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/*
This file is part of TALER
(C) 2018 Taler Systems SA
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU Affero General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file backend/taler-merchant-httpd_tip-query.c
* @brief implement API for authorizing tips to be paid to visitors
* @author Christian Grothoff
* @author Florian Dold
*/
#include "platform.h"
#include <jansson.h>
#include <taler/taler_util.h>
#include <taler/taler_json_lib.h>
#include "taler-merchant-httpd.h"
#include "taler-merchant-httpd_mhd.h"
#include "taler-merchant-httpd_exchanges.h"
#include "taler-merchant-httpd_tip-query.h"
#include "taler-merchant-httpd_tip-reserve-helper.h"
/**
* Maximum number of retries for database operations.
*/
#define MAX_RETRIES 5
/**
* Internal per-request state for processing tip queries.
*/
struct TipQueryContext
{
/**
* This field MUST be first for handle_mhd_completion_callback() to work
* when it treats this struct as a `struct TM_HandlerContext`.
*/
struct TM_HandlerContext hc;
/**
* Merchant instance to use.
*/
const char *instance;
/**
* Context for checking the tipping reserve's status.
*/
struct TMH_CheckTipReserve ctr;
/**
* #GNUNET_YES if the tip query has already been processed
* and we can queue the response.
*/
int processed;
};
/**
* Custom cleanup routine for a `struct TipQueryContext`.
*
* @param hc the `struct TMH_JsonParseContext` to clean up.
*/
static void
cleanup_tqc (struct TM_HandlerContext *hc)
{
struct TipQueryContext *tqc = (struct TipQueryContext *) hc;
TMH_check_tip_reserve_cleanup (&tqc->ctr);
GNUNET_free (tqc);
}
/**
* We've been resumed after processing the reserve data from the
* exchange without error. Generate the final response.
*
* @param tqc context for which to generate the response.
*/
static int
generate_final_response (struct TipQueryContext *tqc)
{
struct GNUNET_CRYPTO_EddsaPublicKey reserve_pub;
struct TALER_Amount amount_available;
GNUNET_CRYPTO_eddsa_key_get_public (&tqc->ctr.reserve_priv.eddsa_priv,
&reserve_pub);
if (0 >
TALER_amount_subtract (&amount_available,
&tqc->ctr.amount_deposited,
&tqc->ctr.amount_withdrawn))
{
char *a1;
char *a2;
GNUNET_break_op (0);
a1 = TALER_amount_to_string (&tqc->ctr.amount_deposited);
a2 = TALER_amount_to_string (&tqc->ctr.amount_withdrawn);
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"amount overflow, deposited %s but withdrawn %s\n",
a1,
a2);
GNUNET_free (a2);
GNUNET_free (a1);
return TALER_MHD_reply_with_error (
tqc->ctr.connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_TIP_QUERY_RESERVE_HISTORY_ARITHMETIC_ISSUE_INCONSISTENT,
"Exchange returned invalid reserve history (amount overflow)");
}
return TALER_MHD_reply_json_pack (
tqc->ctr.connection,
MHD_HTTP_OK,
"{s:o, s:o, s:o, s:o, s:o}",
"reserve_pub",
GNUNET_JSON_from_data_auto (&reserve_pub),
"reserve_expiration",
GNUNET_JSON_from_time_abs (tqc->ctr.reserve_expiration),
"amount_authorized",
TALER_JSON_from_amount (&tqc->ctr.amount_authorized),
"amount_picked_up",
TALER_JSON_from_amount (&tqc->ctr.amount_withdrawn),
"amount_available",
TALER_JSON_from_amount (&amount_available));
}
/**
* Handle a "/tip-query" request.
*
* @param rh context of the handler
* @param connection the MHD connection to handle
* @param[in,out] connection_cls the connection's closure (can be updated)
* @param upload_data upload data
* @param[in,out] upload_data_size number of bytes (left) in @a upload_data
* @param mi merchant backend instance, never NULL
* @return MHD result code
*/
MHD_RESULT
MH_handler_tip_query (struct TMH_RequestHandler *rh,
struct MHD_Connection *connection,
void **connection_cls,
const char *upload_data,
size_t *upload_data_size,
struct MerchantInstance *mi)
{
struct TipQueryContext *tqc;
if (NULL == *connection_cls)
{
tqc = GNUNET_new (struct TipQueryContext);
tqc->hc.cc = &cleanup_tqc;
tqc->ctr.connection = connection;
*connection_cls = tqc;
}
else
{
tqc = *connection_cls;
}
if (0 != tqc->ctr.response_code)
{
MHD_RESULT res;
/* We are *done* processing the request, just queue the response (!) */
if (UINT_MAX == tqc->ctr.response_code)
{
GNUNET_break (0);
return MHD_NO; /* hard error */
}
res = MHD_queue_response (connection,
tqc->ctr.response_code,
tqc->ctr.response);
MHD_destroy_response (tqc->ctr.response);
tqc->ctr.response = NULL;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Queueing response (%u) for /tip-query (%s).\n",
(unsigned int) tqc->ctr.response_code,
res ? "OK" : "FAILED");
return res;
}
if (GNUNET_YES == tqc->processed)
{
/* We've been here before, so TMH_check_tip_reserve() must have
finished and left the result for us. Finish processing. */
return generate_final_response (tqc);
}
if (NULL == mi->tip_exchange)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Instance `%s' not configured for tipping\n",
mi->id);
return TALER_MHD_reply_with_error (
connection,
MHD_HTTP_PRECONDITION_FAILED,
TALER_EC_TIP_QUERY_INSTANCE_DOES_NOT_TIP,
"exchange for tipping not configured for the instance");
}
tqc->ctr.reserve_priv = mi->tip_reserve;
{
enum GNUNET_DB_QueryStatus qs;
for (unsigned int i = 0; i<MAX_RETRIES; i++)
{
db->preflight (db->cls);
qs = db->get_authorized_tip_amount (db->cls,
&tqc->ctr.reserve_priv,
&tqc->ctr.amount_authorized);
if (GNUNET_DB_STATUS_SOFT_ERROR != qs)
break;
}
if (0 > qs)
{
GNUNET_break (0);
return TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_TIP_QUERY_DB_ERROR,
"Merchant database error");
}
if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
{
/* we'll set amount_authorized to zero later once
we know the currency */
tqc->ctr.none_authorized = GNUNET_YES;
}
}
tqc->processed = GNUNET_YES;
TMH_check_tip_reserve (&tqc->ctr,
mi->tip_exchange);
return MHD_YES;
}
/* end of taler-merchant-httpd_tip-query.c */
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