As my first Rails app, I'm trying to put together a simple blog application where users can vote on posts. I generated the Blogpost scaffold with a integer column (entitled "upvote") for keeping track of the vote count.
In the Blogpost model, I created a function:
def self.voteup
blogpost.upvote += 1
end
On the Blogpost index view, I'd like to create a link that does something like:
link_to "Vote up" self.voteup
But this doesn't seem to work. Is it possible to create a link to a method? If not, can you point me in the right direction to accomplish this?
What you are trying to do goes against the MVC design principles. You should do the upvoting inside a controller action. You should probably create a controller action called upvote. And pass in the post id to it. Inside the controller action you can retrive the post with the passed in ID and upvote it.
if you need serious voting in your rails app you can take a look at these gems
I assume that you need to increment upvote column in blogspots table. Redirection to a method is controllers job and we can give links to controller methods only. You can create a method in Blogposts controller like this:
def upvote_blog
blogpost = Blogpost.find(params[:id])
blogpost.upvote += 1
blogpost.save
redirect_to blogpost_path
end
In your index page,
<% #blogposts.each do |blogpost| %>
...
<%= link_to "Vote up", :action => upvote_blog, :id => blogpost.id %>
...
<% end %>
You can not map Model method to link_to in view. you can create an action in controller to access the Model method and map it using link_to, also if the action is other than CRUD, then you should define a route for the same in route.rb
Related
<%= link_to "Profile", #user %>
# => Profile
if i use the above code replacing "Profile" with "Category" and #user with #category/#subcategory what do I then point the html link a href etc to?
Check the documentation for this method here.
The first parameter of the link_to method is the displayed text.
Secondly, you can pass in a single instance of an object which will generate a link to the objects #show action.
You may however pass a link explicitly (most common in my opinion).
This can be done by using the Rails path-helpers (user_path(#user)) or by passing in a string.
In your example, if you exchange #user with #category it would link to the categories #show action instead (Assuming you have a Category model and #category isn't nil.
Again, have a look at the documentation of the link_to method and get familiar with it.
I've got a table full of information at the moment, Ideally i need the information from a database table to be viewed via a link.
I only have the controller and some standard html (the html is just a h1 tag at the moment)
The HTML will be standard throughout like a template.
The way i'm seeing what i want in my head is the users will get a link which would be events_prev/{{id from DB here}} and depending on the ID the information on the page will be populated from the corrisponsing DB Row
Heres my controller
class Events::EventsPrevController < ApplicationController
def index
#events = Event.where(id: id)
end
def show
render :nothing => true
end
end
Sorry if its super confusing.
Welcome to rails.
Ok, there's a couple of things that will get you in the right directions. Firstly, you REALLY need to do a little reading to understand how the controller and the routes and the views are linked together in rails, that'll help you tons.
But moving on to your specific issues:
Parameters:
All data passed via a url (get, post, put, doesn't matter the method) is available in the controller in an array object called params - So that means when want to access the data the user submitted, you'll use something like
#event = Event.where(id: params[:id])
Routes:
It looks like you're trying to use the index page. In rails index is a RESTful route which generally points to a collection of model objects. The show route will point to an individual object so you should instead make your link point to the show path instead of the index path.
You can view the routes available on a model on a command line using:
bundle exec rake routes
An example of what your routes might look like:
prev_events GET /prev_events(.:format) prev_events#index
POST /prev_events(.:format) prev_events#create
new_prev_event GET /prev_events/new(.:format) prev_events#new
edit_prev_event GET /prev_events/:id/edit(.:format) prev_events#edit
prev_event GET /prev_events/:id(.:format) prev_events#show
PATCH /prev_events/:id(.:format) prev_events#update
PUT /prev_events/:id(.:format) prev_events#update
DELETE /prev_events/:id(.:format) prev_events#destroy
Link
Based on the routing table, you now should see that the link you need your users to click on might look like this (given that event is your object:
<%= link_to event.title, event_path(event.id) %>
or shortcutted
<%= link_to event.title, event %>
View
For the view this is entirely dependent on the data in the Event model. Since the data is stored in #event you'll simple use the attributes on the event model to render the html however use like, e.g.
<h3><%= #event.title %></h3>
<span><%= #event.start_time %></span>
You should read up on Rails controllers: by default the action index is used to show all of the records and what you're talking about should belong to the show action. The default routes take care of the id passing to your show action.
Index action is mean to show list of items in view and Show action is used to show a single item.
what you are doing in index is actually mean to be in show action.
Reason:
#events = Event.where(id: id)
this line will give u a single record in every case it means it should be in Show action.
your code should look like:
def show
#event = Event.find(params[:id])
[your logic: what you want to do with that #event]
end
I have a Character model that has a show page. On the show page, I have a loop of comments that are dynamically generated via a partial. In that comments partial, I have another partial for votes, which contains voting buttons. Naturally, I want to allow votes on comments.
I am unsure how to get the comment object into the votes controller (or VotesController module, depending on the implementation) for creating a vote.
Getting the character object id to the votes controller is simple enough, since the actual view is the character show page, but obtaining a specific comment's id that is genrated from a partial, by clicking a vote button in a partial that is nested in the comments partial is causing me to draw a blank for the syntax of accessing that comment.
