PureBasic

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. PureBasic

IncludeFile "CkJsonObject.pb"
IncludeFile "CkDateTime.pb"
IncludeFile "CkSocket.pb"
IncludeFile "CkStream.pb"
IncludeFile "CkRest.pb"
IncludeFile "CkDtObj.pb"

Procedure ChilkatExample()

    success.i = 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.

    socket.i = CkSocket::ckCreate()
    If socket.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    maxWaitMs.i = 5000
    success = CkSocket::ckConnect(socket,"content.dropboxapi.com",443,1,maxWaitMs)
    If success <> 1
        Debug CkSocket::ckLastErrorText(socket)
        Debug "Connect Fail Reason: " + Str(CkSocket::ckConnectFailReason(socket))
        CkSocket::ckDispose(socket)
        ProcedureReturn
    EndIf

    ; Set the download bandwidth throttle rate to 50000 bytes per second.
    CkSocket::setCkBandwidthThrottleDown(socket, 50000)

    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Tell the REST object to use the connected socket.
    CkRest::ckUseConnection(rest,socket,1)

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

    ; Add request headers.
    CkRest::ckAddHeader(rest,"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",
    ; }

    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckAppendString(json,"path","/Homework/lit/hamlet.xml")
    CkRest::ckAddHeader(rest,"Dropbox-API-Arg",CkJsonObject::ckEmit(json))

    ; Setup a file stream for the download
    fileStream.i = CkStream::ckCreate()
    If fileStream.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStream::setCkSinkFile(fileStream, "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.
    expectedStatus.i = 200
    CkRest::ckSetResponseBodyStream(rest,expectedStatus,1,fileStream)

    responseStr.s = CkRest::ckFullRequestNoBody(rest,"POST","/2/files/download")
    If CkRest::ckLastMethodSuccess(rest) = 0
        Debug CkRest::ckLastErrorText(rest)
        CkSocket::ckDispose(socket)
        CkRest::ckDispose(rest)
        CkJsonObject::ckDispose(json)
        CkStream::ckDispose(fileStream)
        ProcedureReturn
    EndIf

    ; When successful, Dropbox responds with a 200 response code.
    If CkRest::ckResponseStatusCode(rest) <> 200
        ; Examine the request/response to see what happened.
        Debug "response status code = " + Str(CkRest::ckResponseStatusCode(rest))
        Debug "response status text = " + CkRest::ckResponseStatusText(rest)
        Debug "response header: " + CkRest::ckResponseHeader(rest)
        Debug "response body (if any): " + responseStr
        Debug "---"
        Debug "LastRequestStartLine: " + CkRest::ckLastRequestStartLine(rest)
        Debug "LastRequestHeader: " + CkRest::ckLastRequestHeader(rest)
        CkSocket::ckDispose(socket)
        CkRest::ckDispose(rest)
        CkJsonObject::ckDispose(json)
        CkStream::ckDispose(fileStream)
        ProcedureReturn
    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:
    apiResult.s = CkRest::ckResponseHdrByName(rest,"dropbox-api-result")
    Debug 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...
    jsonResult.i = CkJsonObject::ckCreate()
    If jsonResult.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::setCkEmitCompact(jsonResult, 0)
    CkJsonObject::ckLoad(jsonResult,apiResult)
    ; Show the JSON pretty-printed...
    Debug CkJsonObject::ckEmit(jsonResult)

    ; Sample code to get data from the JSON response:
    size.i = CkJsonObject::ckIntOf(jsonResult,"size")
    Debug "size = " + Str(size)

    rev.s = CkJsonObject::ckStringOf(jsonResult,"rev")
    Debug "rev = " + rev

    clientModified.s = CkJsonObject::ckStringOf(jsonResult,"client_modified")
    ckdt.i = CkDateTime::ckCreate()
    If ckdt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkDateTime::ckSetFromTimestamp(ckdt,clientModified)
    bLocalTime.i = 1
    dt.i = CkDtObj::ckCreate()
    If dt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkDateTime::ckToDtObj(ckdt,bLocalTime,dt)

    Debug Str(CkDtObj::ckDay(dt)) + "/" + Str(CkDtObj::ckMonth(dt)) + "/" + Str(CkDtObj::ckYear(dt)) + " " + Str(CkDtObj::ckHour(dt)) + ":" + Str(CkDtObj::ckMinute(dt))


    CkSocket::ckDispose(socket)
    CkRest::ckDispose(rest)
    CkJsonObject::ckDispose(json)
    CkStream::ckDispose(fileStream)
    CkJsonObject::ckDispose(jsonResult)
    CkDateTime::ckDispose(ckdt)
    CkDtObj::ckDispose(dt)


    ProcedureReturn
EndProcedure