I have heard that it's best not to actually have any html in your helpers; my question is, Why not? And furthermore, if you were trying to generate an html list or something like that, how can I avoid actual tags?
Thanks!
-fREW
My advice - if it's small pieces of HTML (a couple of tags) don't worry about it. More than that - think about partials (as pulling strings of html together in a helper is a pain that's what the views are good at).
I regularly include HTML in my helpers (either directly or through calls to Rails methods like link_to). My world has not come crashing down around me. In fact I'd to so far as to say my code is very clean, maintainable and understandable because of it.
Only last night I wrote a link_to_user helper to spits out html with normal link to the user along with the user's icon next to it. I could have done it in a partial, but I think link_to_user is a much cleaner way to handle it.
I don't see that there's anything wrong with it. The majority of the rails helpers generate HTML code (which is their purpose) - to me this implies that's what you're supposed to do yourself.
There is however the ever-present issue of code readability. If you have a helper which just builds a big string of raw HTML, then it's going to be hard to understand. While it's fine to generate HTML in helpers, you should do it using things like content_tag, and render :partial rather than just return %Q(<a href="#{something}">#{text}>)
This isn't a full answer to your question, but you can create html in your tags via the content_tag method. My guess as to why would be cleanliness of code.
Also, content_tag allows you to nest tags in blocks. Check out this blog post on content_tag.
On Rails 3 you can use *html_safe* String method to make your helper methods return html tags that won't be escaped.
As mentioned before, helpers are generally thought to be used as business logic, for doing something that drives view code, but is not view code itself. The most conventional place to put things that generate snippets of view code is a partial. Partials can call a helper if needed, but for the sake of keeping things separated, it's best to keep business in the helper and view in the partial.
Also, bear in mind this is all convention, not hard and fast rules. If there's a good reason to break the convention, do what works best.
I put html into partials usually.
Think about semantics. If you put html in a string, you lose the semantic aspect of it: it becomes a string instead of markup. Very different. For example, you cannot validate a string, but you can validate markup.
The reason I wanna put html in a helper instead of partial (and how I found this thread) is terseness. I would like to be able to write =hr instead of =render 'hr'.
To answer the question I didn't ask ;-) : to un-escape HTML in a helper, try this
def hr
raw '<hr />'
end
Related
I am working on a Rails application whose HAML templates frequently make use of a routine called sanitize. I have deduced from context that this routine sanitizes user-controlled HTML. Example:
# views/feed_items/_about.html.haml
%h3 Summary:
.description
= sanitize #feed_item.description
I want to make this routine add 'rel=nofollow' to all outbound links, in addition to what it's already doing. What is the most straightforward way to do that?
N.B. I am not having any luck finding the definition of this method, or the official configuration knobs for it. The vendor directory has two different HTML sanitizer gems in it and I can't even figure out which one is being used. This is a large, complicated web application that I did not write, and I barely understand Ruby, let alone all of Rails' extensions to it. Please assume I do not know any of the things that you think are obvious.
The sanitizer will strip out the rel tags if they exist.
I ran into a similar issue and added an additional helper method - clean_links to the ApplicationHelper module, and called it after sanitizing the content.
# application_helper.rb
def clean_links html
html.gsub!(/\\2')
html.html_safe
end
This method looks for all <a> tags, and adds rel="nofollow". The html_safe method is necessary or else the HTML will be displayed as a string (it's already been sanitized).
This solution treats all links equally, so if you only want this for links pointing outside the domain, you'll have to update the REGEX accordingly.
In your view: <%= clean_links sanitize(#something) %>
So, first the content is sanitized, then you add the rel="nofollow" tag before displaying the link.
Actually there's a built-in way:
sanitize "your input", scrubber: Loofah::Scrubbers::NoFollow.new
I am creating a method to generate an XML document via Ruby Builder.
Where should I put the method that created the XML markup? Should it be a method on the model?
I plan to have the XML document pull from multiple models via associations, so I think I need to have it in the controller or a helper, but I would like some in put on the best place.
If it's practical for you, I'd put it in your views folder. This lets you follow the traditional pattern of "load stuff in the controller; render stuff in the view," and has the extra perk of keeping what's probably a messy and very specific method in its own file and out of the way.
Now, I'm not sure if there's a Ruby Builder template format, but you could always just wrap your code in <%= ... %> and treat it like a regular ERB file - should work about the same.
Hope that helps!
