From 42d1ff064f8d56ec7ec9e0b50d1c8eed8485f538 Mon Sep 17 00:00:00 2001 From: Přemysl Eric Janouch Date: Sat, 17 Oct 2020 19:56:38 +0200 Subject: json-rpc-test-server: comment on some CGI details There are some unresolved issues in the CGI clients that needed a more precise description. --- json-rpc-test-server.c | 41 +++++++++++++++++++++++++++++++++-------- 1 file changed, 33 insertions(+), 8 deletions(-) diff --git a/json-rpc-test-server.c b/json-rpc-test-server.c index cdf7790..07a2dd5 100644 --- a/json-rpc-test-server.c +++ b/json-rpc-test-server.c @@ -1654,15 +1654,37 @@ struct request_handler LIST_HEADER (struct request_handler) /// Install ourselves as the handler for the request, if applicable. + /// If the request contains data, check it against CONTENT_LENGTH. + /// ("Transfer-Encoding: chunked" should be dechunked by the HTTP server, + /// however it is possible that it mishandles this situation.) /// Sets @a continue_ to false if further processing should be stopped, /// meaning the request has already been handled. + /// Note that starting the response before receiving all data denies you + /// the option of returning error status codes based on the data. bool (*try_handle) (struct request *request, struct str_map *headers, bool *continue_); /// Handle incoming data. "len == 0" means EOF. /// Returns false if there is no more processing to be done. - // FIXME: the EOF may or may not be delivered when request is cut short, - // we should fix FastCGI not to deliver it on CONTENT_LENGTH mismatch + /// EOF is never delivered on a network error (see client_read_loop()). + // XXX: the EOF may or may not be delivered when the request is cut short: + // - client_scgi delivers an EOF when it itself receives an EOF without + // considering any mismatch, and it can deliver another one earlier + // when the counter just goes down to 0... depends on what we return + // from here upon the first occasion (whether we want to close). + // - FCGI_ABORT_REQUEST /might/ not close the stdin and it /might/ cover + // a CONTENT_LENGTH mismatch, since this callback wouldn't get invoked. + // The FastCGI specification explicitly says to compare CONTENT_LENGTH + // against the number of received bytes, which may only be smaller. + // + // We might want to adjust client_scgi and client_fcgi to not invoke + // request_push(EOF) when CONTENT_LENGTH hasn't been reached and remove + // the extra EOF generation from client_scgi (why is it there, does the + // server keep the connection open, or is it just a precaution?) + // + // The finalization callback takes care of any needs to destruct data. + // If we handle this reliably in all clients, try_handle won't have to, + // as it will run in a stricter-than-CGI scenario. bool (*push_cb) (struct request *request, const void *data, size_t len); /// Destroy the handler's data stored in the request object @@ -1784,7 +1806,9 @@ request_handler_json_rpc_push // TODO: check buf.len against CONTENT_LENGTH; if it's less, then the // client hasn't been successful in transferring all of its data. - // See also comment on request_handler::push_cb. + // See also comment on request_handler::push_cb. For JSON-RPC, though, + // it shouldn't matter as an incomplete request will be invalid and + // clients have no reason to append unnecessary trailing bytes. struct str response = str_make (); str_append (&response, "Status: 200 OK\n"); @@ -1947,8 +1971,8 @@ request_handler_static_try_handle request_write (request, buf, len); fclose (fp); - // TODO: this should rather not be returned all at once but in chunks; - // file read requests never return EAGAIN + // TODO: this should rather not be returned all at once but in chunks + // (consider Transfer-Encoding); file read requests never return EAGAIN // TODO: actual file data should really be returned by a callback when // the socket is writable with nothing to be sent (pumping the entire // file all at once won't really work if it's huge). @@ -2395,14 +2419,15 @@ client_scgi_on_content (void *user_data, const void *data, size_t len) print_debug ("SCGI request got more data than CONTENT_LENGTH"); return false; } - // We're in a slight disagreement with the specification since + // We're in a slight disagreement with the SCGI specification since // this tries to write output before it has read all the input if (!request_push (&self->request, data, len)) return false; + if ((self->remaining_content -= len)) + return true; // Signalise end of input to the request handler - return (self->remaining_content -= len) != 0 - || request_push (&self->request, NULL, 0); + return request_push (&self->request, NULL, 0); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- cgit v1.2.3-70-g09d2