Classic ASP

Read the REST Response Body in Chunks

Demonstrates Rest.ReadRespChunkBd, which reads the response body one chunk at a time, appending each chunk to a BinData. A return value of 0 signals the body is complete, while -1 indicates a read failure.

Background. Chunked reading lets an application process a large response incrementally rather than buffering the entire body at once. It is used after ReadResponseHeader within the staged request model.

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Classic ASP

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

set rest = Server.CreateObject("Chilkat.Rest")
bTls = 1
bAutoReconnect = 1
success = rest.Connect("example.com",443,bTls,bAutoReconnect)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rest.LastErrorText) & "</pre>"
    Response.End
End If

success = rest.SendReqNoBody("GET","/api/largefile")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rest.LastErrorText) & "</pre>"
    Response.End
End If

statusCode = rest.ReadResponseHeader()
If (statusCode < 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rest.LastErrorText) & "</pre>"
    Response.End
End If

'  Check for the expected success status code.  If the response is not 200, the body is likely
'  error text formatted as JSON, XML, or HTML rather than the expected content.  In that case read
'  the body as text, report it, and return.
If (statusCode <> 200) Then
    set sbError = Server.CreateObject("Chilkat.StringBuilder")
    success = rest.ReadRespSb(sbError)
    If (success = 0) Then
        Response.Write "<pre>" & Server.HTMLEncode( rest.LastErrorText) & "</pre>"
        Response.End
    End If

    Response.Write "<pre>" & Server.HTMLEncode( "Request failed with status code " & statusCode) & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( sbError.GetAsString()) & "</pre>"
    Response.End
End If

'  The status code is 200.  Read the response body in chunks, appending each chunk to the BinData.
'  Each call waits until at least the requested number of bytes is available, unless the response
'  ends first.  A return value of 0 means the final bytes were returned and the body is complete;
'  -1 indicates a read failure.
set bdBody = Server.CreateObject("Chilkat.BinData")
chunkResult = rest.ReadRespChunkBd(8192,bdBody)
Do While chunkResult > 0
    chunkResult = rest.ReadRespChunkBd(8192,bdBody)
Loop
If (chunkResult < 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rest.LastErrorText) & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( "Received " & bdBody.NumBytes & " bytes.") & "</pre>"

%>
</body>
</html>