exchange

Base system with REST service to issue digital coins, run by the payment service provider
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exchange_api_get-transfers-WTID.c (12959B)


      1 /*
      2   This file is part of TALER
      3   Copyright (C) 2014-2026 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
     15   <http://www.gnu.org/licenses/>
     16 */
     17 /**
     18  * @file lib/exchange_api_get-transfers-WTID.c
     19  * @brief Implementation of the GET /transfers/$WTID request
     20  * @author Christian Grothoff
     21  */
     22 #include "taler/platform.h"
     23 #include <jansson.h>
     24 #include <microhttpd.h> /* just for HTTP status codes */
     25 #include <gnunet/gnunet_util_lib.h>
     26 #include <gnunet/gnunet_curl_lib.h>
     27 #include "taler/taler_exchange_service.h"
     28 #include "taler/taler_json_lib.h"
     29 #include "exchange_api_handle.h"
     30 #include "taler/taler_signatures.h"
     31 #include "exchange_api_curl_defaults.h"
     32 
     33 
     34 /**
     35  * @brief A GET /transfers/$WTID Handle
     36  */
     37 struct TALER_EXCHANGE_GetTransfersHandle
     38 {
     39 
     40   /**
     41    * Base URL of the exchange.
     42    */
     43   char *base_url;
     44 
     45   /**
     46    * The url for this request.
     47    */
     48   char *url;
     49 
     50   /**
     51    * Handle for the request.
     52    */
     53   struct GNUNET_CURL_Job *job;
     54 
     55   /**
     56    * Function to call with the result.
     57    */
     58   TALER_EXCHANGE_GetTransfersCallback cb;
     59 
     60   /**
     61    * Closure for @e cb.
     62    */
     63   TALER_EXCHANGE_GET_TRANSFERS_RESULT_CLOSURE *cb_cls;
     64 
     65   /**
     66    * CURL context to use.
     67    */
     68   struct GNUNET_CURL_Context *ctx;
     69 
     70   /**
     71    * The keys of the exchange this request handle will use.
     72    */
     73   struct TALER_EXCHANGE_Keys *keys;
     74 
     75   /**
     76    * Wire transfer identifier to look up.
     77    */
     78   struct TALER_WireTransferIdentifierRawP wtid;
     79 
     80 };
     81 
     82 
     83 /**
     84  * We got a #MHD_HTTP_OK response for the /transfers/$WTID request.
     85  * Check that the response is well-formed and if it is, call the
     86  * callback.  If not, return an error code.
     87  *
     88  * This code is very similar to
     89  * merchant_api_track_transfer.c::check_transfers_get_response_ok.
     90  * Any changes should likely be reflected there as well.
     91  *
     92  * @param gth handle to the operation
     93  * @param json response we got
     94  * @return #GNUNET_OK if we are done and all is well,
     95  *         #GNUNET_SYSERR if the response was bogus
     96  */
     97 static enum GNUNET_GenericReturnValue
     98 check_transfers_get_response_ok (
     99   struct TALER_EXCHANGE_GetTransfersHandle *gth,
    100   const json_t *json)
    101 {
    102   const json_t *details_j;
    103   struct TALER_Amount total_expected;
    104   struct TALER_EXCHANGE_GetTransfersResponse tgr = {
    105     .hr.reply = json,
    106     .hr.http_status = MHD_HTTP_OK
    107   };
    108   struct TALER_EXCHANGE_TransferData *td
    109     = &tgr.details.ok.td;
    110   struct GNUNET_JSON_Specification spec[] = {
    111     TALER_JSON_spec_amount_any ("total",
    112                                 &td->total_amount),
    113     TALER_JSON_spec_amount_any ("wire_fee",
    114                                 &td->wire_fee),
    115     GNUNET_JSON_spec_fixed_auto ("merchant_pub",
    116                                  &td->merchant_pub),
    117     GNUNET_JSON_spec_fixed_auto ("h_payto",
    118                                  &td->h_payto),
    119     GNUNET_JSON_spec_timestamp ("execution_time",
    120                                 &td->execution_time),
    121     GNUNET_JSON_spec_array_const ("deposits",
