merchant

taler-merchant-httpd_post-orders-ORDER_ID-refund.c (25154B)

---

 /*
   This file is part of TALER
   (C) 2020-2022 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 src/backend/taler-merchant-httpd_post-orders-ORDER_ID-refund.c
  * @brief handling of POST /orders/$ID/refund requests
  * @author Jonathan Buchanan
  */
 #include "platform.h"
 struct CoinRefund;
 #define TALER_EXCHANGE_POST_COINS_REFUND_RESULT_CLOSURE struct CoinRefund
 #include <taler/taler_dbevents.h>
 #include <taler/taler_signatures.h>
 #include <taler/taler_json_lib.h>
 #include <taler/taler_exchange_service.h>
 #include "taler-merchant-httpd.h"
 #include "taler-merchant-httpd_exchanges.h"
 #include "taler-merchant-httpd_get-exchanges.h"
 #include "taler-merchant-httpd_post-orders-ORDER_ID-refund.h"
 #include "merchant-database/insert_refund_proof.h"
 #include "merchant-database/lookup_contract_terms.h"
 #include "merchant-database/lookup_refund_proof.h"
 #include "merchant-database/lookup_refunds_detailed.h"
 #include "merchant-database/event_notify.h"
 #include "merchant-database/preflight.h"
 
 
 /**
  * Information we keep for each coin to be refunded.
  */
 struct CoinRefund
 {
 
   /**
    * Kept in a DLL.
    */
   struct CoinRefund *next;
 
   /**
    * Kept in a DLL.
    */
   struct CoinRefund *prev;
 
   /**
    * Request to connect to the target exchange.
    */
   struct TMH_EXCHANGES_KeysOperation *fo;
 
   /**
    * Handle for the refund operation with the exchange.
    */
   struct TALER_EXCHANGE_PostCoinsRefundHandle *rh;
 
   /**
    * Request this operation is part of.
    */
   struct PostRefundData *prd;
 
   /**
    * URL of the exchange for this @e coin_pub.
    */
   char *exchange_url;
 
   /**
    * Fully reply from the exchange, only possibly set if
    * we got a JSON reply and a non-#MHD_HTTP_OK error code
    */
   json_t *exchange_reply;
 
   /**
    * When did the merchant grant the refund. To be used to group events
    * in the wallet.
    */
   struct GNUNET_TIME_Timestamp execution_time;
 
   /**
    * Coin to refund.
    */
   struct TALER_CoinSpendPublicKeyP coin_pub;
 
   /**
    * Refund transaction ID to use.
    */
   uint64_t rtransaction_id;
 
   /**
    * Unique serial number identifying the refund.
    */
   uint64_t refund_serial;
 
   /**
    * Amount to refund.
    */
   struct TALER_Amount refund_amount;
 
   /**
    * Public key of the exchange affirming the refund.
    */
   struct TALER_ExchangePublicKeyP exchange_pub;
 
   /**
    * Signature of the exchange affirming the refund.
    */
   struct TALER_ExchangeSignatureP exchange_sig;
 
   /**
    * HTTP status from the exchange, #MHD_HTTP_OK if
    * @a exchange_pub and @a exchange_sig are valid.
    */
   unsigned int exchange_status;
 
   /**
    * HTTP error code from the exchange.
    */
   enum TALER_ErrorCode exchange_code;
 
 };
 
 
 /**
  * Context for the operation.
  */
 struct PostRefundData
 {
 
   /**
    * Hashed version of contract terms. All zeros if not provided.
    */
   struct TALER_PrivateContractHashP h_contract_terms;
 
   /**
    * DLL of (suspended) requests.
    */
   struct PostRefundData *next;
 
   /**
    * DLL of (suspended) requests.
    */
   struct PostRefundData *prev;
 
   /**
    * Refunds for this order. Head of DLL.
    */
   struct CoinRefund *cr_head;
 
   /**
    * Refunds for this order. Tail of DLL.
    */
   struct CoinRefund *cr_tail;
 
   /**
    * Context of the request.
    */
   struct TMH_HandlerContext *hc;
 
   /**
    * Entry in the #resume_timeout_heap for this check payment, if we are
    * suspended.
    */
   struct TMH_SuspendedConnection sc;
 
