title: Generate Signed URL in S3 using boto3
body: <p>In Boto, I used to generate a signed URL using the below function.</p>
  
  <pre><code>import boto
  conn = boto.connect_s3()
  bucket = conn.get_bucket(bucket_name, validate=True)
  key = bucket.get_key(key)
  signed_url = key.generate_url(expires_in=3600)
  </code></pre>
  
  <p>How do I do the exact same thing in boto3?<br>
  I searched through boto3 GitHub <a href="https://github.com/boto/boto3/search?q=generate_url&amp;unscoped_q=generate_url" rel="noreferrer">codebase</a> but could not find a single reference to generate_url.<br>
  Has the function name changed?</p>