    122                                   &details_j),
    123     GNUNET_JSON_spec_fixed_auto ("exchange_sig",
    124                                  &td->exchange_sig),
    125     GNUNET_JSON_spec_fixed_auto ("exchange_pub",
    126                                  &td->exchange_pub),
    127     GNUNET_JSON_spec_end ()
    128   };
    129 
    130   if (GNUNET_OK !=
    131       GNUNET_JSON_parse (json,
    132                          spec,
    133                          NULL, NULL))
    134   {
    135     GNUNET_break_op (0);
    136     return GNUNET_SYSERR;
    137   }
    138   if (GNUNET_OK !=
    139       TALER_amount_set_zero (td->total_amount.currency,
    140                              &total_expected))
    141   {
    142     GNUNET_break_op (0);
    143     return GNUNET_SYSERR;
    144   }
    145   if (GNUNET_OK !=
    146       TALER_EXCHANGE_test_signing_key (
    147         gth->keys,
    148         &td->exchange_pub))
    149   {
    150     GNUNET_break_op (0);
    151     return GNUNET_SYSERR;
    152   }
    153   td->details_length = json_array_size (details_j);
    154   {
    155     struct GNUNET_HashContext *hash_context;
    156     struct TALER_TrackTransferDetails *details;
    157 
    158     details = GNUNET_new_array (td->details_length,
    159                                 struct TALER_TrackTransferDetails);
    160     td->details = details;
    161     hash_context = GNUNET_CRYPTO_hash_context_start ();
    162     for (unsigned int i = 0; i < td->details_length; i++)
    163     {
    164       struct TALER_TrackTransferDetails *detail = &details[i];
    165       struct json_t *detail_j = json_array_get (details_j, i);
    166       struct GNUNET_JSON_Specification spec_detail[] = {
    167         GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
    168                                      &detail->h_contract_terms),
    169         GNUNET_JSON_spec_fixed_auto ("coin_pub", &detail->coin_pub),
    170         TALER_JSON_spec_amount ("deposit_value",
    171                                 total_expected.currency,
    172                                 &detail->coin_value),
    173         TALER_JSON_spec_amount ("deposit_fee",
    174                                 total_expected.currency,
    175                                 &detail->coin_fee),
    176         GNUNET_JSON_spec_mark_optional (
    177           TALER_JSON_spec_amount ("refund_total",
    178                                   total_expected.currency,
    179                                   &detail->refund_total),
    180           NULL),
    181         GNUNET_JSON_spec_end ()
    182       };
    183 
    184       GNUNET_assert (GNUNET_OK ==
    185                      TALER_amount_set_zero (td->total_amount.currency,
    186                                             &detail->refund_total));
    187       if ( (GNUNET_OK !=
    188             GNUNET_JSON_parse (detail_j,
    189                                spec_detail,
    190                                NULL, NULL)) ||
    191            (0 >
    192             TALER_amount_add (&total_expected,
    193                               &total_expected,
    194                               &detail->coin_value)) ||
    195            (0 >
    196             TALER_amount_subtract (&total_expected,
    197                                    &total_expected,
    198                                    &detail->coin_fee)) )
    199       {
    200         GNUNET_break_op (0);
    201         GNUNET_CRYPTO_hash_context_abort (hash_context);
    202         GNUNET_free (details);
    203         return GNUNET_SYSERR;
    204       }
    205       /* build up big hash for signature checking later */
    206       TALER_exchange_online_wire_deposit_append (
    207         hash_context,
    208         &detail->h_contract_terms,
    209         td->execution_time,
    210         &detail->coin_pub,
    211         &detail->coin_value,
