/*
This file is part of TALER
(C) 2017, 2019 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
*/
/**
* @file backend/taler-merchant-httpd_check-payment.c
* @brief implementation of /check-payment handler
* @author Florian Dold
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include
#include
#include
#include
#include "taler-merchant-httpd.h"
#include "taler-merchant-httpd_mhd.h"
#include "taler-merchant-httpd_exchanges.h"
#include "taler-merchant-httpd_check-payment.h"
/**
* Maximum number of retries for database operations.
*/
#define MAX_RETRIES 5
/**
* Data structure we keep for a check payment request.
*/
struct CheckPaymentRequestContext
{
/**
* Must be first for #handle_mhd_completion_callback.
*/
struct TM_HandlerContext hc;
/**
* Entry in the #resume_timeout_heap for this check payment, if we are
* suspended.
*/
struct TMH_SuspendedConnection sc;
/**
* Which merchant instance is this for?
*/
struct MerchantInstance *mi;
/**
* URL where the final contract can be found for this payment.
*/
char *final_contract_url;
/**
* order ID for the payment
*/
const char *order_id;
/**
* Where to get the contract
*/
const char *contract_url;
/**
* session of the client
*/
const char *session_id;
/**
* fulfillment URL of the contract (valid as long as
* @e contract_terms is valid).
*/
const char *fulfillment_url;
/**
* Contract terms of the payment we are checking. NULL when they
* are not (yet) known.
*/
json_t *contract_terms;
/**
* Hash of @e contract_terms, set only once @e contract_terms
* is available.
*/
struct GNUNET_HashCode h_contract_terms;
/**
* Total refunds granted for this payment. Only initialized
* if @e refunded is set to #GNUNET_YES.
*/
struct TALER_Amount refund_amount;
/**
* Set to #GNUNET_YES if this payment has been refunded and
* @e refund_amount is initialized.
*/
int refunded;
/**
* Initially #GNUNET_SYSERR. If we queued a response, set to the
* result code (i.e. #MHD_YES or #MHD_NO).
*/
int ret;
};
/**
* Clean up the session state for a check payment request.
*
* @param hc must be a `struct CheckPaymentRequestContext *`
*/
static void
cprc_cleanup (struct TM_HandlerContext *hc)
{
struct CheckPaymentRequestContext *cprc = (struct
CheckPaymentRequestContext *) hc;
if (NULL != cprc->contract_terms)
json_decref (cprc->contract_terms);
GNUNET_free_non_null (cprc->final_contract_url);
GNUNET_free (cprc);
}
/**
* Function called with information about a refund.
* It is responsible for summing up the refund amount.
*
* @param cls closure
* @param coin_pub public coin from which the refund comes from
* @param rtransaction_id identificator of the refund
* @param reason human-readable explaination of the refund
* @param refund_amount refund amount which is being taken from coin_pub
* @param refund_fee cost of this refund operation
*/
static void
process_refunds_cb (void *cls,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
uint64_t rtransaction_id,
const char *reason,
const struct TALER_Amount *refund_amount,
const struct TALER_Amount *refund_fee)
{
struct CheckPaymentRequestContext *cprc = cls;
if (cprc->refunded)
{
GNUNET_assert (GNUNET_SYSERR !=
TALER_amount_add (&cprc->refund_amount,
&cprc->refund_amount,
refund_amount));
return;
}
cprc->refund_amount = *refund_amount;
cprc->refunded = GNUNET_YES;
}
/**
* The client did not yet pay, send it the payment request.
*
* @param cprc check pay request context
* @return #MHD_YES on success
*/
static int
send_pay_request (struct CheckPaymentRequestContext *cprc)
{
int ret;
char *already_paid_order_id = NULL;
char *taler_pay_uri;
struct GNUNET_TIME_Relative remaining;
remaining = GNUNET_TIME_absolute_get_remaining (cprc->sc.long_poll_timeout);
if (0 != remaining.rel_value_us)
{
/* long polling: do not queue a response, suspend connection instead */
TMH_compute_pay_key (cprc->order_id,
&cprc->mi->pubkey,
&cprc->sc.key);
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Suspending /check-payment on key %s\n",
GNUNET_h2s (&cprc->sc.key));
TMH_long_poll_suspend (&cprc->sc);
return MHD_YES;
}
/* Check if resource_id has been paid for in the same session
* with another order_id.
