fix for proper handling of absolute http URIs

pystac/asset.py

@@ -105,13 +105,12 @@ def get_absolute_href(self) -> str | None:
             str: The absolute HREF of this asset, or None if an absolute HREF could not
                 be determined.
         """
-        if utils.is_absolute_href(self.href):
+        item_self = self.owner.get_self_href() if self.owner is not None else None
+        if utils.is_absolute_href(self.href, item_self):
             return self.href
         else:
-            if self.owner is not None:
-                item_self = self.owner.get_self_href()
-                if item_self is not None:
-                    return utils.make_absolute_href(self.href, item_self)
+            if item_self is not None:
+                return utils.make_absolute_href(self.href, item_self)
             return None
 
     def to_dict(self) -> dict[str, Any]:
@@ -341,7 +340,7 @@ def make_asset_hrefs_relative(self) -> Assets:
         """
         self_href = self.get_self_href()
         for asset in self.assets.values():
-            if is_absolute_href(asset.href):
+            if is_absolute_href(asset.href, self_href):
                 if self_href is None:
                     raise STACError(
                         "Cannot make asset HREFs relative if no self_href is set."
@@ -360,7 +359,7 @@ def make_asset_hrefs_absolute(self) -> Assets:
         """
         self_href = self.get_self_href()
         for asset in self.assets.values():
-            if not is_absolute_href(asset.href):
+            if not is_absolute_href(asset.href, self_href):
                 if self_href is None:
                     raise STACError(
                         "Cannot make relative asset HREFs absolute "
@@ -380,10 +379,10 @@ def get_self_href(self) -> str | None:
 
 
 def _absolute_href(href: str, owner: Assets | None, action: str = "access") -> str:
-    if utils.is_absolute_href(href):
+    item_self = owner.get_self_href() if owner else None
+    if utils.is_absolute_href(href, item_self):
         return href
     else:
-        item_self = owner.get_self_href() if owner else None
         if item_self is None:
             raise ValueError(
                 f"Cannot {action} file if asset href ('{href}') is relative "

pystac/item.py

@@ -226,7 +226,7 @@ def set_self_href(self, href: str | None) -> None:
             # Make sure relative asset links remain valid.
             for asset in self.assets.values():
                 asset_href = asset.href
-                if not is_absolute_href(asset_href):
+                if not is_absolute_href(asset_href, prev_href):
                     abs_href = make_absolute_href(asset_href, prev_href)
                     new_relative_href = make_relative_href(abs_href, new_href)
                     asset.href = new_relative_href

pystac/utils.py

@@ -378,19 +378,27 @@ def make_absolute_href(
         return _make_absolute_href_path(parsed_source, parsed_start, start_is_dir)
 
 
-def is_absolute_href(href: str) -> bool:
+def is_absolute_href(href: str, start_href: str | None = None) -> bool:
     """Determines if an HREF is absolute or not.
 
     May be used on either local file paths or URLs.
 
     Args:
         href : The HREF to consider.
+        start_href : The HREF that will be used as the basis for checking if
+          ``source_href`` is a relative path. Defaults to the current
+          working directory.
 
     Returns:
         bool: ``True`` if the given HREF is absolute, ``False`` if it is relative.
     """
     parsed = safe_urlparse(href)
-    return parsed.scheme not in ["", "file"] or os.path.isabs(parsed.path)
+    parsed_start_scheme = "" if start_href is None else safe_urlparse(start_href).scheme
+
+    if parsed_start_scheme in ["", "file"]:
+        return parsed.scheme not in ["", "file"] or os.path.isabs(parsed.path)
+    else:
+        return parsed.scheme not in ["", "file"]
 
 
 def datetime_to_str(dt: datetime, timespec: str = "auto") -> str:

tests/test_utils.py

@@ -197,14 +197,17 @@ def test_make_absolute_href_windows(
 def test_is_absolute_href() -> None:
     # Test cases of (href, expected)
     test_cases = [
-        ("item.json", False),
-        ("./item.json", False),
-        ("../item.json", False),
-        ("http://stacspec.org/item.json", True),
+        ("item.json", False, None),
+        ("./item.json", False, None),
+        ("../item.json", False, None),
+        ("http://stacspec.org/item.json", True, None),
+        ("/item.json", True, None),
+        ("/item.json", False, "http://stacspec.org/"),
+        ("http://stacspec.org/item.json", True, "http://stacspec.org/"),
     ]
 
-    for href, expected in test_cases:
-        actual = is_absolute_href(href)
+    for href, expected, start_href in test_cases:
+        actual = is_absolute_href(href, start_href)
         assert actual == expected