.. _cpp:

C++ S3 Examples

Setup

The following contains includes and globals that will be used in later examples:

.. code-block:: cpp

#include "libs3.h"
#include <stdlib.h>
#include <iostream>
#include <fstream>

const char access_key[] = "ACCESS_KEY";
const char secret_key[] = "SECRET_KEY";
const char host[] = "HOST";
const char sample_bucket[] = "sample_bucket";
const char sample_key[] = "hello.txt";
const char sample_file[] = "resource/hello.txt";
const char *security_token = NULL;
const char *auth_region = NULL;

S3BucketContext bucketContext =
{
	host,
	sample_bucket,
	S3ProtocolHTTP,
	S3UriStylePath,
	access_key,
	secret_key,
	security_token,
	auth_region
};

S3Status responsePropertiesCallback(
		const S3ResponseProperties *properties,
		void *callbackData)
{
	return S3StatusOK;
}

static void responseCompleteCallback(
		S3Status status,
		const S3ErrorDetails *error,
		void *callbackData)
{
	return;
}

S3ResponseHandler responseHandler =
{
	&responsePropertiesCallback,
	&responseCompleteCallback
};

Creating (and Closing) a Connection

This creates a connection so that you can interact with the server.

.. code-block:: cpp

S3_initialize("s3", S3_INIT_ALL, host);
// Do stuff...
S3_deinitialize();

Listing Owned Buckets

This gets a list of buckets that you own. This also prints out the bucket name, owner ID, and display name for each bucket.

.. code-block:: cpp

static S3Status listServiceCallback(
		const char *ownerId,
		const char *ownerDisplayName,
		const char *bucketName,
		int64_t creationDate, void *callbackData)
{
	bool *header_printed = (bool*) callbackData;
	if (!*header_printed) {
		*header_printed = true;
		printf("%-22s", "       Bucket");
		printf("  %-20s  %-12s", "     Owner ID", "Display Name");
		printf("\n");
		printf("----------------------");
		printf("  --------------------" "  ------------");
		printf("\n");
	}

	printf("%-22s", bucketName);
	printf("  %-20s  %-12s", ownerId ? ownerId : "", ownerDisplayName ? ownerDisplayName : "");
	printf("\n");

	return S3StatusOK;
}

S3ListServiceHandler listServiceHandler =
{
	responseHandler,
	&listServiceCallback
};
bool header_printed = false;
S3_list_service(S3ProtocolHTTP, access_key, secret_key, security_token, host, 
                auth_region, NULL, 0, &listServiceHandler, &header_printed);

Creating a Bucket

This creates a new bucket.

.. code-block:: cpp

S3_create_bucket(S3ProtocolHTTP, access_key, secret_key, NULL, host, sample_bucket, S3CannedAclPrivate, NULL, NULL, &responseHandler, NULL);

Listing a Bucket's Content

This gets a list of objects in the bucket. This also prints out each object's name, the file size, and last modified date.

.. code-block:: cpp

static S3Status listBucketCallback(
		int isTruncated,
		const char *nextMarker,
		int contentsCount,
		const S3ListBucketContent *contents,
		int commonPrefixesCount,
		const char **commonPrefixes,
		void *callbackData)
{
	printf("%-22s",	"      Object Name");
	printf("  %-5s  %-20s", "Size", "   Last Modified");
	printf("\n");
	printf("----------------------");
	printf("  -----" "  --------------------");
	printf("\n");

    for (int i = 0; i < contentsCount; i++) {
	char timebuf[256];
		char sizebuf[16];
	const S3ListBucketContent *content = &(contents[i]);
		time_t t = (time_t) content->lastModified;

		strftime(timebuf, sizeof(timebuf), "%Y-%m-%dT%H:%M:%SZ", gmtime(&t));
		sprintf(sizebuf, "%5llu", (unsigned long long) content->size);
		printf("%-22s  %s  %s\n", content->key, sizebuf, timebuf);
    }

    return S3StatusOK;
}

S3ListBucketHandler listBucketHandler =
{
	responseHandler,
	&listBucketCallback
};
S3_list_bucket(&bucketContext, NULL, NULL, NULL, 0, NULL, 0, &listBucketHandler, NULL);

The output will look something like this::

myphoto1.jpg 251262 2011-08-08T21:35:48.000Z myphoto2.jpg 262518 2011-08-08T21:38:01.000Z

Deleting a Bucket

.. note::

The bucket must be empty! Otherwise it won't work!

