XML Formatter QoL improvements (#88)

- Rewritten backend methods for prettifing and minimizing XMLs
- Added "Clear" and "Insert default XML" buttons in XML Formatter.
- Added place to display error messages in case of any

Co-authored-by: Adam Bem <adam.bem@zoho.eu>
Reviewed-on: R11/release11-tools-web#88

Backend-libXML/Parser.py

@@ -14,7 +14,9 @@ def prettify(source: str) -> str:
         prolog_end = source.find("?>") + 2
         prolog = source[prolog_start:prolog_end] + "\n"
         source = source[prolog_end: ]
-    xml = etree.XML(source)
+    
+    parser = etree.XMLParser(remove_blank_text=True)
+    xml = etree.fromstring(source, parser=parser)
     return prolog + etree.tostring(xml, pretty_print=True).decode()
 
 def minimize(source: str) -> str:
@@ -23,18 +25,18 @@ def minimize(source: str) -> str:
     :param source: XML
     :return: minimized XML
     """
-    result = source
     
-    to_remove = ["   ", "  ", "\t", "\n"]
-    to_substitute = [(" <", "<"), ("> ", ">"), ("</ ", "</"), (" >", ">")]
+    prolog = ""
+    prolog_start = source.find("<?")
     
-    for chars in to_remove:
-        result = result.replace(chars, "")
+    if prolog_start != -1:
+        prolog_end = source.find("?>") + 2
+        prolog = source[prolog_start:prolog_end]
+        source = source[prolog_end: ]
     
-    for e in to_substitute:
-        result = result.replace(e[0], e[1])
-    
-    return result
+    parser = etree.XMLParser(remove_blank_text=True)
+    xml = etree.fromstring(source, parser=parser)
+    return prolog + etree.tostring(xml, pretty_print=False).decode()
 
 
 def xpath(source: str, xpath: str) -> str: