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Easy CSV import/export
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saverio-kantox and am-kantox Support limited file recognization (#12)
In some OSs or some versions of the `file` command line tool, Excel files are recognized as `Zip archive data, at least vN.N to extract`. When the files come as ActionDispatch::Http::UploadedFile then it has an uninteresting filename so the extension cannot be used anyways.

With this change, Office packaged files are recognized.
Latest commit a9312ea Mar 29, 2019


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Easy dealing with CSV import, including, but not limited to:

✓ import in any format: String, csv, xlsx; ✓ additional input formatting; ✓ input checkers; ✓ callbacks on errors; ✓ producing of “suggested edits” version of input (both csv and xlsx formats).


Add this line to your application's Gemfile:

gem 'see_as_vee'

And then execute:

$ bundle

Or install it yourself as:

$ gem install see_as_vee


Load and validate

    sheet = SeeAsVee.harvest(
      'spec/fixtures/velocity.xlsx', # file exists ⇒ will be loaded
      formatters: { reference: ->(v) { v.round.to_s } }, # safe reference input
      checkers: { reference: ->(v) { v.nil? } }, # must be present
      skip_blank_rows: true # Optional, defaults to false
    ) do |idx, errors, hash| # row index, errors, row as hash { header: value }
      # Errors: {"Reference"=>"☣2̶4̶3̶7̶2̶3̶1̶1̶4̶"}
      expect(errors["Reference"]).to eq "#{SeeAsVee::Sheet::CELL_ERROR_MARKER}2̶4̶3̶7̶2̶3̶1̶1̶4̶"
      # Hash: {"Reference"=>"☣2̶4̶3̶7̶2̶3̶1̶1̶4̶", ... }
      expect(hash["Reference"]).to eq "#{SeeAsVee::Sheet::CELL_ERROR_MARKER}2̶4̶3̶7̶2̶3̶1̶1̶4̶"
    csv, xlsx = sheet.produce csv: true, xlsx: true
    # in CSV cells, that did not pass validation, are striked out
    expect(File.exist?(csv.path)).to eq true
    expect(csv.length > 0).to eq true
    # in XLSX cells, that did not pass validation, are marked with red background
    expect(File.exist?(xlsx.path)).to eq true
    expect(xlsx.length > 0).to eq true


From the version 0.4.0 we support dry validation of the data given:

# Dry::Validation.Form if you are using dry-validation < 0.12
schema = Dry::Validation.Params do
  required(:reference) { filled? > str? }
validation = SeeAsVee.validate('spec/fixtures/velo.csv', schema)
expect(validation.all? { |vr| vr.errors.empty? }).to be true

The returned value is an array of validation results.


require 'see_as_vee'
    #⇒ trueSeeAsVee.csv(
    ▷   [{name: 'Aleksei', value: 42}, {name: 'John', value: 3.14}], col_sep: "\t"
    ▷ )
    #⇒ #<File:/tmp/am/see_as_vee20161109-6031-6he5m7.csv>
    #  -rw------- 1 am am 32 nov  9 07:18 /tmp/am/see_as_vee20161109-6031-6he5m7.csv
    ▶ .cat /tmp/am/see_as_vee20161109-6031-6he5m7.csv
    #⇒ name	value
    #  Aleksei	42
    #  John	3.14

Expand GROUP_CONCAT column

From the version 0.4.6 we support expanding the column given as an Array instance

require 'see_as_vee'
    #⇒ trueSeeAsVee.csv(
    ▷   [{name: 'Aleksei', value: 42, nicks: %w|matiushkin mudasobwa am-kantox|},
    ▷    {name: 'Saverio', value: 3.14, nicks: %w|trioni rewritten saverio-kantox|}],
    ▷   ungroup: :nicks)
    #⇒ #<File:/tmp/am/see_as_vee20161109-6031-6he5m7.csv>
    #  -rw------- 1 am am 32 nov  9 07:18 /tmp/am/see_as_vee20161109-6031-6he5m7.csv
    ▶ .cat /tmp/am/see_as_vee20161109-6031-6he5m7.csv
    #⇒ name	    value nick 1      nick 2     nick 3
    #  Aleksei  42    matiushkin  mudasobwa  am-kantox
    #  Saverio  3.14  trioni      rewritten  saverio-kantox

From the version 0.4.5 we support expanding the column produced by GROUP_CONCAT

require 'see_as_vee'
    #⇒ trueSeeAsVee.csv(
    ▷   [{name: 'Aleksei', value: 42, nicks: 'matiushkin,mudasobwa,am-kantox'},
    ▷    {name: 'Saverio', value: 3.14, nicks: 'trioni,rewritten,saverio-kantox'}],
    ▷   ungroup: :nicks)
    #⇒ #<File:/tmp/am/see_as_vee20161109-6031-6he5m7.csv>
    #  -rw------- 1 am am 32 nov  9 07:18 /tmp/am/see_as_vee20161109-6031-6he5m7.csv
    ▶ .cat /tmp/am/see_as_vee20161109-6031-6he5m7.csv
    #⇒ name	    value nick 1      nick 2     nick 3
    #  Aleksei  42    matiushkin  mudasobwa  am-kantox
    #  Saverio  3.14  trioni      rewritten  saverio-kantox


0.6.1 allow explicit UTF-16 LE with BOM to please MS Excel users

0.5.4 deal with duplicated and empty headers

0.5.2 accept empty headers

0.5.1 skip_blank_rows

0.5.0 supporting all versions of dry-validation

0.4.9 squish

0.4.8 bugfix allow same lines in the input

0.4.5 support for expanding GROUP_CONCAT column

0.4.0 support for Dry::Validation

0.3.0 support for XLSX options

0.2.5 support for CSV options


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at[USERNAME]/see_as_vee. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.

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