• Scope
• Motivation
• Installation
• Usage
  • Filters
    • Defaults
    • Custom
  • Worker
    • Enumerator
    • Consuming results
    • Mode
    • File check
    • Logger

This gem is aimed to lazily collect a list of files by path and a set of filters.

This gem is helpful to purge obsolete files or to promote relevant ones, by calling external services (CDN APIs) and/or local file system actions (copy, move, delete, etc).
By working lazily, this library is aimed to work with a subset of large files list: just remember to apply a subset method to the final enumerator.

Add this line to your application's Gemfile:

gem "file_scanner"

And then execute:

bundle

Or install it yourself as:

gem install file_scanner

The first step is to provide the filters list to select file paths for which the call method is truthy.

If you specify no filters the default ones are loaded, selecting files by:

• checking if file is older than 30 days
• checking if file size is within 0KB and 5KB
• checking if file basename matches the specified regexp (if any)

You can update default filters behaviour by passing custom arguments:

a_week_ago = FileScanner::Filters::LastAccess.new(Time.now-7*24*3600)
one_two_mb = FileScanner::Filters::SizeRange.new(min: 1024**2, max: 2*1024**2)
hidden = FileScanner::Filters::MatchingName.new(/^\./)
filters = [a_week_ago, one_two_mb, hidden]

It is convenient to create custom filters by using Proc instances that satisfy the callable protocol:

filters << ->(file) { File.directory?(file) }

The second step is to create the Worker instance by providing the path to scan and the list of filters to apply.

The call method of the worker return a lazy enumerator with the filtered elements:

worker = FileScanner::Worker.new(path: "~/Downloads", filters: filters, slice: 35)
p worker.call
=> #<Enumerator::Lazy: ...

To leverage on the lazy behaviour remember to call a subset method on the resulting enumerator:

worker.call.take(1000).each do |file|
  # perform action on filtered files
end

By default the worker does select paths by applying any of the matching filters: it suffice just one of the filters to match to grab the path.
In case you want restrict paths selection by all matching filters, just specify the all option:

worker = FileScanner::Worker.new(loader: loader, filters: filters, all: true)
worker.call # will filter by applying all? predicate

By default the worker does collect both directories and files. In case you want restrict selction by files only, just specify the filecheck option:

worker = FileScanner::Worker.new(loader: loader, filters: filters, filecheck: true)
worker.call # skip directories

If you dare to trace what the worker is doing (including errors), you can specify a logger to the worker class:

my_logger = Logger.new("my_file.log")
worker = FileScanner::Worker.new(loader: loader, logger: my_logger)