improve smoketests, warnings and error-messages:

* docker: warn if there are config-files in ~/.config/copyparty
   because somebody copied their config into
   /cfg/copyparty instead of /cfg as intended

* docker: warn if there are no config-files in an included directory

* make misconfigured reverse-proxies more obvious
  * explain cors rejections in server log
  * indicate cors rejection in error toast

copyparty/__main__.py

@@ -395,7 +395,7 @@ def configure_ssl_ciphers(al: argparse.Namespace) -> None:
 
 def args_from_cfg(cfg_path: str) -> list[str]:
     lines: list[str] = []
-    expand_config_file(lines, cfg_path, "")
+    expand_config_file(None, lines, cfg_path, "")
     lines = upgrade_cfg_fmt(None, argparse.Namespace(vc=False), lines, "")
 
     ret: list[str] = []

copyparty/authsrv.py

@@ -863,7 +863,7 @@ class AuthSrv(object):
     ) -> None:
         self.line_ctr = 0
 
-        expand_config_file(cfg_lines, fp, "")
+        expand_config_file(self.log, cfg_lines, fp, "")
         if self.args.vc:
             lns = ["{:4}: {}".format(n, s) for n, s in enumerate(cfg_lines, 1)]
             self.log("expanded config file (unprocessed):\n" + "\n".join(lns))
@@ -2101,27 +2101,47 @@ def split_cfg_ln(ln: str) -> dict[str, Any]:
     return ret
 
 
-def expand_config_file(ret: list[str], fp: str, ipath: str) -> None:
+def expand_config_file(log: Optional["NamedLogger"], ret: list[str], fp: str, ipath: str) -> None:
     """expand all % file includes"""
     fp = absreal(fp)
     if len(ipath.split(" -> ")) > 64:
         raise Exception("hit max depth of 64 includes")
 
     if os.path.isdir(fp):
-        names = os.listdir(fp)
-        crumb = "#\033[36m cfg files in {} => {}\033[0m".format(fp, names)
-        ret.append(crumb)
-        for fn in sorted(names):
+        names = list(sorted(os.listdir(fp)))
+        cnames = [x for x in names if x.lower().endswith(".conf")]
+        if not cnames:
+            t = "warning: tried to read config-files from folder '%s' but it does not contain any "
+            if names:
+                t += ".conf files; the following files were ignored: %s"
+                t = t % (fp, ", ".join(names[:8]))
+            else:
+                t += "files at all"
+                t = t % (fp,)
+
+            if log:
+                log(t, 3)
+
+            ret.append("#\033[33m %s\033[0m" % (t,))
+        else:
+            zs = "#\033[36m cfg files in %s => %s\033[0m" % (fp, cnames)
+            ret.append(zs)
+
+        for fn in cnames:
             fp2 = os.path.join(fp, fn)
-            if not fp2.endswith(".conf") or fp2 in ipath:
+            if fp2 in ipath:
                 continue
 
-            expand_config_file(ret, fp2, ipath)
+            expand_config_file(log, ret, fp2, ipath)
 
-        if ret[-1] == crumb:
-            # no config files below; remove breadcrumb
-            ret.pop()
+        return
 
+    if not os.path.exists(fp):
+        t = "warning: tried to read config from '%s' but the file/folder does not exist" % (fp,)
+        if log:
+            log(t, 3)
+
+        ret.append("#\033[31m %s\033[0m" % (t,))
         return
 
     ipath += " -> " + fp
@@ -2135,7 +2155,7 @@ def expand_config_file(ret: list[str], fp: str, ipath: str) -> None:
                 fp2 = ln[1:].strip()
                 fp2 = os.path.join(os.path.dirname(fp), fp2)
                 ofs = len(ret)
-                expand_config_file(ret, fp2, ipath)
+                expand_config_file(log, ret, fp2, ipath)
                 for n in range(ofs, len(ret)):
                     ret[n] = pad + ret[n]
                 continue

