I'm currently working on an ERB View class for a gem. With this class I would like to have some helper methods for ERB templates.
It's okay about basic helpers like h(string). I found erbh gem who help me to understand more how context works.
But now I'm trying to create a content_for method like there is in Rails or Sinatra.
On first time I was using simple Proc to capture the view block and then just calling call method to print it. It was working enough at the beginning.
But after having completed views I saw wired thinks, some content are printed multiple times.
So I take a look on the Sinatra ContentFor helper to understand how they did it and I copy some methods of this helper. I have no errors, but the block return are always empty... and I don't really know why.
My knowledge about ERB are not good enough to know how ERB buffering works.
Code
Here a gist who explain the status of my code. I extracted the code from my library and simplified it a bit.
https://gist.github.com/nicolas-brousse/ac7f5454a1a45bae30c52dae826d587f/66cf76c97c35a02fc6bf4a3bc13d8d3b587356de
What I would like?
I just would like to have content_for methods works like they do with Rails and Sinatra.
Thanks!
After reading this blog article I finally found why it wasn't working. I don't know if I did it in the best way and cleaner way but it works.
So the bug was mainly from the ERB initilization. By using a property instead a local variable as eoutvar it now works.
erb = ERB.new(str, nil, "<>", "#_erbout")
I also change a bit the capture method who is used by content_for helper.
It looks like this now (gist)
def content_for(key, content = nil, &block)
block ||= proc { |*| content }
content_blocks[key.to_sym] << capture_later(&block)
end
def content_for?(key)
content_blocks[key.to_sym].any?
end
def yield_content(key, default = nil)
return default if content_blocks[key.to_sym].empty?
content_blocks[key.to_sym].map { |b| capture(&b) }.join
end
def capture(&block)
#capture = nil
#_erbout, _buf_was = '', #_erbout
result = yield
#_erbout = _buf_was
result.strip.empty? && #capture ? #capture : result
end
def capture_later(&block)
proc { |*| #capture = capture(&block) }
end
Related
My goal is to set an instance variable using AFMotion's AFMotion::HTTP.get method.
I've set up a Post model. I would like to have something like:
class Post
...
def self.all
response = AFMotion::HTTP.get("localhost/posts.json")
objects = JSON.parse(response)
results = objects.map{|x| Post.new(x)}
end
end
But according to the docs, AFMotion requires some sort of block syntax that looks and seems to behave like an async javascript callback. I am unsure how to use that.
I would like to be able to call
#posts = Post.all in the ViewController. Is this just a Rails dream? Thanks!
yeah, the base syntax is async, so you don't have to block the UI while you're waiting for the network to respond. The syntax is simple, place all the code you want to load in your block.
class Post
...
def self.all
AFMotion::HTTP.get("localhost/posts.json") do |response|
if result.success?
p "You got JSON data"
# feel free to parse this data into an instance var
objects = JSON.parse(response)
#results = objects.map{|x| Post.new(x)}
elsif result.failure?
p result.error.localizedDescription
end
end
end
end
Since you mentioned Rails, yeah, this is a lil different logic. You'll need to place the code you want to run (on completion) inside the async block. If it's going to change often, or has nothing to do with your Model, then pass in a &block to yoru method and use that to call back when it's done.
I hope that helps!
How can I use views and layouts with Ruby and ERB (not Rails)?
Today i'm using this code to render my view:
def render(template_path, context = self)
template = File.read(template_path)
ERB.new(template).result(context.get_binding)
end
This works very well, but how can I implement the same function, but to render the template inside a layout? I want to call render_with_layout(template_path, context = self), and so that it will have a default layout.
Since you tagged it with Sinatra I assume that you us Sinatra.
By default you view is rendered in your default layout called layout.erb
get "/" do
erb :index
end
This renders your view index with the default layout.
If you need multiple layouts you can specify them.
get "/foo" do
erb :index, :layout => :nameofyourlayoutfile
end
* If you don't use Sinatra you may want to borrow the code from there.
If you use the Tilt gem (which I think is what Sinatra uses) you could do something like
template_layout = Tilt::ERBTemplate.new(layout)
template_layout.render {
Tilt::ERBTemplate.new(template).render(context.get_binding)
}
If you are using Sinatra so it has a good docimentation and one of the topics it's nested layouts (see Sinatra README)
Also good idea to use special default layout file (layout.haml or layout.erb in your view directory) This file will be always use to render others. This is example for layout.haml:
!!!5
%html
%head
##<LOADING CSS AND JS, TILE, DESC., KEYWORDS>
%body
=yield ## THE OTHER LAYOUTS WILL BE DISPALYED HERE
%footer
# FOOTER CONTENT
Thanks for all the answers!
I solved it finally by doing this, I hope someone else also can find this code useful:
def render_with_layout(template_path, context = self)
template = File.read(template_path)
render_layout do
ERB.new(template).result(context.get_binding)
end
end
def render_layout
layout = File.read('views/layouts/app.html.erb')
ERB.new(layout).result(binding)
end
And I call it like this:
def index
#books = Book.all
body = render_with_layout('views/books/index.html.erb')
[200, {}, [body]]
end
Then it will render my view, with the hardcoded (so far) layout..
