exchange

exchange_api_contracts_get.c (7541B)

---

 /*
   This file is part of TALER
   Copyright (C) 2022 Taler Systems SA
 
   TALER is free software; you can redistribute it and/or modify it under the
   terms of the GNU 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 lib/exchange_api_contracts_get.c
  * @brief Implementation of the /contracts/ GET request
  * @author Christian Grothoff
  */
 #include "taler/platform.h"
 #include <jansson.h>
 #include <microhttpd.h> /* just for HTTP status codes */
 #include <gnunet/gnunet_util_lib.h>
 #include <gnunet/gnunet_json_lib.h>
 #include <gnunet/gnunet_curl_lib.h>
 #include "taler/taler_json_lib.h"
 #include "taler/taler_exchange_service.h"
 #include "exchange_api_handle.h"
 #include "taler/taler_signatures.h"
 #include "exchange_api_curl_defaults.h"
 
 
 /**
  * @brief A Contract Get Handle
  */
 struct TALER_EXCHANGE_ContractsGetHandle
 {
 
   /**
    * The url for this request.
    */
   char *url;
 
   /**
    * Handle for the request.
    */
   struct GNUNET_CURL_Job *job;
 
   /**
    * Function to call with the result.
    */
   TALER_EXCHANGE_ContractGetCallback cb;
 
   /**
    * Closure for @a cb.
    */
   void *cb_cls;
 
   /**
    * Private key needed to decrypt the contract.
    */
   struct TALER_ContractDiffiePrivateP contract_priv;
 
   /**
    * Public key matching @e contract_priv.
    */
   struct TALER_ContractDiffiePublicP cpub;
 
 };
 
 
 /**
  * Function called when we're done processing the
  * HTTP /track/transaction request.
  *
  * @param cls the `struct TALER_EXCHANGE_ContractsGetHandle`
  * @param response_code HTTP response code, 0 on error
  * @param response parsed JSON result, NULL on error
  */
 static void
 handle_contract_get_finished (void *cls,
                               long response_code,
                               const void *response)
 {
   struct TALER_EXCHANGE_ContractsGetHandle *cgh = cls;
   const json_t *j = response;
   struct TALER_EXCHANGE_ContractGetResponse dr = {
     .hr.reply = j,
     .hr.http_status = (unsigned int) response_code
   };
 
   cgh->job = NULL;
   switch (response_code)
   {
   case 0:
     dr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
     break;
   case MHD_HTTP_OK:
     {
       void *econtract;
       size_t econtract_size;
       struct TALER_PurseContractSignatureP econtract_sig;
       struct GNUNET_JSON_Specification spec[] = {
         GNUNET_JSON_spec_fixed_auto ("purse_pub",
                                      &dr.details.ok.purse_pub),
         GNUNET_JSON_spec_fixed_auto ("econtract_sig",
                                      &econtract_sig),
         GNUNET_JSON_spec_varsize ("econtract",
                                   &econtract,
                                   &econtract_size),
         GNUNET_JSON_spec_end ()
       };
 
