I have a controller action somewhat similar to this:
def reports
puts params
#stats = Client.stats(params)
puts params
end
The initial params might look like this:
{ end: '2012-01-01 21:00:19' }
And in my Client model, I have this:
def self.stats(opts)
opts[:start] = (Time.now - 30.days).to_i
...do some calculations..
return stats
end
If I inspect the params object that was sent before and after the function runs, I can see it's been modified by the self.stats method.
In the example above, I'm not sending 'start' in the initial params, the method adds it for the calculations - as expected.
What I was not expecting was that the function would modify the original hash!
Can someone explain why this is happening?
--EDIT--
I forgot to say I tried to create a copy of the params and use that instead, same issue.
def reports
a = params
#stats = Client.stats(a)
puts params
end
The params are still updated?!
That's, because your function call gets a reference to the params not a copy. If you do something like opts[:start] = (Time.now - 30.days).to_i you are editing the params object.
a = params: now both variables point to the same place in the memory. You copied the pointer only.
Google for ruby object copy or ruby deep copy or search at stackoverflow for it. At a first try you could try params.clone.
Whenever you are updating any value of params, take a copy of params like this
a = params.clone
It will create a new element in memory
if you do like this it wont create a new element in memory it will point the same memory
a = params
Try this
Related
for example:
if the user login at 10:45 AM and logs out and then when he login's again the value of last_sign_in should be 10:45 AM and current_sign_in value should be current Time.
def method_name
old_current, new_current = self.current_sign_in_at, Time.now.utc
self.last_sign_in_at = old_current || new_current
self.current_sign_in_at = new_current
end
That method looks fine, though it's not currently saving the attributes.
Assuming this method is in user.rb, you just need to add:
def method_name
old_current, new_current = current_sign_in_at, Time.now.utc
self.last_sign_in_at = old_current || new_current
self.current_sign_in_at = new_current
save
end
You could also look at using update_attributes or similar.
It sounds like you'll just need to call this method on the user in the relevant controller action. If you post a little more code, I can tailor this, though hopefully that'll get you in the right direction.
I'm setting up Backburner as a work queue, and my job items need to return JSON for the resulting data they create. I'm not sure how to structure this. As a test I've tried doing:
class PrintJob
include Backburner::Performable
def self.print(text)
puts text
return "results"
end
end
Backburner.configure do |config|
config.beanstalk_url = ["beanstalk://127.0.0.1"]
# etc
end
val = PrintJob.async.print('some cool text')
puts val
and running Backburner.work inside IRB. The puts works but the return value comes back as true instead of "results".
Is there a way to get return values out of async methods? Or should I try a different approach, e.g. having one queue for jobs and another for results? If so, how can I associate the result 'job' with the original work it belongs to?
Note: I'm eventually using Sinatra and not Rails.
If I have a method like this:
require 'tweetstream'
# client is an instance of TweetStream::Client
# twitter_ids is an array of up to 1000 integers
def add_first_users_to_stream(client, twitter_ids)
# Add the first 100 ids to sitestream.
client.sitestream(twitter_ids.slice!(0,100))
# Add any extra IDs individually.
twitter_ids.each do |id|
client.control.add_user(id)
end
return client
end
I want to use rspec to test that:
client.sitestream is called, with the first 100 Twitter IDs.
client.control.add_user() is called with the remaining IDs.
The second point is trickiest for me -- I can't work out how to stub (or whatever) a method on an object that is itself a property of an object.
(I'm using Tweetstream here, although I expect the answer could be more general. If it helps, client.control would be an instance of TweetStream::SiteStreamClient.)
(I'm also not sure a method like my example is best practice, accepting and returning the client object like that, but I've been trying to break my methods down so that they're more testable.)
