Question

I’m curious about the best practice in creating web services which support both XML and JSON output.

At the moment, my service is very XML oriented (see below), but I want to add JSON support.

Here’s one example:

  def create
    render_authentication_error and return if !@user
    render_parameter_not_found_error("item") and return if params[:item].nil?
    render_parameter_not_found_error("name") and return if params[:item][:name].blank?
    @item = Item.new(params[:item])
    begin 
      if !@item.save 
        raise "Item not saved" 
      end 
    rescue 
      render_resource_not_saved_error("Error saving #{@item.name}")
    else 
      render_resource_created(:location => item_path(@item))
    end 
  end

There are helper methods in ApplicationController that renders XML accordingly.

I’m not sure how to go about adding respond_to block here since I need to do validations. Is there a way to retrieve format in a controller outside of respond_to block so that I can output error messages in a given format as well?

respond_to do |format|
  format.html { render :json => @item.to_json }
  format.xml { render :xml => @item }
end 

Let me know if you need any clarification.

UPDATE I suppose I’m looking something similar to respond_with in Rails 3. I’m on Rails 2.3 still.. I wonder if it can be done in 2.3?

UPDATE Inherited Resources seems like what I’m looking for.

Thanks!

Answer 1

Replace @person with @item, but there’s the idea:

respond_to do |format|
  if @person.save 
    format.html { 
      flash[:notice] = 'Person was successfully created.'
      redirect_to @person 
    }
    format.js { render :json => @person, :status => :created, :location => @person} 
    format.xml  { render :xml => @person, :status => :created, :location => @person }
  else
    format.html { render :partial => "form" }
    format.js { render :json=>@person.errors, :status => :unprocessable_entity }
    format.xml  { render :xml => @person.errors, :status => :unprocessable_entity }
  end
end