minddistrict · icemac · Feb 14, 2024 · Feb 14, 2024
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1,10 @@
+.coverage
+.project
+.pydevproject
+.Python
+.vscode
+*.egg-info
+*.pyc
+*.swo
+*.swp
+build/
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
@@ -0,0 +1,18 @@
+repos:
+- repo: https://github.com/pre-commit/pre-commit-hooks
+  rev: v4.5.0
+  hooks:
+  - id: check-added-large-files
+  - id: check-ast
+  - id: check-case-conflict
+  - id: check-merge-conflict
+  - id: check-yaml
+  - id: end-of-file-fixer
+  - id: trailing-whitespace
+  - id: mixed-line-ending
+- repo: https://github.com/astral-sh/ruff-pre-commit
+  rev: v0.2.1
+  hooks:
+    - id: ruff
+      args: [ --fix ]
+    - id: ruff-format
diff --git a/.pre-commit-hooks.yaml b/.pre-commit-hooks.yaml
@@ -0,0 +1,7 @@
+- id: check-chameleon
+  name: Check Chameleon templates
+  description: Check for syntax and accessibility misuse in Chameleon templates.
+  entry: check-chameleon
+  language: python
+  types: [text]
+  files: \.cpt$
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -0,0 +1,7 @@
+Change log
+==========
+
+1.0 (unreleased)
+----------------
+
+- Initial release.
diff --git a/README.md b/README.md
@@ -1,2 +1,2 @@
 # pre-commit-check-chameleon
-Check chameleon templates for missing HTML attributes via pre-commit
+Check for syntax and accessibility misuse in Chameleon templates.
diff --git a/setup.py b/setup.py
@@ -0,0 +1,24 @@
+from setuptools import find_packages
+from setuptools import setup
+
+version = "1.0.dev0"
+
+setup(
+    name="pre-commit-check-chameleon",
+    version=version,
+    package_dir={"": "src"},
+    packages=find_packages("src"),
+    include_package_data=True,
+    zip_safe=False,
+    install_requires=[
+        "lxml",
+    ],
+    extras_require={
+        "test": [
+            "testfixtures",
+        ],
+    },
+    entry_points={
+        "console_scripts": ["check-chameleon = check_chameleon.check_chameleon:main"]
+    },
+)
diff --git a/src/check_chameleon/__init__.py b/src/check_chameleon/__init__.py
diff --git a/src/check_chameleon/check_chameleon.py b/src/check_chameleon/check_chameleon.py
@@ -0,0 +1,225 @@
+import argparse
+import io
+import re
+import typing
+
+import lxml.etree
+
+NSMAP = {
+    "xhtml": "http://www.w3.org/1999/xhtml",
+    "tal": "http://xml.zope.org/namespaces/tal",
+}
+
+DOCTYPE_WRAPPER = """<!DOCTYPE html [<!ENTITY nbsp 'no-break space'>
+<!ENTITY times 'multiplication sign'>]>
+{0}"""
+
+TAL_ATTRIBUTES = "{{{0}}}attributes".format(NSMAP["tal"])
+TAL_CONTENT_XPATH = (
+    "./@tal:content|.//*/@tal:content|" ".//*/@tal:replace|.//tal:block/@replace"
+)
+
+
+def attribute(node, name):
+    found = node.attrib.get(name)
+    if found is not None:
+        return found
+    tal_attributes = node.attrib.get(TAL_ATTRIBUTES)
+    if tal_attributes is not None and name in tal_attributes:
+        for attr in tal_attributes.split(";"):
+            attr = attr.strip()
+            key, value = [el.strip() for el in attr.split(None, 1)]
+            if name == key:
+                return value
+    x_ng_attr_attribute = node.attrib.get("x-ng-attr-{0}".format(name))
+    if x_ng_attr_attribute is not None:
+        return x_ng_attr_attribute
+    x_ng_attribute = node.attrib.get("x-ng-{0}".format(name))
+    if x_ng_attribute is not None:
+        return x_ng_attribute
+    return None
+
+
+class Context:
+    errors: typing.List[str]
+    checks = None
+
+    def __init__(self, filename: str, a11y_lint_exclude=None):
+        with open(filename, "r") as stream:
+            content = stream.read()
+        self.errors = []
+        self.node = None
+        if "<!DOCTYPE" not in content:
+            content = DOCTYPE_WRAPPER.format(content)
+            self.lineno_offset = len(DOCTYPE_WRAPPER.splitlines()) - 1
+        else:
+            self.lineno_offset = 0
+        self.filename = filename
+        self.content = content
+        self.a11y_lint_exclude = a11y_lint_exclude
+
+    @classmethod
+    def add_check(cls, func):
+        if cls.checks is None:
+            cls.checks = []
+        cls.checks.append(func)
+        return func
+
+    def report(self, node, msg):
+        self.errors.append(
+            "{0}:{1} {2}".format(
+                self.filename, node.sourceline - self.lineno_offset, msg
+            )
+        )
+
+    def run(self):
+        try:
+            self.node = lxml.etree.parse(io.StringIO(self.content)).getroot()
+        except lxml.etree.XMLSyntaxError as e:
+            # Line number offset correction.