    212         &detail->coin_fee);
    213     }
    214     /* Check signature */
    215     GNUNET_CRYPTO_hash_context_finish (hash_context,
    216                                        &td->h_details);
    217     if (GNUNET_OK !=
    218         TALER_exchange_online_wire_deposit_verify (
    219           &td->total_amount,
    220           &td->wire_fee,
    221           &td->merchant_pub,
    222           &td->h_payto,
    223           &td->h_details,
    224           &td->exchange_pub,
    225           &td->exchange_sig))
    226     {
    227       GNUNET_break_op (0);
    228       GNUNET_free (details);
    229       return GNUNET_SYSERR;
    230     }
    231     if (0 >
    232         TALER_amount_subtract (&total_expected,
    233                                &total_expected,
    234                                &td->wire_fee))
    235     {
    236       GNUNET_break_op (0);
    237       GNUNET_free (details);
    238       return GNUNET_SYSERR;
    239     }
    240     if (0 !=
    241         TALER_amount_cmp (&total_expected,
    242                           &td->total_amount))
    243     {
    244       GNUNET_break_op (0);
    245       GNUNET_free (details);
    246       return GNUNET_SYSERR;
    247     }
    248     gth->cb (gth->cb_cls,
    249              &tgr);
    250     gth->cb = NULL;
    251     GNUNET_free (details);
    252   }
    253   return GNUNET_OK;
    254 }
    255 
    256 
    257 /**
    258  * Function called when we're done processing the
    259  * HTTP GET /transfers/$WTID request.
    260  *
    261  * @param cls the `struct TALER_EXCHANGE_GetTransfersHandle`
    262  * @param response_code HTTP response code, 0 on error
    263  * @param response parsed JSON result, NULL on error
    264  */
    265 static void
    266 handle_transfers_get_finished (void *cls,
    267                                long response_code,
    268                                const void *response)
    269 {
    270   struct TALER_EXCHANGE_GetTransfersHandle *gth = cls;
    271   const json_t *j = response;
    272   struct TALER_EXCHANGE_GetTransfersResponse tgr = {
    273     .hr.reply = j,
    274     .hr.http_status = (unsigned int) response_code
    275   };
    276 
    277   gth->job = NULL;
    278   switch (response_code)
    279   {
    280   case 0:
    281     tgr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
    282     break;
    283   case MHD_HTTP_OK:
    284     if (GNUNET_OK ==
    285         check_transfers_get_response_ok (gth,
    286                                          j))
    287     {
    288       GNUNET_assert (NULL == gth->cb);
    289       TALER_EXCHANGE_get_transfers_cancel (gth);
    290       return;
    291     }
    292     GNUNET_break_op (0);
    293     tgr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
    294     tgr.hr.http_status = 0;
    295     break;
    296   case MHD_HTTP_BAD_REQUEST:
    297     /* This should never happen, either us or the exchange is buggy
    298        (or API version conflict); just pass JSON reply to the application */
    299     tgr.hr.ec = TALER_JSON_get_error_code (j);
    300     tgr.hr.hint = TALER_JSON_get_error_hint (j);
    301     break;
    302   case MHD_HTTP_FORBIDDEN:
    303     /* Nothing really to verify, exchange says one of the signatures is
    304        invalid; as we checked them, this should never happen, we
    305        should pass the JSON reply to the application */
    306     tgr.hr.ec = TALER_JSON_get_error_code (j);
    307     tgr.hr.hint = TALER_JSON_get_error_hint (j);
    308     break;
    309   case MHD_HTTP_NOT_FOUND:
    310     /* Exchange does not know about transaction;
    311        we should pass the reply to the application */
    312     tgr.hr.ec = TALER_JSON_get_error_code (j);
    313     tgr.hr.hint = TALER_JSON_get_error_hint (j);
    314     break;
    315   case MHD_HTTP_INTERNAL_SERVER_ERROR:
