CURLOPT_FILEでHTTPレスポンスをファイルに直接書き込んでいくサンプル ref: http://qiita.com/Hiraku/items/9fb7a0df060e0424921d

stream.js

var http = require('http');

http.createServer(function(req, res){
    var i = 0;
    var id = 100 * Math.random() | 0;

    res.writeHead(200, {'Content-Type': 'text/plain'});
    setInterval(function(){
        var result = id + ':' + ++i;
        console.log(result);
        res.write(result + '\n');
    }, 1000);
}).listen(1337, 'localhost');

console.log('Server running at http://localhost:1337/');

streamclient.php

<?php
const TIMEOUT = 10;

$mh = curl_multi_init();

$ch1 = curl_init('http://localhost:1337/');
$fh1 = fopen('result1.txt', 'w');
curl_setopt($ch1, CURLOPT_FILE, $fh1);
curl_multi_add_handle($mh, $ch1);

$ch2 = curl_init('http://localhost:1337/');
$fh2 = fopen('result2.txt', 'w');
curl_setopt($ch2, CURLOPT_FILE, $fh2);
curl_multi_add_handle($mh, $ch2);

//curl_multi start
do $stat = curl_multi_exec($mh, $running);
while ($stat === CURLM_CALL_MULTI_PERFORM);
if (!$running || $stat !== CURLM_OK) {
    throw new RuntimeException("$running $stat");
}

//curl_multi wait
do switch (curl_multi_select($mh, TIMEOUT)) {
    case -1: // selectに失敗するケースがあるらしい https://bugs.php.net/bug.php?id=61141
        usleep(10);
        do $stat = curl_multi_exec($mh, $running);
        while ($stat === CURLM_CALL_MULTI_PERFORM);
        continue 2;

    case 0: //timeout
        continue 2;

    default:
        //何か変化があった
        do $stat = curl_multi_exec($mh, $running);
        while ($stat === CURLM_CALL_MULTI_PERFORM);

        //強制書き込み
        fflush($fh1);
        fflush($fh2);
} while ($running);