I'm writing a wrapper for an XML API using Nokogiri to build the XML for submission.
In order to keep my code DRY, I'm using custom blocks for the first time and just getting to grips with how to pass variables back and forth and how that works.
What I'm doing at the moment is this:
# Generic action
def action(xml, action_title, test=false)
xml.request do
xml.login do
xml.username("my_user")
xml.password("my_pass")
end
xml.action(action_title)
xml.params do
yield
end
end
end
# Specific action
def get_users(city = "", gender = "")
build = Nokogiri::XML::Builder.new do |xml|
action(xml, "getusers") do
xml.city(city) unless city.blank?
xml.gender(gender) unless gender.blank?
end
end
do_stuff_to(build)
end
Ideally, I'd like to the specific action method to look like this:
def get_users(city = "", gender = "")
action("getusers") do |xml|
xml.city(city) unless city.blank?
xml.gender(gender) unless gender.blank?
end
end
In doing so, I'd want the other logic currently in the specific action method to be moved to the generic action method with the generic action method returning the results of do_stuff_to(build).
What I'm struggling with is how to pass the xml object from action() back to get_users(). What should action() look like in order to achieve this?
Turns out this was quite simple. The action method needs to be changed so it looks like this:
def action(action_title)
build = Nokogiri::XML::Builder.new do |xml|
xml.request do
xml.login do
xml.username("my_user")
xml.password("my_pass")
end
xml.action(action_title)
xml.params do
yield xml
end
end
end
do_stuff_to(build)
end
That meant the specific action method could be called like this to the same effect:
def get_users(city = "", gender = "")
action("getusers") do |xml|
xml.city(city) unless city.blank?
xml.gender(gender) unless gender.blank?
end
end
I wanna to write code like this
require 'sinatra'
class MyModel
def edit(request)
# ...
updateOK = true
redirect '/article_view' if updateOK
:article_edit
end
end
get '/article_view' do erb :article_view end
get '/article_edit' do erb :article_edit end
post '/article_edit' do
model = MyModel.new
erb model.edit(request)
end
but it dosn't work, it tips that: undefined method `redirect' for #<MyModel:0x24e3910>
Is there any way to invoke redirect method in the my custom model?
Haha, I know how to make the code works, despite it write in wrong way.
require 'sinatra'
class MyModel
def edit(context)
# ...
updateOK = true
context.redirect '/article_view' if updateOK
:article_edit
end
end
get '/' do erb :index end
get '/article_view' do erb :article_view end
get '/article_edit' do erb :article_edit end
post '/article_edit' do
model = MyModel.new
erb model.edit(self)
end
Don't. The model is not responsible for routing or redirecting.
Also, your post route looks borked. You are sending POST data to it which it then passes to the model. The model is created and saved. You can split up these two and if the model.save method returns true you redirect.
post '/model/new' do
model = Model.new params
redirect to("/model/#{model.id}") if model.save
end
Not everybody likes to forfard params to the model, so be careful about that too.
For edits you'd normally use the PUT method because you know the models address. So be careful to not mix them up (unless you know what you're doing) It will save you a lot of thinking.
I'm trying to get a list of active record results to display as a plist for being consumed by the iphone. I'm using the plist gem v 3.0.
My model is called Post. And I want Post.all (or any array or Posts) to display correctly as a Plist.
I have it working fine for one Post instance:
[http://pastie.org/580902][1]
that is correct, what I would expect. To get that behavior I had to do this:
class Post < ActiveRecord::Base
def to_plist
attributes.to_plist
end
end
However, when I do a Post.all, I can't get it to display what I want. Here is what happens:
http://pastie.org/580909
I get marshalling. I want output more like this:
[http://pastie.org/580914][2]
I suppose I could just iterate the result set and append the plist strings. But seems ugly, I'm sure there is a more elegant way to do this.
I am rusty on Ruby right now, so the elegant way isn't obvious to me. Seems like I should be able to override ActiveRecord and make result-sets that pull back more than one record take the ActiveRecord::Base to_plist and make another to_plist implementation. In rails, this would go in environment.rb, right?
I took the easy way out:
private
# pass in posts resultset from finds
def posts_to_plist(posts)
plist_array = []
posts.each do |post|
plist_array << post.attributes
end
plist_array.to_plist
end
public
# GET /posts
# GET /posts.xml
def index
#posts = Post.all
##posts = [{:a=>"blah"}, {:b=>"blah2"}]
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => posts_to_plist(#posts) }
end
end
I found this page searching for the same answer. I think you have the right approach, though I'm also a newbie (on Rails) and not sure the right way to do it. I added this to application_helper.rb. Seems to work.
require 'plist'
module ApplicationHelper
class ActiveRecord::Base
public
include Plist::Emit
def to_plist
self.attribute_names.inject({}) do |attrs, name|
value = self.read_attribute(name)
if !value.nil?
attrs[name] = value
end
attrs
end
end
end
end
According to the plist project README, you should implement "to_plist_node", as opposed to "to_plist".
You should also mixin Plist::Emit to your ActiveRecord class.