Aiohttp: Parser.parse doesn't work after request body was read.

When a content of a request is read before parser.parse is called (with location=('json',)), parser returns that JSON fields are missing in the request.

Example code:

async def handler(request):
    data = await request.json()
    args = await parser.parse(handler_args, req=request, locations=('json',))
    return web.Response()

The issue is the following line of code https://github.com/sloria/webargs/blob/dev/webargs/aiohttpparser.py#L92 specifically req.has_body. This attribute has an unfortunate name and it’s not constant over a lifetime of a request. It checks if there are more bytes to read. Once the body is read by await request.json() there are no more bytes to read and value of req.has_body is False.

[sloria]

@lafrech. I agree. Ok, I’ll release those when I’m off the clock.

[sloria]

Thanks! Good call on reporting that issue on aiohttp; looks like the maintainers are open to changing the behavior or adding a separate method.

Since webargs will need to support the current releases of aiohttp, it will need to be fixed in webargs, so a PR would be greatly appreciated.