static struct http_backend *choose_backend_from_list(
struct http_message *hm, struct http_backend *backends, int num_backends) {
int i;
struct ns_str vhost = {"", 0};
const struct ns_str *host = ns_get_http_header(hm, "host");
if (host != NULL) vhost = *host;
const char *vhost_end = vhost.p;
while (vhost_end < vhost.p + vhost.len && *vhost_end != ':') {
vhost_end++;
}
vhost.len = vhost_end - vhost.p;
struct http_backend *chosen = NULL;
for (i = 0; i < num_backends; i++) {
struct http_backend *be = &backends[i];
if (has_prefix(&hm->uri, be->uri_prefix) &&
matches_vhost(&vhost, be->vhost) &&
(chosen == NULL ||
/* Prefer most specific URI prefixes */
strlen(be->uri_prefix) > strlen(chosen->uri_prefix) ||
/* Among prefixes of the same length chose the least used. */
(strlen(be->uri_prefix) == strlen(chosen->uri_prefix) &&
be->usage_counter < chosen->usage_counter))) {
chosen = be;
}
}
return chosen;
}
static void choose_backend(struct ns_connection *nc) {
struct http_message hm;
struct iobuf *io = &nc->recv_iobuf;
int req_len = ns_parse_http(io->buf, io->len, &hm);
if (req_len < 0 || (req_len == 0 && io->len >= NS_MAX_HTTP_REQUEST_SIZE)) {
/* Invalid, or too large request */
nc->flags |= NSF_CLOSE_IMMEDIATELY;
} else if (req_len == 0) {
/* Do nothing, request is not yet fully buffered */
} else {
/*
* Got HTTP request, look which backend to use. Round-robin over the
* backends with the same uri_prefix and vhost.
*/
struct ns_str vhost = *ns_get_http_header(&hm, "host");
const char *vhost_end = vhost.p;
while(vhost_end < vhost.p + vhost.len &&
*vhost_end != ':') {
vhost_end++;
}
vhost.len = vhost_end - vhost.p;
int i, chosen = -1;
for (i = 0; i < s_num_http_backends; i++) {
if (has_prefix(&hm.uri, s_http_backends[i].uri_prefix) &&
matches_vhost(&vhost, s_http_backends[i].vhost) &&
(chosen == -1 || s_http_backends[i].usage_counter <
s_http_backends[chosen].usage_counter)) {
chosen = i;
}
}
if (chosen == -1) {
/* No backend with given uri_prefix found, bail out */
ns_printf(nc, "%s%s\r\n", s_error_404, s_content_len_0);
} else if (s_http_backends[chosen].redirect != 0) {
ns_printf(nc, "HTTP/1.1 302 Found\r\nLocation: %s\r\n\r\n",
s_http_backends[chosen].host_port);
nc->flags |= NSF_SEND_AND_CLOSE;
} else if ((nc->proto_data = ns_connect(nc->mgr,
s_http_backends[chosen].host_port, ev_handler)) == NULL) {
/* Connection to backend failed */
ns_printf(nc, "%s%s\r\n", s_error_500, s_content_len_0);
} else {
/*
* Forward request to the backend. Note that we can insert extra headers
* to pass information to the backend.
* Store backend index as user_data for the backend connection.
*/
((struct ns_connection *) nc->proto_data)->proto_data = nc;
((struct ns_connection *) nc->proto_data)->user_data =
(void *) (long) chosen;
s_http_backends[chosen].usage_counter++;
ns_send(nc->proto_data, io->buf, io->len);
iobuf_remove(io, io->len);
}
}
}
