(Visual Basic 6.0) REST Download Bandwidth Throttle

Demonstrates how to use download bandwidth throttling with the REST API. This example will download a file from Drobox using a file stream, with a limit on the bandwidth that can be used for the transfer.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' A Dropbox access token should have been previously obtained.
' Dropbox access tokens do not expire.
' See Dropbox Access Token.

' To use bandwidth throttling, the connection should be made using the socket API.
' This provides numerous properties to customize the connection, such as
' BandwidthThrottleDown, BandwidthThrottleUp, ClientIpAddress, ClintPort, Http Proxy,
' KeepAlive, PreferIpv6, RequireSslCertVerify, SoRcvBuf, SoSndBuf, SoReuseAddr,
' SOCKS proxy, TcpNoSDelay, TlsPinSet, TlsCipherSuite, SslAllowedCiphers, etc.

Dim socket As New ChilkatSocket
Dim maxWaitMs As Long
maxWaitMs = 5000
Dim success As Long
success = socket.Connect("content.dropboxapi.com",443,1,maxWaitMs)
If (success <> 1) Then
    Debug.Print socket.LastErrorText
    Debug.Print "Connect Fail Reason: " & socket.ConnectFailReason
    Exit Sub
End If

' Set the download bandwidth throttle rate to 50000 bytes per second.
socket.BandwidthThrottleDown = 50000

Dim rest As New ChilkatRest

' Tell the REST object to use the connected socket.
success = rest.UseConnection(socket,1)

' The remainder of this example is identical to the example at:
' Dropbox Download File.

' Add request headers.
success = rest.AddHeader("Authorization","Bearer DROPBOX_ACCESS_TOKEN")

' The download "parameters" are contained in JSON passed in an HTTP request header.
' This is the JSON indicating the file to be downloaded:
' { 
'    "path": "/Homework/lit/hamlet.xml",
' }

Dim json As New ChilkatJsonObject
success = json.AppendString("path","/Homework/lit/hamlet.xml")
success = rest.AddHeader("Dropbox-API-Arg",json.Emit())

' Setup a file stream for the download
Dim fileStream As New ChilkatStream
fileStream.SinkFile = "qa_output/hamletFromDropbox.xml"

' Indicate that the call to FullRequestNoBody should send the response body
' to fileStream if the response status code is 200.
' If a non-success response status code is received, then nothing
' is streamed to the output file and the error response is returned by FullRequestNoBody.
Dim expectedStatus As Long
expectedStatus = 200
success = rest.SetResponseBodyStream(expectedStatus,1,fileStream)

Dim responseStr As String
responseStr = rest.FullRequestNoBody("POST","/2/files/download")
If (rest.LastMethodSuccess <> 1) Then
    Debug.Print rest.LastErrorText
    Exit Sub
End If

' When successful, Dropbox responds with a 200 response code.
If (rest.ResponseStatusCode <> 200) Then
    ' Examine the request/response to see what happened.
    Debug.Print "response status code = " & rest.ResponseStatusCode
    Debug.Print "response status text = " & rest.ResponseStatusText
    Debug.Print "response header: " & rest.ResponseHeader
    Debug.Print "response body (if any): " & responseStr
    Debug.Print "---"
    Debug.Print "LastRequestStartLine: " & rest.LastRequestStartLine
    Debug.Print "LastRequestHeader: " & rest.LastRequestHeader
    Exit Sub
End If

' Information about the downloaded file is also available as JSON in a response header.
' The "dropbox-api-result" response header contains the information.  For example:
Dim apiResult As String
apiResult = rest.ResponseHdrByName("dropbox-api-result")
Debug.Print apiResult

' In this case, the pretty-formatted dropbox-api-result JSON looks like this:
' { 
'   "name": "hamlet.xml",
'   "path_lower": "/homework/lit/hamlet.xml",
'   "path_display": "/Homework/lit/hamlet.xml",
'   "id": "id:74FkdeNuyKAAAAAAAAAAAQ",
'   "client_modified": "2016-06-02T23:19:00Z",
'   "server_modified": "2016-06-02T23:19:00Z",
'   "rev": "9482db15f",
'   "size": 279658
' }

' Load the JSON, pretty-print it, and demonstrate how to get some values...
Dim jsonResult As New ChilkatJsonObject
jsonResult.EmitCompact = 0
success = jsonResult.Load(apiResult)
' Show the JSON pretty-printed...
Debug.Print jsonResult.Emit()

' Sample code to get data from the JSON response:
Dim size As Long
size = jsonResult.IntOf("size")
Debug.Print "size = " & size

Dim rev As String
rev = jsonResult.StringOf("rev")
Debug.Print "rev = " & rev

Dim clientModified As String
clientModified = jsonResult.StringOf("client_modified")
Dim ckdt As New CkDateTime
success = ckdt.SetFromTimestamp(clientModified)
Dim bLocalTime As Long
bLocalTime = 1
Dim dt As DtObj
Set dt = ckdt.GetDtObj(bLocalTime)
Debug.Print dt.Day & "/" & dt.Month & "/" & dt.Year & " " & dt.Hour & ":" & dt.Minute