Uhttpd CGI programming

For Developers
1

I want to upload files to my device using HTTP POST. I have successfully written some script in Lua that parses the environment variables, and prints the POST content. However I'm looking for some library that parses the content, so I can store the uploaded file directly to the filesysyem.

The preferred scripting language is Lua, but if there's other solution, I'm open.

Thank you for your help,
Levente

2

Not sure if you need any other libs perse.

Technically, if you read the body of a POST request, and use simple lua io, that should work on it's own.
So, something like this for writing files:
https://www.lua.org/pil/21.2.html

And then read from the stdin of the script.
Something like : https://www.lua.org/pil/21.1.html

I'm not completely sure about all this, but this is how it works with CGI shell scripts.
So, it should also work for lua.

3

Yes, but I don't want to reinvent the wheel. I guess there are lots of
implementation that already do this, like cgilua, I just can't integrate it
to my project.

Levente

4

You could borrow code from LuCI (luci.http.protocol contains a parser for MIME and url encoded POST bodies) or use "haserl" for this task.

1 Like
5

Can you give me some pointers where can I find this?

Thanks,
Levente

6

So I tried to put together something like this, but it doesn't seem to work. I get 502 Bad Gateway error.

#!/usr/bin/lua


http = require "luci.http"
proto = require "luci.http.protocol"


local fileOpened = 0
local fileP

function filecb(t, data, isLast)

	if fileOpened == 0 then
		FileP = io.open("/tmp/blabla", "wb")
		fileOpened = 1
	end

	FileP:write(data)

	if isLast then
		io.close(FileP)
	end

end


src = http.source()
httpMsg = proto.parse_message_header(src)

proto.parse_message_body(src, httpMsg, filecb)

http.close()

I'm sure this is not that simple...

Lev

7

@leventelist - Were you able to close down on the HTTP post usage or did you change your approach?

We have a similar issue where the file upload is required via HTTP Post.

8

I changed the approach... But I made it work somhow, but it was a PITA.

9

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