refactor: replace bleach with nh3 (ammonia) (#295)

pyproject.toml

@@ -7,7 +7,7 @@ authors = [
 ]
 readme = "README.rst"
 license = {text = "Apache License, Version 2.0"}
-dependencies = ["bleach>=2.1.0", "docutils>=0.13.1", "Pygments>=2.5.1"]
+dependencies = ["nh3>=0.2.14", "docutils>=0.13.1", "Pygments>=2.5.1"]
 classifiers = [
   "Intended Audience :: Developers",
   "License :: OSI Approved :: Apache Software License",

readme_renderer/clean.py

@@ -12,16 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import functools
-from typing import Any, Dict, Iterator, List, Optional
+from typing import Dict, Optional, Set
 
-import bleach
-import bleach.callbacks
-import bleach.linkifier
-import bleach.sanitizer
+import nh3
 
 
-ALLOWED_TAGS = [
+ALLOWED_TAGS = {
     # Bleach Defaults
     "a", "abbr", "acronym", "b", "blockquote", "code", "em", "i", "li", "ol",
     "strong", "ul",
@@ -32,102 +28,62 @@
     "span", "sub", "summary", "sup", "table", "tbody", "td", "th", "thead",
     "tr", "tt", "kbd", "var", "input", "section", "aside", "nav", "s", "figure",
     "figcaption",
-]
+}
 
 ALLOWED_ATTRIBUTES = {
     # Bleach Defaults
-    "a": ["href", "title"],
-    "abbr": ["title"],
-    "acronym": ["title"],
+    "a": {"href", "title"},
+    "abbr": {"title"},
+    "acronym": {"title"},
 
     # Custom Additions
-    "*": ["id"],
-    "hr": ["class"],
-    "img": ["src", "width", "height", "alt", "align", "class"],
-    "span": ["class"],
-    "th": ["align", "class"],
-    "td": ["align", "colspan", "rowspan"],
-    "div": ["align", "class"],
-    "h1": ["align"],
-    "h2": ["align"],
-    "h3": ["align"],
-    "h4": ["align"],
-    "h5": ["align"],
-    "h6": ["align"],
-    "code": ["class"],
-    "p": ["align", "class"],
-    "pre": ["lang"],
-    "ol": ["start"],
-    "input": ["type", "checked", "disabled"],
-    "aside": ["class"],
-    "dd": ["class"],
-    "dl": ["class"],
-    "dt": ["class"],
-    "ul": ["class"],
-    "nav": ["class"],
-    "figure": ["class"],
+    "*": {"id"},
+    "hr": {"class"},
+    "img": {"src", "width", "height", "alt", "align", "class"},
+    "span": {"class"},
+    "th": {"align", "class"},
+    "td": {"align", "colspan", "rowspan"},
+    "div": {"align", "class"},
+    "h1": {"align"},
+    "h2": {"align"},
+    "h3": {"align"},
+    "h4": {"align"},
+    "h5": {"align"},
+    "h6": {"align"},
+    "code": {"class"},
+    "p": {"align", "class"},
+    "pre": {"lang"},
+    "ol": {"start"},
+    "input": {"type", "checked", "disabled"},
+    "aside": {"class"},
+    "dd": {"class"},
+    "dl": {"class"},
+    "dt": {"class"},
+    "ul": {"class"},
+    "nav": {"class"},
+    "figure": {"class"},
 }
 
