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/*
This file is part of TALER
(C) 2014-2020 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_refund.c
* @brief HTTP serving layer mainly intended to communicate with the frontend
* @author Marcello Stanisci
*/
#include "platform.h"
#include <jansson.h>
#include <taler/taler_signatures.h>
#include <taler/taler_json_lib.h>
#include "taler-merchant-httpd.h"
#include "taler-merchant-httpd_refund.h"
/**
* How often do we retry the non-trivial refund INSERT database
* transaction?
*/
#define MAX_RETRIES 5
/**
* Closure for #process_refunds_cb.
*/
struct ProcessRefundData
{
/**
* The array containing all the refund permissions.
*/
json_t *response;
/**
* Hashed version of contract terms; needed by the callback
* to pack the response.
*/
const struct GNUNET_HashCode *h_contract_terms;
/**
* Both public and private key are needed by the callback
*/
const struct MerchantInstance *merchant;
/**
* Return code: #TALER_EC_NONE if successful.
*/
enum TALER_ErrorCode ec;
};
/**
* Function called with information about a refund.
* It is responsible for packing up the data to return.
*
* @param cls closure
* @param coin_pub public coin from which the refund comes from
* @param exchange_url URL of the exchange that issued @a coin_pub
* @param rtransaction_id identificator of the refund
* @param reason human-readable explanation of the refund
* @param refund_amount refund amount which is being taken from @a coin_pub
* @param refund_fee cost of this refund operation
*/
static void
process_refunds_cb (void *cls,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const char *exchange_url,
uint64_t rtransaction_id,
const char *reason,
const struct TALER_Amount *refund_amount,
const struct TALER_Amount *refund_fee)
{
struct ProcessRefundData *prd = cls;
struct GNUNET_CRYPTO_EddsaSignature sig;
json_t *element;
(void) exchange_url;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Found refund of %s for coin %s with reason `%s' in database\n",
TALER_B2S (coin_pub),
TALER_amount2s (refund_amount),
reason);
{
struct TALER_RefundRequestPS rr = {
.purpose.purpose = htonl (TALER_SIGNATURE_MERCHANT_REFUND),
.purpose.size = htonl (sizeof (rr)),
.h_contract_terms = *prd->h_contract_terms,
.coin_pub = *coin_pub,
.merchant = prd->merchant->pubkey,
.rtransaction_id = GNUNET_htonll (rtransaction_id)
};
TALER_amount_hton (&rr.refund_amount,
refund_amount);
TALER_amount_hton (&rr.refund_fee,
refund_fee);
GNUNET_CRYPTO_eddsa_sign (&prd->merchant->privkey.eddsa_priv,
&rr,
&sig);
}
element = json_pack ("{s:o, s:o, s:o, s:I, s:o}",
"refund_amount", TALER_JSON_from_amount (refund_amount),
"refund_fee", TALER_JSON_from_amount (refund_fee),
"coin_pub", GNUNET_JSON_from_data_auto (coin_pub),
"rtransaction_id", (json_int_t) rtransaction_id,
"merchant_sig", GNUNET_JSON_from_data_auto (&sig));
if (NULL == element)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Could not pack refund response element\n");
prd->ec = TALER_EC_PARSER_OUT_OF_MEMORY;
return;
}
if (-1 == json_array_append_new (prd->response,
element))
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Could not append a response's element\n");
prd->ec = TALER_EC_PARSER_OUT_OF_MEMORY;
return;
}
}
/**
* Get the JSON representation of a refund.
*
* @param merchant_pub the merchant's public key
* @param mi merchant instance
* @param ret_ec where to store error code
* @param ret_errmsg where to store error message
* @return NULL on error, JSON array with refunds on success
*/
json_t *
TM_get_refund_json (const struct MerchantInstance *mi,
const struct GNUNET_HashCode *h_contract_terms,
enum TALER_ErrorCode *ret_ec,
const char **ret_errmsg)
{
enum GNUNET_DB_QueryStatus qs;
struct ProcessRefundData prd;
prd.response = json_array ();
if (NULL == prd.response)
{
GNUNET_break (0);
return NULL;
}
prd.h_contract_terms = h_contract_terms;
prd.merchant = mi;
prd.ec = TALER_EC_NONE;
db->preflight (db->cls);
for (unsigned int i = 0; i<MAX_RETRIES; i++)
{
qs = db->get_refunds_from_contract_terms_hash (db->cls,
&mi->pubkey,
h_contract_terms,
&process_refunds_cb,
&prd);
if (GNUNET_DB_STATUS_SOFT_ERROR != qs)
break;
}
if (0 > qs)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Database hard error on refunds_from_contract_terms_hash lookup: %s\n",
GNUNET_h2s (h_contract_terms));
json_decref (prd.response);
*ret_ec = TALER_EC_REFUND_LOOKUP_DB_ERROR;
*ret_errmsg = "Failed to lookup refunds for contract";
}
if (TALER_EC_NONE != prd.ec)
{
json_decref (prd.response);
/* NOTE: error already logged by the callback */
*ret_ec = prd.ec;
*ret_errmsg = "Could not generate a response";
}
return prd.response;
}
/* end of taler-merchant-httpd_refund.c */
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