I had a task to analyse the value of a cookie set by a tool on the subdomain. The value of the cookie set looked something like this:
"18337|20120404|True#Q0A|18342|21-30|20120404|18344#Q1|18349|NO PARTNER|20120404|18351#Q2|18352|EMPLOYED|20120404|18353#Q4|18432|STRUGGLING|18539|WANT|20120404|18541#Q3|18358|EMPLOYED|20120404|18359#"
My task was to try to decipher the values of set inside the cookie and how they changed depending on the progress through the application that set the values. I was told the answers to questions sat next to the ID of the question. For example, the answer to the “age” question (21-30) was related to the question 18342 and would always appear as |18342|21-30|. I started out with some tests and ended up with a method like this:
class Answers
attr_accessor :age, :employment_status, :has_partner
def parse(cookie_contents)
items = cookie_contents.split("|")
items.each_index do | i |
current = items[i]
if (current == "18342")
@age = items[i+1]
elsif (current == "18352")
@employment_status = items[i+1]
elsif (current == "18349")
@current_partner = items[i+1]
end
end
end
end
Of course, I wanted to avoid the growing if-else statement so found a way that I could do it dynamically and focus just on the mapping from an ID to an attribute. The resulting code looked like this:
class Answers
attr_accessor :age, :employment_status, :has_partner
Mappings = {
"18342" => :age=,
"18352" => :employment_status=,
"18349" => :has_partner=
}
def parse(cookie_contents)
items = cookie_contents.split("|")
items.each_index do | i |
current = items[i]
if (Mappings.has_key?(current))
self.public_send(Mappings[current], items[i+1])
end
end
end
end
By the end of the analysis, I discovered that multiple IDs mapped to the same properties and all I had to do was add another entry into the map defining which ID mapped to what property on the object. With java/.net being more of my background, I was pleased to see how brief the code turned out to be.
