Class: RightScraper::Scanners::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/right_scraper/scanners/base.rb

Overview

Base class for scanning filesystems. Subclasses should override #notice and may override #new, #begin, #end and #notice_dir.

Overriding #new is useful for getting additional arguments. Overriding #begin allows you to do processing before the scan of a given resource begins; overriding #end allows you to do processing after it completes.

Most processing will occur in #notice, which notifies you that a file has been detected, and in #notice_dir. In #notice you are handed the relative position of the file from the start of the resource; so if you were scanning /a/resource and noticed a file b/c, #notice would be called with "b/c", even though the full pathname is /a/resource/b/c. If you decide you need the actual data, #notice takes a block which will return that data to you if you yield.

In #notice_dir you are handed the relative position of a directory. The return value determines whether you find the directory worth recursing into, or not–as an example, when looking for the metadata.json file it is never necessary to descend past the topmost directory of the resource, but the same is not true when building a manifest.

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Base

Returns a new instance of Base.

Parameters:

  • options (Hash) (defaults to: {}) —

    for scanner



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# File 'lib/right_scraper/scanners/base.rb', line 57

def initialize(options={})
  unless @logger = options[:logger]
    raise ::ArgumentError, ':logger is required'
  end
end

Instance Method Details

#begin(resource) ⇒ Object

Begin a scan for the given resource.

Parameters ===

resource(RightScraper::Resource::Base)

resource to scan



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# File 'lib/right_scraper/scanners/base.rb', line 72

def begin(resource)
end

#end(resource) ⇒ Object

Finish a scan for the given resource.

Parameters ===

resource(RightScraper::Resource::Base)

resource that just finished

scanning



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# File 'lib/right_scraper/scanners/base.rb', line 80

def end(resource)
end

#finish ⇒ Object

Notification that all scans for this repository have completed.



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# File 'lib/right_scraper/scanners/base.rb', line 65

def finish
end

#notice(relative_position) ⇒ Object

Notice a file during scanning.

Block ===

Return the data for this file. We use a block because it may not always be necessary to read the data.

Parameters ===

relative_position(String)

relative pathname for pathname from root of resource



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# File 'lib/right_scraper/scanners/base.rb', line 92

def notice(relative_position)
end

#notice_dir(relative_position) ⇒ Object

Notice a directory during scanning. Returns true if the scanner should recurse into the directory (the default behavior)

Parameters ===

relative_position(String)

relative pathname for the directory from root of resource

Returns ===

Boolean

should the scanning recurse into the directory



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# File 'lib/right_scraper/scanners/base.rb', line 104

def notice_dir(relative_position)
  true
end