I have a flash_helper that I inconveniently downloaded from some web tutorial, which is now coming back to whack me on the head. On the good side, I'm sure the many talented coders here will find this easy. :)
# application_helper
def flash_helper
[:notice, :warning, :message].map { |f| content_tag(:div, flash[f], :class => f) if flash[f] }
end
This code, combined with <%= flash_helper %> in my views, is leading to the following html code generated:
["<div class=\"notice\">Your account has been reactivated.</div>", nil, nil]
...which renders as this rather unattractive string in the view itself:
["<div class=\"notice\">Your account has been reactivated.</div>", nil, nil]
How do I rewrite the code to sort this out?
[nil, nil, nil]
The above string is being sent to all of my views by the flash_helper code above when there is no flash. How can that code be rewritten to output nothing when there is no flash?
You need launch html_safe on all your String, on an array.
# application_helper
def flash_helper
[:notice, :warning, :message].map { |f|
content_tag(:div, flash[f].html_safe, :class => f) if flash[f]
}.compact
end
By default Rails 3 escapes HTML unless told otherwise. All you need to do is call .html_safe on the string being generated. Here is an overview:
HTML SAFE
Related
I am reading the book Agile web developpment with rails 4.
there is a part where the products' cart is showing only if it is not empty, my question is the function in the view send to the helper only 2 attributes while in the implementation there are 3 parameters.
in the view I have the bellow code, which render to _cart where I have the cart show
<%= hidden_div_if(#cart.line_items.empty?, id: 'cart') do %>
<%= render #cart %>
<% end %>
the helper has:
module ApplicationHelper
def hidden_div_if(condition, attributes = {}, &block)
if condition
attributes["style"] = "display: none"
end
content_tag("div", attributes, &block) end
end
My question is the &block in this case receives id: 'cart' but is it a optional attibute? that why it comes with &. but what about attributes = {}?
I am really not sure how that is happening, could someone explain me a bit?
Thanks!!
The code between and including do and end is the block, and this is the third argument for hidden_div_if, which is simply passed on to content_tag. The & in the definition of hidden_div_if captures the block in your view, whereas the & in the call to content_tag expands it again to pass it along.
The answer here explains this idea nicely with a few examples. I recommend testing everything out yourself in irb to get a feel for it.
I'm making a style guide where I output the code on the right that is displayed on the left.
I know that adding %% escapes ERB
I have written a helper that takes the contents of a block and renders the code in two places one showing the html and I want the other to show the source ERB that created the html.
The problem is I get back HTML where I wanted ERB.
The View Code
<%= display_code do %>
<%= link_to "Button", "/style_guide, class: "btn" %>
<% end %>
The Helper Code
module StyleGuideHelper
def display_code(&block)
content = with_output_buffer(&block)
html = ""
html << content_tag(:div, content, class: "rendered-code")
html << content_tag(:div, escape_erb(content), class: "source-code-preview")
html.html_safe
end
def escape_erb(code)
code = code.gsub("%=", "%%=")
end
end
Expected Result
Button <%= link_to "Button", "/style_guide, class: "btn" %>
Actual Result
Button Button
Cheers
The issue is that this helper runs the block (link_to "Button", ...) -- it never sees the source code inside the block, just its output. You could replace escape_erb with h to capture the resulting HTML, but that won't pop back up to the ERB that generated it.
As I see it, your options are:
Break out examples into partials, then make a helper that a) renders the partial and b) displays the underlying file.
Specify your ERB fragments as strings (heredocs?), pass the string into the helper, and have the helper a) evaluate it via ERB.new(string).result(binding) to render the result and b) display the string.
Make the helper determine what part of the view invoked it, then parse the .erb well enough to find the block. Catch is, the precise format of what you see in callers is subject to change without notice due to the way views are compiled.
Make a helper that uses crazy metaprogramming juju to evaluate the block in both an ERB context as well as your own special context that intercepts the code being evaluated and turns it back into markup.
...sorted in approximate order of complexity and odds of success.
