Where should I put XML Builder code? - ruby-on-rails

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!

Related

Where to put reusable HTML code in rails?

I'm writing a rails app that allows users to delete records of various sorts. After pressing a delete button, I'd like to show a confirm dialog using bootstrap. I'd like to use this same dialog in several of my views, so I'll need to include the same HTML snippet in most of my pages.
I'm new to rails and I'm still learning the conventions. Can anyone suggest the best (or standard) place to put the dialog code? Should it be a partial in views/layouts/_confirm_delete_dialog.html.erb, should it go inside application.html.erb, or should I put it somewhere else?
Thanks in advance for your advice,
D.
Within your Views folder, you can create a general folder (called whatever you want). If you have a variable that you need to pass through to the general layout, you can definitely do so, but you will want to make sure that the information that you're passing through doesn't cause conflicts with the fields pulled from the model. For example, if you have two models and one has a public field but the other doesn't then you will not want to have a generic message that is using the public field. However, something like the created_at or updated_at would be okay.
You would use a code similar to,
<%= render 'general/simple_message', :f => f %>
In your views folder, you would have a directory called general and a file called _simple_message.html.erb.

how do i dynamically change my format rendering engine in rails?

My default templating engine is haml, but I would to sometimes change it to erb if i specify a specific parameter?
For example, I am pasting in some html code and would just like to test the code without HAML complaining about its format.
Any idea how to do this?
do something like:
if params[:render_erb]
render 'file.html.erb'
else
render 'file.html.haml'
end
and call the action with ?render_erb=true
or
render "file.html.#{params[:render]}" ir params[:render]
and call it ?render=haml or ?render=erb (or nothing and it will use the default
at the end of the controller's action that you are using
Am I wrong that you simply need to save file as your_file.html.erb instead of your_file.html.haml?
You can use different templates in the same application, and you can use different template engines for views, partials, and layouts, but as far as I know you can't duck in and out of multiple template engines within the same template file.
If you just want to drop some code in using a different template language, then I'd put it in a separate partial. That certainly seems easiest in this particular case.

Where should I place code which generates Excel spreadsheet?

I am using spreadsheet gem to generate native Excel file. This is not CSV, XML file. Ordinary Ruby code is used to create the file. The generated Excel file (kept in StringIO) is forwarded to a client using send_data method. I need send_data method because of its parameters like disposition.
The data for the Excel is retrieved in controller method just like for ordinary HTML, JS requests. However I placed the code to generate the spreadsheet in controller protected method. Not in a view as I should.
Is there an elegant solution to above problem compliant with MVC design pattern?
Update: There is no popular and accepted by all solution to above problem but at least I know all possible ideas.
The lib directory is meant as a place for code that isn't strictly part of the MVC structure, but will be needed by multiple models, views, or controllers. It can be brought in with a require when needed.
However, if you only need the code in a single controller, you'd be just as well off putting it into that controller's helper. That way it's auto-loaded and at your fingertips. Plus, it makes sense: it's code to help a specific controller.
Either way, don't leave it in your controller or try to wedge it into your view.
Create an excel library in your lib folder in which you include your xls generation routine as well as a method that overrides ActionController's render method.
In a model that should be rendered as xls implement a method called to_excel method which generates a hash that you can provide to your xls routine.
Doing it this way, you'll get something really "Railsy". In your controller you'll just call
render :xls => #model
i just did this today for my app hope this helps for an excel o/p ; never used any plugin
controller:
def export
pr = Program.find(session[:pr_id])
headers['Content-Type']="application/vnd.ms-excel"
headers['Content-Dispositon']='attachment;filename="report.xls"'
#voucherdatas = Voucherdata.find_all_by_pr_name(pr.pr_name)
end
view: export.html.erb
manager
"reports/voucherdatas", :object =>#voucherdatas %>
routes.rb
map.resources :reports ,:collection =>{:export =>:get}
whereever u want the link give
link_to "Export As Excel", export_reports_url, :popup=>true

Parsing a 'template' in rails (alternatives to gsub)

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

Why shouldn't Helpers have html in them?

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

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