Objective-C

(using AWS Signature Version 2) Streaming Download to File

See more Amazon S3 (new) Examples

The main purpose of this example is to demonstrate how to use the older Signature Version 2 authentication w/ S3. It uses V2 authentication to download a file. 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;
// The file is located in the bucket named "chilkat100", which becomes part of the domain:
success = [rest Connect: @"chilkat100.s3.amazonaws.com" port: [NSNumber numberWithInt: port] tls: bTls autoReconnect: bAutoReconnect];

// 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";

// For AWS Signature Version 2, the following two properties need to be set:
authAws.SignatureVersion = [NSNumber numberWithInt:2];
// See http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#ConstructingTheCanonicalizedResourceElement
authAws.CanonicalizedResourceV2 = @"/chilkat100/starfish.jpg";

success = [rest SetAuthAws: authAws];

// 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);
    }

}