This code below will allow you to retrieve the code for a given block.
class ERBSource
ERB = ::ActionView::Template::Handlers::ERB
def self.for(block)
new(block).source
end
attr_reader :block, :file, :line_number
def initialize(block)
#block = block
#file, #line_number = *block.source_location
end
def source
lines = File.readlines(file)
relevant_lines = lines[(line_number - 1)..-1] || []
extract_first_expression(relevant_lines)
end
private
def extract_first_expression(lines)
code = lines.slice[0,1].join # add the first two lines so it has to iterate less
lines.each do |line|
code << line
return code if correct_syntax?(compile_erb(code))
end
raise SyntaxError, "unexpected $end"
end
def correct_syntax?(code)
stderr = $stderr
$stderr.reopen(IO::NULL)
RubyVM::InstructionSequence.compile(code)
$stderr.reopen(stderr)
true
rescue Exception
$stderr.reopen(stderr)
false
end
def compile_erb(code)
ERB.erb_implementation.new(
code,
:escape => false,
:trim => (ERB.erb_trim_mode == "-")
).src
end
end
This is what the helper looks like
module StyleGuideHelper
def render_example(name, &block)
code = ERBSource.for(block)
content_tag(:h2, name) +
content_tag(:div, &block) +
content_tag(:pre, content_tag(:code, code))
end
end
Using rails 2. I want a link to the current page (whatever it is) that keeps all of the params the same but changes the format to 'csv'. (setting the format can be done by having format=csv in the params or by putting .csv at the end of the path). Eg
posts/1
=> posts/1.csv OR posts/1?format=csv
posts?name=jim
=> posts.csv?name=jim OR posts?name=jim&format=csv
I tried this as a hacky attempt
request.url+"&format=csv"
and that works fine if there are params in the current url (case 2 above) but breaks if there aren't (case 1). I could come up with more hacky stuff along these lines, eg testing if the request has params, but i'm thinking there must be a nicer way.
cheers, max
EDIT - btw, it's not guaranteed that the current page could have a named route associated with it, in case that's relevant: we could have got there via the generic "/:controller/:action/:id" route.
<%= link_to "This page in CSV", {:format => :csv } %>
<%= link_to "This page in PDF", {:format => :pdf } %>
<%= link_to "This page in JPEG", {:format => :jpeg } %>
EDIT
Add helper
def current_url(new_params)
url_for :params => params.merge(new_params)
end
then use this
<%= link_to "This page in CSV", current_url(:format => :csv ) %>
EDIT 2
Or improve your hack:
def current_url(new_params)
params.merge!(new_params)
string = params.map{ |k,v| "#{k}=#{v}" }.join("&")
request.uri.split("?")[0] + "?" + string
end
EDIT
IMPORTANT! #floor - your approach above has a serious problem - it directly modifies params, so if you've got anything after a call to this method which uses params (such as will_paginate links for example) then that will get the modified version which you used to build your link. I changed it to call .dup on params and then modify the duplicated object rather than modifying params directly. – #Max Williams
You can use:
link_to "text of link", your_controller_path(format:'csv',params: request.query_parameters)
#floor's answer was great, I found it very useful.
Although the method can be improved by using the to_params method rather than contructing your own, like so:
def current_url(new_params)
params.merge!(new_params)
"#{request.uri}#{params.to_params}"
end
I have a controller which does the following line before rendering the view and outputting an error.
flash[:error]="Flash error"
flash[:info] = "Flash info"
I would like to format this nicely. For that I wrote a helper which looks like this
def show_flash
a=""
[:success, :info, :error, :warning].each do |key|
a += content_tag(:div, flash[key], :id => key, :class => "#{key}") unless flash[key].blank?
end
end
In my view, I call:
<%= show_flash %>
When I try to run this, the web page renders the full text of show_flash, including the div tags, angle brackets and all. When I inspect the element (using Firefox or Chrome), it shows the text surrounded with double quotes.
Then I tried changing one line in the helper as follows:
a = content_tag(:div, flash[key], :id=>key, :class=>"#{key]") unless flash[key].blank?
i.e. I would only capture the last content tag (error) instead of both of them.
In the second case, the web browser rendered the div tag formatted properly with my CSS rules for the "error" class. I didn't see any div tags printed out in the browser.
Why did concatenating two content_tag elements cause me this grief?
I appreciate any help you can give me.
Because "" wasn't marked as html_safe. This is part of Rails' XSS protection that is enabled by default in Rails 3.
You may find this Railscast on XSS protection informative.
