merchant

Merchant backend to process payments, run by merchants
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pg_select_exchanges.c (4209B)

      1 /*
      2    This file is part of TALER
      3    Copyright (C) 2026 Taler Systems SA
      4 
      5    TALER is free software; you can redistribute it and/or modify it under the
      6    terms of the GNU General Public License as published by the Free Software
      7    Foundation; either version 3, or (at your option) any later version.
      8 
      9    TALER is distributed in the hope that it will be useful, but WITHOUT ANY
     10    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
     11    A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
     12 
     13    You should have received a copy of the GNU General Public License along with
     14    TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
     15  */
     16 /**
     17  * @file backenddb/pg_select_exchanges.c
     18  * @brief Implementation of the select_exchanges function for Postgres
     19  * @author Christian Grothoff
     20  */
     21 #include "taler/platform.h"
     22 #include <taler/taler_error_codes.h>
     23 #include <taler/taler_dbevents.h>
     24 #include <taler/taler_pq_lib.h>
     25 #include "pg_select_exchanges.h"
     26 #include "pg_helper.h"
     27 
     28 /**
     29  * Context used for TMH_PG_lookup_exchanges().
     30  */
     31 struct LookupExchangesContext
     32 {
     33   /**
     34    * Function to call with the results.
     35    */
     36   TALER_MERCHANTDB_ExchangesCallback cb;
     37 
     38   /**
     39    * Closure for @a cb.
     40    */
     41   void *cb_cls;
     42 
     43   /**
     44    * Did database result extraction fail?
     45    */
     46   bool extract_failed;
     47 };
     48 
     49 
     50 /**
     51  * Function to be called with the results of a SELECT statement
     52  * that has returned @a num_results results about product exchanges.
     53  *
     54  * @param[in,out] cls of type `struct LookupExchangesContext *`
     55  * @param result the postgres result
     56  * @param num_results the number of results in @a result
     57  */
     58 static void
     59 lookup_exchanges_cb (void *cls,
     60                      PGresult *result,
     61                      unsigned int num_results)
     62 {
     63   struct LookupExchangesContext *plc = cls;
     64 
     65   for (unsigned int i = 0; i < num_results; i++)
     66   {
     67     char *exchange_url;
     68     struct GNUNET_TIME_Absolute next_download;
     69     struct GNUNET_TIME_Absolute keys_expiration;
     70     uint32_t hc;
     71     uint32_t ec;
     72     struct GNUNET_PQ_ResultSpec rs[] = {
     73       GNUNET_PQ_result_spec_absolute_time ("first_retry",
     74                                            &next_download),
     75       GNUNET_PQ_result_spec_absolute_time ("expiration_time",
     76                                            &keys_expiration),
     77       GNUNET_PQ_result_spec_string ("exchange_url",
     78                                     &exchange_url),
     79       GNUNET_PQ_result_spec_uint32 ("exchange_http_status",
     80                                     &hc),
     81       GNUNET_PQ_result_spec_uint32 ("exchange_ec_code",
     82                                     &ec),
     83       GNUNET_PQ_result_spec_end
     84     };
     85 
     86     if (GNUNET_OK !=
     87         GNUNET_PQ_extract_result (result,
     88                                   rs,
     89                                   i))
     90     {
     91       GNUNET_break (0);
     92       plc->extract_failed = true;
     93       return;
     94     }
     95     plc->cb (plc->cb_cls,
     96              exchange_url,
     97              next_download,
     98              keys_expiration,
     99              (unsigned int) hc,
    100              (enum TALER_ErrorCode) ec);
    101     GNUNET_PQ_cleanup_result (rs);
    102   }
    103 }
    104 
    105 
    106 enum GNUNET_DB_QueryStatus
    107 TMH_PG_select_exchanges (void *cls,
    108                          TALER_MERCHANTDB_ExchangesCallback cb,
    109                          void *cb_cls)
    110 {
    111   struct PostgresClosure *pg = cls;
    112   struct LookupExchangesContext plc = {
    113     .cb = cb,
    114     .cb_cls = cb_cls,
    115     /* Can be overwritten by the lookup_exchanges_cb */
    116     .extract_failed = false,
    117   };
    118   struct GNUNET_PQ_QueryParam params[] = {
    119     GNUNET_PQ_query_param_end
    120   };
    121   enum GNUNET_DB_QueryStatus qs;
    122 
    123   check_connection (pg);
    124   PREPARE (pg,
    125            "select_exchanges",
    126            "SELECT"
    127            "  exchange_url"
    128            " ,first_retry"
    129            " ,expiration_time"
    130            " ,exchange_http_status"
    131            " ,exchange_ec_code"
    132            " FROM merchant_exchange_keys");
    133   qs = GNUNET_PQ_eval_prepared_multi_select (
    134     pg->conn,
    135     "select_exchanges",
    136     params,
    137     &lookup_exchanges_cb,
    138     &plc);
    139   /* If there was an error inside lookup_exchanges_cb, return a hard error. */
    140   if (plc.extract_failed)
    141   {
    142     GNUNET_break (0);
    143     return GNUNET_DB_STATUS_HARD_ERROR;
    144   }
    145   return qs;
    146 }