ceph/doc/radosgw/s3/cpp.rst

.. _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";

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

	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, host, 0, &listServiceHandler, &header_printed);


Creating a Bucket
-----------------

This creates a new bucket.

.. code-block:: cpp

	S3_create_bucket(S3ProtocolHTTP, access_key, secret_key, 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, &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, host, sample_bucket, NULL, &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, &putObjectHandler, &data);


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, &getObjectHandler, outfile);


Delete an Object
----------------

This deletes an object.

.. code-block:: cpp

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