title: Understanding of Base and dynamic URL in HTTP Request Activity in Azure data factory
body: <p>I am trying to use Azure data Factory to get data from an API call and then use the Copy data activity to push it into a destination. I am trying to use the HTTP request activity as source in my Copy data activity action. My inputs are as follows in the HTTP Request Source:</p>
  <pre><code>Base URL: https://ABCDEF.com
  Relative URL:Parameter
  Parameter Passed:@concat('/bulk/v1/activities/export/',variables('Export ID Activities'),'/file.json?client_id=ClientID&amp;client_secret=ClientSecret')
  Headers:'Authorization: Bearer ABCDEF'
  </code></pre>
  <p>I get the Export ID variable from another call which works without an issue. Even this call works without an issue in Postman. But I get the following error if I try debugging the issue. I think that the issue is with my relative URL. Can relative URL bits and pieces of URL or can it only contain query parameters for an API call?.</p>
  <pre><code>{&quot;code&quot;:&quot;BadRequest&quot;,&quot;message&quot;:&quot;ErrorCode=InvalidTemplate, ErrorMessage=Unable to parse expression 'body('Copy data2ComposeRuntimeVariables')&quot;,&quot;details&quot;:null,&quot;error&quot;:null} 
  </code></pre>