(Visual FoxPro) 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

LOCAL loSocket
LOCAL lnMaxWaitMs
LOCAL lnSuccess
LOCAL loRest
LOCAL loJson
LOCAL loFileStream
LOCAL lnExpectedStatus
LOCAL lcResponseStr
LOCAL lcApiResult
LOCAL loJsonResult
LOCAL lnSize
LOCAL lcRev
LOCAL lcClientModified
LOCAL loCkdt
LOCAL lnBLocalTime
LOCAL loDt

* 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.

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Socket')
loSocket = CreateObject('Chilkat.Socket')
lnMaxWaitMs = 5000
lnSuccess = loSocket.Connect("content.dropboxapi.com",443,1,lnMaxWaitMs)
IF (lnSuccess <> 1) THEN
    ? loSocket.LastErrorText
    ? "Connect Fail Reason: " + STR(loSocket.ConnectFailReason)
    RELEASE loSocket
    CANCEL
ENDIF

* Set the download bandwidth throttle rate to 50000 bytes per second.
loSocket.BandwidthThrottleDown = 50000

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rest')
loRest = CreateObject('Chilkat.Rest')

* Tell the REST object to use the connected socket.
loRest.UseConnection(loSocket,1)

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

* Add request headers.
loRest.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",
* }

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')
loJson.AppendString("path","/Homework/lit/hamlet.xml")
loRest.AddHeader("Dropbox-API-Arg",loJson.Emit())

* Setup a file stream for the download
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Stream')
loFileStream = CreateObject('Chilkat.Stream')
loFileStream.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.
lnExpectedStatus = 200
loRest.SetResponseBodyStream(lnExpectedStatus,1,loFileStream)

lcResponseStr = loRest.FullRequestNoBody("POST","/2/files/download")
IF (loRest.LastMethodSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loSocket
    RELEASE loRest
    RELEASE loJson
    RELEASE loFileStream
    CANCEL
ENDIF

* When successful, Dropbox responds with a 200 response code.
IF (loRest.ResponseStatusCode <> 200) THEN
    * Examine the request/response to see what happened.
    ? "response status code = " + STR(loRest.ResponseStatusCode)
    ? "response status text = " + loRest.ResponseStatusText
    ? "response header: " + loRest.ResponseHeader
    ? "response body (if any): " + lcResponseStr
    ? "---"
    ? "LastRequestStartLine: " + loRest.LastRequestStartLine
    ? "LastRequestHeader: " + loRest.LastRequestHeader
    RELEASE loSocket
    RELEASE loRest
    RELEASE loJson
    RELEASE loFileStream
    CANCEL
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:
lcApiResult = loRest.ResponseHdrByName("dropbox-api-result")
? lcApiResult

* 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...
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJsonResult = CreateObject('Chilkat.JsonObject')
loJsonResult.EmitCompact = 0
loJsonResult.Load(lcApiResult)
* Show the JSON pretty-printed...
? loJsonResult.Emit()

* Sample code to get data from the JSON response:
lnSize = loJsonResult.IntOf("size")
? "size = " + STR(lnSize)

lcRev = loJsonResult.StringOf("rev")
? "rev = " + lcRev

lcClientModified = loJsonResult.StringOf("client_modified")
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.CkDateTime')
loCkdt = CreateObject('Chilkat.CkDateTime')
loCkdt.SetFromTimestamp(lcClientModified)
lnBLocalTime = 1
loDt = loCkdt.GetDtObj(lnBLocalTime)
? STR(loDt.Day) + "/" + STR(loDt.Month) + "/" + STR(loDt.Year) + " " + STR(loDt.Hour) + ":" + STR(loDt.Minute)
RELEASE loDt

RELEASE loSocket
RELEASE loRest
RELEASE loJson
RELEASE loFileStream
RELEASE loJsonResult
RELEASE loCkdt