On Sat, Feb 15, 2025 at 5:17 PM Dan Fandrich via curl-library <curl-library@lists.haxx.se> wrote: > > On Sat, Feb 15, 2025 at 04:21:04PM +0100, Jeroen Ooms via curl-library wrote: > > For the R bindings, we have a popular debugging mode to 'dry-run' a > > http request. By this we mean that the user builds and performs a > > http-request in the regular way, but instead of actually connecting to > > the requested host, we trick libcurl to make the http request to a > > local server, which records the full payload that libcurl has > > uploaded, and we return this blob to the user. > > > > Currently the way this is implemented is a bit cumbersome. We first > > start a http-server in the background. Then we take the handle > > provided by the user, and replace CURLOPT_URL to substitute the host > > with "http://localhost";. Then we modify CURLOPT_HTTPHEADER to set the > > 'Host' request header to the host:port that was specified by the user > > in the original url, and let libcurl perform the request. The fake > > server always returns 200. > > > > Especially the part where we need to run our own http server is a bit > > annoying. I was wondering if there would perhaps be a simpler method > > trick libcurl to send a http request to a local file or buffer, from > > where we can read it. Preferably something that we can do entirely in > > C (things like nc are difficult to port). > > When curl is talking HTTP, it expects an HTTP server on the other end. > Avoiding > that is not going to be generally possible. But, if you're just interested in > the client side of the transaction and stick with HTTP (not HTTPS) and HTTP > 1.1 and avoid a negotiated authentication protocol, you might be able to get > away with providing a CURLOPT_OPENSOCKETFUNCTION that points to a file and > setting instantaneous CURLOPT_EXPECT_100_TIMEOUT_MS and > CURLOPT_SERVER_RESPONSE_TIMEOUT timeouts. It's quite possible that libcurl > won't like a file descriptor in place of a socket, but you might get lucky.
Thanks this is worth trying. I think it does not have to be a file per-se; I could open a local socket and read that to a buffer while curl is uploading. The difficult part is that I need a callback function for the moment where libcurl is done uploading (When curlopt_verbose says "Request completely sent off") such that I know I have received full request data and can close() the socket at that point. -- Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-library Etiquette: https://curl.se/mail/etiquette.html
