use trial with gem paypal-sdk-rest - ruby-on-rails

Question

I have my site in ruby on rails and for subscription payments I am using the paypal paypal-sdk-rest gem. But I need the first payment to have a lower value and then the next payment to have the normal value so that users can subscribe and test the subscription. I have been reading in the paypal api and a trial with a lower value can be applied. Is it possible to apply trial to the paypal gem paypal-sdk-rest? this is my code of how I create the plans:
def creacion_planes
plan = Plan.new({
:name => 'Monthly $20',
:description => '$20 plan (monthly charge)',
:type => 'infinite',
:payment_definitions => [{
:name => 'Plan monthly $20',
:type => 'REGULAR',
:frequency_interval => '1',
:frequency => 'MONTH', #WEEK, DAY, YEAR, MONTH.
:cycles => '0',
:amount => {
:currency => 'USD',
:value => '20.00'
}
}],
:merchant_preferences => {
:return_url => complete_paypal_checkouts_planes_url,
:cancel_url => update_plan_url,
:max_fail_attempts => '0',
:auto_bill_amount => 'YES',
:initial_fail_amount_action => 'CONTINUE'
}
})
# Create plan
if plan.create
# Plan update activation object
plan_update = {
:op => 'replace',
:path => '/',
:value => {
:state => 'ACTIVE'
}
}
# Activate plan
if plan.update(plan_update)
puts("Billing plan activated with ID [#{plan.id}]")
redirect_to success_payment_path(:plan_id => plan.id, :plan => "plan_mensual20")
else
logger.error payment.error.inspect
end
else
logger.error payment.error.inspect
end
end
And this is my code of how I create the agreement:
def create
agreement = Agreement.new({
:name => params[:name],
:description => params[:description],
:start_date => (Time.now + 20*60).utc.iso8601, #'2020-04-26T23:00:04Z' (Time.now + 1.days).utc.iso8601
:plan => {
:id => params[:plan_id]
},
:payer => {
:payment_method => 'paypal'
}
})
if agreement.create
redirect = agreement.links.find{|v| v.rel == "approval_url" }.href
redirect_to redirect
else
logger.error agreement.error.inspect
end
end

Answer 1

Do not use that old paypal-ruby-sdk. It is obsolete and uses an old version of billing plans, which is not compatible with the current subscriptions API.
Instead, integrate the subscriptions API via direct HTTPS calls. Here is the guide: https://developer.paypal.com/docs/subscriptions/
An example with a trial period is provided.