一、前言 出于数据安全性考虑,某些破坏性链接应该使用post请求,比如一个删除记录的请求。除了脚本确认以外,服务端还需要post验证,因为脚本是可以绕过的。想像你的页面上有一个删除链接,只作了客户端脚本确认(老的scaffold生成代码有这问题),被google找到了,它一个请求就会让你的数据丢失。rails对于这类请求的处理,是通过verify方法,默认的scaffold生成代码有如下内容:
<!--<br><br>Code highlighting produced by Actipro CodeHighlighter (freeware)<br>http://www.CodeHighlighter.com/<br><br>--> # GETs should be safe (see http://www.w3.org/2001/tag/doc/whenToUseGet.html) verify :method => :post, :only => [ :destroy, :create, :update ], :redirect_to => { :action => :list }只有post请求时,destroy才会被允许,如果是get,就会被重定向到list。二、实现我自己实现了一个method_dispatch,当请求一个/test/a时,如果是get,则会直接执行TestController#a;如果是post,则会执行TestController#a_post,a_post应该是protected,这样不会直接暴露给客户,get/post就严格区分开来了。method_dispatch现在是直接实现在ApplicationController中的,代码如下:
<!--<br><br>Code highlighting produced by Actipro CodeHighlighter (freeware)<br>http://www.CodeHighlighter.com/<br><br>-->class ApplicationController < ActionController::Base protected def self.method_dispatch(*methods) before_filter :do_method_dispatch, :only => methods.flatten.map(&:to_sym) end private def do_method_dispatch if request.post? && respond_to?("#{action_name}_post") eval("#{action_name}_post") return false end endend由于ApplicationController里面的方法会被子类继承到,所以必须严格处理访问级别。使用如下:
<!--<br><br>Code highlighting produced by Actipro CodeHighlighter (freeware)<br>http://www.CodeHighlighter.com/<br><br>-->class TestController < ApplicationController method_dispatch :a def index end def a render :text => 'get a' end def b render :text => 'get b' end protected def a_post render :text => 'post a' end def b_post render :text => 'post b' endend注意a_post,b_post要被保护起来防止直接调用。index.rhtml里面演示了使用get和post的情况:
<!--<br><br>Code highlighting produced by Actipro CodeHighlighter (freeware)<br>http://www.CodeHighlighter.com/<br><br>--><%= link_to "Get a", :action => 'a' %><%= link_to "Post a", {:action => 'a'}, {:post => true} %><br /><%= link_to "Get b", :action => 'b' %><%= link_to "Post b", {:action => 'b'}, {:post => true} %><br />rails在处理有:post => true参数的link_to时,生成的代码如下:
<!--<br><br>Code highlighting produced by Actipro CodeHighlighter (freeware)<br>http://www.CodeHighlighter.com/<br><br>--><a href="/test/a" onclick="var f = document.createElement('form'); this.parentNode.appendChild(f); f.method = 'POST'; f.action = this.href; f.submit();return false;">Post a</a>经测试上面代码工作情况良好,使用get访问/test/a时,显示get a;使用post访问时,显示post a。使用get访问/test/b时,显示get b;使用post时,显示get b,因为b并没有使用method_dispatch。三、应用下面的posts_controller.rb是scaffold生成的:
<!--<br><br>Code highlighting produced by Actipro CodeHighlighter (freeware)<br>http://www.CodeHighlighter.com/<br><br>-->class PostsController < ApplicationController def index list render :action => 'list' end # GETs should be safe (see http://www.w3.org/2001/tag/doc/whenToUseGet.html) verify :method => :post, :only => [ :destroy, :create, :update ], :redirect_to => { :action => :list } def list @post_pages, @posts = paginate :posts, :per_page => 10 end def show @post = Post.find(params[:id]) end def new @post = Post.new end def create @post = Post.new(params[:post]) if @post.save flash[:notice] = 'Post was successfully created.' redirect_to :action => 'list' else render :action => 'new' end end def edit @post = Post.find(params[:id]) end def update @post = Post.find(params[:id]) if @post.update_attributes(params[:post]) flash[:notice] = 'Post was successfully updated.' redirect_to :action => 'show', :id => @post else render :action => 'edit' end end def destroy Post.find(params[:id]).destroy redirect_to :action => 'list' endend可以看到,它添加了verify,但action过多,需要在verify中维护一份对应方法名,稍不留神就容易出现漏洞。我把它修改如下:
<!--<br><br>Code highlighting produced by Actipro CodeHighlighter (freeware)<br>http://www.CodeHighlighter.com/<br><br>-->class PostsController < ApplicationController method_dispatch :new, :edit, :destroy def index list render :action => 'list' end def list @post_pages, @posts = paginate :posts, :per_page => 10 end def show @post = Post.find(params[:id]) end def new @post = Post.new end def edit @post = Post.find(params[:id]) end def destroy render :inline => <<->EOS Are you sure? <%= link_to "Yes", {}, :post => true %> <%= link_to "No", :action => 'edit', :id => params[:id]%> EOS end protected def destroy_post Post.find(params[:id]).destroy redirect_to :action => 'list' end def edit_post @post = Post.find(params[:id]) if @post.update_attributes(params[:post]) flash[:notice] = 'Post was successfully updated.' redirect_to :action => 'show', :id => @post else render :action => 'edit' end end def new_post @post = Post.new(params[:post]) if @post.save flash[:notice] = 'Post was successfully created.' redirect_to :action => 'list' else render :action => 'new' end endend相应地,还需要把new.rhtml中的action从create修改到new,把edit.rhtml中的action从update修改到edit。这样的修改把必须使用post请求的action隐藏起来,而相应的get操作是不修改或删除记录的,如果以post请求,才会自动调用这些保护的方法。 |