module documentation

Context-free flattener/serializer for rendering Python objects, possibly complex or arbitrarily nested, as strings.

Function attributeEscapingDoneOutside Escape some character or UTF-8 byte data for inclusion in the top level of an attribute. attributeEscapingDoneOutside actually passes the data through unchanged, because writeWithAttributeEscaping handles the quoting of the text within attributes outside the generator returned by ...
Function escapedCDATA Escape CDATA for inclusion in a document.
Function escapedComment Within comments the sequence --> can be mistaken as the end of the comment. To ensure consistent parsing and valid output the sequence is replaced with -->. Furthermore, whitespace is added when a comment ends in a dash...
Function escapeForContent Escape some character or UTF-8 byte data for inclusion in an HTML or XML document, by replacing metacharacters (&<>) with their entity equivalents (&amp;&lt;&gt;).
Function writeWithAttributeEscaping Decorate a write callable so that all output written is properly quoted for inclusion within an XML attribute value.
Constant BUFFER_SIZE Undocumented
Type Variable T For documentation purposes, read FlattenableRecursive as Flattenable. However, since mypy doesn't support recursive type definitions (yet?), we'll put Any in the actual definition.
Function _flattenElement Make root slightly more flat by yielding all its immediate contents as strings, deferreds or generators that are recursive calls to itself.
Async Function _flattenTree Make root into an iterable of bytes and Deferred by doing a depth first traversal of the tree.
Function _fork Create a new Deferred based on d that will fire and fail with d's result or error, but will not modify d's callback type.
Function _getSlotValue Find the value of the named slot in the given stack of slot data.
def attributeEscapingDoneOutside(data: Union[bytes, str]) -> bytes: (source)

Escape some character or UTF-8 byte data for inclusion in the top level of an attribute. attributeEscapingDoneOutside actually passes the data through unchanged, because writeWithAttributeEscaping handles the quoting of the text within attributes outside the generator returned by _flattenElement; this is used as the dataEscaper argument to that _flattenElement call so that that generator does not redundantly escape its text output.

Parameters
data:Union[bytes, str]The string to escape.
Returns
bytesThe string, unchanged, except for encoding.
def escapedCDATA(data: Union[bytes, str]) -> bytes: (source)

Escape CDATA for inclusion in a document.

Parameters
data:Union[bytes, str]The string to escape.
Returns
bytesThe quoted form of data. If data is unicode, return a utf-8 encoded string.
def escapedComment(data: Union[bytes, str]) -> bytes: (source)

Within comments the sequence --> can be mistaken as the end of the comment. To ensure consistent parsing and valid output the sequence is replaced with --&gt;. Furthermore, whitespace is added when a comment ends in a dash. This is done to break the connection of the ending - with the closing -->.

Parameters
data:Union[bytes, str]The string to escape.
Returns
bytesThe quoted form of data. If data is unicode, return a utf-8 encoded string.
def escapeForContent(data: Union[bytes, str]) -> bytes: (source)

Escape some character or UTF-8 byte data for inclusion in an HTML or XML document, by replacing metacharacters (&<>) with their entity equivalents (&amp;&lt;&gt;).

This is used as an input to _flattenElement's dataEscaper parameter.

Parameters
data:Union[bytes, str]The string to escape.
Returns
bytesThe quoted form of data. If data is str, return a utf-8 encoded string.
def writeWithAttributeEscaping(write: Callable[[bytes], object]) -> Callable[[bytes], None]: (source)

Decorate a write callable so that all output written is properly quoted for inclusion within an XML attribute value.

If a Tag x is flattened within the context of the contents of another Tag y, the metacharacters (<>&") delimiting x should be passed through unchanged, but the textual content of x should still be quoted, as usual. For example: <y><x>&amp;</x></y>. That is the default behavior of _flattenElement when escapeForContent is passed as the dataEscaper.

