proxy-packer.js/index.js

175 lines
5.3 KiB
JavaScript

'use strict';
module.exports.create = function (opts) {
var machine = { onMessage: opts.onMessage };
machine._version = 1;
machine.state = 0;
machine.states = { 0: 'version', 1: 'headerLength', 2: 'header', 3: 'data'/*, 4: 'error'*/ };
machine.states_length = Object.keys(machine.states).length;
machine.chunkIndex = 0;
machine.fns = {};
machine.fns.version = function (chunk) {
//console.log('');
//console.log('[version]');
if ((255 - machine._version) !== chunk[machine.chunkIndex]) {
console.error("not v" + machine._version + " (or data is corrupt)");
// no idea how to fix this yet
}
machine.chunkIndex += 1;
return true;
};
machine.headerLen = 0;
machine.fns.headerLength = function (chunk) {
//console.log('');
//console.log('[headerLength]');
machine.headerLen = chunk[machine.chunkIndex];
machine.chunkIndex += 1;
return true;
};
machine.buf = null;
machine.bufIndex = 0;
//var buf = Buffer.alloc(4096);
machine.fns.header = function (chunk) {
//console.log('');
//console.log('[header]');
var curSize = machine.bufIndex + (chunk.length - machine.chunkIndex);
var partLen = 0;
var str = '';
var part;
if (curSize < machine.headerLen) {
// I still don't have the whole header,
// so just create a large enough buffer,
// write these bits, and wait for the next chunk.
if (!machine.buf) {
machine.buf = Buffer.alloc(machine.headerLen);
}
// partLen should be no more than the available size
partLen = Math.min(machine.headerLen - machine.bufIndex, chunk.length - machine.chunkIndex);
part = chunk.slice(machine.chunkIndex, machine.chunkIndex + partLen);
chunk.copy(machine.buf, machine.bufIndex, machine.chunkIndex, machine.chunkIndex + partLen);
machine.chunkIndex += partLen; // this MUST be chunk.length
machine.bufIndex += partLen;
return false;
}
else {
// it's now ready to discover the whole header
if (machine.buf) {
str += machine.buf.slice(0, machine.bufIndex).toString();
}
partLen = machine.headerLen - str.length;
part = chunk.slice(machine.chunkIndex, machine.chunkIndex + partLen);
str += part.toString();
machine.chunkIndex += partLen;
machine.buf = null; // back to null
machine.bufIndex = 0; // back to 0
machine._headers = str.split(/,/g);
machine.family = machine._headers[0];
machine.address = machine._headers[1];
machine.port = machine._headers[2];
machine.bodyLen = parseInt(machine._headers[3], 10) || -1;
machine.service = machine._headers[4];
return true;
}
};
machine.fns.data = function (chunk) {
//console.log('');
//console.log('[data]');
var curSize = machine.bufIndex + (chunk.length - machine.chunkIndex);
//console.log('curSize:', curSize);
//console.log('bodyLen:', machine.bodyLen, typeof machine.bodyLen);
var partLen = 0;
partLen = Math.min(machine.bodyLen - machine.bufIndex, chunk.length - machine.chunkIndex);
if (curSize < machine.bodyLen) {
//console.log('curSize < bodyLen');
// I still don't have the whole header,
// so just create a large enough buffer,
// write these bits, and wait for the next chunk.
if (!machine.buf) {
machine.buf = Buffer.alloc(machine.bodyLen);
}
chunk.copy(machine.buf, machine.bufIndex, machine.chunkIndex, machine.chunkIndex + partLen);
machine.chunkIndex += partLen; // this MUST be chunk.length
machine.bufIndex += partLen;
return false;
}
if (machine.bufIndex > 0) {
// the completing remainder of the body is in the current slice
chunk.copy(machine.buf, machine.bufIndex, machine.chunkIndex, machine.chunkIndex + partLen);
}
else {
// the whole body is in the current slice
machine.buf = chunk.slice(machine.chunkIndex, machine.chunkIndex + partLen);
}
machine.bufIndex += partLen;
machine.onMessage({
family: machine.family
, address: machine.address
, port: machine.port
, data: machine.buf.slice(0, machine.bufIndex)
, service: machine.service
});
machine.chunkIndex += partLen; // === chunk.length
machine.buf = null; // reset to null
machine.bufIndex = 0; // reset to 0
return true;
};
machine.fns.addChunk = function (chunk) {
//console.log('');
//console.log('[addChunk]');
machine.chunkIndex = 0;
while (machine.chunkIndex < chunk.length) {
//console.log('chunkIndex:', machine.chunkIndex, 'state:', machine.state);
if (true === machine.fns[machine.states[machine.state]](chunk)) {
machine.state += 1;
machine.state %= machine.states_length;
}
}
};
return machine;
};
module.exports.pack = function (address, data) {
var version = 1;
var header = Buffer.from([
/*servername,*/ address.family, address.address, address.port, data.byteLength
, (data.service || 'https')
].join(','));
var meta = Buffer.from([ 255 - version, header.length ]);
var buf = Buffer.alloc(meta.byteLength + header.byteLength + data.byteLength);
meta.copy(buf, 0, 0, meta.byteLength);
header.copy(buf, 2, 0, header.byteLength);
data.copy(buf, 2 + header.byteLength, 0, data.byteLength);
return buf;
};