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node_avro.cc
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node_avro.cc
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#include <avro/BinaryEncoder.hh>
#include <avro/Compiler.hh>
#include <avro/Decoder.hh>
#include <avro/Encoder.hh>
#include <avro/Generic.hh>
#include <avro/Specific.hh>
#include <avro/Symbol.hh>
#include <avro/ValidSchema.hh>
#include <avro/buffer/Buffer.hh>
#include <avro/buffer/BufferStream.hh>
#include <avro/json/JsonEncoder.hh>
#include <node.h>
#include <node_buffer.h>
#include <v8.h>
using namespace std;
using namespace v8;
/*
Takes two arguments, an Avro schema as a JSON string, and an Avro
value as a JSON string, and returns a buffer containing the encoded
data.
*/
static Handle<Value> JsonStringToAvroBuffer(const Arguments& args) {
HandleScope scope;
// Check arguments
if (args.Length() != 2) {
ThrowException(Exception::TypeError(String::New("Wrong number of arguments")));
return scope.Close(Undefined());
}
Handle<Value> schemaString = args[0];
Handle<Value> jsonString = args[1];
if (!schemaString->IsString()) {
ThrowException(Exception::TypeError(String::New("Schema must be a string")));
return scope.Close(Undefined());
}
if (!jsonString->IsString()) {
ThrowException(Exception::TypeError(String::New("JSON must be a string")));
return scope.Close(Undefined());
}
// Compile schema
String::Utf8Value schemaUtf8Value(schemaString);
uint8_t *schemaBytes = (uint8_t *) *schemaUtf8Value;
avro::ValidSchema schema = avro::compileJsonSchemaFromMemory(schemaBytes, schemaUtf8Value.length());
// Decode JSON from string
String::Utf8Value jsonUtf8Value(jsonString);
uint8_t *jsonBytes = (uint8_t *) *jsonUtf8Value;
auto_ptr<avro::InputStream> in = avro::memoryInputStream(jsonBytes, jsonUtf8Value.length());
avro::DecoderPtr decoder = avro::jsonDecoder(schema);
decoder->init(*in);
avro::GenericDatum datum(schema);
avro::decode(*decoder, datum);
// Encode datum to output stream backed by stringstream
stringstream ss(stringstream::out);
auto_ptr<avro::OutputStream> out = avro::ostreamOutputStream(ss);
avro::EncoderPtr encoder = avro::binaryEncoder();
encoder->init(*out);
avro::encode(*encoder, datum);
encoder->flush();
out->flush();
string s = ss.str();
// Copy data to buffer and return it
avro::BinaryEncoder *binaryEncoder = (avro::BinaryEncoder *) &(*encoder);
avro::StreamWriter &sw = binaryEncoder->getStreamWriter();
Handle<Value> buffer = node::Buffer::New((char *) s.data(), sw.getBytesWritten())->handle_;
return scope.Close(buffer);
}
/*
Takes two arguments, an Avro schema as a JSON string, and a buffer
containing encoded data, and returns a JSON string containing the
decoded Avro value.
*/
static Handle<Value> AvroBufferToJsonString(const Arguments& args) {
HandleScope scope;
// Check arguments
if (args.Length() != 2) {
ThrowException(Exception::TypeError(String::New("Wrong number of arguments")));
return scope.Close(Undefined());
}
Handle<Value> schemaString = args[0];
Handle<Value> avroBuffer = args[1];
if (!schemaString->IsString()) {
ThrowException(Exception::TypeError(String::New("Schema must be a string")));
return scope.Close(Undefined());
}
if (!node::Buffer::HasInstance(avroBuffer)) {
ThrowException(Exception::TypeError(String::New("Not a buffer")));
return scope.Close(Undefined());
}
// Compile schema
String::Utf8Value schemaUtf8Value(schemaString);
uint8_t *schemaBytes = (uint8_t *) *schemaUtf8Value;
avro::ValidSchema schema = avro::compileJsonSchemaFromMemory(schemaBytes, schemaUtf8Value.length());
// Decode data from buffer
auto_ptr<avro::InputStream> in =
avro::memoryInputStream((uint8_t *) node::Buffer::Data(avroBuffer->ToObject()),
node::Buffer::Length(avroBuffer->ToObject()));
avro::DecoderPtr decoder = avro::binaryDecoder();
decoder->init(*in);
avro::GenericDatum datum(schema);
avro::decode(*decoder, datum);
// Encode data to JSON
stringstream ss(stringstream::out);
auto_ptr<avro::OutputStream> out = avro::ostreamOutputStream(ss);
avro::EncoderPtr encoder = avro::jsonEncoder(schema);
encoder->init(*out);
avro::encode(*encoder, datum);
encoder->flush();
out->flush();
string s = ss.str();
avro::parsing::JsonEncoder<avro::parsing::SimpleParser<avro::parsing::JsonHandler> > *jsonEncoder =
(avro::parsing::JsonEncoder<avro::parsing::SimpleParser<avro::parsing::JsonHandler> > *) &(*encoder);
avro::StreamWriter &sw = jsonEncoder->getStreamWriter();
return scope.Close(String::New((char *) s.data(), sw.getBytesWritten()));
}
void init(Handle<Object> target) {
target->Set(String::NewSymbol("jsonStringToAvroBuffer"),
FunctionTemplate::New(JsonStringToAvroBuffer)->GetFunction());
target->Set(String::NewSymbol("avroBufferToJsonString"),
FunctionTemplate::New(AvroBufferToJsonString)->GetFunction());
}
NODE_MODULE(avro, init)