(I am using acts_as_votable for votes, and acts_as_commentable for comments.)
app/views/characters/show.html.haml
= render partial: 'comments/comment', collection: #comments, as: :comment
app/views/comments/_form.html.haml
.comment{ :id => "comment-#{comment.id}" }
%hr
= render partial: 'votes/vote_comment'
%h4
#comment body
app/views/votes/_vote_comment.html.haml
.vote-comment-buttons
= link_to image_tag("upvote.png"), votes_upvote_path(), method: :post, remote: true
= link_to image_tag("downvote.png"), votes_downvote_path(), method: :post, remote: true
app/controllers/votes.html.haml
VotesController < ApplicationController
def upvote
# Need the specific comment or comment id whose vote button was clicked.
end
def downvote
# Need the specific comment or comment id whose vote button was clicked.
end
end
Well, here are the basic tips:
You can not pass ruby objects through HTTP, but you can pass id and type of them to build them in your controller.
Even when you type something like comment_path(comment), only id of that comment is passed to your action. That is easily checked by observing your action code (it should contain something like Comment.find(params[:id])).
Passing any desired amout of additional parameters can be done with just providing them to your route helpers, like that: some_voting_path(commentable_id: 14, commentable_type: 'character').
You can access that params inside of your action with params['commentable_type'] or whatever values you pass with your URL. In case you follow passing id and type approach, you should be able to do some metaprogramming:
def upvote_method
model = params[:commentable_type].camelize.constantize # => e.g., Post
object = model.find(params[:commentable_id]) # => post object
# here goes your inner logics
end
Beware that in case you send your request using GET method, these params are gonna be shown in your browser URL. However, you should not use GET for your purpose here, as voting changes the state of objects in your database.
So, I have search form, and search is avaliable obviously from any page.
I thought that it makes sense, that such action from application controller is placed in layouts/views folder.
But I just don't get- Rails doesn't see it. So I can't do this? How then should I provide action, avaliable from any page?
Code:
def tests_search
#tests=Test.test_search(params[:query])
respond_to do |format|
format.html
end
end
Route:
search_tests GET /search_tests(.:format) application#tests_search
Form:
<%= form_tag search_tests_path, {:id=>'test_search',:method => :get} do%>
Error:
Unknown action
The action 'tests_search' could not be found for ApplicationControllerr
You should create a new search controller. Use rails g controller search index which will create a search controller with a index action (you could also call the action something like result). Then add a search/_form.html.erb file in your search view folder, with the form:
<%= form_tag search_path, {:id=>'test_search',:method => :get} do |f| %>
and render this in your layout/application.html.erb where you want it to be:
<%= render "search/form" %>
This way you have a search form on any pages, that uses the SearchController to handle the search requests.
I would recommend using other controller to do this. It can be for example SearchController even if there will be only one method.
Notice that ApplicationController is controller that every other controller in application inherits from by default. So if it wouldn't be the case, it could make sense, but now every controller will inherit your test_search action, which is not desired.
If your search form will be a partial, then there is no difference whether this is in ApplicationController or in any other controller. You just have to point to right route.
Initially you have to explain yourself the flow. What you need is some partial which is rendered on all pages, and if a user adds some input to it and submits, he gets some output. Right? Good. So you start by creating a new partial somewhere in
app/views/shared/_search.html.erb
Then, you create your route in routes.rb to point to a controller's action. You don't have to place this in application_controller. Instead, create your search_controller.rb and create some action which responds to the form submission there.
Whenever you want to render your search form on other pages, you simply call render partial (more on that here) with something like
<%= render "shared/search" %>
This is good if you created the file above. Make sure your action exists and the name is correct, in your case it should be:
def test_search
...
end
Good luck.
I have two models Station and Broadcast. Broadcast belongs_to Station and has a station_id column.
I don't know how to make new method in BroadcastController to expect the station_id value and how to create a new Broadcast with right station_id in it.
I'd recommend against using a link_to here. Using a 'get' action to change/add data on the server is generally frowned upon. Also, I wouldn't use the 'new' action, as it's used by convention in a Rails Restful route to present a form, not actually persist data. All that said, the simple answer to your question is to pass a value through the link_to helper like so:
link_to 'Add broadcast', new_broadcast_path(:station_id => station.id)
...and your 'new' method on BroadcastsController would do:
def new
#broadcast = BroadCast.new(:station_id => params[:station_id])
if #broadcast.save
flash[:notice] = "New broadcast created!"
redirect :back # or whatever
else
# etc.
end
end
But, again, this is not the right way to do this. What you probably want to do is stay within the Rails (and web) conventions and use a form to create the new broadcast record by way of the 'create' action on the controller. You might place this form next to your stations on the index view which presents a button that points to the correct 'create' action of BroadcastsController, and uses a hidden_field to set the station_id. Something like (EDIT: better use of hidden_field):
<% form_for :broadcast do |f| %>
<%= f.hidden_field :station_id, :value=> station.id %>
<%= submit_tag 'Add broadcast' %>
<% end %>
Assuming you've set a restful route in routes.rb for broadcast like:
map.resources :broadcasts
...then your form will automatically point to a 'create' action on BroadcastsController, which you should write to look something like:
def create
#broadcast = BroadCast.new(params[:broadcast])
if #broadcast.save
# etc., etc.
end
The Rails Guides are a good place to get more comfortable with the Rails controller actions. I'd also spend some time looking over the RESTful actions and how they're used in Rails as well.
You actually do specify a station_id for your Broadcast model, such as
script/generate scaffold broadcast name:string station_id:integer ...
so when you add a broadcast record, it will ask you for a station_id.