*/
if ( (NULL != cprc->session_id) &&
(NULL != cprc->fulfillment_url) )
{
enum GNUNET_DB_QueryStatus qs;
qs = db->find_session_info (db->cls,
&already_paid_order_id,
cprc->session_id,
cprc->fulfillment_url,
&cprc->mi->pubkey);
if (qs < 0)
{
/* 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 (cprc->sc.con,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_CHECK_PAYMENT_DB_FETCH_ORDER_ERROR,
"db error fetching pay session info");
}
}
taler_pay_uri = TMH_make_taler_pay_uri (cprc->sc.con,
cprc->order_id,
cprc->session_id,
cprc->mi->id);
ret = TALER_MHD_reply_json_pack (cprc->sc.con,
MHD_HTTP_OK,
"{s:s, s:s, s:b, s:s?}",
"taler_pay_uri", taler_pay_uri,
"contract_url", cprc->final_contract_url,
"paid", 0,
"already_paid_order_id",
already_paid_order_id);
GNUNET_free (taler_pay_uri);
GNUNET_free_non_null (already_paid_order_id);
return ret;
}
/**
* Parse the "contract_terms" in @a cprc and set the
* "fulfillment_url" and the "h_contract_terms" in @a cprc
* accordingly.
*
* On errors, the response is being queued and the status
* code set in @cprc "ret".
*
* @param cprc[in,out] context to process
* @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
*/
static int
parse_contract_terms (struct CheckPaymentRequestContext *cprc)
{
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_string ("fulfillment_url",
&cprc->fulfillment_url),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (cprc->contract_terms,
spec,
NULL, NULL))
{
GNUNET_break (0);
cprc->ret
= TALER_MHD_reply_with_error (cprc->sc.con,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_CHECK_PAYMENT_DB_FETCH_CONTRACT_TERMS_ERROR,
"Merchant database error (contract terms corrupted)");
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
TALER_JSON_hash (cprc->contract_terms,
&cprc->h_contract_terms))
{
GNUNET_break (0);
cprc->ret
= TALER_MHD_reply_with_error (cprc->sc.con,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_CHECK_PAYMENT_FAILED_COMPUTE_PROPOSAL_HASH,
"Failed to hash proposal");
return GNUNET_SYSERR;
}
return GNUNET_OK;
}
/**
* Check that we are aware of @a order_id and if so request the payment,
* otherwise generate an error response.
*
* @param cprc session state
* @return status code to return to MHD for @a connection
*/
static int
check_order_and_request_payment (struct CheckPaymentRequestContext *cprc)
{
enum GNUNET_DB_QueryStatus qs;
if (NULL != cprc->contract_terms)
{
/* This should never happen. */
GNUNET_break (0);
json_decref (cprc->contract_terms);
cprc->contract_terms = NULL;
}
qs = db->find_order (db->cls,
&cprc->contract_terms,
cprc->order_id,
&cprc->mi->pubkey);
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 (cprc->sc.con,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_CHECK_PAYMENT_DB_FETCH_ORDER_ERROR,
"db error fetching order");
}
if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
{
return TALER_MHD_reply_with_error (cprc->sc.con,
MHD_HTTP_NOT_FOUND,
TALER_EC_CHECK_PAYMENT_ORDER_ID_UNKNOWN,
"unknown order_id");
}
if (GNUNET_OK !=
parse_contract_terms (cprc))
return cprc->ret;
/* Offer was not picked up yet, but we ensured that it exists */
return send_pay_request (cprc);
}
/**
* Manages a /check-payment call, checking the status
* of a payment and, if necessary, constructing the URL
* for a payment redirect URL.
*
* @param rh context of the handler
* @param connection the MHD connection to handle
* @param[in,out] connection_cls the connection's closure (can be updated)
* @param upload_data upload data
* @param[in,out] upload_data_size number of bytes (left) in @a upload_data
* @param mi merchant backend instance, never NULL
* @return MHD result code
*/
int
MH_handler_check_payment (struct TMH_RequestHandler *rh,
struct MHD_Connection *connection,
void **connection_cls,
const char *upload_data,
size_t *upload_data_size,
struct MerchantInstance *mi)
{
struct CheckPaymentRequestContext *cprc = *connection_cls;
enum GNUNET_DB_QueryStatus qs;
int ret;
if (NULL == cprc)
{
const char *long_poll_timeout_s;
/* First time here, parse request and check order is known */
cprc = GNUNET_new (struct CheckPaymentRequestContext);
cprc->hc.cc = &cprc_cleanup;
cprc->ret = GNUNET_SYSERR;
cprc->sc.con = connection;
cprc->mi = mi;
*connection_cls = cprc;
cprc->order_id = MHD_lookup_connection_value (connection,
MHD_GET_ARGUMENT_KIND,
"order_id");
if (NULL == cprc->order_id)
{
/* order_id is required but missing */
GNUNET_break_op (0);
return TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_PARAMETER_MISSING,
