Drop disallowed control characters and strip blank characters

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Add utility function to compute ZIM Tags #164, including deduplication #156
+- Metadata does not automatically drops control characters #159
 
 ### Fixed
 

src/zimscraperlib/zim/creator.py

@@ -30,6 +30,7 @@
 
 import libzim.writer  # pyright: ignore
 import PIL.Image
+import regex
 
 from zimscraperlib import logger
 from zimscraperlib.constants import (
@@ -65,6 +66,9 @@
     re.MULTILINE | re.DOTALL,
 )
 
+# All control characters are disallowed in str metadata except \n, \r and \t
+UNWANTED_CONTROL_CHARACTERS_REGEX = regex.compile(r"(?![\n\t\r])\p{C}")
+
 
 def mimetype_for(
     path: str,
@@ -250,6 +254,11 @@ def add_metadata(
         content: str | bytes | datetime.date | datetime.datetime | Iterable[str],
         mimetype: str = "text/plain;charset=UTF-8",
     ):
+        # drop control characters before passing them to libzim
+        if isinstance(content, str):
+            content = UNWANTED_CONTROL_CHARACTERS_REGEX.sub("", content).strip(
+                " \r\n\t"
+            )
         if not self.disable_metadata_checks:
             self.validate_metadata(name, content)
         if name == "Date" and isinstance(content, (datetime.date, datetime.datetime)):
@@ -304,6 +313,13 @@ def config_metadata(
             }
         )
         self._metadata.update(extras)
+        for metadata_key, metadata_value in self._metadata.items():
+            # drop control characters so that proper value is stored in memory and
+            # logged in DEBUG mode ; also strip blank characters
+            if isinstance(metadata_value, str):
+                self._metadata[metadata_key] = UNWANTED_CONTROL_CHARACTERS_REGEX.sub(
+                    "", metadata_value
+                ).strip(" \r\n\t")
         return self
 
     def config_dev_metadata(self, **extras: str):

tests/zim/test_zim_creator.py

@@ -724,6 +724,57 @@ def test_config_metadata(tmp_path, png_image, tags):
     assert reader.get_text_metadata("TestMetadata") == "Test Metadata"
 
 
+def test_config_metadata_control_characters(tmp_path):
+    fpath = tmp_path / "test_config.zim"
+    creator = Creator(fpath, "").config_dev_metadata(
+        Description="\t\n\r\n \tA description \awith  \bcontrol characters\v",
+        LongDescription="A description \rwith \a\ncontrol characters\tsss\t\n\r\n \t",
+        Creator="  A creator ",
+    )
+    assert creator._metadata["Description"] == "A description with  control characters"
+    assert (
+        creator._metadata["LongDescription"]
+        == "A description \rwith \ncontrol characters\tsss"
+    )
+    assert creator._metadata["Creator"] == "A creator"
+    with creator:
+        creator.add_metadata(
+            "Description_1",
+            "\t\n\r\n \tA description \awith  \bcontrol characters\v",
+        )
+        creator.add_metadata(
+            "LongDescription_1",
+            "A description \rwith \a\ncontrol characters\tsss\t\n\r\n \t",
+        )
+        creator.add_metadata(
+            "Creator_1",
+            "  A creator ",
+        )
+        pass
+
+    assert fpath.exists()
+
+    reader = Archive(fpath)
+    assert (
+        reader.get_text_metadata("Description")
+        == "A description with  control characters"
+    )
+    assert (
+        reader.get_text_metadata("LongDescription")
+        == "A description \rwith \ncontrol characters\tsss"
+    )
+    assert reader.get_text_metadata("Creator") == "A creator"
+    assert (
+        reader.get_text_metadata("Description_1")
+        == "A description with  control characters"
+    )
+    assert (
+        reader.get_text_metadata("LongDescription_1")
+        == "A description \rwith \ncontrol characters\tsss"
+    )
+    assert reader.get_text_metadata("Creator_1") == "A creator"
+
+
 @pytest.mark.parametrize(
     "name,value,valid",
     [