output values being converted?

rubyonrails-talk
1

Hi all,

I've got a c++ program that inserts data into a mysql database, its a 32 length varchar column in question that contains sha256 hashes such as

018cf0b47256973ab6f08a720208c28c34d85722

Unfortunately, when I come to read this in rails and print out the hash in a view, it prints out a short integer like 847.

I've tried it in irb, I can see the hash correctly as the return value of a .find, but it still comes out wrong when I print it directly:

=> @hash = FileHash.find(:first)

#<FileHash id: 423, hash: "018cf0b47256973ab6f08a720208c28c34d85722", size: 1393>

=> @hash.size

1393

=> @hash.hash

847

I can't think what would be causing this, I've never come across anything quite like this before. I'm not using any unusual encodings or anything, at least, I'm using the same a I always have without problems.

Hope someone can shed light on this.

Thanks

Matt

2

Well to answer my own question yet again:

It turns out that hash is a method defined by activerecord already. I originally had problems naming my model Hash so I changed it to FileHash. I didn't realise that hash was a method as well as a class.

Changing the column name in the db, rails and the c++ app has fixed the problem :slight_smile:

Matt

3

You could have also accessed the original column as:

   @hash['hash']

which forces the name 'hash' to be treated as an attribute name of the model.

FYI, you also run into the same kind of problem with other names that conflict with exiting methods.

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

4

All objects in ruby have a hash method for which the following statement should hold

a.hash != b.hash => a!=b

Among other things it is used when you use something as a key in a Hash.

Fred