Request to get image in processor

1 
let $'image' = true => call 'network'::'http' with (
	$'server'         = $'image url'
	$'path'           = ""
	$'authentication' = unset
	$'request'        = new (
		'method' = option 'get'
		'headers' = {
			create [ "Authorization" ] var 'api key'
		}
	)
) || throw "HTTP request to get image failed"

The above request yields a binary response stored in $‘image’, which contains data of an image (JPEG or PNG). I’m am figuring out whether it is possible to encode this image? Can anybody help me please.

To illustrate the result I wish to achieve: the following cURL would uncode and save the image locally when executed on my OS terminal.

curl --location $'image url' \
--header 'var 'api key'' > image.jpeg
2

After you have downloaded an image like this in a processor.alan, you can upload it to the “files resource” that is available for your Alan application. This would result in a “file token” that you can send back to the application, which can work with files if you create a property of the type file. If you also report the extension (like png or jpg) then the browser will show a preview as well and allow the end user to download the file.

So you follow these steps in general:

  1. Download binary data from an external system.
  2. Upload the binary data to the files resource linked to your Alan app.
  3. You will receive a ‘file token’ from the files resource.
  4. You can send the ‘file token’ back to your Alan app, where you should store it in a property of the type ‘file’.

As you do not have direct file system access from a processor.alan, this is the best way to get your file data to the end user and/or another system.

In theory you could also let your processor.alan behave as a web proxy that accepts a request from an end user, injects the Authorization header with an API key (that should probably be secret for the end user), performs the request and sends the response data (an image) back to the end user. This requires adding a “web hook” to your processor.alan.

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3

Thank you!

I would love to have help with the second problem as well, which is the following status 302 I receive after doing the get request. Following the location of the header does not provide me with an image and seems rather explanatory instead of redirective. Looking at the headers there might be a problem with the fact I am sending the request from the Kjerner servers? Executing the same get request via my OS terminal does not yield any problems . How to prevent this?

{
  "status": 302,
  "headers": {
    "vary": "Accept-Encoding",
    "location": "https://www.facebook.com/unsupportedbrowser",
    "strict-transport-security": "max-age=15552000; preload",
    "content-type": "text/html; charset=\"utf-8\"",
    "x-fb-debug": "mAmbm3YLlGA3ZYcXA6B6leOrzLATb/6PVh1Iq9ZZCkp1c/nsmIFjpeF1YEgEn/PQBhjtFKfMeFc6b1a2J36KLg==",
    "content-length": "0",
    "date": "Sat, 04 Jan 2025 23:06:54 GMT"
  },
  "content": ""
}
4

There probably is a difference in the headers that get sent with the request from our connector vs. curl in your OS terminal.

Please share with me (in a private message) the output of your curl command after adding the -v flag for verbose output. This should include all request headers.

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5

I am now struggling with the following: my webhook receives the mime_type to describe the document type. I wish to convert this to the correct extension so it can be processed by the Alan application. Does Alan has any build-in converter? Below I illustrate what I want to achieve, I know the syntax is invalid and only for illustrative purpose. Any tips are welcome!

'Type' = create 'Attached' (
    'Type' = ^ ^ $'type'
    'Document' = file (
        token = $'result'.'reply type'.'body'.'result'.'body'.'token'
        extension = switch $'extension' => switch $'mime_type' (
            | "image/jpeg" => "jpg"
            | "image/png" => "png"
            | "image/gif" => "gif"
            | "application/pdf" => "pdf"
            | "text/plain" => "txt"
            | "text/html" => "html"
            | "application/json" => "json"
            | "audio/mpeg" => "mp3"
            | "video/mp4" => "mp4"
            | "image/webp" => "webp"
            | "image/svg+xml" => "svg"
            | _ => throw "Unsupported MIME type"
        )
    )
)
6

If you want to translate from MIME type to file extension or the other way around, then a lookup table like you describe is the best way to go.

Is this really the only information about the file that your webhook receives? If you already have a filename, it might be easier to just split that in filename + extension and send the file token + extension back to the Alan app.

7

That sounds like a better solution. How can I split the filename from the extension? Thank you in for your help :raised_hands:t3:

8

This should work to split the filename in parts:

let $'filename_parts' = $'file path' => parse as pattern ( 'filename': $ text *"." 'extension': $ text ) || throw "invalid format"
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