title: Azure Function App Proxy to a blob storage account
body: <p>Experimenting with the new function <a href="https://docs.microsoft.com/en-us/azure/azure-functions/functions-proxies" rel="nofollow noreferrer">proxy feature</a>, I get a http 500 error with a proxy configured as follows:</p>
  
  <p>Route template:
  /content/{*filename}</p>
  
  <p>Backend URL: <a href="https://my-storage-account.blob.core.windows.net/public/" rel="nofollow noreferrer">https://my-storage-account.blob.core.windows.net/public/</a>{*filename}</p>
  
  <p>Where the backend is just a public container on a blob storage account.</p>
  
  <p>I've tried files with and without a file extension:  favicon.ico and just a (text) file called test.</p>
  
  <p>Requesting <a href="https://my-function-app.azurewebsites.net/content/favicon.ico" rel="nofollow noreferrer">https://my-function-app.azurewebsites.net/content/favicon.ico</a> yields a 404.</p>
  
  <p>Requesting <a href="https://my-function-app.azurewebsites.net/content/test" rel="nofollow noreferrer">https://my-function-app.azurewebsites.net/content/test</a> (the file without an extension called "test"), yields a http 500 error.</p>
  
  <p>What am I doing wrong?  </p>
  
  <p><strong>Note:</strong> I have the /api/ prefix removed by using the routePrefix option in host.json - which works fine for all my functions.  Requesting the urls above with the addition of /api/ yields a 404 for <em>both</em> urls.</p>