 
-class DisabledCheckboxInputsFilter:
-    # The typeshed for bleach (html5lib) filters is incomplete, use `typing.Any`
-    # See https://github.com/python/typeshed/blob/505ea726415016e53638c8b584b8fdc9c722cac1/stubs/bleach/bleach/html5lib_shim.pyi#L7-L8 # noqa E501
-    def __init__(self, source: Any) -> None:
-        self.source = source
-
-    def __iter__(self) -> Iterator[Dict[str, Optional[str]]]:
-        for token in self.source:
-            if token.get("name") == "input":
-                # only allow disabled checkbox inputs
-                is_checkbox, is_disabled, unsafe_attrs = False, False, False
-                for (_, attrname), value in token.get("data", {}).items():
-                    if attrname == "type" and value == "checkbox":
-                        is_checkbox = True
-                    elif attrname == "disabled":
-                        is_disabled = True
-                    elif attrname != "checked":
-                        unsafe_attrs = True
-                        break
-                if is_checkbox and is_disabled and not unsafe_attrs:
-                    yield token
-            else:
-                yield token
-
-    def __getattr__(self, name: str) -> Any:
-        return getattr(self.source, name)
-
-
 def clean(
     html: str,
-    tags: Optional[List[str]] = None,
-    attributes: Optional[Dict[str, List[str]]] = None
+    tags: Optional[Set[str]] = None,
+    attributes: Optional[Dict[str, Set[str]]] = None
 ) -> Optional[str]:
     if tags is None:
         tags = ALLOWED_TAGS
     if attributes is None:
         attributes = ALLOWED_ATTRIBUTES
 
-    # Clean the output using Bleach
-    cleaner = bleach.sanitizer.Cleaner(
-        tags=tags,
-        attributes=attributes,
-        filters=[
-            # Bleach Linkify makes it easy to modify links, however, we will
-            # not be using it to create additional links.
-            functools.partial(
-                bleach.linkifier.LinkifyFilter,
-                callbacks=[
-                    lambda attrs, new: attrs if not new else None,
-                    bleach.callbacks.nofollow,
-                ],
-                skip_tags=["pre"],
-                parse_email=False,
-            ),
-            DisabledCheckboxInputsFilter,
-        ],
-    )
     try:
-        cleaned = cleaner.clean(html)
+        cleaned = nh3.clean(
+            html,
+            tags=ALLOWED_TAGS,
+            attributes=ALLOWED_ATTRIBUTES,
+            link_rel="nofollow",
+            url_schemes={"http", "https", "mailto"},
+        )
+
         return cleaned
     except ValueError:
         return None

readme_renderer/txt.py

@@ -21,4 +21,4 @@
 
 def render(raw: str, **kwargs: Any) -> Optional[str]:
     rendered = html_escape(raw).replace("\n", "<br>")
-    return clean(rendered, tags=["br"])
+    return clean(rendered, tags={"br"})

tests/fixtures/test_CommonMark_006.html

@@ -1 +1 @@
-<iframe src="http://mymalicioussite.com/">Click here</iframe>
+Click here

tests/fixtures/test_CommonMark_007.html

@@ -1,4 +1,2 @@
 <p>Something naughty this way comes</p>
-&lt;script&gt;
-    alert("Hello");
-&lt;/script&gt;
+

tests/fixtures/test_CommonMark_008.html

@@ -4,13 +4,13 @@
         <span class="bp">self</span><span class="o">.</span><span class="n">name</span> <span class="o">=</span> <span class="n">name</span>
 
     <span class="k">def</span> <span class="nf">make_sound</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
-        <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;Ruff!&#39;</span><span class="p">)</span>
+        <span class="nb">print</span><span class="p">(</span><span class="s1">'Ruff!'</span><span class="p">)</span>
 
-<span class="n">dog</span> <span class="o">=</span> <span class="n">Dog</span><span class="p">(</span><span class="s1">&#39;Fido&#39;</span><span class="p">)</span>
+<span class="n">dog</span> <span class="o">=</span> <span class="n">Dog</span><span class="p">(</span><span class="s1">'Fido'</span><span class="p">)</span>
 </pre>
 <p>and then here is some bash:</p>
-<pre lang="bash"><span class="k">if</span><span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="s2">&quot;</span><span class="nv">$1</span><span class="s2">&quot;</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s2">&quot;--help&quot;</span><span class="w"> </span><span class="o">]</span><span class="p">;</span><span class="w"> </span><span class="k">then</span>
-<span class="w">    </span><span class="nb">echo</span><span class="w"> </span><span class="s2">&quot;OK&quot;</span>
+<pre lang="bash"><span class="k">if</span><span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="s2">"</span><span class="nv">$1</span><span class="s2">"</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s2">"--help"</span><span class="w"> </span><span class="o">]</span><span class="p">;</span><span class="w"> </span><span class="k">then</span>
+<span class="w">    </span><span class="nb">echo</span><span class="w"> </span><span class="s2">"OK"</span>
 <span class="k">fi</span>
 </pre>
 <p>or click <a href="http://www.surveymonkey.com" rel="nofollow">SurveyMonkey</a></p>

