Objective-C

REST Stream Response to File (Streaming Download) (Amazon S3)

See more Amazon S3 (new) Examples

Demonstrates how to stream the response body directly to a file. (The example shows how to stream a JPG from the Amazon S3 service.) Objective-C

#import <CkoRest.h>
#import <CkoAuthAws.h>
#import <CkoStream.h>
#import <NSString.h>

BOOL success = NO;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

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

//  Connect to the Amazon AWS REST server.
BOOL bTls = YES;
int port = 443;
BOOL bAutoReconnect = YES;
success = [rest Connect: @"s3.amazonaws.com" port: [NSNumber numberWithInt: port] tls: bTls autoReconnect: bAutoReconnect];

//  ----------------------------------------------------------------------------
//  Important: For buckets created in regions outside us-east-1,
//  there are three important changes that need to be made.
//  See Working with S3 Buckets in Non-us-east-1 Regions for the details.
//  ----------------------------------------------------------------------------

//  Provide AWS credentials for the REST call.
CkoAuthAws *authAws = [[CkoAuthAws alloc] init];
authAws.AccessKey = @"AWS_ACCESS_KEY";
authAws.SecretKey = @"AWS_SECRET_KEY";
authAws.ServiceName = @"s3";
success = [rest SetAuthAws: authAws];

//  Set the bucket name via the HOST header.
//  In this case, the bucket name is "chilkat100".
rest.Host = @"chilkat100.s3.amazonaws.com";

//  Send the request to download the JPG.
success = [rest SendReqNoBody: @"GET" uriPath: @"/starfish.jpg"];
if (success != YES) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

//  Read the response header.
int responseStatusCode = [[rest ReadResponseHeader] intValue];
if (responseStatusCode < 0) {
    NSLog(@"%@",rest.LastErrorText);
    return;
}

NSLog(@"%@%d",@"Response status code = ",responseStatusCode);

//  We expect a 200 response status if the JPG data is coming.
//  Otherwise, we'll get a string response body with an error message(or no response body).
if (responseStatusCode == 200) {

    CkoStream *bodyStream = [[CkoStream alloc] init];

    //  The stream's sink will be a file.
    bodyStream.SinkFile = @"qa_output/starfish.jpg";

    //  Read the response body to the stream.  Given that we've
    //  set the stream's sink to a file, it will stream directly
    //  to the file.
    success = [rest ReadRespBodyStream: bodyStream autoSetStreamCharset: YES];
    if (success != YES) {
        NSLog(@"%@",rest.LastErrorText);
        return;
    }

    NSLog(@"%@",@"Successfully received the JPG file.");

}
else {
    NSString *errResponse = [rest ReadRespBodyString];
    if (rest.LastMethodSuccess != YES) {
        NSLog(@"%@",rest.LastErrorText);
    }
    else {
        NSLog(@"%@",errResponse);
    }

}