llsd_parse.py

import xml.etree.ElementTree as ET
import uuid
import datetime
import base64

def parseLLSD(element):
    if element.tag == "undef":
        return None
    
    elif element.tag == "boolean":
        if element.text.lower() == "true" or element.text == "1":
            return True
        elif element.text.lower() == "false" or element.text == "0" or element.text == "":
            return False
        else:
            raise ValueError("Bad value for bool: {}".format(element.text))
    
    elif element.tag == "string":
        return element.text or ""
    
    elif element.tag == "integer":
        return int(element.text or 0)
    
    elif element.tag == "real":
        return float(element.text or 0.0)
    
    elif element.tag == "uuid":
        return uuid.UUID(element.text or "00000000-0000-0000-0000-000000000000")
    
    elif element.tag == "date":
        date = []
        buf = ""
        position = 0
        for c in element.text:
            if c == "-":
                if position == 0 and len(buf) == 4:
                    date.append(int(buf))
                    buf = ""
                elif position == 1 and len(buf) == 2:
                    date.append(int(buf))
                    buf = ""
                else:
                    raise ValueError("Bad value for date: Unexpected \"{}\"".format(c))
                position += 1
            elif c.lower() == "t":
                if position == 2 and len(buf) == 2:
                    date.append(int(buf))
                    buf = ""
                else:
                    raise ValueError("Bad value for date: Unexpected \"{}\"".format(c))
                position += 1
            elif c == ":":
                if position == 3 and len(buf) == 2:
                    date.append(int(buf))
                    buf = ""
                elif position == 4 and len(buf) == 2:
                    date.append(int(buf))
                    buf = ""
                else:
                    raise ValueError("Bad value for date: Unexpected \"{}\"".format(c))
                position += 1
            elif c == ".":
                if position == 5 and len(buf) == 2:
                    date.append(int(buf))
                    buf = ""
                else:
                    raise ValueError("Bad value for date: Unexpected \"{}\"".format(c))
                position += 1
            elif c.lower() == "z":
                if position == 6:
                    date.append(int(buf))
                    buf = ""
                else:
                    raise ValueError("Bad value for date: Unexpected \"{}\"".format(c))
                position += 1
            else:
                buf += c
        
        if buf != "":
            raise ValueError("Bad value for date: Unemptied Buffer \"{}\"".format(buf))
        elif not (position == 3 or position == 6 or position == 7):
            raise ValueError("Bad value for date: Unexpected end of string")
        
        return datetime.datetime(*date)
    
    elif element.tag == "uri":
        return element.text or ""
    
    elif element.tag == "binary":
        encoding = element.attrib.get("encoding", "base64").lower()
        if encoding == "base64":
            return base64.b64decode(element.text)
        elif encoding == "base16":
            return base64.b16decode(element.text)
        elif encoding == "base85":
            return base64.b85decode(element.text)
        else:
            raise ValueError("Bad encoding for binary: {}".format(encoding))
        
    elif element.tag == "map":
        result = {}
        for i in range(0, len(element), 2):
            if element[i].tag != "key":
                raise ValueError("Unexpected element in map(Expected key): {}".format(element[i].tag))
            result[element[i].text] = parseLLSD(element[i+1])
        return result
    
    elif element.tag == "array":
        result = []
        for child in element:
            result.append(parseLLSD(child))
        return result
    
    else:
        raise ValueError("Unexpected element {}".format(element.tag))