tests/fixtures/test_GFM_019.html

@@ -1,3 +1,3 @@
 <p><a href="http://commonmark.org" rel="nofollow">http://commonmark.org</a></p>
 <p>(Visit <a href="https://encrypted.google.com/search?q=Markup+(business)" rel="nofollow">https://encrypted.google.com/search?q=Markup+(business)</a>)</p>
-<p>Anonymous FTP is available at <a>ftp://foo.bar.baz</a>.</p>
+<p>Anonymous FTP is available at <a rel="nofollow">ftp://foo.bar.baz</a>.</p>

tests/fixtures/test_GFM_020.html

@@ -1 +1 @@
-<p><a href="mailto:foo@bar.baz">foo@bar.baz</a></p>
+<p><a href="mailto:foo@bar.baz" rel="nofollow">foo@bar.baz</a></p>

tests/fixtures/test_GFM_021.html

@@ -1 +1 @@
-<p>hello@mail+xyz.example isn't valid, but <a href="mailto:hello+xyz@mail.example">hello+xyz@mail.example</a> is.</p>
+<p>hello@mail+xyz.example isn't valid, but <a href="mailto:hello+xyz@mail.example" rel="nofollow">hello+xyz@mail.example</a> is.</p>

tests/fixtures/test_GFM_022.html

@@ -1,4 +1,4 @@
-<p><a href="mailto:a.b-c_d@a.b">a.b-c_d@a.b</a></p>
-<p><a href="mailto:a.b-c_d@a.b">a.b-c_d@a.b</a>.</p>
+<p><a href="mailto:a.b-c_d@a.b" rel="nofollow">a.b-c_d@a.b</a></p>
+<p><a href="mailto:a.b-c_d@a.b" rel="nofollow">a.b-c_d@a.b</a>.</p>
 <p>a.b-c_d@a.b-</p>
 <p>a.b-c_d@a.b_</p>

tests/fixtures/test_GFM_024.html

@@ -1,17 +1,17 @@
 <ul>
-<li><input type="checkbox" disabled> Valid unchecked checkbox</li>
-<li><input type="checkbox" checked disabled> Valid checked checkbox</li>
-<li> Invalid enabled checkbox</li>
+<li><input type="checkbox" disabled=""> Valid unchecked checkbox</li>
+<li><input type="checkbox" checked="" disabled=""> Valid checked checkbox</li>
+<li><input type="checkbox"> Invalid enabled checkbox</li>
 <li>
-
+<input>
 </li>
 <li>
-
+<input type="submit">
 </li>
 <li>
-
+<input>
 </li>
 <li>
-
+<input type="checkbox" checked="">
 </li>
 </ul>

tests/fixtures/test_GFM_doublequotes.html

@@ -2,7 +2,7 @@
 <pre><code>This is code text.
 </code></pre>
 <pre lang="python3"><span class="k">def</span> <span class="nf">this_is_python</span><span class="p">():</span>
-<span class="w">    </span><span class="sd">&quot;&quot;&quot;This is a docstring.&quot;&quot;&quot;</span>
+<span class="w">    </span><span class="sd">"""This is a docstring."""</span>
     <span class="k">pass</span>
 </pre>
 <pre lang="go"><span class="kd">func</span><span class="w"> </span><span class="nx">ThisIsGo</span><span class="p">(){</span>