    316     /* Server had an internal issue; we should retry, but this API
    317        leaves this to the application */
    318     tgr.hr.ec = TALER_JSON_get_error_code (j);
    319     tgr.hr.hint = TALER_JSON_get_error_hint (j);
    320     break;
    321   default:
    322     /* unexpected response code */
    323     GNUNET_break_op (0);
    324     tgr.hr.ec = TALER_JSON_get_error_code (j);
    325     tgr.hr.hint = TALER_JSON_get_error_hint (j);
    326     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
    327                 "Unexpected response code %u/%d for transfers get\n",
    328                 (unsigned int) response_code,
    329                 (int) tgr.hr.ec);
    330     break;
    331   }
    332   if (NULL != gth->cb)
    333     gth->cb (gth->cb_cls,
    334              &tgr);
    335   TALER_EXCHANGE_get_transfers_cancel (gth);
    336 }
    337 
    338 
    339 struct TALER_EXCHANGE_GetTransfersHandle *
    340 TALER_EXCHANGE_get_transfers_create (
    341   struct GNUNET_CURL_Context *ctx,
    342   const char *url,
    343   struct TALER_EXCHANGE_Keys *keys,
    344   const struct TALER_WireTransferIdentifierRawP *wtid)
    345 {
    346   struct TALER_EXCHANGE_GetTransfersHandle *gth;
    347 
    348   gth = GNUNET_new (struct TALER_EXCHANGE_GetTransfersHandle);
    349   gth->ctx = ctx;
    350   gth->base_url = GNUNET_strdup (url);
    351   gth->keys = TALER_EXCHANGE_keys_incref (keys);
    352   gth->wtid = *wtid;
    353   return gth;
    354 }
    355 
    356 
    357 enum TALER_ErrorCode
    358 TALER_EXCHANGE_get_transfers_start (
    359   struct TALER_EXCHANGE_GetTransfersHandle *gth,
    360   TALER_EXCHANGE_GetTransfersCallback cb,
    361   TALER_EXCHANGE_GET_TRANSFERS_RESULT_CLOSURE *cb_cls)
    362 {
    363   char arg_str[sizeof (struct TALER_WireTransferIdentifierRawP) * 2 + 32];
    364   CURL *eh;
    365 
    366   if (NULL != gth->job)
    367   {
    368     GNUNET_break (0);
    369     return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
    370   }
    371   gth->cb = cb;
    372   gth->cb_cls = cb_cls;
    373   {
    374     char wtid_str[sizeof (struct TALER_WireTransferIdentifierRawP) * 2];
    375     char *end;
    376 
    377     end = GNUNET_STRINGS_data_to_string (&gth->wtid,
    378                                          sizeof (gth->wtid),
    379                                          wtid_str,
    380                                          sizeof (wtid_str));
    381     *end = '\0';
    382     GNUNET_snprintf (arg_str,
    383                      sizeof (arg_str),
    384                      "transfers/%s",
    385                      wtid_str);
    386   }
    387   gth->url = TALER_url_join (gth->base_url,
    388                              arg_str,
    389                              NULL);
    390   if (NULL == gth->url)
    391     return TALER_EC_GENERIC_CONFIGURATION_INVALID;
    392   eh = TALER_EXCHANGE_curl_easy_get_ (gth->url);
    393   if (NULL == eh)
    394     return TALER_EC_GENERIC_CONFIGURATION_INVALID;
    395   gth->job = GNUNET_CURL_job_add_with_ct_json (gth->ctx,
    396                                                eh,
    397                                                &handle_transfers_get_finished,
    398                                                gth);
    399   if (NULL == gth->job)
    400     return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
    401   return TALER_EC_NONE;
    402 }
    403 
    404 
    405 void
    406 TALER_EXCHANGE_get_transfers_cancel (
    407   struct TALER_EXCHANGE_GetTransfersHandle *gth)
    408 {
    409   if (NULL != gth->job)
    410   {
    411     GNUNET_CURL_job_cancel (gth->job);
    412     gth->job = NULL;
    413   }
    414   GNUNET_free (gth->url);
    415   GNUNET_free (gth->base_url);
    416   TALER_EXCHANGE_keys_decref (gth->keys);
    417   GNUNET_free (gth);
    418 }
    419 
    420 
    421 /* end of exchange_api_get-transfers-WTID.c */