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CarrierWaveの使い方


Gemfile

gem 'carrierwave'


$ bundle install


uploaderを作成

$ rails g uploader image

app/uploaders/image_uploader.rbが作成される


image_uploader.rb

class ImageUploader < CarrierWave::Uploader::Base

# リサイズしたり画像形式を変更するのに必要
# Include RMagick or MiniMagick support:
# include CarrierWave::RMagick
# include CarrierWave::MiniMagick

# Choose what kind of storage to use for this uploader:
storage :file
# storage :fog

# Override the directory where uploaded files will be stored.
# This is a sensible default for uploaders that are meant to be mounted:
def store_dir
"uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
end

# Provide a default URL as a default if there hasn't been a file uploaded:
# def default_url(*args)
# # For Rails 3.1+ asset pipeline compatibility:
# # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
#
# "/images/fallback/" + [version_name, "default.png"].compact.join('_')
# end

# Process files as they are uploaded:
# process scale: [200, 300]
#
# def scale(width, height)
# # do something
# end

# Create different versions of your uploaded files:
# version :thumb do
# process resize_to_fit: [50, 50]
# end

# Add a white list of extensions which are allowed to be uploaded.
# For images you might use something like this:
# アップロードできる拡張子を制限
def extension_whitelist
%w(jpg jpeg gif png)
end

# Override the filename of the uploaded files:
# Avoid using model.id or version_name here, see uploader/store.rb for details.
def filename
"something.jpg" if original_filename
end
end


画像用のカラムを追加

※今回はuserモデルに追加を想定

$ rails g migration add_image_to_user image:string

モデルに追加


user.rb

class User < ApplicationRecord

mount_uploader :image, ImageUploader
end

permitにimageを追加


controller.rb

:image


入力側


edit.rb

    <%= f.label :顔画像 %>

<%=
f.file_field :image %>

表示側


show.rb

<img src="<%= @user.image %>" width="100">