tests/fixtures/test_GFM_malicious_pre.html

@@ -1,6 +1,6 @@
 <p>This is normal text.</p>
 <pre lang="python3"><span class="k">def</span> <span class="nf">this_is_python</span><span class="p">():</span>
-<span class="w">    </span><span class="sd">&quot;&quot;&quot;This is a docstring.&quot;&quot;&quot;</span>
+<span class="w">    </span><span class="sd">"""This is a docstring."""</span>
     <span class="k">pass</span>
-<span class="o">&lt;</span><span class="n">script</span> <span class="nb">type</span><span class="o">=</span><span class="s2">&quot;text/javascript&quot;</span><span class="o">&gt;</span><span class="n">alert</span><span class="p">(</span><span class="s1">&#39;I am evil.&#39;</span><span class="p">);</span><span class="o">&lt;/</span><span class="n">script</span><span class="o">&gt;</span>
+<span class="o">&lt;</span><span class="n">script</span> <span class="nb">type</span><span class="o">=</span><span class="s2">"text/javascript"</span><span class="o">&gt;</span><span class="n">alert</span><span class="p">(</span><span class="s1">'I am evil.'</span><span class="p">);</span><span class="o">&lt;/</span><span class="n">script</span><span class="o">&gt;</span>
 </pre>

tests/fixtures/test_rst_008.html

@@ -8,8 +8,8 @@
 
 </span><span class="n">dog</span> <span class="o">=</span> <span class="n">Dog</span><span class="p">(</span><span class="s1">'Fido'</span><span class="p">)</span></code></pre>
 <p>and then here is some bash:</p>
-<pre><code><span class="k">if</span><span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="s2">&quot;</span><span class="nv">$1</span><span class="s2">&quot;</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s2">&quot;--help&quot;</span><span class="w"> </span><span class="o">]</span><span class="p">;</span><span class="w"> </span><span class="k">then</span><span class="w">
-    </span><span class="nb">echo</span><span class="w"> </span><span class="s2">&quot;OK&quot;</span><span class="w">
+<pre><code><span class="k">if</span><span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="s2">"</span><span class="nv">$1</span><span class="s2">"</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s2">"--help"</span><span class="w"> </span><span class="o">]</span><span class="p">;</span><span class="w"> </span><span class="k">then</span><span class="w">
+    </span><span class="nb">echo</span><span class="w"> </span><span class="s2">"OK"</span><span class="w">
 </span><span class="k">fi</span></code></pre>
 <p>or click <a href="http://www.surveymonkey.com" rel="nofollow">SurveyMonkey</a></p>
 <pre><code>An unknown code fence block</code></pre>

tests/fixtures/test_rst_bibtex.html

@@ -1,2 +1,2 @@
-<pre><code><span class="nc">&#64;article</span><span class="p">{</span><span class="nl">the_impact_of_pygments_docutils_config_and_html5</span><span class="p">,</span><span class="w">
+<pre><code><span class="nc">@article</span><span class="p">{</span><span class="nl">the_impact_of_pygments_docutils_config_and_html5</span><span class="p">,</span><span class="w">
   </span><span class="na">year</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><s>{2022}</s><span class="p">,</span></code></pre>

tests/fixtures/test_rst_docinfo.html

@@ -6,7 +6,7 @@
 <dd class="created"><p>mer 02 ago 2017 14:49:24 CEST</p>
 </dd>
 <dt class="author">Author<span class="colon">:</span></dt>
-<dd class="author"><p>Lele Gaifax &lt;<a href="mailto:lele&#37;&#52;&#48;metapensiero&#46;it">lele<span>&#64;</span>metapensiero<span>&#46;</span>it</a>&gt;</p></dd>
+<dd class="author"><p>Lele Gaifax &lt;<a href="mailto:lele%40metapensiero.it" rel="nofollow">lele<span>@</span>metapensiero<span>.</span>it</a>&gt;</p></dd>
 <dt class="license">License<span class="colon">:</span></dt>
 <dd class="license"><p>GNU General Public License version 3 or later</p>
 </dd>

tests/fixtures/test_rst_linkify.html

@@ -42,7 +42,7 @@ <h2>Development</h2>
 <dd><p><a href="http://multigtfs.readthedocs.org/" rel="nofollow">http://multigtfs.readthedocs.org/</a></p>
 </dd>
 <dt>IRC<span class="colon">:</span></dt>
-<dd><p><a>irc://irc.freenode.net/tulsawebdevs</a></p>
+<dd><p><a rel="nofollow">irc://irc.freenode.net/tulsawebdevs</a></p>
 </dd>
 </dl>
 </section>