title: How to get message body attribute on blob input?
body: <p>I have an azure function with a service bus trigger:</p>
  
  <pre><code>  public static async Task&lt;string&gt; Run(
          [ServiceBusTrigger("sometopic", "somesub",Connection = "SbConnectionString")] Message message,
          [Blob("files/upload/{userId}/user.jpeg", FileAccess.Write)] Stream file,
          string userId,
          ILogger log)
      {
  
            ..some code
      }
  </code></pre>
  
  <p>But I´m getting this error: </p>
  
  <blockquote>
    <p>The 'Run' function is in error:
    Microsoft.Azure.WebJobs.Host: Error indexing method
    'ResponseTopicEmail'. Microsoft.Azure.WebJobs.Host: Unable to resolve
    binding parameter 'userId'. Binding expressions must map to
    either a value provided by the trigger or a property of the value the
    trigger is bound to, or must be a system binding expression (e.g.
    sys.randguid, sys.utcnow, etc.).</p>
  </blockquote>
  
  <p>Is there a way to get some property from the <code>Message</code> body and use it to get the blob output?</p>