ngx-lua POST request body limit?

[Colin MacRae]

Quick summary: I have a webpage with a single text area form input and submit button. When a user hits submit, the form is sent as a POST, with data in the request body. This string is then parsed, and submitted as a key-value pair to the redis cache backend. This is to store from-to URL redirects. This works fine with 50 lines, (100 URLs), but anything more than 100 lines (200 URLs) there is no data sent, and I am seeing a nil value.

The numbers I've stated I'm sure are arbitrary, but is this a known limit? I don't see anything in the logs from nginx regarding body_size too large, and I have tried various ways of increasing this apparent limit without any change in behaviour. The strannge thing is I can't find any errors.

I'm using this:

ngx.req.read_body()

local data = ngx.req.get_body_data()

if data ~= nil then
  -- do something here

else

   ngx.say("Body too large...for some reason.")

end

And seeing the "Body too large..." issue.

Any insight into this would be greatly appreciated.

Rgds,

Colin

[Jim Robinson]

Check if it's in the body file, which is used when nginx decided it will be more efficient to use a temp file. As an example:

-- if the body is in memory record it as request.body,

-- otherwise if it is stored in a file record it as

-- request.body_file.

ngx.req.read_body()

request.body = ngx.req.get_body_data()

if not request.body then

        local file = ngx.req.get_body_file()

        if file then

                request.body_file = file

        end

end

...

-- if a body_file exists, ready it into memory

if request.body_file then

        local fh, err = io.open(request.body_file, "rb")

        if err then

                ngx.status = ngx.HTTP_INTERNAL_SERVER_ERROR

                ngx.log(ngx.ERR, "error reading request.body_file:", err)

                return

        end

        request.body = fh:read("*all")

        fh:close()

end

[Colin MacRae]

I had no idea nginx did that! Jim, you are my hero! Thanks!

I had been scratching my head over this for some time

Colin