title: Magento : how to set canonical URL for product?
body: <p>I'm using megento 1.7.0.2, some products have 3 or 4 different urls :</p>
  
  <pre><code>example.com/category1/product1.html
  example.com/category1/category2/product1.html
  example.com/prodcut1.html
  ...
  </code></pre>
  
  <p>In the HTML code of Prodcut1, magento is adding this tag :</p>
  
  <pre><code>&lt;link rel="canonical" href="http://example.com/product1.html"&gt;
  </code></pre>
  
  <p>How can choose another URL ? e.g : </p>
  
  <pre><code>&lt;link rel="canonical" href="http://example.com/category1/category2/product1.html"&gt;
  </code></pre>