   /**
    * order ID for the payment
    */
   const char *order_id;
 
   /**
    * Where to get the contract
    */
   const char *contract_url;
 
   /**
    * fulfillment URL of the contract (valid as long as
    * @e contract_terms is valid).
    */
   const char *fulfillment_url;
 
   /**
    * session of the client
    */
   const char *session_id;
 
   /**
    * Contract terms of the payment we are checking. NULL when they
    * are not (yet) known.
    */
   json_t *contract_terms;
 
   /**
    * Total refunds granted for this payment. Only initialized
    * if @e refunded is set to true.
    */
   struct TALER_Amount refund_amount;
 
   /**
    * Did we suspend @a connection and are thus in
    * the #prd_head DLL (#GNUNET_YES). Set to
    * #GNUNET_NO if we are not suspended, and to
    * #GNUNET_SYSERR if we should close the connection
    * without a response due to shutdown.
    */
   enum GNUNET_GenericReturnValue suspended;
 
   /**
    * Return code: #TALER_EC_NONE if successful.
    */
   enum TALER_ErrorCode ec;
 
   /**
    * HTTP status to use for the reply, 0 if not yet known.
    */
   unsigned int http_status;
 
   /**
    * Set to true if we are dealing with an unclaimed order
    * (and thus @e h_contract_terms is not set, and certain
    * DB queries will not work).
    */
   bool unclaimed;
 
   /**
    * Set to true if this payment has been refunded and
    * @e refund_amount is initialized.
    */
   bool refunded;
 
   /**
    * Set to true if a refund is still available for the
    * wallet for this payment.
    */
   bool refund_available;
 
   /**
    * Set to true if the client requested HTML, otherwise
    * we generate JSON.
    */
   bool generate_html;
 
 };
 
 
 /**
  * Head of DLL of (suspended) requests.
  */
 static struct PostRefundData *prd_head;
 
 /**
  * Tail of DLL of (suspended) requests.
  */
 static struct PostRefundData *prd_tail;
 
 
 /**
  * Function called when we are done processing a refund request.
  * Frees memory associated with @a ctx.
  *
  * @param ctx a `struct PostRefundData`
  */
 static void
 refund_cleanup (void *ctx)
 {
   struct PostRefundData *prd = ctx;
   struct CoinRefund *cr;
 
   while (NULL != (cr = prd->cr_head))
   {
     GNUNET_CONTAINER_DLL_remove (prd->cr_head,
                                  prd->cr_tail,
                                  cr);
     json_decref (cr->exchange_reply);
     GNUNET_free (cr->exchange_url);
     if (NULL != cr->fo)
     {
       TMH_EXCHANGES_keys4exchange_cancel (cr->fo);
       cr->fo = NULL;
     }
     if (NULL != cr->rh)
     {
       TALER_EXCHANGE_post_coins_refund_cancel (cr->rh);
       cr->rh = NULL;
     }
     GNUNET_free (cr);
   }
   json_decref (prd->contract_terms);
   GNUNET_free (prd);
 }
 
 
 /**
  * Force resuming all suspended order lookups, needed during shutdown.
  */
 void
 TMH_force_wallet_refund_order_resume (void)
 {
   struct PostRefundData *prd;
 
   while (NULL != (prd = prd_head))
   {
     GNUNET_CONTAINER_DLL_remove (prd_head,
                                  prd_tail,
                                  prd);
     GNUNET_assert (GNUNET_YES == prd->suspended);
     prd->suspended = GNUNET_SYSERR;
     MHD_resume_connection (prd->sc.con);
   }
 }
 
 
 /**
  * Check if @a prd has exchange requests still pending.
  *
  * @param prd state to check
  * @return true if activities are still pending
  */
 static bool
 exchange_operations_pending (struct PostRefundData *prd)
 {
   for (struct CoinRefund *cr = prd->cr_head;
        NULL != cr;
        cr = cr->next)
   {
     if ( (NULL != cr->fo) ||
          (NULL != cr->rh) )
       return true;
   }
   return false;
 }
 
