Clean path manually to avoid resolution of symlinks via normpath.

src/sewerrat/_utils.py

@@ -1,4 +1,5 @@
 import requests
+import os
 
 
 def format_error(res):
@@ -10,3 +11,31 @@ def format_error(res):
         return requests.HTTPError(res.status_code, res.text)
     else:
         return requests.HTTPError(res.status_code)
+
+
+def clean_path(path: str) -> str:
+    # Don't use os.path.abspath, as this calls normpath; you would end up
+    # resolving symlinks that the user wants to respect, e.g., for mounted
+    # drives with aliased locations to network shares. Rather, we just do the
+    # bare minimum required to obtain a clean absolute path, analogous to
+    # Golang's filepath.Clean().
+    if not path.startswith('/'):
+        path = os.getcwd() + "/" + path
+
+    components = path.split("/")
+    keep = []
+    for comp in components:
+        if comp == "..":
+            if len(keep):
+                keep.pop()
+        elif comp == "":
+            # no-op, it's a redundant '//' or we're at the start.
+            pass
+        elif comp == ".":
+            # no-op as well.
+            pass
+        else:
+            keep.append(comp)
+
+    keep = [""] + keep # add back the root.
+    return '/'.join(keep)

src/sewerrat/deregister.py

@@ -27,7 +27,7 @@ def deregister(path: str, url: str, retry: int = 3, wait: float = 1):
             Number of seconds to wait for a file write to synchronise before
             requesting verification during each retry.
     """
-    path = os.path.abspath(path)
+    path = ut.clean_path(path)
     res = requests.post(url + "/deregister/start", json = { "path": path }, allow_redirects=True)
     if res.status_code >= 300:
         raise ut.format_error(res)

src/sewerrat/register.py

@@ -38,10 +38,7 @@ def register(path: str, names: List[str], url: str, retry: int = 3, wait: int =
     if len(names) == 0:
         raise ValueError("expected at least one entry in 'names'")
 
-    path = os.path.abspath(path)
-    if url is None:
-        url = rest_url()
-
+    path = ut.clean_path(path)
     res = requests.post(url + "/register/start", json = { "path": path }, allow_redirects=True)
     if res.status_code >= 300:
         raise ut.format_error(res)

tests/test_utils.py

@@ -0,0 +1,25 @@
+from sewerrat import _utils as ut
+
+
+def test_clean_path():
+    x = ut.clean_path("foo/bar")
+    assert x.endswith("/foo/bar")
+    assert x.startswith("/")
+
+    x = ut.clean_path("//absd//a//foo/bar")
+    assert x == "/absd/a/foo/bar"
+
+    x = ut.clean_path("//absd//a//../foo/bar")
+    assert x == "/absd/foo/bar"
+
+    x = ut.clean_path("/xxxx/bbb/../../foo/bar")
+    assert x == "/foo/bar"
+
+    x = ut.clean_path("/../absd")
+    assert x == "/absd"
+
+    x = ut.clean_path("/absd/./bar/./")
+    assert x == "/absd/bar"
+
+    x = ut.clean_path("/a/b/c/d/")
+    assert x == "/a/b/c/d"