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copied!<p>They're both ways to add additional actions to a resource-based route in Rails.</p> <blockquote> <ul> <li>A member route requires an ID, because it acts on a member.</li> <li>A collection route doesn't require an ID because it acts on a collection of objects.</li> </ul> </blockquote> <p>I like to think of them in terms of RESTful URLs. Consider the basics for a resource/model <code>Foo</code></p> <pre><code>GET /foo # FooController#index GET /foo/:id # FooController#show GET /foo/new # FooController#new POST /foo # FooController#create GET /foo/:id/edit # FooController#edit PUT /foo/:id # FooController#update DELETE /foo/:id # FooController#destroy </code></pre> <p>Notice how:</p> <ul> <li>Some routes have :id placeholders for Foo.id, and so refer to a <em>specific</em> Foo</li> <li>Some routes have no :id, and thus refer to <em>all</em> Foos (and/or no specific foo, as in #new and #create)</li> <li>Some routes (index/create, show/update/destroy) have the same URL, and use HTTP methods to differentiate between them</li> <li>Some routes (edit/show) are basically the same (method & URL prefix) except for a different suffix (including "no suffix") at the end.</li> </ul> <p>Member routes and collection routes let you add additional routes/actions using the same techniques as I listed above.</p> <p>A member route adds a custom action to a <em>specific instance</em> using the URL suffix and HTTP method you provide. So, if you had a member route declaration of <code>:member => { :bar => :get }</code>. you'd get an additional route of:</p> <pre><code>GET /foo/:id/bar # FooController#bar </code></pre> <p>Note how it overloads <code>GET /foo/:id</code> in the same way that `edit' does. This is how you'd implement a "delete" action that provides a UI for the "destroy" action.</p> <p>Similarly, a collection route adds an overload to the <em>collection</em> and/or a non-specific instance (it's up to you to decide exactly what it implies). So, if you declared <code>:collection => { :baz => :get }</code>, you'd get an additional route:</p> <pre><code>GET /foo/baz # FooController#baz </code></pre> <p>...in very much the same way as <code>new</code>.</p> <p>You can also customize the HTTP method.</p> <p>For example, I just recently had a project where I needed a "reply" action on a <code>Comment</code>. It's basically the same idea as <code>Comment#create</code> (which uses POST), except that it's in reference to a specific parent <code>Comment</code>. So, I created a member route: <code>:member => { :reply => :post }</code>. This gave me:</p> <pre><code>POST /comment/:id/reply # CommentController#reply </code></pre> <p>This keeps the routes restful while still expanding upon the basic 7 actions.</p>

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