 
 /**
  * Check if @a prd is ready to be resumed, and if so, do it.
  *
  * @param prd refund request to be possibly ready
  */
 static void
 check_resume_prd (struct PostRefundData *prd)
 {
   if ( (TALER_EC_NONE == prd->ec) &&
        exchange_operations_pending (prd) )
     return;
   GNUNET_CONTAINER_DLL_remove (prd_head,
                                prd_tail,
                                prd);
   GNUNET_assert (prd->suspended);
   prd->suspended = GNUNET_NO;
   MHD_resume_connection (prd->sc.con);
   TALER_MHD_daemon_trigger ();
 }
 
 
 /**
  * Notify applications waiting for a client to obtain
  * a refund.
  *
  * @param prd refund request with the change
  */
 static void
 notify_refund_obtained (struct PostRefundData *prd)
 {
   struct TMH_OrderPayEventP refund_eh = {
     .header.size = htons (sizeof (refund_eh)),
     .header.type = htons (TALER_DBEVENT_MERCHANT_REFUND_OBTAINED),
     .merchant_pub = prd->hc->instance->merchant_pub
   };
 
   GNUNET_CRYPTO_hash (prd->order_id,
                       strlen (prd->order_id),
                       &refund_eh.h_order_id);
   TALER_MERCHANTDB_event_notify (TMH_db,
                                  &refund_eh.header,
                                  NULL,
                                  0);
 }
 
 
 /**
  * Callbacks of this type are used to serve the result of submitting a
  * refund request to an exchange.
  *
  * @param cls a `struct CoinRefund`
  * @param rr response data
  */
 static void
 refund_cb (struct CoinRefund *cr,
            const struct TALER_EXCHANGE_PostCoinsRefundResponse *rr)
 {
   const struct TALER_EXCHANGE_HttpResponse *hr = &rr->hr;
 
   cr->rh = NULL;
   cr->exchange_status = hr->http_status;
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Exchange refund status for coin %s is %u\n",
               TALER_B2S (&cr->coin_pub),
               hr->http_status);
   switch (hr->http_status)
   {
   case MHD_HTTP_OK:
     {
       enum GNUNET_DB_QueryStatus qs;
 
       cr->exchange_pub = rr->details.ok.exchange_pub;
       cr->exchange_sig = rr->details.ok.exchange_sig;
       qs = TALER_MERCHANTDB_insert_refund_proof (TMH_db,
                                                  cr->refund_serial,
                                                  &rr->details.ok.exchange_sig,
                                                  &rr->details.ok.exchange_pub);
       if (0 >= qs)
       {
         /* generally, this is relatively harmless for the merchant, but let's at
            least log this. */
         GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                     "Failed to persist exchange response to /refund in database: %d\n",
                     qs);
       }
       else
       {
         notify_refund_obtained (cr->prd);
       }
     }
     break;
   default:
     cr->exchange_code = hr->ec;
     cr->exchange_reply = json_incref ((json_t*) hr->reply);
     break;
   }
   check_resume_prd (cr->prd);
 }
 
 
 /**
  * Function called with the result of a
  * #TMH_EXCHANGES_keys4exchange()
  * operation.
  *
  * @param cls a `struct CoinRefund *`
  * @param keys keys of exchange, NULL on error
  * @param exchange representation of the exchange
  */
 static void
 exchange_found_cb (void *cls,
                    struct TALER_EXCHANGE_Keys *keys,
                    struct TMH_Exchange *exchange)
 {
   struct CoinRefund *cr = cls;
   struct PostRefundData *prd = cr->prd;
 
   (void) exchange;
   cr->fo = NULL;
   if (NULL == keys)
   {
     prd->http_status = MHD_HTTP_GATEWAY_TIMEOUT;
     prd->ec = TALER_EC_MERCHANT_GENERIC_EXCHANGE_TIMEOUT;
     check_resume_prd (prd);
     return;
   }
   cr->rh = TALER_EXCHANGE_post_coins_refund_create (
     TMH_curl_ctx,
     cr->exchange_url,
     keys,
     &cr->refund_amount,
     &prd->h_contract_terms,
     &cr->coin_pub,
     cr->rtransaction_id,
     &prd->hc->instance->merchant_priv);
   GNUNET_assert (NULL != cr->rh);
   GNUNET_assert (TALER_EC_NONE ==
                  TALER_EXCHANGE_post_coins_refund_start (cr->rh,
                                                          &refund_cb,
                                                          cr));
 }
 
