This app uses Ruby 3.1.2 so make sure you have it on your machine. To run script
bundle
./parser.rb webserver.logTo run unit and integration tests
rspecFinally, to check compliance with linters
rubocop
reek
The design is based on a Presentation, Domain, and Data approach. Each layer will be described separately. Let's start with Data Layer.
To store statistics about page views Hash structure looks like the best choice. Hash supports the uniqueness of its keys. Lookup and insert operations are very cheap on hash, so we can take advantage of that. We store pages (strings) as hash keys.
For the first part of the task (list of pages with total views), the hash values are integers. Here we only need to save the total number of visits for each page. This structure is represented by HashOfIntegers Ruby class.
For the second part of the task (unique page views), the hash values are Sets. Set also supports the uniqueness of its elements and quickly inserts new items. We store unique IP addresses in Set (check HashOfSets class).
On this layer, we also have statistics collectors StatCollector that use one of the above-described structures to gather necessary information. It provides a unified interface to store statistics regardless of the underlying data structure.
On this layer, we have our business logic. The main entity here is LogProcessor class that iterates over log lines and fills in statistics collectors with data. Under the hood, it uses LogReader to validate, access, and read a file.
Here we have several classes (end with Presenter) that know how to display statistics or errors to the end user.
