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A Python JSON implementation of the Thrift protocol
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
#
from TProtocol import *
import json, base64, sys
__all__ = ['TJSONProtocol', 'TJSONProtocolFactory']
VERSION = 1
COMMA = ','
COLON = ':'
LBRACE = '{'
RBRACE = '}'
LBRACKET = '['
RBRACKET = ']'
QUOTE = '"'
BACKSLASH = '\\'
ZERO = '0'
ESCSEQ = '\\u00'
ESCAPE_CHAR = '"\\bfnrt'
ESCAPE_CHAR_VALS = ['"', '\\', '\b', '\f', '\n', '\r', '\t']
HEXA_CHAR = '0123456789abcdef'
NUMERIC_CHAR = '+-.0123456789Ee'
CTYPES = {TType.BOOL: 'tf',
TType.BYTE: 'i8',
TType.I16: 'i16',
TType.I32: 'i32',
TType.I64: 'i64',
TType.DOUBLE: 'dbl',
TType.STRING: 'str',
TType.STRUCT: 'rect',
TType.LIST: 'lst',
TType.SET: 'set',
TType.MAP: 'map'}
JTYPES = {}
for key in CTYPES.keys():
JTYPES[CTYPES[key]] = key
class JSONBaseContext():
def __init__(self, protocol):
self.protocol = protocol
self.first = True
def doIO(self, function):
pass
def write(self):
pass
def read(self):
pass
def escapeNum(self):
return False
class JSONListContext(JSONBaseContext):
def doIO(self, function):
if self.first is True:
self.first = False
else:
function(COMMA)
def write(self):
self.doIO(self.protocol.trans.write)
def read(self):
self.doIO(self.protocol.readJSONSyntaxChar)
class JSONPairContext(JSONBaseContext):
colon = True
def doIO(self, function):
if self.first is True:
self.first = False
self.colon = True
else:
function(COLON if self.colon == True else COMMA)
self.colon = not self.colon
def write(self):
self.doIO(self.protocol.trans.write)
def read(self):
self.doIO(self.protocol.readJSONSyntaxChar)
def escapeNum(self):
return self.colon
class LookaheadReader():
hasData = False
data = ''
def __init__(self, protocol):
self.protocol = protocol
def read(self):
if self.hasData is True:
self.hasData = False
else:
self.data = self.protocol.trans.read(1)
return self.data
def peek(self):
if self.hasData is False:
self.data = self.protocol.trans.read(1)
self.hasData = True
return self.data
class TJSONProtocolBase(TProtocolBase):
def __init__(self, trans):
TProtocolBase.__init__(self, trans)
def resetWriteContext(self):
self.contextStack = []
self.context = JSONBaseContext(self)
def resetReadContext(self):
self.resetWriteContext()
self.reader = LookaheadReader(self)
def pushContext(self, ctx):
self.contextStack.append(ctx)
self.context = ctx
def popContext(self):
self.contextStack.pop()
def writeJSONString(self, string):
self.context.write()
self.trans.write(json.dumps(string))
def writeJSONNumber(self, number):
self.context.write()
jsNumber = str(number)
if self.context.escapeNum():
jsNumber = "%s%s%s" % (QUOTE, jsNumber, QUOTE)
self.trans.write(jsNumber)
def writeJSONBase64(self, binary):
self.context.write()
self.trans.write(QUOTE)
self.trans.write(base64.b64encode(binary))
self.trans.write(QUOTE)
def writeJSONObjectStart(self):
self.context.write()
self.trans.write(LBRACE)
self.pushContext(JSONPairContext(self))
def writeJSONObjectEnd(self):
self.popContext()
self.trans.write(RBRACE)
def writeJSONArrayStart(self):
self.context.write()
self.trans.write(LBRACKET)
self.pushContext(JSONListContext(self))
def writeJSONArrayEnd(self):
self.popContext()
self.trans.write(RBRACKET)
def readJSONSyntaxChar(self, character):
current = self.reader.read()
if character != current:
raise TProtocolException(TProtocolException.INVALID_DATA,
"Unexpected character: %s" % current)
def readJSONString(self, skipContext):
string = []
if skipContext is False:
self.context.read()
self.readJSONSyntaxChar(QUOTE)
while True:
character = self.reader.read()
if character == QUOTE:
break
if character == ESCSEQ[0]:
character = self.reader.read()
if character == ESCSEQ[1]:
self.readJSONSyntaxChar(ZERO)
self.readJSONSyntaxChar(ZERO)
character = json.JSONDecoder().decode('"\u00%s"' % self.trans.read(2))
else:
off = ESCAPE_CHAR.find(char)
if off == -1:
raise TProtocolException(TProtocolException.INVALID_DATA,
"Expected control char")
character = ESCAPE_CHAR_VALS[off]
string.append(character)
return ''.join(string)
def isJSONNumeric(self, character):
return (True if NUMERIC_CHAR.find(character) != - 1 else False)
def readJSONQuotes(self):
if (self.context.escapeNum()):
self.readJSONSyntaxChar(QUOTE)
def readJSONNumericChars(self):
numeric = []
while True:
character = self.reader.peek()
if self.isJSONNumeric(character) is False:
break
numeric.append(self.reader.read())
return ''.join(numeric)
def readJSONInteger(self):
self.context.read()
self.readJSONQuotes()
numeric = self.readJSONNumericChars()
self.readJSONQuotes()
try:
return int(numeric)
except ValueError:
raise TProtocolException(TProtocolException.INVALID_DATA,
"Bad data encounted in numeric data")
def readJSONDouble(self):
self.context.read()
if self.reader.peek() == QUOTE:
string = self.readJSONString(True)
try:
double = float(string)