 
 /**
  * Function called with information about a refund.
  * It is responsible for summing up the refund amount.
  *
  * @param cls closure
  * @param refund_serial unique serial number of the refund
  * @param timestamp time of the refund (for grouping of refunds in the wallet UI)
  * @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 pending true if the this refund was not yet processed by the wallet/exchange
  */
 static void
 process_refunds_cb (void *cls,
                     uint64_t refund_serial,
                     struct GNUNET_TIME_Timestamp timestamp,
                     const struct TALER_CoinSpendPublicKeyP *coin_pub,
                     const char *exchange_url,
                     uint64_t rtransaction_id,
                     const char *reason,
                     const struct TALER_Amount *refund_amount,
                     bool pending)
 {
   struct PostRefundData *prd = cls;
   struct CoinRefund *cr;
 
   for (cr = prd->cr_head;
        NULL != cr;
        cr = cr->next)
     if (cr->refund_serial == refund_serial)
       return;
   /* already known */
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Found refund of %s for coin %s with reason `%s' in database\n",
               TALER_amount2s (refund_amount),
               TALER_B2S (coin_pub),
               reason);
   cr = GNUNET_new (struct CoinRefund);
   cr->refund_serial = refund_serial;
   cr->exchange_url = GNUNET_strdup (exchange_url);
   cr->prd = prd;
   cr->coin_pub = *coin_pub;
   cr->rtransaction_id = rtransaction_id;
   cr->refund_amount = *refund_amount;
   cr->execution_time = timestamp;
   GNUNET_CONTAINER_DLL_insert (prd->cr_head,
                                prd->cr_tail,
                                cr);
   if (prd->refunded)
   {
     GNUNET_assert (0 <=
                    TALER_amount_add (&prd->refund_amount,
                                      &prd->refund_amount,
                                      refund_amount));
     return;
   }
   prd->refund_amount = *refund_amount;
   prd->refunded = true;
   prd->refund_available |= pending;
 }
 
 
 /**
  * Obtain refunds for an order.
  *
  * @param rh context of the handler
  * @param connection the MHD connection to handle
  * @param[in,out] hc context with further information about the request
  * @return MHD result code
  */
 enum MHD_Result
 TMH_post_orders_ID_refund (const struct TMH_RequestHandler *rh,
                            struct MHD_Connection *connection,
                            struct TMH_HandlerContext *hc)
 {
   struct PostRefundData *prd = hc->ctx;
   enum GNUNET_DB_QueryStatus qs;
 
   if (NULL == prd)
   {
     prd = GNUNET_new (struct PostRefundData);
     prd->sc.con = connection;
     prd->hc = hc;
     prd->order_id = hc->infix;
     hc->ctx = prd;
     hc->cc = &refund_cleanup;
     {
       enum GNUNET_GenericReturnValue res;
 
       struct GNUNET_JSON_Specification spec[] = {
         GNUNET_JSON_spec_fixed_auto ("h_contract",
                                      &prd->h_contract_terms),
         GNUNET_JSON_spec_end ()
       };
       res = TALER_MHD_parse_json_data (connection,
                                        hc->request_body,
                                        spec);
       if (GNUNET_OK != res)
         return (GNUNET_NO == res)
                ? MHD_YES
                : MHD_NO;
     }
 
     TALER_MERCHANTDB_preflight (TMH_db);
     {
       json_t *contract_terms;
       uint64_t order_serial;
 
       qs = TALER_MERCHANTDB_lookup_contract_terms (TMH_db,
                                                    hc->instance->settings.id,
                                                    hc->infix,
                                                    &contract_terms,
                                                    &order_serial,
                                                    NULL);
       if (0 > qs)
       {
         /* single, read-only SQL statements should never cause
            serialization problems */
         GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR != qs);
         /* Always report on hard error as well to enable diagnostics */
         GNUNET_break (GNUNET_DB_STATUS_HARD_ERROR == qs);
         return TALER_MHD_reply_with_error (connection,
                                            MHD_HTTP_INTERNAL_SERVER_ERROR,
                                            TALER_EC_GENERIC_DB_FETCH_FAILED,
                                            "contract terms");
       }
       if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
       {
         json_decref (contract_terms);
         return TALER_MHD_reply_with_error (connection,
                                            MHD_HTTP_NOT_FOUND,
                                            TALER_EC_MERCHANT_GENERIC_ORDER_UNKNOWN,
                                            hc->infix);
       }
       {
         struct TALER_PrivateContractHashP h_contract_terms;
 
