mysql - How to validate a binary field using Ruby on Rails? -

i want ensure binary field has value. added validation code below.

class foo < activerecord::base   validates :b, presence: true end

however, change seems cause error.

$ rails c > foo.create(b:file.read('b.jpg'))  argumenterror: invalid byte sequence in utf-8

the error doesn't appear. when binary data has non-ascii codes.

how can validate binary field?

i made environment below. image file(b.jpg, less 16kb) needed.

$ rails --version rails 4.2.0 $ rails new test_binary --database=mysql $ cd test_binary/ $ rails g model foo b:binary $ rake db:create db:migrate

file.read returns string claim have utf-8 encoding default. means this:

foo.create(b:file.read('b.jpg'))

is really:

some_utf8_string = file.read('b.jpg') foo.create(b: some_utf8_string)

but jpeg valid utf-8 string you're going argumenterror whenever tries treat utf-8.

you can specify encoding when read jpeg:

foo.create(b: file.read('b.jpeg', encoding: 'binary'))

that should past encoding problem.

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