.. code-block:: cpp

S3_delete_bucket(S3ProtocolHTTP, S3UriStylePath, access_key, secret_key, 0, host, sample_bucket, NULL, NULL, 0, &responseHandler, NULL);

Creating an Object (from a file)

This creates a file hello.txt.

.. code-block:: cpp

#include <sys/stat.h>
typedef struct put_object_callback_data
{
    FILE *infile;
    uint64_t contentLength;
} put_object_callback_data;


static int putObjectDataCallback(int bufferSize, char *buffer, void *callbackData)
{
    put_object_callback_data *data = (put_object_callback_data *) callbackData;

    int ret = 0;

    if (data->contentLength) {
	int toRead = ((data->contentLength > (unsigned) bufferSize) ? (unsigned) bufferSize : data->contentLength);
		ret = fread(buffer, 1, toRead, data->infile);
    }
    data->contentLength -= ret;
    return ret;
}

put_object_callback_data data;
struct stat statbuf;
if (stat(sample_file, &statbuf) == -1) {
	fprintf(stderr, "\nERROR: Failed to stat file %s: ", sample_file);
	perror(0);
	exit(-1);
}

int contentLength = statbuf.st_size;
data.contentLength = contentLength;

if (!(data.infile = fopen(sample_file, "r"))) {
	fprintf(stderr, "\nERROR: Failed to open input file %s: ", sample_file);
	perror(0);
	exit(-1);
}

S3PutObjectHandler putObjectHandler =
{
	responseHandler,
	&putObjectDataCallback
};

S3_put_object(&bucketContext, sample_key, contentLength, NULL, NULL, 0, &putObjectHandler, &data);
fclose(data.infile);

Download an Object (to a file)

This downloads a file and prints the contents.

.. code-block:: cpp

static S3Status getObjectDataCallback(int bufferSize, const char *buffer, void *callbackData)
{
	FILE *outfile = (FILE *) callbackData;
	size_t wrote = fwrite(buffer, 1, bufferSize, outfile);
	return ((wrote < (size_t) bufferSize) ? S3StatusAbortedByCallback : S3StatusOK);
}

S3GetObjectHandler getObjectHandler =
{
	responseHandler,
	&getObjectDataCallback
};
FILE *outfile = stdout;
S3_get_object(&bucketContext, sample_key, NULL, 0, 0, NULL, 0, &getObjectHandler, outfile);

Delete an Object

This deletes an object.

.. code-block:: cpp

S3ResponseHandler deleteResponseHandler =
{
	0,
	&responseCompleteCallback
};
S3_delete_object(&bucketContext, sample_key, 0, 0, &deleteResponseHandler, 0);

Change an Object's ACL

This changes an object's ACL to grant full control to another user.

.. code-block:: cpp

#include <string.h>
char ownerId[] = "owner";
char ownerDisplayName[] = "owner";
char granteeId[] = "grantee";
char granteeDisplayName[] = "grantee";

S3AclGrant grants[] = {
	{
		S3GranteeTypeCanonicalUser,
		{{}},
		S3PermissionFullControl
	},
	{
		S3GranteeTypeCanonicalUser,
		{{}},
		S3PermissionReadACP
	},
	{
		S3GranteeTypeAllUsers,
		{{}},
		S3PermissionRead
	}
};

strncpy(grants[0].grantee.canonicalUser.id, ownerId, S3_MAX_GRANTEE_USER_ID_SIZE);
strncpy(grants[0].grantee.canonicalUser.displayName, ownerDisplayName, S3_MAX_GRANTEE_DISPLAY_NAME_SIZE);

strncpy(grants[1].grantee.canonicalUser.id, granteeId, S3_MAX_GRANTEE_USER_ID_SIZE);
strncpy(grants[1].grantee.canonicalUser.displayName, granteeDisplayName, S3_MAX_GRANTEE_DISPLAY_NAME_SIZE);

S3_set_acl(&bucketContext, sample_key, ownerId, ownerDisplayName, 3, grants, 0, &responseHandler, 0);

Generate Object Download URL (signed)

This generates a signed download URL that will be valid for 5 minutes.

.. code-block:: cpp

#include <time.h>
char buffer[S3_MAX_AUTHENTICATED_QUERY_STRING_SIZE];
int64_t expires = time(NULL) + 60 * 5; // Current time + 5 minutes

S3_generate_authenticated_query_string(buffer, &bucketContext, sample_key, expires, NULL, "GET");