"order_id required");
}
cprc->contract_url = MHD_lookup_connection_value (connection,
MHD_GET_ARGUMENT_KIND,
"contract_url");
if (NULL == cprc->contract_url)
{
cprc->final_contract_url = TALER_url_absolute_mhd (connection,
"/public/proposal",
"instance", mi->id,
"order_id",
cprc->order_id,
NULL);
GNUNET_assert (NULL != cprc->final_contract_url);
}
else
{
cprc->final_contract_url = GNUNET_strdup (cprc->contract_url);
}
cprc->session_id = MHD_lookup_connection_value (connection,
MHD_GET_ARGUMENT_KIND,
"session_id");
long_poll_timeout_s = MHD_lookup_connection_value (connection,
MHD_GET_ARGUMENT_KIND,
"timeout");
if (NULL != long_poll_timeout_s)
{
unsigned int timeout;
if (1 != sscanf (long_poll_timeout_s,
"%u",
&timeout))
{
GNUNET_break_op (0);
return TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_PARAMETER_MALFORMED,
"timeout must be non-negative number");
}
cprc->sc.long_poll_timeout
= GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_multiply (
GNUNET_TIME_UNIT_SECONDS,
timeout));
}
else
{
cprc->sc.long_poll_timeout = GNUNET_TIME_UNIT_ZERO_ABS;
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Starting /check-payment processing with timeout %s\n",
GNUNET_STRINGS_absolute_time_to_string (
cprc->sc.long_poll_timeout));
}
if (NULL != cprc->contract_terms)
{
json_decref (cprc->contract_terms);
cprc->contract_terms = NULL;
}
db->preflight (db->cls);
qs = db->find_contract_terms (db->cls,
&cprc->contract_terms,
cprc->order_id,
&mi->pubkey);
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_CHECK_PAYMENT_DB_FETCH_CONTRACT_TERMS_ERROR,
"db error fetching contract terms");
}
if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
{
/* Check that we're at least aware of the order */
return check_order_and_request_payment (cprc);
}
GNUNET_assert (NULL != cprc->contract_terms);
if (GNUNET_OK !=
parse_contract_terms (cprc))
return cprc->ret;
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Checkig payment status for order `%s' with contract %s\n",
cprc->order_id,
GNUNET_h2s (&cprc->h_contract_terms));
GNUNET_assert (NULL != cprc->contract_terms);
/* Check if the order has been paid for. */
if (NULL != cprc->session_id)
{
/* Check if paid within a session. */
char *already_paid_order_id = NULL;
qs = db->find_session_info (db->cls,
&already_paid_order_id,
cprc->session_id,
cprc->fulfillment_url,
&mi->pubkey);
if (qs < 0)
{
/* 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_CHECK_PAYMENT_DB_FETCH_ORDER_ERROR,
"db error fetching pay session info");
}
else if (0 == qs)
{
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Order `%s' was not yet paid for session `%s'\n",
cprc->order_id,
cprc->session_id);
ret = send_pay_request (cprc);
GNUNET_free_non_null (already_paid_order_id);
return ret;
}
GNUNET_break (1 == qs);
GNUNET_break (0 == strcmp (cprc->order_id,
already_paid_order_id));
GNUNET_free_non_null (already_paid_order_id);
}
else
{
/* Check if paid regardless of session. */
json_t *xcontract_terms = NULL;
qs = db->find_paid_contract_terms_from_hash (db->cls,
&xcontract_terms,
&cprc->h_contract_terms,
&mi->pubkey);
if (0 > 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_PAY_DB_FETCH_TRANSACTION_ERROR,
"Merchant database error");
}
if (0 == qs)
{
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Order `%s' (contract `%s') was not yet paid\n",
cprc->order_id,
GNUNET_h2s (&cprc->h_contract_terms));
return send_pay_request (cprc);
}
GNUNET_break (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs);
GNUNET_assert (NULL != xcontract_terms);
json_decref (xcontract_terms);
}
/* Accumulate refunds, if any. */
for (unsigned int i = 0; iget_refunds_from_contract_terms_hash (db->cls,
&mi->pubkey,
&cprc->h_contract_terms,
&process_refunds_cb,
cprc);
if (GNUNET_DB_STATUS_SOFT_ERROR != qs)
break;
}
if (0 > qs)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Database hard error on refunds_from_contract_terms_hash lookup: %s\n",
GNUNET_h2s (&cprc->h_contract_terms));
return TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_PAY_DB_FETCH_TRANSACTION_ERROR,
"Merchant database error");
}
if (cprc->refunded)
return TALER_MHD_reply_json_pack (connection,
MHD_HTTP_OK,
"{s:o, s:b, s:b, s:o}",
"contract_terms", cprc->contract_terms,
"paid", 1,
"refunded", cprc->refunded,
"refund_amount",
TALER_JSON_from_amount (
&cprc->refund_amount));
return TALER_MHD_reply_json_pack (connection,
MHD_HTTP_OK,
"{s:o, s:b, s:b }",
"contract_terms", cprc->contract_terms,
"paid", 1,
"refunded", 0);
}