         if (GNUNET_OK !=
             TALER_JSON_contract_hash (contract_terms,
                                       &h_contract_terms))
         {
           GNUNET_break (0);
           json_decref (contract_terms);
           return TALER_MHD_reply_with_error (connection,
                                              MHD_HTTP_INTERNAL_SERVER_ERROR,
                                              TALER_EC_GENERIC_FAILED_COMPUTE_JSON_HASH,
                                              NULL);
         }
         json_decref (contract_terms);
         if (0 != GNUNET_memcmp (&h_contract_terms,
                                 &prd->h_contract_terms))
         {
           return TALER_MHD_reply_with_error (
             connection,
             MHD_HTTP_FORBIDDEN,
             TALER_EC_MERCHANT_GENERIC_CONTRACT_HASH_DOES_NOT_MATCH_ORDER,
             NULL);
         }
       }
     }
   }
   if (GNUNET_SYSERR == prd->suspended)
     return MHD_NO; /* we are in shutdown */
 
   if (TALER_EC_NONE != prd->ec)
   {
     GNUNET_break (0 != prd->http_status);
     /* kill pending coin refund operations immediately, just to be
        extra sure they don't modify 'prd' after we already created
        a reply (this might not be needed, but feels safer). */
     for (struct CoinRefund *cr = prd->cr_head;
          NULL != cr;
          cr = cr->next)
     {
       if (NULL != cr->fo)
       {
         TMH_EXCHANGES_keys4exchange_cancel (cr->fo);
         cr->fo = NULL;
       }
       if (NULL != cr->rh)
       {
         TALER_EXCHANGE_post_coins_refund_cancel (cr->rh);
         cr->rh = NULL;
       }
     }
     return TALER_MHD_reply_with_error (connection,
                                        prd->http_status,
                                        prd->ec,
                                        NULL);
   }
 
   qs = TALER_MERCHANTDB_lookup_refunds_detailed (TMH_db,
                                                  hc->instance->settings.id,
                                                  &prd->h_contract_terms,
                                                  &process_refunds_cb,
                                                  prd);
   if (0 > qs)
   {
     GNUNET_break (0);
     return TALER_MHD_reply_with_error (connection,
                                        MHD_HTTP_INTERNAL_SERVER_ERROR,
                                        TALER_EC_GENERIC_DB_FETCH_FAILED,
                                        "detailed refunds");
   }
   if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
   {
     /* We have a contract, which means the order was paid, but there
        are no coins (maybe paid with a token?), and thus we cannot
        do any refunds */
     return TALER_MHD_reply_static (connection,
                                    MHD_HTTP_NO_CONTENT,
                                    NULL,
                                    NULL,
                                    0);
   }
 
   /* Now launch exchange interactions, unless we already have the
      response in the database! */
   for (struct CoinRefund *cr = prd->cr_head;
        NULL != cr;
        cr = cr->next)
   {
     qs = TALER_MERCHANTDB_lookup_refund_proof (TMH_db,
                                                cr->refund_serial,
                                                &cr->exchange_sig,
                                                &cr->exchange_pub);
     switch (qs)
     {
     case GNUNET_DB_STATUS_HARD_ERROR:
     case GNUNET_DB_STATUS_SOFT_ERROR:
       return TALER_MHD_reply_with_error (connection,
                                          MHD_HTTP_INTERNAL_SERVER_ERROR,
                                          TALER_EC_GENERIC_DB_FETCH_FAILED,
                                          "refund proof");
     case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
       if (NULL == cr->exchange_reply)
       {
         /* We need to talk to the exchange */
         cr->fo = TMH_EXCHANGES_keys4exchange (cr->exchange_url,
                                               false,
                                               &exchange_found_cb,
                                               cr);
         if (NULL == cr->fo)
         {
           GNUNET_break (0);
           return TALER_MHD_reply_with_error (connection,
                                              MHD_HTTP_INTERNAL_SERVER_ERROR,
                                              TALER_EC_MERCHANT_GENERIC_EXCHANGE_UNTRUSTED,
                                              cr->exchange_url);
         }
       }
       break;
     case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
       /* We got a reply earlier, set status accordingly */
       cr->exchange_status = MHD_HTTP_OK;
       break;
     }
   }
 