+            msg = e.msg
+            for line_number in re.findall("line ([0-9]+)", msg):
+                msg = msg.replace(
+                    "line {0}".format(line_number),
+                    "line {0}".format(int(line_number) - self.lineno_offset),
+                )
+            self.errors.append("{0}: {1}".format(self.filename, msg))
+        else:
+            for check in self.checks:
+                if self.a11y_lint_exclude is not None:
+                    if self.filename.startswith(self.a11y_lint_exclude):
+                        continue
+                check(self)
+        return self.errors
+
+
+@Context.add_check
+def missing_href(context):
+    for link in context.node.xpath("//xhtml:a|//a", namespaces=NSMAP):
+        href = attribute(link, "href")
+        if href is None:
+            context.report(
+                link,
+                "The <a> element is missing the href attribute."
+                " Without the href attribute an anchor represents"
+                " a placeholder for where a link might otherwise have"
+                " been placed and is invisible for screen readers."
+                " If the <a> is used to create interactive clickable"
+                " elements, consider using the <button type=“button”>"
+                " element instead for this.",
+            )
+        elif href.strip() == "#":
+            if attribute(link, "role") == "button":
+                continue
+            if attribute(link, "preventDefault"):
+                continue
+            context.report(
+                link,
+                'The <a> element href attribute should not be a single "#",'
+                " it can cause the page to scroll back to the top and it adds"
+                " an entry to the browser history, so it takes an additiona "
+                " click of the back button to go to the previous page."
+                " Consider using a <button type=“button”> element to create"
+                " interactive clickable elements.",
+            )
+
+
+@Context.add_check
+def missing_alt(context):
+    for image in context.node.xpath("//xhtml:img|//img", namespaces=NSMAP):
+        alt = attribute(image, "alt")
+        if alt is None:
+            context.report(
+                image,
+                "The <img> element requires an alt attribute. The alt"
+                " attribute provides descriptive information for an image if a"
+                " user for some reason cannot view it (because of slow"
+                " connection, an error, or if the user uses a screen reader)."
+                " If the image is considered decorative, the alt attribute"
+                " should be left empty, but not removed, so screen readers"
+                " will ignore the image.",
+            )
+
+
+@Context.add_check
+def missing_link_content(context):
+    for link in context.node.xpath("//xhtml:a|//a", namespaces=NSMAP):
+        if link.xpath(".//text()"):
+            continue
+        if link.xpath(".//xhtml:img|.//img", namespaces=NSMAP):
+            continue
+        if link.xpath(TAL_CONTENT_XPATH, namespaces=NSMAP):
+            continue
+        if attribute(link, "aria-label"):
+            continue
+        context.report(
+            link,
+            "The <a> element requires descriptive content that help users"
+            " better understand what they can expect if they click the link."
+            " An <a> element without descriptive text will only announce the"
+            " href path to screen reader users. Keep in mind that users of"
+            " screen readers have trouble distinguishing icons and need"
+            " descriptive text to understand the context of the <button>."
+            " Consider adding descriptive content in the form of text, an"
+            " aria-label attribute or an image.",
+        )
+
+
+@Context.add_check
+def missing_button_content(context):
+    for button in context.node.xpath("//xhtml:button|//button", namespaces=NSMAP):
+        if button.xpath(".//text()"):
+            continue
+        if button.xpath(TAL_CONTENT_XPATH, namespaces=NSMAP):
+            continue
+        if attribute(button, "aria-label"):
+            continue
+        context.report(
+            button,
+            "The <button> element requires descriptive text that helps users"
+            " understand what they can expect when they click it. Keep in mind"
+            " that users of screen readers have trouble distinguishing icons"
+            " and need descriptive text to understand the context of the"
+            " <button>. Consider adding descriptive text in the form of text"
+            " or an aria-label attribute.",
+        )
+
+
+@Context.add_check
+def missing_for(context):
+    for label in context.node.xpath("//xhtml:label|//label", namespaces=NSMAP):
+        if label.xpath(".//xhtml:input|.//input", namespaces=NSMAP):
+            continue
+        if label.xpath(".//xhtml:select|.//select", namespaces=NSMAP):
+            continue
+        if label.xpath(".//xhtml:textarea|.//textarea", namespaces=NSMAP):
+            continue
+        label_for = attribute(label, "for")
+        if label_for is None:
+            context.report(
+                label,
+                "The <label> element needs to be explicitly associated with a"
+                " form control through the use of nesting or the for"
+                " attribute, whose value needs to correspond to the value of"
+                " the id attribute of the associated form control element"
+                " (<input>, <textarea> and <select>).",
+            )
+
+
+def main(argv: typing.Optional[typing.Sequence[str]] = None) -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--a11y-lint-exclude")
+    parser.add_argument("filenames", nargs="*")
+    args = parser.parse_args(argv)
+
+    errors = []
+    for filename in args.filenames:
+        errors += Context(filename, a11y_lint_exclude=args.a11y_lint_exclude).run()
+    if len(errors):
+        print("\n".join(errors))
+        return 1
+    return 0
+
+
+if __name__ == "__main__":  # pragma: no cover
+    exit(main())
diff --git a/src/check_chameleon/tests/__init__.py b/src/check_chameleon/tests/__init__.py