if self.context.escapeNum is False and double != inf and double != nan:
raise TProtocolException(TProtocolException.INVALID_DATA,
"Numeric data unexpectedly quoted")
return double
except ValueError:
raise TProtocolException(TProtocolException.INVALID_DATA,
"Bad data encounted in numeric data")
else:
if self.context.escapeNum() is True:
self.readJSONSyntaxChar(QUOTE)
try:
return float(self.readJSONNumericChars())
except ValueErro:
raise TProtocolException(TProtocolException.INVALID_DATA,
"Bad data encounted in numeric data")
def readJSONBase64(self):
string = self.readJSONString(False)
return base64.b64decode(string)
def readJSONObjectStart(self):
self.context.read()
self.readJSONSyntaxChar(LBRACE)
self.pushContext(JSONPairContext(self))
def readJSONObjectEnd(self):
self.readJSONSyntaxChar(RBRACE)
self.popContext()
def readJSONArrayStart(self):
self.context.read()
self.readJSONSyntaxChar(LBRACKET)
self.pushContext(JSONListContext(self))
def readJSONArrayEnd(self):
self.readJSONSyntaxChar(RBRACKET)
self.popContext()
class TJSONProtocol(TJSONProtocolBase):
def readMessageBegin(self):
self.resetReadContext()
self.readJSONArrayStart()
if self.readJSONInteger() != VERSION:
raise TProtocolException(TProtocolException.BAD_VERSION,
"Message contained bad version.")
name = self.readJSONString(False)
typen = self.readJSONInteger()
seqid = self.readJSONInteger()
return (name, typen, seqid)
def readMessageEnd(self):
self.readJSONArrayEnd()
def readStructBegin(self):
self.readJSONObjectStart()
def readStructEnd(self):
self.readJSONObjectEnd()
def readFieldBegin(self):
character = self.reader.peek()
type = 0
id = 0
if character == RBRACE:
type = TType.STOP
else:
id = self.readJSONInteger()
self.readJSONObjectStart()
type = JTYPES[self.readJSONString(False)]
return (None, type, id)
def readFieldEnd(self):
self.readJSONObjectEnd()
def readMapBegin(self):
self.readJSONArrayStart()
keyType = JTYPES[self.readJSONString(False)]
valueType = JTYPES[self.readJSONString(False)]
size = self.readJSONInteger()
self.readJSONObjectStart()
return (keyType, valueType, size)
def readMapEnd(self):
self.readJSONObjectEnd()
self.readJSONArrayEnd()
def readCollectionBegin(self):
self.readJSONArrayStart()
elemType = JTYPES[self.readJSONString(False)]
size = self.readJSONInteger()
return (type, size)
readListBegin = readCollectionBegin
readSetBegin = readCollectionBegin
def readCollectionEnd(self):
self.readJSONArrayEnd()
readSetEnd = readCollectionEnd
readListEnd = readCollectionEnd
def readBool(self):
return (False if self.readJSONInteger() == 0 else True)
def readNumber(self):
return self.readJSONInteger()
readByte = readNumber
readI16 = readNumber
readI32 = readNumber
readI64 = readNumber
def readDouble(self):
return self.readJSONDouble()
def readString(self):
return self.readJSONString(False)
def readBinary(self):
return self.readJSONBase64()
def writeMessageBegin(self, name, request_type, seqid):
self.resetWriteContext()
self.writeJSONArrayStart()
self.writeJSONNumber(VERSION)
self.writeJSONString(name)
self.writeJSONNumber(request_type)
self.writeJSONNumber(seqid)
def writeMessageEnd(self):
self.writeJSONArrayEnd()
def writeStructBegin(self, name):
self.writeJSONObjectStart()
def writeStructEnd(self):
self.writeJSONObjectEnd()
def writeFieldBegin(self, name, type, id):
self.writeJSONNumber(id)
self.writeJSONObjectStart()
self.writeJSONString(CTYPES[type])
def writeFieldEnd(self):
self.writeJSONObjectEnd()
def writeFieldStop(self):
pass
def writeMapBegin(self, ktype, vtype, size):
self.writeJSONArrayStart()
self.writeJSONString(CTYPES[ktype])
self.writeJSONString(CTYPES[vtype])
self.writeJSONNumber(size)
self.writeJSONObjectStart()
def writeMapEnd(self):
self.writeJSONObjectEnd()
self.writeJSONArrayEnd()
def writeListBegin(self, etype, size):
self.writeJSONArrayStart()
self.writeJSONString(CTYPES[etype])
self.writeJSONNumber(size)
def writeListEnd(self):
self.writeJSONArrayEnd()
def writeSetBegin(self, etype, size):
self.writeJSONArrayStart()
self.writeJSONString(CTYPES[etype])
self.writeJSONNumber(size)
def writeSetEnd(self):
self.writeJSONArrayEnd()
def writeBool(self, boolean):
self.writeJSONNumber(1 if boolean is True else 0)
def writeInteger(self, integer):
self.writeJSONNumber(integer)
writeByte = writeInteger
writeI16 = writeInteger
writeI32 = writeInteger
writeI64 = writeInteger
def writeDouble(self, dbl):
self.writeJSONNumber(dbl)
def writeString(self, string):
self.writeJSONString(string)
def writeBinary(self, binary):
self.writeJSONBase64(binary)
class TJSONProtocolFactory:
def __init__(self):
pass
def getProtocol(self, trans):
return TJSONProtocol(trans)
@fanchy

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commented Nov 5, 2013

Wonderful!

@johnjullies

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commented Apr 21, 2016

How can I use this to serialize thrift to JSON?

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