How does one use rescue in Ruby without the begin and end block
RubyRuby Problem Overview
I know of the standard technique of having a begin
How does one just use the rescue block on its own.
How does it work and how does it know which code is being monitored?
Ruby Solutions
Solution 1 - Ruby
A method "def" can serve as a "begin" statement:
def foo
...
rescue
...
end
Solution 2 - Ruby
You can also rescue inline:
1 + "str" rescue "EXCEPTION!"
will print out "EXCEPTION!" since 'String can't be coerced into Fixnum'
Solution 3 - Ruby
I'm using the def / rescue combination a lot with ActiveRecord validations:
def create
@person = Person.new(params[:person])
@person.save!
redirect_to @person
rescue ActiveRecord::RecordInvalid
render :action => :new
end
I think this is very lean code!
Solution 4 - Ruby
Example:
begin
# something which might raise an exception
rescue SomeExceptionClass => some_variable
# code that deals with some exception
ensure
# ensure that this code always runs
end
Here, def
as a begin
statement:
def
# something which might raise an exception
rescue SomeExceptionClass => some_variable
# code that deals with some exception
ensure
# ensure that this code always runs
end
Solution 5 - Ruby
Bonus! You can also do this with other sorts of blocks. E.g.:
[1, 2, 3].each do |i|
if i == 2
raise
else
puts i
end
rescue
puts 'got an exception'
end
Outputs this in irb
:
1
got an exception
3
=> [1, 2, 3]