issues: 870125126

Hi,

I have started developing a plugin to export records as a spreadsheet file. It could be ods or xlsx, whatever is easier.

I have spotted the following packages:

• ods files: https://pypi.org/project/odswriter/
• xlsx files: https://openpyxl.readthedocs.io/en/stable/index.html (quite powerful) or https://xlsxwriter.readthedocs.io/ (faster)

This is the code I have so far, I test it with the --plugins-dir option:

```python from datasette import hookimpl from datasette.utils.asgi import Response import odswriter as ods

def render_spreadsheet(rows): with ods.writer(open("test.ods","wb")) as odsfile: for row in rows: odsfile.writerow(["String", "ABCDEF123456", "123456"]) return Response(odsfile, content_type="application/vnd.oasis.opendocument.spreadsheet", status=200)

@hookimpl def register_output_renderer(): return {"extension": "ods", "render": render_spreadsheet}

```

I get the following error:

``` Traceback (most recent call last): File "/home/colin/.local/lib/python3.8/site-packages/datasette/app.py", line 1128, in route_path await response.asgi_send(send) File "/home/colin/.local/lib/python3.8/site-packages/datasette/utils/asgi.py", line 339, in asgi_send body = body.encode("utf-8") AttributeError: 'ODSWriter' object has no attribute 'encode' ERROR: Exception in ASGI application Traceback (most recent call last): File "/home/colin/.local/lib/python3.8/site-packages/datasette/app.py", line 1128, in route_path await response.asgi_send(send) File "/home/colin/.local/lib/python3.8/site-packages/datasette/utils/asgi.py", line 339, in asgi_send body = body.encode("utf-8") AttributeError: 'ODSWriter' object has no attribute 'encode'

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File "/home/colin/.local/lib/python3.8/site-packages/uvicorn/protocols/http/h11_impl.py", line 396, in run_asgi result = await app(self.scope, self.receive, self.send) File "/home/colin/.local/lib/python3.8/site-packages/uvicorn/middleware/proxy_headers.py", line 45, in call return await self.app(scope, receive, send) File "/home/colin/.local/lib/python3.8/site-packages/datasette/utils/asgi.py", line 161, in call await self.app(scope, receive, send) File "/home/colin/.local/lib/python3.8/site-packages/datasette/tracer.py", line 75, in call await self.app(scope, receive, send) File "/home/colin/.local/lib/python3.8/site-packages/asgi_csrf.py", line 107, in app_wrapped_with_csrf await app(scope, receive, wrapped_send) File "/home/colin/.local/lib/python3.8/site-packages/datasette/app.py", line 1086, in call return await self.route_path(scope, receive, send, path) File "/home/colin/.local/lib/python3.8/site-packages/datasette/app.py", line 1133, in route_path return await self.handle_500(request, send, exception) File "/home/colin/.local/lib/python3.8/site-packages/datasette/app.py", line 1267, in handle_500 await asgi_send_html( File "/home/colin/.local/lib/python3.8/site-packages/datasette/utils/asgi.py", line 217, in asgi_send_html await asgi_send( File "/home/colin/.local/lib/python3.8/site-packages/datasette/utils/asgi.py", line 237, in asgi_send await asgi_start(send, status, headers, content_type) File "/home/colin/.local/lib/python3.8/site-packages/datasette/utils/asgi.py", line 246, in asgi_start await send( File "/home/colin/.local/lib/python3.8/site-packages/asgi_csrf.py", line 103, in wrapped_send await send(event) File "/home/colin/.local/lib/python3.8/site-packages/uvicorn/protocols/http/h11_impl.py", line 482, in send raise RuntimeError(msg % message_type) RuntimeError: Expected ASGI message 'http.response.body', but got 'http.response.start'. ```

I tried with AsgiFileDownload like in DatabaseDownload to deal with the binary nature of the ods file, but the renderer expects a Response:

<datasette.utils.asgi.AsgiFileDownload object at 0x7f5b9bd503d0> should be dict or Response

However, the Response class only supports the following methods, not binary:

• html
• text
• json
• redirect

How would you suggest me to proceed to have my ods file downloaded?