Add support for html files

1 files changed, 69 insertions, 0 deletions

diff --git a/libmat2/html.py b/libmat2/html.py
new file mode 100644
index 0000000..d0e9a2b
--- /dev/null
+++ b/libmat2/html.py
@@ -0,0 +1,69 @@
+from html import parser
+from typing import Dict, Any, List, Tuple
+
+from . import abstract
+
+
+class HTMLParser(abstract.AbstractParser):
+    mimetypes = {'text/html', }
+    def __init__(self, filename):
+        super().__init__(filename)
+        self.__parser = _HTMLParser()
+        with open(filename) as f:
+            self.__parser.feed(f.read())
+        self.__parser.close()
+
+    def get_meta(self) -> Dict[str, Any]:
+        return self.__parser.get_meta()
+
+    def remove_all(self) -> bool:
+        return self.__parser.remove_all(self.output_filename)
+
+
+class _HTMLParser(parser.HTMLParser):
+    """Python doesn't have a validating html parser in its stdlib, so
+    we're using an internal queue to track all the opening/closing tags,
+    and hoping for the best.
+    """
+    def __init__(self):
+        super().__init__()
+        self.__textrepr = ''
+        self.__meta = {}
+        self.__validation_queue = []
+
+    def handle_starttag(self, tag: str, attrs: List[Tuple[str, str]]):
+        self.__textrepr += self.get_starttag_text()
+        self.__validation_queue.append(tag)
+
+    def handle_endtag(self, tag: str):
+        if not self.__validation_queue:
+            raise ValueError
+        elif tag != self.__validation_queue.pop():
+            raise ValueError
+        # There is no `get_endtag_text()` method :/
+        self.__textrepr += '</' + tag + '>\n'
+
+    def handle_data(self, data: str):
+        if data.strip():
+            self.__textrepr += data
+
+    def handle_startendtag(self, tag: str, attrs: List[Tuple[str, str]]):
+        if tag == 'meta':
+            meta = {k:v for k, v in attrs}
+            name = meta.get('name', 'harmful metadata')
+            content = meta.get('content', 'harmful data')
+            self.__meta[name] = content
+        else:
+            self.__textrepr += self.get_starttag_text()
+
+    def remove_all(self, output_filename: str) -> bool:
+        if self.__validation_queue:
+            raise ValueError
+        with open(output_filename, 'w') as f:
+            f.write(self.__textrepr)
+        return True
+
+    def get_meta(self) -> Dict[str, Any]:
+        if self.__validation_queue:
+            raise ValueError
+        return self.__meta