feat: strict mode for parsing (#55)

* feat: strict mode for parsing

* docs: lax and strict parsing and serialization

README.rst

@@ -45,6 +45,8 @@ Parsing::
     doc = Document.parse(samplexml)
     print(doc.trade.agreement.seller.name)
 
+``Document.parse()`` taskes a boolean parameter ``strict`` which defaults to ``True``. This means that the parser will raise an error if it encounters any unknown element. If you set it to ``False``, the parser will not raise an error and parse whatever it can.
+
 Generating::
 
     import os
@@ -136,6 +138,7 @@ Generating::
     with open("output.pdf", "wb") as f:
         f.write(new_pdf_bytes)
 
+``Document.serialize()`` will validate the generated XML against the specified schema and raise an error if it is not valid. If you want to avoid validation, you can set the ``schema`` parameter to ``None``.
 
 Development
 -----------

drafthorse/models/container.py

@@ -19,9 +19,9 @@ def get_tag(self):
     def empty_element(self):
         return self.child_type()
 
-    def add_from_etree(self, root):
+    def add_from_etree(self, root, strict=True):
         childel = self.empty_element()
-        childel.from_etree(root)
+        childel.from_etree(root, strict)
         self.add(childel)
 
 
@@ -46,7 +46,7 @@ def append_to(self, node):
             self.set_element(el, child)
             el.append_to(node)
 
-    def add_from_etree(self, root):
+    def add_from_etree(self, root, strict=True):
         self.add(root.text)
 
 
@@ -60,7 +60,7 @@ def set_element(self, el, child):
         el._amount = child[0]
         el._currency = child[1]
 
-    def add_from_etree(self, root):
+    def add_from_etree(self, root, strict=True):
         self.add((root.text, root.attrib.get("currencyID")))
 
 
@@ -74,7 +74,7 @@ def set_element(self, el, child):
         el._text = child[1]
         el._scheme_id = child[0]
 
-    def add_from_etree(self, root):
+    def add_from_etree(self, root, strict=True):
         self.add((root.attrib["schemeID"], root.text))
 
 
@@ -87,5 +87,5 @@ def empty_element(self):
     def set_element(self, el, child):
         el._text = child
 
-    def add_from_etree(self, root):
+    def add_from_etree(self, root, strict=True):
         self.add(root.text)

drafthorse/models/elements.py

@@ -88,7 +88,7 @@ def __setattr__(self, key, value):
             )
         return super().__setattr__(key, value)
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         if (
             hasattr(self, "Meta")
             and hasattr(self.Meta, "namespace")
@@ -109,19 +109,19 @@ def from_etree(self, root):
             if child.tag in field_index:
                 name, _childel = field_index[child.tag]
                 if isinstance(getattr(self, name), Container):
-                    getattr(self, name).add_from_etree(child)
+                    getattr(self, name).add_from_etree(child, strict)
                 else:
-                    getattr(self, name).from_etree(child)
-            else:
+                    getattr(self, name).from_etree(child, strict)
+            elif strict:
                 raise TypeError("Unknown element {}".format(child.tag))
         return self
 
     @classmethod
-    def parse(cls, xmlinput):
+    def parse(cls, xmlinput, strict=True):
         from lxml import etree
 
         root = etree.fromstring(xmlinput)
-        return cls().from_etree(root)
+        return cls().from_etree(root, strict)
 
 
 class StringElement(Element):
@@ -149,7 +149,7 @@ def to_etree(self):
         node.text = self._text
         return node
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         self._text = root.text
         self._set_on_input = True
         return self
@@ -168,7 +168,7 @@ def to_etree(self):
     def __str__(self):
         return self._value
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         self._value = Decimal(root.text)
         self._set_on_input = True
         return self
@@ -189,7 +189,7 @@ def to_etree(self):
     def __str__(self):
         return "{} {}".format(self._amount, self._unit_code)
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         self._amount = Decimal(root.text)
         self._unit_code = root.attrib["unitCode"]
         self._set_on_input = True
@@ -211,7 +211,7 @@ def to_etree(self):
             del node.attrib["currencyID"]
         return node
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         self._amount = Decimal(root.text)
         self._currency = root.attrib.get("currencyID") or None
         self._set_on_input = True
@@ -235,7 +235,7 @@ def to_etree(self):
         node.attrib["listVersionID"] = self._list_version_id
         return node
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         self._text = Decimal(root.text)
         self._list_id = root.attrib["listID"]
         self._list_version_id = root.attrib["listVersionID"]
@@ -260,7 +260,7 @@ def to_etree(self):
         node.text = self._text
         return node
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         self._mime_code = root.attrib["mimeCode"]
         self._filename = root.attrib["filename"]
         self._text = root.text
@@ -283,7 +283,7 @@ def to_etree(self):
         node.attrib["schemeAgencyID"] = self._scheme_id
         return node
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         self._text = root.text
         self._scheme_id = root.attrib["schemeAgencyID"]
         self._set_on_input = True
@@ -306,7 +306,7 @@ def to_etree(self):
             node.attrib["schemeID"] = self._scheme_id
         return node
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         self._text = root.text
         try:
             self._scheme_id = root.attrib["schemeID"]
@@ -346,11 +346,14 @@ def to_etree(self):
             t.append(node)
         return t
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         if len(root) != 1:
             raise TypeError("Date containers should have one child")
         if root[0].tag != "{%s}%s" % (self._date_time_namespace, "DateTimeString"):
-            raise TypeError("Tag %s not recognized" % root[0].tag)
+            if strict:
+                raise TypeError("Tag %s not recognized" % root[0].tag)
+            else:
+                return self
         self._format = root[0].attrib["format"]
         if self._format == "102":
             self._value = datetime.strptime(root[0].text, "%Y%m%d").date()
@@ -362,7 +365,7 @@ def from_etree(self, root):
                 self._value = w.monday()
             else:
                 self._value = datetime.strptime(root[0].text + "1", "%G%V%u").date()
-        else:
+        elif strict:
             raise TypeError(
                 "Date format %s cannot be parsed" % root[0].attrib["format"]
             )
@@ -384,7 +387,7 @@ def to_etree(self):
             t.text = self._value.strftime("%Y-%m-%dT%H:%M:%S")
         return t
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         try:
             self._value = datetime.strptime(root.text, "%Y-%m-%dT%H:%M:%S").date()
         except Exception:
@@ -416,7 +419,7 @@ def to_etree(self):
     def __str__(self):
         return "{}".format(self._value)
 
-    def from_etree(self, root):
+    def from_etree(self, root, strict=True):
         if len(root) != 1:
             raise TypeError("Indicator containers should have one child")
         if root[0].tag != "{%s}%s" % (NS_UDT, "Indicator"):