Experiment : Web API Document Download of HTML File Resulting in a 404

If you attempt to follow the link in the interface designer what is the result?

Hi Aaron,

I get the following when I click on the URL provided in the test console.

The response headers are all correct, i.e. Content-Type: text/html, Content-Disposition: inline; filename="index.html".

What I have tried now is removing the .html from the URL and resolving that to the html document on Appian. This retrieves the HTML document and displays the HTML correctly, i.e. Hello World. Even if I change the extension to .abc it works fine. It is only happening on certain file extensions before it even gets to the Web API expression. So the Appian web server is definitely catching these and returning 404.

I assume this is being applied as an added security measure.

Hi Aaron,

I get the following when I click on the URL provided in the test console.

The response headers are all correct, i.e. Content-Type: text/html, Content-Disposition: inline; filename="index.html".

What I have tried now is removing the .html from the URL and resolving that to the html document on Appian. This retrieves the HTML document and displays the HTML correctly, i.e. Hello World. Even if I change the extension to .abc it works fine. It is only happening on certain file extensions before it even gets to the Web API expression. So the Appian web server is definitely catching these and returning 404.

I assume this is being applied as an added security measure.

As it is happening on only specific file extensions, it sounds like it might be an issue with your whitelist. Assuming you stuck to the template there will be the following in your code:

local!extensionWhitelist: {"pdf", "txt", "png", "jpg", "jpeg"}

or(
length(local!pathArray) <> 1,
isnull(local!document),
not(contains(local!extensionWhitelist, document(local!document, "extension")))
)

Removing the whitelist constraint or, altering it to include your file type should fix this issue.

The html extension is added to the extension whitelist, so this is not the issue. When there is a .html included in the filename, the call is being blocked before it arrives at the Web API expression.

Have you attempted removing the whitelist and seeing if it works? Any additional information you can provide on the changes you've made will be helpful.

I have stripped it down to the bare essentials. See following snippet below :

with(
  local!files: {
    "index.html"
  },
  local!ids: {
    99999
  },
  local!pathArray: fn!cast('type!{http://www.appian.com/ae/types/2009}Text?list', http!request.pathSegments),
  local!file: index(local!pathArray, 1, null),
  local!index: wherecontains(local!file, local!files),
  local!id: index(index(local!ids, local!index, null), 1, null),
  a!httpResponse(
    headers: {},
    body: todocument(local!id)
  )
)