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.

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

$socket = New-Object Chilkat.Socket

#  Connect to chilkatsoft.com over TLS.
$bTls = $true
$maxWaitMs = 5000
$success = $socket.Connect("chilkatsoft.com",443,$bTls,$maxWaitMs)
if ($success -eq $false) {
    $($socket.LastErrorText)
    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 -eq $false) {
    $($socket.LastErrorText)
    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-Object Chilkat.StringBuilder
$success = $socket.ReceiveSb($sb)
if ($success -eq $false) {
    $($socket.LastErrorText)
    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 -eq $false) {
    $($sb.LastErrorText)
    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.
$("Characters received so far (headers + partial body): " + $sb.Length)
$("Expected response body size (Content-Length): " + $contentLength + " bytes")

#  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.