       if (GNUNET_OK !=
           GNUNET_JSON_parse (j,
                              spec,
                              NULL, NULL))
       {
         GNUNET_break_op (0);
         dr.hr.http_status = 0;
         dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
         break;
       }
       if (GNUNET_OK !=
           TALER_wallet_econtract_upload_verify (
             econtract,
             econtract_size,
             &cgh->cpub,
             &dr.details.ok.purse_pub,
             &econtract_sig))
       {
         GNUNET_break (0);
         dr.hr.http_status = 0;
         dr.hr.ec = TALER_EC_EXCHANGE_CONTRACTS_SIGNATURE_INVALID;
         GNUNET_JSON_parse_free (spec);
         break;
       }
       dr.details.ok.econtract = econtract;
       dr.details.ok.econtract_size = econtract_size;
       cgh->cb (cgh->cb_cls,
                &dr);
       GNUNET_JSON_parse_free (spec);
       TALER_EXCHANGE_contract_get_cancel (cgh);
       return;
     }
   case MHD_HTTP_BAD_REQUEST:
     dr.hr.ec = TALER_JSON_get_error_code (j);
     dr.hr.hint = TALER_JSON_get_error_hint (j);
     /* This should never happen, either us or the exchange is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
   case MHD_HTTP_FORBIDDEN:
     dr.hr.ec = TALER_JSON_get_error_code (j);
     dr.hr.hint = TALER_JSON_get_error_hint (j);
     /* Nothing really to verify, exchange says one of the signatures is
        invalid; as we checked them, this should never happen, we
        should pass the JSON reply to the application */
     break;
   case MHD_HTTP_NOT_FOUND:
     dr.hr.ec = TALER_JSON_get_error_code (j);
     dr.hr.hint = TALER_JSON_get_error_hint (j);
     /* Exchange does not know about transaction;
        we should pass the reply to the application */
     break;
   case MHD_HTTP_INTERNAL_SERVER_ERROR:
     dr.hr.ec = TALER_JSON_get_error_code (j);
     dr.hr.hint = TALER_JSON_get_error_hint (j);
     /* Server had an internal issue; we should retry, but this API
        leaves this to the application */
     break;
   default:
     /* unexpected response code */
     dr.hr.ec = TALER_JSON_get_error_code (j);
     dr.hr.hint = TALER_JSON_get_error_hint (j);
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                 "Unexpected response code %u/%d for exchange GET contracts\n",
                 (unsigned int) response_code,
                 (int) dr.hr.ec);
     GNUNET_break_op (0);
     break;
   }
   cgh->cb (cgh->cb_cls,
            &dr);
   TALER_EXCHANGE_contract_get_cancel (cgh);
 }
 
 
 struct TALER_EXCHANGE_ContractsGetHandle *
 TALER_EXCHANGE_contract_get (
   struct GNUNET_CURL_Context *ctx,
   const char *url,
   const struct TALER_ContractDiffiePrivateP *contract_priv,
   TALER_EXCHANGE_ContractGetCallback cb,
   void *cb_cls)
 {
   struct TALER_EXCHANGE_ContractsGetHandle *cgh;
   CURL *eh;
   char arg_str[sizeof (cgh->cpub) * 2 + 48];
 
   cgh = GNUNET_new (struct TALER_EXCHANGE_ContractsGetHandle);
   cgh->cb = cb;
   cgh->cb_cls = cb_cls;
   GNUNET_CRYPTO_ecdhe_key_get_public (&contract_priv->ecdhe_priv,
                                       &cgh->cpub.ecdhe_pub);
   {
     char cpub_str[sizeof (cgh->cpub) * 2];
     char *end;
 
     end = GNUNET_STRINGS_data_to_string (&cgh->cpub,
                                          sizeof (cgh->cpub),
                                          cpub_str,
                                          sizeof (cpub_str));
     *end = '\0';
     GNUNET_snprintf (arg_str,
                      sizeof (arg_str),
                      "contracts/%s",
                      cpub_str);
   }
 
   cgh->url = TALER_url_join (url,
                              arg_str,
                              NULL);
   if (NULL == cgh->url)
   {
     GNUNET_free (cgh);
     return NULL;
   }
   cgh->contract_priv = *contract_priv;
 
   eh = TALER_EXCHANGE_curl_easy_get_ (cgh->url);
   if (NULL == eh)
   {
     GNUNET_break (0);
     GNUNET_free (cgh->url);
     GNUNET_free (cgh);
     return NULL;
   }
   cgh->job = GNUNET_CURL_job_add (ctx,
                                   eh,
                                   &handle_contract_get_finished,
                                   cgh);
   return cgh;
 }
 
 
 void
 TALER_EXCHANGE_contract_get_cancel (
   struct TALER_EXCHANGE_ContractsGetHandle *cgh)
 {
   if (NULL != cgh->job)
   {
     GNUNET_CURL_job_cancel (cgh->job);
     cgh->job = NULL;
   }
   GNUNET_free (cgh->url);
   GNUNET_free (cgh);
 }
 
 
 /* end of exchange_api_contracts_get.c */