I often see, touted as one of the big benefits of ASP.NET MVC, the fact that it gets you closer to the actual page markup, as opposed to the pseudomarkup of WebForms.
If that's the case, then why does the HtmlHelper exist? It seems like all this LabelFor, TextBoxFor stuff is just as much pseudomarkup as <asp:Label> and <asp:TextBox> are in WebForms.
What am I missing? Why is there an HtmlHelper class? Do people use it in real life?
Whilst you are right in saying that HtmlHelper functions do abstract away the exact markup rendered, the big advantage of this is that the views are more DRY and you are able to pass in the necessary parameters to the functions in order to customise the HTML generated.
Rather than having to manually type out a full <input /> tag, complete with value=<%= Model.Property %>, Html.TextBoxFor is a more concise way of outputting the same thing. And as with all DRY approaches, if you need to change the HTML for all textboxes in your application (e.g. to output a new attribute) all you need to do is change the HtmlHelper method.
They seem to me a little like simple, lightweight partial views that are just designed to output some consistent HTML given some input.
The point of HTML helpers is to eliminate tedious and repetitive <input> tags.
Unlike server-side controls, HTML helpers emit raw, (fairly-)predictable HTML.
It simplifies the creation of those and allows them to be strongly named. Of course people use this!
I don't quite agree with the answers, and i somehow agree with you.
You can think of the helpers as pre-built custom controls, if you want to have some code generated you can make use of the helpers, if you want a clean approach and get closer to the html then don't.
The important point here is that MVC allows you to get close to the html, but does not limit you to only that.
You can create your own helper that created the markup you wish, and use that instead.
At the end of the day, it comes down to your own preference, and you can choose to or choose not to be closer to the html
I have a 'template' system in my CMS rails app. Basically the whole HTML template is stored in a database column and it has key code in the string (like <!--THEME_Body-->) that gets replaced with content generated by the application.
I use an actual layout to render the template. All that is in the layout is:
<%= generate_theme.gsub!('<!--THEME_Body-->', yield) -%>
That helper takes the correct theme and further gsubs other area like Meta data and Breadcrumbs.
I'm just wondering if there's a better way to go about this? Perhaps using content_for or something like that?
That's a pretty good way of going about it, although I would make use of Ruby's sexy syntax to combine all the lines into something a little more syntactically correct - it speeds the script up and it looks a damn sight nicer too!
tags = {
'<!--THEME_Body-->' => yield,
'<!--THEME_Head-->' => yield(:head),
'<!--STYLESHEET-->' => stylesheet_link_tag('application')
}
tags.each { |str, rep| generate_theme.gsub!(str, rep) }
Bear in mind that this code should not go in a view - it should ideally be put in a model, as it's to do with the application's data, but it could also go in a helper somewhere. If it's an instance variable in a model, you could just call
generate_theme.parse
And that code could be executed - it looks a lot better and sticks to the standard MVC convention of cleaning up the view as much as possible.
Jamie
I created an html helper
Html.BreadCrumb(IDictionary<string, string> crumbs)
Where the first string is the label and the second string is the URL.
The helper creates the html required (an unordered list, some classes for first element, current element, last element, dead element and separators etc)
All working nice, but I do this by creating a stringbuilder, pumping all the html in it and returning the stringbuilder's content as a string.
I figure in this example it doesn't matter all that much, but what if an Html helper is churning out a big load of html? Isn't there a way to push it to Response.Write instead of a stringbuilder?
Or any other issues/improvements you have?
BTW we have a naming pattern in ASP.NET MVC for the various rendering techniques.
Helpers that return a string of what they are should be named what they are. For example, Url.Action() and Html.TextBox() return those exact items. Thus, these helpers should be used with the <%= %> syntax.
Helpers that render directly to the output stream should start with Render. For example, Html.RenderPartial(). These are used with the <% %> syntax.
Helpers that use the IDisposable pattern should be named with Begin/End. For example, Html.BeginForm() and Html.EndForm(). These should also be used with the <% %> syntax.
Thanks,
Eilon
It certainly is possible to use Response.Write instead of returning a string; see the source for System.Web.Mvc.Ajax.Form (in AjaxExtensions.cs) in the MVC source for an example.
You then call the helper with <% instead of <%=.
Will it be any faster? I doubt it, but it's easy to test.
I don't think you will have any performance problems as long as the size of the HTML pages you produce is reasonable. And when you really start to create pages of megabytes in size, then you should ask yourself, why are you creating such huge HTML files?