https://github.com/costajob/file_scanner

A library to lazily collect a list of files by path and a set of filters.
https://github.com/costajob/file_scanner

filesystem lazy-evaluation ruby scanner

Last synced: 13 days ago
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A library to lazily collect a list of files by path and a set of filters.

• Host: GitHub
• URL: https://github.com/costajob/file_scanner
• Owner: costajob
• Created: 2017-07-21T07:09:36.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2017-08-28T13:13:35.000Z (about 7 years ago)
• Last Synced: 2024-09-01T06:51:55.163Z (2 months ago)
• Topics: filesystem, lazy-evaluation, ruby, scanner
• Language: Ruby
• Homepage:
• Size: 57.6 KB
• Stars: 0
• Watchers: 14
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
## Table of Contents

* [Scope](#scope)

* [Motivation](#motivation)

* [Installation](#installation)

* [Usage](#usage)

  * [Filters](#filters)

    * [Defaults](#defaults)

    * [Custom](#custom)

  * [Worker](#worker)

    * [Enumerator](#enumerator)

    * [Consuming results](#consuming-results)

    * [Mode](#mode)

    * [File check](#file-check)

    * [Logger](#logger)

## Scope

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

## Motivation

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.

## Installation

Add this line to your application's Gemfile:

```ruby

gem "file_scanner"

```

And then execute:

```shell

bundle

```

Or install it yourself as:

```shell

gem install file_scanner

```

## Usage

### Filters

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

#### Defaults

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:

```ruby

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]

```

#### Custom

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

```ruby

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

```

### Worker

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

#### Enumerator

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

```ruby

worker = FileScanner::Worker.new(path: "~/Downloads", filters: filters, slice: 35)

p worker.call

=> #