ReceiveSb Returns Only the Immediately Available Data

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Demonstrates that Socket.ReceiveSb returns only the data immediately available and not the entire response. The example connects to chilkatsoft.com over TLS and requests big_helloWorld.txt, a large text file of roughly 74,000 lines. A single ReceiveSb call returns just the first portion of the response, and the example reports how many characters were received compared with the total size given by the response Content-Length header.

<?php

$success = 0;

$socket = new COM("Chilkat.Socket");

//  Connect to chilkatsoft.com over TLS.
$bTls = 1;
$maxWaitMs = 5000;
$success = $socket->Connect('chilkatsoft.com',443,$bTls,$maxWaitMs);
if ($success == 0) {
    print $socket->LastErrorText . "\n";
    exit;
}

$socket->StringCharset = 'utf-8';

//  Send an HTTP GET request for big_helloWorld.txt, a large text file of roughly 74,000 lines of
//  "Hello World!".  This uses a minimal HTTP request only to exercise ReceiveSb against a public
//  server -- for real HTTP work, use the Chilkat Http, Rest, or HttpCurl classes instead.
$httpReq = 'GET /big_helloWorld.txt HTTP/1.1\r\nHost: chilkatsoft.com\r\nConnection: close\r\n\r\n';
$success = $socket->SendString($httpReq);
if ($success == 0) {
    print $socket->LastErrorText . "\n";
    exit;
}

//  Call ReceiveSb a single time.  It returns only the bytes that are immediately available --
//  typically just the first network packet -- and does NOT wait for the entire response to arrive.
$sb = new COM("Chilkat.StringBuilder");
$success = $socket->ReceiveSb($sb);
if ($success == 0) {
    print $socket->LastErrorText . "\n";
    exit;
}

//  The response begins with HTTP headers.  The Content-Length header gives the total size, in bytes,
//  of the response body.
$contentLength = $sb->getBetween('Content-Length: ','\r\n');
if ($sb->LastMethodSuccess == 0) {
    print $sb->LastErrorText . "\n";
    exit;
}

//  Compare what this single ReceiveSb returned against the full size of the expected response.  The
//  received amount is only a small fraction of the total.
print 'Characters received so far (headers + partial body): ' . $sb->Length . "\n";
print 'Expected response body size (Content-Length): ' . $contentLength . ' bytes' . "\n";

//  A single ReceiveSb call returns whatever is currently available, so it cannot indicate whether the
//  full response has arrived.  This makes it difficult to know when a response is complete: the
//  application must either know how many bytes to expect (for example from a Content-Length header or
//  an application-defined length prefix) and keep receiving until that many bytes are collected, or
//  keep receiving until the peer closes the connection.

?>