Xbase++

REST Download Bandwidth Throttle

See more REST Examples

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. Xbase++

LOCAL nSuccess
LOCAL oSocket
LOCAL nMaxWaitMs
LOCAL oRest
LOCAL oJson
LOCAL oFileStream
LOCAL nExpectedStatus
LOCAL cResponseStr
LOCAL cApiResult
LOCAL oJsonResult
LOCAL nSize
LOCAL cRev
LOCAL cClientModified
LOCAL oCkdt
LOCAL nBLocalTime
LOCAL oDt

nSuccess := 0

//  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.

oSocket := CreateObject("Chilkat.Socket")
nMaxWaitMs := 5000
nSuccess := oSocket:Connect("content.dropboxapi.com", 443, 1, nMaxWaitMs)
IF (nSuccess != 1)
    ? oSocket:LastErrorText
    ? "Connect Fail Reason: " + Str(oSocket:ConnectFailReason)
    oSocket:destroy()
    RETURN
ENDIF

//  Set the download bandwidth throttle rate to 50000 bytes per second.
oSocket:BandwidthThrottleDown := 50000

oRest := CreateObject("Chilkat.Rest")

//  Tell the REST object to use the connected socket.
oRest:UseConnection(oSocket, 1)

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

//  Add request headers.
oRest: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",
//  }

oJson := CreateObject("Chilkat.JsonObject")
oJson:AppendString("path", "/Homework/lit/hamlet.xml")
oRest:AddHeader("Dropbox-API-Arg", oJson:Emit())

//  Setup a file stream for the download
oFileStream := CreateObject("Chilkat.Stream")
oFileStream: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.
nExpectedStatus := 200
oRest:SetResponseBodyStream(nExpectedStatus, 1, oFileStream)

cResponseStr := oRest:FullRequestNoBody("POST", "/2/files/download")
IF (oRest:LastMethodSuccess == 0)
    ? oRest:LastErrorText
    oSocket:destroy()
    oRest:destroy()
    oJson:destroy()
    oFileStream:destroy()
    RETURN
ENDIF

//  When successful, Dropbox responds with a 200 response code.
IF (oRest:ResponseStatusCode != 200)
    //  Examine the request/response to see what happened.
    ? "response status code = " + Str(oRest:ResponseStatusCode)
    ? "response status text = " + oRest:ResponseStatusText
    ? "response header: " + oRest:ResponseHeader
    ? "response body (if any): " + cResponseStr
    ? "---"
    ? "LastRequestStartLine: " + oRest:LastRequestStartLine
    ? "LastRequestHeader: " + oRest:LastRequestHeader
    oSocket:destroy()
    oRest:destroy()
    oJson:destroy()
    oFileStream:destroy()
    RETURN
ENDIF

//  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:
cApiResult := oRest:ResponseHdrByName("dropbox-api-result")
? cApiResult

//  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...
oJsonResult := CreateObject("Chilkat.JsonObject")
oJsonResult:EmitCompact := 0
oJsonResult:Load(cApiResult)
//  Show the JSON pretty-printed...
? oJsonResult:Emit()

//  Sample code to get data from the JSON response:
nSize := oJsonResult:IntOf("size")
? "size = " + Str(nSize)

cRev := oJsonResult:StringOf("rev")
? "rev = " + cRev

cClientModified := oJsonResult:StringOf("client_modified")
oCkdt := CreateObject("Chilkat.CkDateTime")
oCkdt:SetFromTimestamp(cClientModified)
nBLocalTime := 1
oDt := CreateObject("Chilkat.DtObj")
oCkdt:ToDtObj(nBLocalTime, oDt)

? Str(oDt:Day) + "/" + Str(oDt:Month) + "/" + Str(oDt:Year) + " " + Str(oDt:Hour) + ":" + Str(oDt:Minute)

oSocket:destroy()
oRest:destroy()
oJson:destroy()
oFileStream:destroy()
oJsonResult:destroy()
oCkdt:destroy()
oDt:destroy()