It turns out that when going from Rails 2 to Rails 3, html escaping is enabled by default, and you must explicitly disable it before concatenating content_tag strings. The code looks like:
def show_flash
a=content_tag(:span, "",:escape=>false)
[:success, :info, :error, :warning].each do |key|
a = a+content_tag(:div, flash[key], :id => key, :class => "#{key}", :escape=>false) unless flash[key].blank?
end
a
end
That option, :escape=>false is what it took to make it work.
Andrew Marshall pointed me in the right direction, and after some searching, I stumbled on the words of wisdom from Yehuda. That's where the :escape clause became obvious.
I'm trying to generate a JSON response that includes some HTML. Thus, I have /app/views/foo/bar.json.erb:
{
someKey: 'some value',
someHTML: "<%= h render(:partial => '/foo/baz') -%>"
}
I want it to render /app/views/foo/_baz.html.erb, but it will only render /app/views/foo/_baz.json.erb. Passing :format => 'html' doesn't help.
Beginning with Rails 3.2.3, when calling render :partial (only works outside of the respond_to block).
render formats: [ :html ]
instead of
render format: 'html'
What's wrong with
render :partial => '/foo/baz.html.erb'
? I just tried this to render an HTML ERB partial from inside an Atom builder template and it worked fine. No messing around with global variables required (yeah, I know they have "#" in front of them, but that's what they are).
Your with_format &block approach is cool though, and has the advantage that you only specify the format, whereas the simple approach specifies the template engine (ERB/builder/etc) as well.
Rails 4 will allow you to pass a formats parameter. So you can do
render(:partial => 'form', :formats => [:html])}
Note you can do something similar in Rails 3 but it wouldn't pass that format to any sub partials (if form calls other partials).
You can have the Rails 4 ability in Rails 3 by creating config/initializers/renderer.rb:
class ActionView::PartialRenderer
private
def setup_with_formats(context, options, block)
formats = Array(options[:formats])
#lookup_context.formats = formats | #lookup_context.formats
setup_without_formats(context, options, block)
end
alias_method_chain :setup, :formats
end
See http://railsguides.net/2012/08/29/rails3-does-not-render-partial-for-specific-format/
For Rails 3, the with_format block works, but it's a little different:
def with_format(format, &block)
old_formats = formats
self.formats = [format]
block.call
self.formats = old_formats
nil
end
Building on roninek's response, I've found the best solution to be the following:
in /app/helpers/application.rb:
def with_format(format, &block)
old_format = #template_format
#template_format = format
result = block.call
#template_format = old_format
return result
end
In /app/views/foo/bar.json:
<% with_format('html') do %>
<%= h render(:partial => '/foo/baz') %>
<% end %>
An alternate solution would be to redefine render to accept a :format parameter.
I couldn't get render :file to work with locals and without some path wonkiness.
In Rails 3, the View has a formats array, which means you can set it to look for [:mobile, :html]. Setting that will default to looking for :mobile templates, but fall back to :html templates. The effects of setting this will cascade down into inner partials.
The best, but still flawed way, that I could find to set this was to put this line at the top of each full mobile template (but not partials).
<% self.formats = [:mobile, :html] %>
The flaw is that you have to add that line to multiple templates. If anyone knows a way to set this once, from application_controller.rb, I'd love to know it. Unfortunately, it doesn't work to add that line to your mobile layout, because the templates are rendered before the layout.
Just elaborating on what zgchurch wrote:
taking exceptions into account
returning the result of the called block
Thought it might be useful.
def with_format(format, &block)
old_formats = formats
begin
self.formats = [format]
return block.call
ensure
self.formats = old_formats
end
end
You have two options:
1) use render :file
render :file => "foo/_baz.json.erb"
2) change template format to html by setting #template_format variable
<% #template_format = "html" %>
<%= h render(:partial => '/foo/baz') %>
I had a file named 'api/item.rabl' and I wanted to render it from an HTML view so I had to use:
render file: 'api/item', formats: [:json]
(file because the file have no underscore in the name, formats and not format (and passes and array))
It seems that passing a formats option will render it properly in newer Rails version, at least 3.2:
{
someKey: 'some value',
someHTML: "<%= h render('baz', formats: :html) -%>"
}
I came across this thread when I was trying to render an XML partial in another xml.builder view file.
Following is a nice way to do it
xml.items :type => "array" do
#items.each do |item|
xml << render(:partial => 'shared/partial.xml.builder', :locals => { :item => item })
end
end
And yeah... Full file name works here as well...