However, when a Tag x is flattened within the context of an attribute of another Tag y, then the metacharacters delimiting x should be quoted so that it can be parsed from the attribute's value. In the DOM itself, this is not a valid thing to do, but given that renderers and slots may be freely moved around in a twisted.web.template template, it is a condition which may arise in a document and must be handled in a way which produces valid output. So, for example, you should be able to get <y attr="&lt;x /&gt;" />. This should also be true for other XML/HTML meta-constructs such as comments and CDATA, so if you were to serialize a comment in an attribute you should get <y attr="&lt;-- comment --&gt;" />. Therefore in order to capture these meta-characters, flattening is done with write callable that is wrapped with writeWithAttributeEscaping.

The final case, and hopefully the much more common one as compared to serializing Tag and arbitrary IRenderable objects within an attribute, is to serialize a simple string, and those should be passed through for writeWithAttributeEscaping to quote without applying a second, redundant level of quoting.

Parameters
write:Callable[[bytes], object]A callable which will be invoked with the escaped bytes.
Returns
Callable[[bytes], None]A callable that writes data with escaping.
BUFFER_SIZE = (source)

Undocumented

Value
2**16

For documentation purposes, read FlattenableRecursive as Flattenable. However, since mypy doesn't support recursive type definitions (yet?), we'll put Any in the actual definition.

Value
TypeVar('T')
def _flattenElement(request: Optional[IRequest], root: Flattenable, write: Callable[[bytes], object], slotData: List[Optional[Mapping[str, Flattenable]]], renderFactory: Optional[IRenderable], dataEscaper: Callable[[Union[bytes, str]], bytes]) -> Generator[Union[Generator[Any, Any, Any], Deferred[Flattenable]], None, None]: (source)

Make root slightly more flat by yielding all its immediate contents as strings, deferreds or generators that are recursive calls to itself.

Parameters
request:Optional[IRequest]A request object which will be passed to IRenderable.render.
root:FlattenableAn object to be made flatter. This may be of type unicode, str, slot, Tag, tuple, list, types.GeneratorType, Deferred, or an object that implements IRenderable.
write:Callable[[bytes], object]A callable which will be invoked with each bytes produced by flattening root.
slotData:List[Optional[Mapping[str, Flattenable]]]A list of dict mapping str slot names to data with which those slots will be replaced.
renderFactory:Optional[IRenderable]If not None, an object that provides IRenderable.
dataEscaper:Callable[[Union[bytes, str]], bytes]A 1-argument callable which takes bytes or unicode and returns bytes, quoted as appropriate for the rendering context. This is really only one of two values: attributeEscapingDoneOutside or escapeForContent, depending on whether the rendering context is within an attribute or not. See the explanation in writeWithAttributeEscaping.
Returns
Generator[Union[Generator[Any, Any, Any], Deferred[Flattenable]], None, None]An iterator that eventually writes bytes to write. It can yield other iterators or Deferreds; if it yields another iterator, the caller will iterate it; if it yields a Deferred, the result of that Deferred will be another generator, in which case it is iterated. See _flattenTree for the trampoline that consumes said values.
async def _flattenTree(request: Optional[IRequest], root: Flattenable, write: Callable[[bytes], object]): (source)

Make root into an iterable of bytes and Deferred by doing a depth first traversal of the tree.

Parameters
request:Optional[IRequest]A request object which will be passed to IRenderable.render.
root:FlattenableAn object to be made flatter. This may be of type unicode, bytes, slot, Tag, tuple, list, types.GeneratorType, Deferred, or something providing IRenderable.
write:Callable[[bytes], object]A callable which will be invoked with each bytes produced by flattening root.
Returns
A Deferred-returning coroutine that resolves to None.
def _fork(d: Deferred[T]) -> Deferred[T]: (source)

Create a new Deferred based on d that will fire and fail with d's result or error, but will not modify d's callback type.

def _getSlotValue(name: str, slotData: Sequence[Optional[Mapping[str, Flattenable]]], default: Optional[Flattenable] = None) -> Flattenable: (source)

Find the value of the named slot in the given stack of slot data.