I've got a model which one of the column is a hash value, like below
[3] pry(main)> Activity.find(14)
=> #<Activity:0x00007fe625694070
id: 14,
content_basic: {
"content_type"=>"Audio",
"session_overview_image"=>"https://some_domain.com/392/123-woman.png"}
I want to change content_basic['session_overview_image'] to be /392/123-woman.png - how to do that in a rails c?
How about doing it like this:
Activity.find_each do |activity|
img = activity.content_basic['session_overview_image'].gsub('https://some_domain.com', '')
activity.content_basic['session_overview_image'] = img
activity.save
end
This assumes that all of the urls have the same domain that you want to remove. If they don't, then a little bit of URI parsing would be required first.
It also assumes that you are not on one of the older Rails versions (3 of before I believe) where you had to tell ActiveRecord that something has changed in the hash when changing serialized column values.
Related
I have a DI routine where I have a large csv I'm importing with known column format. I first set up a column map:
col_map =
{
4 => :name,
6 => :description,
21 => :in_stock,
...
I then read each line in, and then using the column map, attempt to set the attribute:
i = Item.new
col_map.each do |k,v|
i[v] = chunks[k] #chunks is the line read in split by the delimiter
In my item declaration, I declare two attributes, b/c these are not stored in the database, they're used for other logic:
attr_writer :in_stock
attr_writer :end_date
When the code gets to this line:
i[v] = chunks[k]
I get this message:
X.DEPRECATION WARNING: You're trying to create an attribute `in_stock'. Writing arbitrary attributes on a model is deprecated. Please just use `attr_writer`
But I'm not trying to create an attribute, and I am using attr_writer. I suspect this has something to do with the [] I'm using instead of . for the lvalue.
Can anyone see what I'm doing wrong?
Thanks for any help,
Kevin
Admittedly, the deprecation wording is slightly confusing, but you're seeing this warning because the model[attribute_name] = ... style is only supported for ActiveRecord attributes on the model, not non-persisted attributes added with attr_writer.
You can see the code that produces the warning over here.
To address this I'd use send which will work for all attributes e.g.
i.send("#{v}=", chunks[k])
Is there a way to convert a Rails model into an insert query?
For instance, if I have a model like:
m = Model.new
m.url = "url"
m.header = "header"
How can I get the corresponding SQL query ActiveRecord would generate if I did m.save?
I want to get: "INSERT INTO models(url, header) VALUES('url', 'header')" if possible.
Note: I don't want to actually save the model and get the query back (from log file, etc). I want to get the query IF I chose to save it.
On Rails 4.1, I found the below code snippet working:
record = Post.new(:title => 'Yay', :body => 'This is some insert SQL')
record.class.arel_table.create_insert
.tap { |im| im.insert(record.send(
:arel_attributes_with_values_for_create,
record.attribute_names)) }
.to_sql
Thanks to https://coderwall.com/p/obrxhq/how-to-generate-activerecord-insert-sql
Tested in Rails 3.2.13: I think I got it right this time, it definitely does not persist to the db this time. It also won't fire validations or callbacks so anything they change won't be in the results unless you've called them some other way.
Save this in lib as insert_sqlable.rb and you can then
#in your models or you can send it to ActiveRecord::Base
include InsertSqlable
Then it is model.insert_sql to see it.
#lib/insert_sqlable
module InsertSqlable
def insert_sql
values = arel_attributes_values
primary_key_value = nil
if self.class.primary_key && Hash === values
primary_key_value = values[values.keys.find { |k|
k.name == self.class.primary_key
}]
if !primary_key_value && connection.prefetch_primary_key?(self.class.table_name)
primary_key_value = connection.next_sequence_value(self.class.sequence_name)
values[self.class.arel_table[self.class.primary_key]] = primary_key_value
end
end
im = self.class.arel_table.create_insert
im.into self.class.arel_table
conn = self.class.connection
substitutes = values.sort_by { |arel_attr,_| arel_attr.name }
binds = substitutes.map do |arel_attr, value|
[self.class.columns_hash[arel_attr.name], value]
end
substitutes.each_with_index do |tuple, i|
tuple[1] = conn.substitute_at(binds[i][0], i)
end
if values.empty? # empty insert
im.values = Arel.sql(self.class.connectionconnection.empty_insert_statement_value)
else
im.insert substitutes
end
conn.to_sql(im,binds)
end
end
It turns out the code is in ActiveRecord::Relation and not ActiveRecord::Persistence. The only significant change is the last line which generates the sql instead of performing it.
If you dont want to save the model you call m.destroy when you are done with the object.
You can log the sql query by debugging it like this
Rails.logger.debug "INSERT INTO models(url, header) VALUES(#{m.url}, #{m.header}).inspect
After search a lot over the Internet and forums, I think I found a better solution for your problem: just requires two line of code.
I found a good gem that do exactly what you want, but this gem only works for Rails 3.2 and older. I talked with author and he doesn't want support this gem anymore. So I discovered by myself how to support Rails 4.0 and now I'm maintaining this gem.
Download the "models-to-sql-rails" gem here, supporting Rails 4.0 and older.
With this gem, you can easily do the following. (the examples inside values are just a joke, you will get the correct values when using it in your object).
