title: Posting files to a chat through Slack API
body: <p>I'm trying to deliver videos, through Slack API using Python's library <code>slackclient</code>.</p>
  
  <p>I often use <code>slack.api_call('chat.postMessage'...)</code> and I am familiar with <code>'files.upload'</code> but when I execute</p>
  
  <pre><code>slack = SlackClient(TOKEN)
  slack.api_call('files.upload', file=open('video.mp4', 'rb')...)
  </code></pre>
  
  <p>the file is uploaded to the given channel, but is not posted as a message.</p>
  
  <p>What I am trying to achieve is to create a message which I can send as a private message or to a channel that would look something like this</p>
  
  <p><a href="https://i.stack.imgur.com/v69Eq.png" rel="noreferrer"><img src="https://i.stack.imgur.com/v69Eq.png" alt="enter image description here"></a></p>
  
  <p>and maybe add some text above it if possible.</p>
  
  <p>I've explored the <a href="https://api.slack.com/docs/message-attachments" rel="noreferrer">Attachment</a> section in the docs, but couldn't find anything related to files.
  If there is a way to not supply the file in binary format, but as a link that would also be ok (as long as it is displayed in an embedded fashion).</p>