copyparty/httpcli.py

@@ -518,9 +518,13 @@ class HttpCli(object):
                 return self.handle_options() and self.keepalive
 
             if not cors_k:
+                host = self.headers.get("host", "<?>")
                 origin = self.headers.get("origin", "<?>")
-                self.log("cors-reject {} from {}".format(self.mode, origin), 3)
-                raise Pebkac(403, "no surfing")
+                proto = "https://" if self.is_https else "http://"
+                guess = "modifying" if (origin and host) else "stripping"
+                t = "cors-reject %s because request-header Origin='%s' does not match request-protocol '%s' and host '%s' based on request-header Host='%s' (note: if this request is not malicious, check if your reverse-proxy is accidentally %s request headers, in particular 'Origin', for example by running copyparty with --ihead='*' to show all request headers)"
+                self.log(t % (self.mode, origin, proto, self.host, host, guess), 3)
+                raise Pebkac(403, "rejected by cors-check")
 
             # getattr(self.mode) is not yet faster than this
             if self.mode == "POST":

copyparty/svchub.py

@@ -28,7 +28,7 @@ if True:  # pylint: disable=using-constant-test
     import typing
     from typing import Any, Optional, Union
 
-from .__init__ import ANYWIN, EXE, MACOS, TYPE_CHECKING, EnvParams, unicode
+from .__init__ import ANYWIN, E, EXE, MACOS, TYPE_CHECKING, EnvParams, unicode
 from .authsrv import BAD_CFG, AuthSrv
 from .cert import ensure_cert
 from .mtag import HAVE_FFMPEG, HAVE_FFPROBE
@@ -154,6 +154,8 @@ class SvcHub(object):
         lg.handlers = [lh]
         lg.setLevel(logging.DEBUG)
 
+        self._check_env()
+
         if args.stackmon:
             start_stackmon(args.stackmon, 0)
 
@@ -385,6 +387,17 @@ class SvcHub(object):
 
         Daemon(self.sd_notify, "sd-notify")
 
+    def _check_env(self) -> None:
+        try:
+            files = os.listdir(E.cfg)
+        except:
+            files = []
+
+        hits = [x for x in files if x.lower().endswith(".conf")]
+        if hits:
+            t = "WARNING: found config files in [%s]: %s\n  config files are not expected here, and will NOT be loaded (unless your setup is intentionally hella funky)"
+            self.log("root", t % (E.cfg, ", ".join(hits)), 3)
+
     def _process_config(self) -> bool:
         al = self.args
 

copyparty/web/util.js

@@ -1995,15 +1995,19 @@ function xhrchk(xhr, prefix, e404, lvl, tag) {
     if (tag === undefined)
         tag = prefix;
 
-    var errtxt = (xhr.response && xhr.response.err) || xhr.responseText,
+    var errtxt = ((xhr.response && xhr.response.err) || xhr.responseText) || '',
+        suf = '',
         fun = toast[lvl || 'err'],
         is_cf = /[Cc]loud[f]lare|>Just a mo[m]ent|#cf-b[u]bbles|Chec[k]ing your br[o]wser|\/chall[e]nge-platform|"chall[e]nge-error|nable Ja[v]aScript and cook/.test(errtxt);
 
+    if (errtxt.startsWith('<pre>'))
+        suf = '\n\nerror-details: «' + errtxt.slice(5).split('\n')[0].trim() + '»';
+
     if (xhr.status == 403 && !is_cf)
-        return toast.err(0, prefix + (L && L.xhr403 || "403: access denied\n\ntry pressing F5, maybe you got logged out"), tag);
+        return toast.err(0, prefix + (L && L.xhr403 || "403: access denied\n\ntry pressing F5, maybe you got logged out") + suf, tag);
 
     if (xhr.status == 404)
-        return toast.err(0, prefix + e404, tag);
+        return toast.err(0, prefix + e404 + suf, tag);
 
     if (is_cf && (xhr.status == 403 || xhr.status == 503)) {
         var now = Date.now(), td = now - cf_cha_t;