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/*
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 "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_json_lib.h"
#include "taler_exchange_service.h"
#include "exchange_api_handle.h"
#include "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 */
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