   /* Check if there are still exchange operations pending */
   if (exchange_operations_pending (prd))
   {
     if (GNUNET_NO == prd->suspended)
     {
       prd->suspended = GNUNET_YES;
       MHD_suspend_connection (connection);
       GNUNET_CONTAINER_DLL_insert (prd_head,
                                    prd_tail,
                                    prd);
     }
     return MHD_YES;   /* we're still talking to the exchange */
   }
 
   {
     json_t *ra;
 
     ra = json_array ();
     GNUNET_assert (NULL != ra);
     for (struct CoinRefund *cr = prd->cr_head;
          NULL != cr;
          cr = cr->next)
     {
       json_t *refund;
 
       if (MHD_HTTP_OK != cr->exchange_status)
       {
         if (NULL == cr->exchange_reply)
         {
           refund = GNUNET_JSON_PACK (
             GNUNET_JSON_pack_string ("type",
                                      "failure"),
             GNUNET_JSON_pack_uint64 ("exchange_status",
                                      cr->exchange_status),
             GNUNET_JSON_pack_uint64 ("rtransaction_id",
                                      cr->rtransaction_id),
             GNUNET_JSON_pack_data_auto ("coin_pub",
                                         &cr->coin_pub),
             TALER_JSON_pack_amount ("refund_amount",
                                     &cr->refund_amount),
             GNUNET_JSON_pack_timestamp ("execution_time",
                                         cr->execution_time));
         }
         else
         {
           refund = GNUNET_JSON_PACK (
             GNUNET_JSON_pack_string ("type",
                                      "failure"),
             GNUNET_JSON_pack_uint64 ("exchange_status",
                                      cr->exchange_status),
             GNUNET_JSON_pack_uint64 ("exchange_code",
                                      cr->exchange_code),
             GNUNET_JSON_pack_object_incref ("exchange_reply",
                                             cr->exchange_reply),
             GNUNET_JSON_pack_uint64 ("rtransaction_id",
                                      cr->rtransaction_id),
             GNUNET_JSON_pack_data_auto ("coin_pub",
                                         &cr->coin_pub),
             TALER_JSON_pack_amount ("refund_amount",
                                     &cr->refund_amount),
             GNUNET_JSON_pack_timestamp ("execution_time",
                                         cr->execution_time));
         }
       }
       else
       {
         refund = GNUNET_JSON_PACK (
           GNUNET_JSON_pack_string ("type",
                                    "success"),
           GNUNET_JSON_pack_uint64 ("exchange_status",
                                    cr->exchange_status),
           GNUNET_JSON_pack_data_auto ("exchange_sig",
                                       &cr->exchange_sig),
           GNUNET_JSON_pack_data_auto ("exchange_pub",
                                       &cr->exchange_pub),
           GNUNET_JSON_pack_uint64 ("rtransaction_id",
                                    cr->rtransaction_id),
           GNUNET_JSON_pack_data_auto ("coin_pub",
                                       &cr->coin_pub),
           TALER_JSON_pack_amount ("refund_amount",
                                   &cr->refund_amount),
           GNUNET_JSON_pack_timestamp ("execution_time",
                                       cr->execution_time));
       }
       GNUNET_assert (
         0 ==
         json_array_append_new (ra,
                                refund));
     }
 
     return TALER_MHD_REPLY_JSON_PACK (
       connection,
       MHD_HTTP_OK,
       TALER_JSON_pack_amount ("refund_amount",
                               &prd->refund_amount),
       GNUNET_JSON_pack_array_steal ("refunds",
                                     ra),
       GNUNET_JSON_pack_data_auto ("merchant_pub",
                                   &hc->instance->merchant_pub));
   }
 
   return MHD_YES;
 }
 
 
 /* end of taler-merchant-httpd_post-orders-ORDER_ID-refund.c */