file_field(object_name, method, options = {}) public

Returns a file upload input tag tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). Additional options on the input tag can be passed as a hash with options. These options will be tagged onto the HTML as an HTML element attribute as in the example shown.

Using this method inside a form_for block will set the enclosing form’s encoding to multipart/form-data.


  • Creates standard HTML attributes for the tag.

  • :disabled - If set to true, the user will not be able to use this input.

  • :multiple - If set to true, *in most updated browsers* the user will be allowed to select multiple files.

  • :include_hidden - When multiple: true and include_hidden: true, the field will be prefixed with an <input type="hidden"> field with an empty value to support submitting an empty collection of files.

  • :accept - If set to one or multiple mime-types, the user will be suggested a filter when choosing a file. You still need to set up model validations.


file_field(:user, :avatar)
# => <input type="file" id="user_avatar" name="user[avatar]" />

file_field(:post, :image, multiple: true)
# => <input type="file" id="post_image" name="post[image][]" multiple="multiple" />

file_field(:post, :attached, accept: 'text/html')
# => <input accept="text/html" type="file" id="post_attached" name="post[attached]" />

file_field(:post, :image, accept: 'image/png,image/gif,image/jpeg')
# => <input type="file" id="post_image" name="post[image]" accept="image/png,image/gif,image/jpeg" />

file_field(:attachment, :file, class: 'file_input')
# => <input type="file" id="attachment_file" name="attachment[file]" class="file_input" />
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