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Run a callback only if an attribute has changed in Rails
...tiveRecord::Base
before_save :do_something, if: :will_save_change_to_status_id?
private
def do_something
# ...
end
end
The commit that changed ActiveRecord::Dirty is here: https://github.com/rails/rails/commit/16ae3db5a5c6a08383b974ae6c96faac5b4a3c81
Here is a blog post on these cha...
Git remote branch deleted, but still it appears in 'branch -a'
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git remote prune origin, as suggested in the other answer, will remove all such stale branches. That's probably what you'd want in most cases, but if you want to just remove that particular remote-tracking branch, you should do:
git bran...
Private vs Public in Cache-Control
Can you please describe an example indicating difference between Public and Private Cache-Control in asp.net applications hosted in IIS.
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Python memory usage of numpy arrays
I'm using python to analyse some large files and I'm running into memory issues, so I've been using sys.getsizeof() to try and keep track of the usage, but it's behaviour with numpy arrays is bizarre. Here's an example involving a map of albedos that I'm having to open:
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How does “304 Not Modified” work exactly?
My guess, if it's generated by the browser:
2 Answers
2
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How can I convert a file pointer ( FILE* fp ) to a file descriptor (int fd)?
I have a FILE * , returned by a call to fopen() . I need to get a file descriptor from it, to make calls like fsync(fd) on it. What's the function to get a file descriptor from a file pointer?
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How do I strip non alphanumeric characters from a string and keep spaces?
I want to create a regex that removes all non-alphanumber characters but keeps spaces. This is to clean search input before it hits the db. Here's what I have so far:
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How can I alter a primary key constraint using SQL syntax?
I have a table that is missing a column in its primary key constraint. Instead of editing it through SQL Server, I want to put this in a script to add it as part of our update scripts.
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How to convert a private key to an RSA private key?
Let me explain my question first. I bought a certificate from a CA and used the following format to generate the csr and the private key:
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How to make Sequelize use singular table names
I have an model called User but Sequelize looks for the table USERS whenever I am trying to save in the DB. Does anyone know how to set Sequelize to use singular table names? Thanks.
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