Fix full FTP URLs in direct file downloads

docs/source/changelog.rst

@@ -6,6 +6,8 @@ Dev
 
 Fixes
 
+- Accept full FTP URLs in direct ``cat_file`` and ``get_file`` calls.
+
 - Strip the protocol from the path in ``LocalFileSystem.chmod``.
 
 - Forward the wrapped filesystem's ``local_file`` flag through ``DirFileSystem`` (#1110).

fsspec/implementations/ftp.py

@@ -195,6 +195,7 @@ def info(self, path, **kwargs):
         return out
 
     def get_file(self, rpath, lpath, **kwargs):
+        rpath = self._strip_protocol(rpath)
         if self.isdir(rpath):
             if not os.path.exists(lpath):
                 os.mkdir(lpath)
@@ -216,6 +217,7 @@ def cb(x):
             outfile.close()
 
     def cat_file(self, path, start=None, end=None, **kwargs):
+        path = self._strip_protocol(path)
         if end is not None or (start is not None and start < 0):
             return super().cat_file(path, start, end, **kwargs)
         out = []

fsspec/implementations/tests/test_ftp.py

@@ -217,6 +217,27 @@ def test_cat_get(ftp_writable, tmpdir):
     assert open(fn, "rb").read() == data
 
 
+@pytest.mark.parametrize("start,end", [(None, None), (3, None), (-3, None), (2, 8)])
+def test_cat_file_with_protocol(ftp_writable, start, end):
+    host, port, user, pw = ftp_writable
+    fs = FTPFileSystem(host, port, user, pw)
+    data = b"0123456789"
+    fs.pipe("/url-file", data)
+    url = f"ftp://{host}:{port}/url-file"
+    assert fs.cat_file(url, start=start, end=end) == data[start:end]
+
+
+@pytest.mark.parametrize("file_like", [False, True])
+def test_get_file_with_protocol(ftp_writable, tmp_path, file_like):
+    host, port, user, pw = ftp_writable
+    fs = FTPFileSystem(host, port, user, pw)
+    data = b"download through an FTP URL"
+    fs.pipe("/url-file", data)
+    target = io.BytesIO() if file_like else tmp_path / "download"
+    fs.get_file(f"ftp://{host}:{port}/url-file", target)
+    assert (target.getvalue() if file_like else target.read_bytes()) == data
+
+
 @pytest.mark.parametrize("start", [-3, -10, -100, 0, 3, None])
 def test_cat_file_start(ftp_writable, start):
     host, port, user, pw = ftp_writable