This is actually a pretty straightforward situation for RSpec. The following will work, as an example:
describe "add_first_users_to_stream" do
it "should add ids to client" do
bulk_add_limit = 100
twitter_ids = (0..bulk_add_limit+rand(50)).collect { rand(4000) }
extras = twitter_ids[bulk_add_limit..-1]
client = double('client')
expect(client).to receive(:sitestream).with(twitter_ids[0...bulk_add_limit])
client_control = double('client_control')
expect(client).to receive(:control).exactly(extras.length).times.and_return(client_control)
expect(client_control).to receive(:add_user).exactly(extras.length).times.and_return {extras.shift}
add_first_users_to_stream(client, twitter_ids)
end
end
def test_post_with_file filename = 'test01.xml'
File.open(filename) do |file|
response = #http_client.post(url, {'documents'=>file})
end
end
How do I modify the above method to handle a multi-file-array post/upload?
file_array = ['test01.xml', 'test02.xml']
You mean like this?
def test_post_with_file(file_array=[])
file_array.each do |filename|
File.open(filename) do |file|
response = #http_client.post(url, {'documents'=>file})
end
end
end
I was having the same problem and finally figured out how to do it:
def test_post_with_file(file_array)
form = file_array.map { |n| ['documents[]', File.open(n)] }
response = #http_client.post(#url, form)
end
You can see in the docs how to pass multiple values: http://rubydoc.info/gems/httpclient/HTTPClient#post_content-instance_method .
In the "body" row, I tried without success to use the 4th example. Somehow HttpClient just decides to apply .to_s to each hash in the array.
Then I tried the 2nd solution and it wouldn't work either because only the last value is kept by the server. But I discovered after some tinkering that the second solution works if the parameter name includes the square brackets to indicate there are mutiple values as an array.
Maybe this is a bug in Sinatra (that's what I'm using), maybe the handling of such data is implementation-dependent, maybe the HttpClient doc is outdated/wrong. Or a combination of these.
I try to use the ruby standard csv lib to dump out the arr of object to a csv.file , called 'a.csv'
http://ruby-doc.org/stdlib-1.9.3/libdoc/csv/rdoc/CSV.html#method-c-dump
dump(ary_of_objs, io = "", options = Hash.new)
but in this method, how can i dump into a file?
there is no such examples exists and help. I google it no example to do for me...
Also, the docs said that...
The next method you can provide is an instance method called
csv_headers(). This method is expected to return the second line of
the document (again as an Array), which is to be used to give each
column a header. By default, ::load will set an instance variable if
the field header starts with an # character or call send() passing the
header as the method name and the field value as an argument. This
method is only called on the first object of the Array.
Anyone knows how to pass the instance method csv_headers() to this dump function?
I haven't tested this out yet, but it looks like io should be set to a file. According to the doc you linked "The io parameter can be used to serialize to a File"
Something like:
f = File.open("filename")
dump(ary_of_objs, io = f, options = Hash.new)
The accepted answer doesn't really answer the question so I thought I'd give a useful example.
First of all if you look at the docs at http://ruby-doc.org/stdlib-1.9.3/libdoc/csv/rdoc/CSV.html, if you hover over the method name for dump you see you can click to show source. If you do that you'll see that the dump method attempts to call csv_headers on the first object you pass in from ary_of_objs:
obj_template = ary_of_objs.first
...snip...
headers = obj_template.csv_headers
Then later you see that the method will call csv_dump on each object in ary_of_objs and pass in the headers:
ary_of_objs.each do |obj|
begin
csv << obj.csv_dump(headers)
rescue NoMethodError
csv << headers.map do |var|
if var[0] == #
obj.instance_variable_get(var)
else
obj[var[0..-2]]
end
end
end
end
So we need to augment each entry in array_of_objs to respond to those two methods. Here's an example wrapper class that would take a Hash, and return the hash keys as the CSV headers and then be able to dump each row based on the headers.
class CsvRowDump
def initialize(row_hash)
#row = row_hash
end
def csv_headers
#row.keys
end
def csv_dump(headers)
headers.map { |h| #row[h] }
end
end
There's one more catch though. This dump method wants to write an extra line at the top of the CSV file before the headers, and there's no way to skip that if you call this method due to this code at the top:
# write meta information
begin
csv << obj_template.class.csv_meta
rescue NoMethodError
csv << [:class, obj_template.class]
end
Even if you return '' from CsvRowDump.csv_meta that will still be a blank line where a parse expects the headers. So instead lets let dump write that line and then remove it afterwards when we call dump. This example assumes you have an array of hashes that all have the same keys (which will be the CSV header).
#rows = #hashes.map { |h| CsvRowDump.new(h) }
File.open(#filename, "wb") do |f|
str = CSV::dump(#rows)
f.write(str.split(/\n/)[1..-1].join("\n"))
end