Rails rails 中的 rake 任务，return 报错？
string2020
·
2014年09月24日
·
2388 次阅读
我在 rails 项目里面写了一个任务
namespace :jshop do
desc '导入excel数据'
task :import_tourism_rate => :environment do |t|
res = parse_rate()
if res == 1
puts "product=#{pid_hash[pid]} is parse successed . "
else
puts "product=#{pid_hash[pid]} is parse failed . "
return
end
end
end
这里面有个 return 我是想当 res！= 1 的时候，就退出任务
但是，报错了。
ly@lypc:~/src/jshop$ rake jshop:import_tourism_rate
product=53fc1b5203af787591000008 is parse failed .
rake aborted!
LocalJumpError: unexpected return
/home/ly/src/jshop/lib/tasks/import_tourism_rate.rake:39:in `block (3 levels) in <top (required)>'
/home/ly/src/jshop/lib/tasks/import_tourism_rate.rake:18:in `each'
/home/ly/src/jshop/lib/tasks/import_tourism_rate.rake:18:in `block (2 levels) in <top (required)>'
Tasks: TOP => jshop:import_tourism_rate
(See full trace by running task with --trace)
请问，为什么。
zgm
#1
2014年09月24日
A Rake task is basically a block. A block, except lambdas, doesn't support return but you can skip to the next statement using next which in a rake task has the same effect of using return in a method.
task :foo do
puts "printed"
next
puts "never printed"
end
Or you can move the code in a method and use return in the method.
task :foo do
do_something
end
def do_something
puts "startd"
return
puts "end"
end
I prefer the second choice.
http://stackoverflow.com/questions/2316475/how-do-i-return-early-from-a-rake-task