shop] = SHOPS.fetch(country.to_sym) || DEFAULT_SHOP
end
end
def around_generate(params, &block)
puts params
shop = params.delete(:shop)
yield.tap do |result|
prepend_segment!(result, shop[:country_code]) if shop
end
end
end
end
Now the curious thing is, the params collection does not contain a :shop param when the around_generate method is executed. My code is directly based on the pagination filter included with the routing-filter gem (I'm not using the locale filter as each of these stores is also multilingual - i18n is handled using accept-language header instead). The original pagination filter by Sven Fuchs looks like this:
module RoutingFilter
class Pagination < Filter
PAGINATION_SEGMENT = %r(/page/([\d]+)/?$)
def around_recognize(path, env, &block)
page = extract_segment!(PAGINATION_SEGMENT, path)
yield(path, env).tap do |params|
params[:page] = page.to_i if page
end
end
def around_generate(params, &block)
page = params.delete(:page)
yield.tap do |result|
append_segment!(result, "page/#{page}") if append_page?(page)
end
end
protected
def append_page?(page)
page && page.to_i != 1
end
end
end
In my filter, shop = params.delete(:shop) results in a Nil object error and I can see from "puts params" that it is indeed not present. Does anyone have any suggestions as to why I'm unable to store and retrieve the :shop param?
Edit: I should mention that I have checked that the parameter gets set correctly in around_recognize - a "puts" of the params collection here does indeed contain the correct :shop object.
If you don't pass a :shop param to url_for (or whatever url generation helper you use here) it won't be passed to around_generate either. around_generate wraps around the url generation part of the routing system.
The Pagination filter assumes the same, e.g. it would be called like blog_posts_path(:page => 2).
But maybe that's not what you want. If you have a look at the Locale filter then this assumes that you sometimes pass a locale to the url helper but sometimes you don't. If :locale is not given it will look it up from I18n.locale which is the current locale set for this request. Maybe you want something similar here?
You could also have a look at the controller's default_url_options. IIRC you can set a default option here, too, so maybe this could work for you. I'm not using this approach anywhere though, so I'm just guessing.
HTH

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