For objects:
object.to_sql_insert
# INSERT INTO modelName (field1, field2) VALUES ('Wow, amaze gem', 'much doge')
For array of objets:
array_of_objects.to_sql_insert
# INSERT INTO modelName (field1, field2) VALUES ('Awesome doge', "im fucking cop")
# INSERT INTO modelName (field1, field2) VALUES ('much profit', 'much doge')
# (...)
Just see the Github of this project and you'll find how to install and use this wonderful gem.
My code looks like this:
hash = MyModel.count(:group => 'id', :conditions => 'bla = "bla"')
The returned Hash has keys that are strings. I want them to be ints. I know it would be possible to convert the Hash manually using something like a map construct.
Edit:
Thanks for the responses. Have realised it was a json conversion process that was turning the ids into Strings and rails does in fact use the Fixnum as one might expect.
hash = MyModel.count(group: 'id', conditions: 'bla = "bla"')
should have Fixnum keys by default since id is an instance of Fixnum.
What happens is that ActiveRecord always fetch result as strings and then Rails takes care of converting them to other datatypes according to the type of the database column (we say that they are typecast).
So it's maybe a Rails bug or the 'id' column is not set as integer(which would be surprising).
If you can't fix it, convert them manually:
hash.each_with_object({}) do |(key, value), hash|
hash[key.to_i] = value
end
When I use your code I get integer keys (rails 3.07), what's the column type of id?
If you want to do it manually:
new_hash = hash.inject({}){|h,a| h[a.first.to_i] = a.last; h}
new_hash = Hash[hash.map { |k, v| [k.to_i, v] }
Need to check if a block of attributes has changed before update in Rails 3.
street1, street2, city, state, zipcode
I know I could use something like
if #user.street1 != params[:user][:street1]
then do something....
end
But that piece of code will be REALLY long. Is there a cleaner way?
Check out ActiveModel::Dirty (available on all models by default). The documentation is really good, but it lets you do things such as:
#user.street1_changed? # => true/false
This is how I solved the problem of checking for changes in multiple attributes.
attrs = ["street1", "street2", "city", "state", "zipcode"]
if (#user.changed & attrs).any?
then do something....
end
The changed method returns an array of the attributes changed for that object.
Both #user.changed and attrs are arrays so I can get the intersection (see ary & other ary method). The result of the intersection is an array. By calling any? on the array, I get true if there is at least one intersection.
Also very useful, the changed_attributes method returns a hash of the attributes with their original values and the changes returns a hash of the attributes with their original and new values (in an array).
You can check APIDock for which versions supported these methods.
http://apidock.com/rails/ActiveModel/Dirty
For rails 5.1+ callbacks
As of Ruby on Rails 5.1, the attribute_changed? and attribute_was ActiveRecord methods will be deprecated
Use saved_change_to_attribute? instead of attribute_changed?
#user.saved_change_to_street1? # => true/false
More examples here
ActiveModel::Dirty didn't work for me because the #model.update_attributes() hid the changes. So this is how I detected changes it in an update method in a controller:
def update
#model = Model.find(params[:id])
detect_changes
if #model.update_attributes(params[:model])
do_stuff if attr_changed?
end
end
private
def detect_changes
#changed = []
#changed << :attr if #model.attr != params[:model][:attr]
end
def attr_changed?
#changed.include :attr
end
If you're trying to detect a lot of attribute changes it could get messy though. Probably shouldn't do this in a controller, but meh.
Above answers are better but yet for knowledge we have another approch as well,
Lets 'catagory' column value changed for an object (#design),
#design.changes.has_key?('catagory')
The .changes will return a hash with key as column's name and values as a array with two values [old_value, new_value] for each columns. For example catagory for above is changed from 'ABC' to 'XYZ' of #design,
#design.changes # => {}
#design.catagory = 'XYZ'
#design.changes # => { 'catagory' => ['ABC', 'XYZ'] }
For references change in ROR
I'm using the rails3-jquery-autocomplete gem on a field with non-unique values, but I want the results it retrieves to be duplicate-free. Any ideas on how to accomplish this?
I had the same problem in my project https://github.com/marciomr/Terra-Livre and I solved it doing the following:
I installed rails3-jquery-autocomplete as a plugin in vendor/plugin directory
I changed the file helpers.rb like this:
def json_for_autocomplete(items, method, extra_data)
json = items.collect do |item| # here I put the result in a variable
hash = {"label" => item.send(method), "value" => item.send(method)} #here I removed the id
extra_data.each do |datum|
hash[datum] = item.send(datum)
end if extra_data
hash
end
json.uniq # this line is new
end
I removed the id from the json file and then retrieved uniq values.
Since I didn't need the id it worked fine for me. I think if I need the id I can put it in extra_data, but I am not sure.
I have just forked the project with this alteration: git://github.com/marciomr/rails3-jquery-autocomplete.git
Since I ran into this myself, I thought I would record my own solution for posterity, since it does not require editing the gem's source. This is for the officially maintained fork of the gem: https://github.com/bigtunacan/rails-jquery-autocomplete.
You can handle the json encoding directly via the autocomplete block in the controller, which we can leverage to change the array of records.
Here is an example in which we get a unique list of schools that students go to:
autocomplete :student, :school do |items|
ActiveSupport::JSON.encode( items.uniq{ |i| i["value"] } )
end
"items" is an array of hashes, which by default contain an id, a label, and a value, so this passes only unique values into the json encoder (of your choice).