+# This module contains helper methods for displaying and uploading files
+# for attributes created by +FileColumn+'s +file_column+ method. It will be
+# automatically included into ActionView::Base, thereby making this module's
+# methods available in all your views.
+module FileColumnHelper
+
+ # Use this helper to create an upload field for a file_column attribute. This will generate
+ # an additional hidden field to keep uploaded files during form-redisplays. For example,
+ # when called with
+ #
+ # <%= file_column_field("entry", "image") %>
+ #
+ # the following HTML will be generated (assuming the form is redisplayed and something has
+ # already been uploaded):
+ #
+ # <input type="hidden" name="entry[image_temp]" value="..." />
+ # <input type="file" name="entry[image]" />
+ #
+ # You can use the +option+ argument to pass additional options to the file-field tag.
+ #
+ # Be sure to set the enclosing form's encoding to 'multipart/form-data', by
+ # using something like this:
+ #
+ # <%= form_tag {:action => "create", ...}, :multipart => true %>
+ def file_column_field(object, method, options={})
+ result = ActionView::Helpers::InstanceTag.new(object.dup, method.to_s+"_temp", self).to_input_field_tag("hidden", {})
+ result << ActionView::Helpers::InstanceTag.new(object.dup, method, self).to_input_field_tag("file", options)
+ end
+
+ # Creates an URL where an uploaded file can be accessed. When called for an Entry object with
+ # id 42 (stored in <tt>@entry</tt>) like this
+ #
+ # <%= url_for_file_column(@entry, "image")
+ #
+ # the following URL will be produced, assuming the file "test.png" has been stored in
+ # the "image"-column of an Entry object stored in <tt>@entry</tt>:
+ #
+ # /entry/image/42/test.png
+ #
+ # This will produce a valid URL even for temporary uploaded files, e.g. files where the object
+ # they are belonging to has not been saved in the database yet.
+ #
+ # The URL produces, although starting with a slash, will be relative
+ # to your app's root. If you pass it to one rails' +image_tag+
+ # helper, rails will properly convert it to an absolute
+ # URL. However, this will not be the case, if you create a link with
+ # the +link_to+ helper. In this case, you can pass <tt>:absolute =>
+ # true</tt> to +options+, which will make sure, the generated URL is
+ # absolute on your server. Examples:
+ #
+ # <%= image_tag url_for_file_column(@entry, "image") %>
+ # <%= link_to "Download", url_for_file_column(@entry, "image", :absolute => true) %>
+ #
+ # If there is currently no uploaded file stored in the object's column this method will
+ # return +nil+.
+ def url_for_file_column(object, method, options=nil)
+ case object
+ when String, Symbol
+ object = instance_variable_get("@#{object.to_s}")
+ end
+
+ # parse options
+ subdir = nil
+ absolute = false
+ if options
+ case options
+ when Hash
+ subdir = options[:subdir]
+ absolute = options[:absolute]
+ when String, Symbol
+ subdir = options
+ end
+ end
+
+ relative_path = object.send("#{method}_relative_path", subdir)
+ return nil unless relative_path
+
+ url = ""
+ url << request.relative_url_root.to_s if absolute
+ url << "/"
+ url << object.send("#{method}_options")[:base_url] << "/"
+ url << relative_path
+ end
+
+ # Same as +url_for_file_colum+ but allows you to access different versions
+ # of the image that have been processed by RMagick.
+ #
+ # If your +options+ parameter is non-nil this will
+ # access a different version of an image that will be produced by
+ # RMagick. You can use the following types for +options+:
+ #
+ # * a <tt>:symbol</tt> will select a version defined in the model
+ # via FileColumn::Magick's <tt>:versions</tt> feature.
+ # * a <tt>geometry_string</tt> will dynamically create an
+ # image resized as specified by <tt>geometry_string</tt>. The image will
+ # be stored so that it does not have to be recomputed the next time the
+ # same version string is used.
+ # * <tt>some_hash</tt> will dynamically create an image
+ # that is created according to the options in <tt>some_hash</tt>. This
+ # accepts exactly the same options as Magick's version feature.
+ #
+ # The version produced by RMagick will be stored in a special sub-directory.
+ # The directory's name will be derived from the options you specified
+ # (via a hash function) but if you want
+ # to set it yourself, you can use the <tt>:name => name</tt> option.
+ #
+ # Examples:
+ #
+ # <%= url_for_image_column @entry, "image", "640x480" %>
+ #
+ # will produce an URL like this
+ #
+ # /entry/image/42/bdn19n/filename.jpg
+ # # "640x480".hash.abs.to_s(36) == "bdn19n"
+ #
+ # and
+ #
+ # <%= url_for_image_column @entry, "image",
+ # :size => "50x50", :crop => "1:1", :name => "thumb" %>
+ #
+ # will produce something like this:
+ #
+ # /entry/image/42/thumb/filename.jpg
+ #
+ # Hint: If you are using the same geometry string / options hash multiple times, you should
+ # define it in a helper to stay with DRY. Another option is to define it in the model via
+ # FileColumn::Magick's <tt>:versions</tt> feature and then refer to it via a symbol.
+ #
+ # The URL produced by this method is relative to your application's root URL,
+ # although it will start with a slash.
+ # If you pass this URL to rails' +image_tag+ helper, it will be converted to an
+ # absolute URL automatically.
+ # If there is currently no image uploaded, or there is a problem while loading
+ # the image this method will return +nil+.
+ def url_for_image_column(object, method, options=nil)
+ case object
+ when String, Symbol
+ object = instance_variable_get("@#{object.to_s}")
+ end
+ subdir = nil
+ if options
+ subdir = object.send("#{method}_state").create_magick_version_if_needed(options)
+ end
+ if subdir.nil?
+ nil
+ else
+ url_for_file_column(object, method, subdir)
+ end
+ end
+end
projects / rails.git / blobdiff