Rails before_type_cast validation

[forward]

In the database table, there is an integer column, lets call it age, and I ensure that only numbers (no + or - sign) are inputted with:

validates_format_of :age_before_type_cast, :with => /^[\d]*$/

This works fine but if an error message is generated, it would be something like "age before type cast is invalid". Is there a way to have the error message be more like "age is invalid"?

[Luke Redpath]

I thought the values were only typecast before the were saved, but after they are validated. I could be wrong though. If this is the case however, you shouldn't need to validate the before_type_cast field, just the normal age field.

[forward]

Thanks for the reply. It seems to typecast before validation. If I did this:

u = User.new
u.age = 'asdf'
u.save

with:
validates_format_of :age, :with => /^[\d]*$/

It'll save the age as zero (assuming from typecasting letters) in the database. I seem to be suffering from this unresolved ticket: "Models for tables with numeric columns quietly insert zeroes on invalid user input" (http://dev.rubyonrails.org/ticket/608)

I guess I'll check if its all digits in the validate method but I'm assuming there is a better way.

[samsm]

That is a killer gotcha.

My thanks to you for pointing that out, I'm not sure I would have been aware of that problem otherwise. It's also a reminder how helpful good, thorough testing can be, that's the only other way I'd see myself catching this.

[minimudboy]

In the database table, there is an integer column, lets call it age, and I ensure that only numbers (no + or - sign) are inputted with:

validates_format_of :age_before_type_cast, :with => /^[\d]*$/

This works fine but if an error message is generated, it would be something like "age before type cast is invalid". Is there a way to have the error message be more like "age is invalid"?

I think you just need to add :message to the end like this

validates_format_of :age_before_type_cast, :with => /^[\d]*$/, :message => "age is invalid"

[forward]

Unfortunately, that would produce "Age before type cast age is invalid". The message seems to only affect what comes after the name of the validated variable. Thanks for the tip though.

[lirux]

validates_numericality_of :age, :message => "age must be a number"

[samsm]

validates_numericality_of :age, :message => "age must be a number"

It is interesting to me that that works. I'd have expected it to fail for the same reason that validates_format_of fails. Why does that work?

[forward]

Thanks. That seems to work more like what one would expect. I'll do the other checks on the age input in the validate method.