(Tcl) 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.

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load ./chilkat.dll

# 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.

set socket [new_CkSocket]

set maxWaitMs 5000
set success [CkSocket_Connect $socket "content.dropboxapi.com" 443 1 $maxWaitMs]
if {$success != 1} then {
    puts [CkSocket_lastErrorText $socket]
    puts "Connect Fail Reason: [CkSocket_get_ConnectFailReason $socket]"
    delete_CkSocket $socket
    exit
}

# Set the download bandwidth throttle rate to 50000 bytes per second.
CkSocket_put_BandwidthThrottleDown $socket 50000

set rest [new_CkRest]

# Tell the REST object to use the connected socket.
CkRest_UseConnection $rest $socket 1

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

# Add request headers.
CkRest_AddHeader $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",
# }

set json [new_CkJsonObject]

CkJsonObject_AppendString $json "path" "/Homework/lit/hamlet.xml"
CkRest_AddHeader $rest "Dropbox-API-Arg" [CkJsonObject_emit $json]

# Setup a file stream for the download
set fileStream [new_CkStream]

CkStream_put_SinkFile $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.
set expectedStatus 200
CkRest_SetResponseBodyStream $rest $expectedStatus 1 $fileStream

set responseStr [CkRest_fullRequestNoBody $rest "POST" "/2/files/download"]
if {[CkRest_get_LastMethodSuccess $rest] != 1} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkSocket $socket
    delete_CkRest $rest
    delete_CkJsonObject $json
    delete_CkStream $fileStream
    exit
}

# When successful, Dropbox responds with a 200 response code.
if {[CkRest_get_ResponseStatusCode $rest] != 200} then {
    # Examine the request/response to see what happened.
    puts "response status code = [CkRest_get_ResponseStatusCode $rest]"
    puts "response status text = [CkRest_responseStatusText $rest]"
    puts "response header: [CkRest_responseHeader $rest]"
    puts "response body (if any): $responseStr"
    puts "---"
    puts "LastRequestStartLine: [CkRest_lastRequestStartLine $rest]"
    puts "LastRequestHeader: [CkRest_lastRequestHeader $rest]"
    delete_CkSocket $socket
    delete_CkRest $rest
    delete_CkJsonObject $json
    delete_CkStream $fileStream
    exit
}

# 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:
set apiResult [CkRest_responseHdrByName $rest "dropbox-api-result"]
puts "$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...
set jsonResult [new_CkJsonObject]

CkJsonObject_put_EmitCompact $jsonResult 0
CkJsonObject_Load $jsonResult $apiResult
# Show the JSON pretty-printed...
puts [CkJsonObject_emit $jsonResult]

# Sample code to get data from the JSON response:
set size [CkJsonObject_IntOf $jsonResult "size"]
puts "size = $size"

set rev [CkJsonObject_stringOf $jsonResult "rev"]
puts "rev = $rev"

set clientModified [CkJsonObject_stringOf $jsonResult "client_modified"]
set ckdt [new_CkDateTime]

CkDateTime_SetFromTimestamp $ckdt $clientModified
set bLocalTime 1
# dt is a CkDtObj
set dt [CkDateTime_GetDtObj $ckdt $bLocalTime]
puts [CkDtObj_get_Day $dt]/[CkDtObj_get_Month $dt]/[CkDtObj_get_Year $dt] [CkDtObj_get_Hour $dt]:[CkDtObj_get_Minute $dt]
delete_CkDtObj $dt


delete_CkSocket $socket
delete_CkRest $rest
delete_CkJsonObject $json
delete_CkStream $fileStream
delete_CkJsonObject $jsonResult
delete_CkDateTime $ckdt