Upload a file from ActiveStorage to an API

Question

I'm trying to upload a file to an API with Httparty gem. Here is the requested format, from the documentation of this API:

Method: POST
Content-Type: application/json   
{
  "name": "filename.png",
  "type": 2,
  "buffer": "iVBOR..."
}

My document is stored with ActiveStorage, here is my function to download it and generate the parameters HASH:

def document_params
  {
    "name": @document.file.filename.to_s,
    "type": IDENTIFIERS[@document.document_type],
    "buffer": @document.file.download
  }
end

Then I send the data with this function:

HTTParty.post(
  url,
  headers: request_headers,
  body: document_params.to_json
)

The problem is that when I do document_params.to_json, I get this error:

UndefinedConversionError ("\xC4" from ASCII-8BIT to UTF-8)

If I don't call to_json, data is not sent as a valid json, but as a hash representation like this: {:key=>"value"}

I would like to just send the file data as binary data, without trying to convert it to UTF-8.

Answer 1

I found a solution: encoding the file content to Base64:

def document_params
  {
    "name": @document.file.filename.to_s,
    "type": IDENTIFIERS[@document.document_type],
    "buffer": Base64.encode64(@document.file.download)
  }
end