Objective-C

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. Objective-C

#import <CkoSocket.h>
#import <CkoRest.h>
#import <CkoJsonObject.h>
#import <CkoStream.h>
#import <NSString.h>
#import <CkoDateTime.h>
#import <CkoDtObj.h>

BOOL success = NO;

//  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.

CkoSocket *socket = [[CkoSocket alloc] init];
int maxWaitMs = 5000;
success = [socket Connect: @"content.dropboxapi.com" port: [NSNumber numberWithInt: 443] ssl: YES maxWaitMs: [NSNumber numberWithInt: maxWaitMs]];
if (success != YES) {
    NSLog(@"%@",socket.LastErrorText);
    NSLog(@"%@%d",@"Connect Fail Reason: ",[socket.ConnectFailReason intValue]);
    return;
}

//  Set the download bandwidth throttle rate to 50000 bytes per second.
socket.BandwidthThrottleDown = [NSNumber numberWithInt:50000];

CkoRest *rest = [[CkoRest alloc] init];

//  Tell the REST object to use the connected socket.
[rest UseConnection: socket autoReconnect: YES];

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

//  Add request headers.
[rest AddHeader: @"Authorization" value: @"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",
//  }

CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json AppendString: @"path" value: @"/Homework/lit/hamlet.xml"];
[rest AddHeader: @"Dropbox-API-Arg" value: [json Emit]];

//  Setup a file stream for the download
CkoStream *fileStream = [[CkoStream alloc] init];
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.
int expectedStatus = 200;
[rest SetResponseBodyStream: [NSNumber numberWithInt: expectedStatus] autoSetStreamCharset: YES responseStream: fileStream];

NSString *responseStr = [rest FullRequestNoBody: @"POST" uriPath: @"/2/files/download"];
if (rest.LastMethodSuccess == NO) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

//  When successful, Dropbox responds with a 200 response code.
if ([rest.ResponseStatusCode intValue] != 200) {
    //  Examine the request/response to see what happened.
    NSLog(@"%@%d",@"response status code = ",[rest.ResponseStatusCode intValue]);
    NSLog(@"%@%@",@"response status text = ",rest.ResponseStatusText);
    NSLog(@"%@%@",@"response header: ",rest.ResponseHeader);
    NSLog(@"%@%@",@"response body (if any): ",responseStr);
    NSLog(@"%@",@"---");
    NSLog(@"%@%@",@"LastRequestStartLine: ",rest.LastRequestStartLine);
    NSLog(@"%@%@",@"LastRequestHeader: ",rest.LastRequestHeader);
    return;
}

//  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:
NSString *apiResult = [rest ResponseHdrByName: @"dropbox-api-result"];
NSLog(@"%@",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...
CkoJsonObject *jsonResult = [[CkoJsonObject alloc] init];
jsonResult.EmitCompact = NO;
[jsonResult Load: apiResult];
//  Show the JSON pretty-printed...
NSLog(@"%@",[jsonResult Emit]);

//  Sample code to get data from the JSON response:
int size = [[jsonResult IntOf: @"size"] intValue];
NSLog(@"%@%d",@"size = ",size);

NSString *rev = [jsonResult StringOf: @"rev"];
NSLog(@"%@%@",@"rev = ",rev);

NSString *clientModified = [jsonResult StringOf: @"client_modified"];
CkoDateTime *ckdt = [[CkoDateTime alloc] init];
[ckdt SetFromTimestamp: clientModified];
BOOL bLocalTime = YES;
CkoDtObj *dt = [[CkoDtObj alloc] init];
[ckdt ToDtObj: bLocalTime dtObj: dt];

NSLog(@"%d%@%d%@%d%@%d%@%d",[dt.Day intValue],@"/",[dt.Month intValue],@"/",[dt.Year intValue],@" ",[dt.Hour intValue],@":",[dt.Minute intValue]);