403 ClientError is misleading when export is too large

[seanstory]

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Is your feature request related to a problem? Please describe.

My team is using the client to download files. A line like:

client.export_file(file.id, 'application/pdf', :download_dest => StringIO.new).string

Is raising a Google::Apis::ClientError with an e.inspect like:

#<Google::Apis::ClientError: Invalid request status_code: 403 header: #<HTTP::Message::Headers:0x66aececb @body_encoding=#<Encoding:UTF-8>, @request_absolute_uri=nil, @dumped=false, @request_method="GET", @reason_phrase="Forbidden", @request_uri=#<Addressable::URI:0x9a0 URI:https://www.googleapis.com/drive/v3/files/FILE_ID_HERE/export?alt=media&mimeType=application%2Fpdf>, @http_version="1.1", @body_date=nil, @is_request=false, @request_query={"alt"=>"media", "mimeType"=>"application/pdf"}, @body_size=0, @status_code=403, @body_type=nil, @chunked=false, @header_item=[["Vary", "Origin"], ["Vary", "X-Origin"], ["Content-Type", "application/json; charset=UTF-8"], ["Content-Encoding", "gzip"], ["Date", "Tue, 08 Sep 2020 18:00:04 GMT"], ["Expires", "Tue, 08 Sep 2020 18:00:04 GMT"], ["Cache-Control", "private, max-age=0"], ["X-Content-Type-Options", "nosniff"], ["X-Frame-Options", "SAMEORIGIN"], ["Content-Security-Policy", "frame-ancestors 'self'"], ["X-XSS-Protection", "1; mode=block"], ["Server", "GSE"], ["Alt-Svc", "h3-29=\":443\"; ma=2592000,h3-27=\":443\"; ma=2592000,h3-T051=\":443\"; ma=2592000,h3-T050=\":443\"; ma=2592000,h3-Q050=\":443\"; ma=2592000,h3-Q046=\":443\"; ma=2592000,h3-Q043=\":443\"; ma=2592000,quic=\":443\"; ma=2592000; v=\"46,43\""], ["Transfer-Encoding", "chunked"]], @body_charset=nil>>

This threw us for a real loop, because most of these requests work just fine, it was just an occasional file that consistently got a 403. We finally tested the specific file in https://developers.google.com/drive/api/v3/reference/files/export and found that the full response from the API is:

{
 "error": {
  "errors": [
   {
    "domain": "global",
    "reason": "exportSizeLimitExceeded",
    "message": "This file is too large to be exported."
   }
  ],
  "code": 403,
  "message": "This file is too large to be exported."
 }
}

Describe the solution you'd like
It would be great to get that JSON object back in the ClientError's body field, or some other mechanism.

Describe alternatives you've considered
Right now, we're just having to assume that a 403 from this endpoint means that the file is too large. But that's not great, since https://developers.google.com/drive/api/v3/handle-errors lists a whole bunch of reasons that we might be getting a 403.

[syakovyn]

I have a workaround that requires one extra call to export_file to get the full error message. Whenever client.export_file(file.id, 'application/pdf', :download_dest => StringIO.new).string is raising an error I'm performing one more request without specifying download_dest parameter: client.export_file(file.id, 'application/pdf').string. That time it returns the full body in JSON format as a part of the exception.