-draft API for new /kyc-check endpoint

src/include/taler_exchange_service.h

@@ -1899,6 +1899,110 @@ void
 TALER_EXCHANGE_recoup_cancel (struct TALER_EXCHANGE_RecoupHandle *ph);
 
 
+/* *********************  /kyc* *********************** */
+
+/**
+ * Handle for a ``/kyc-check`` operation.
+ */
+struct TALER_EXCHANGE_KycCheckHandle;
+
+
+/**
+ * KYC status response details.
+ */
+struct TALER_EXCHANGE_KycStatus
+{
+  /**
+   * HTTP status code returned by the exchange.
+   */
+  unsigned int http_status;
+
+  /**
+   * Taler error code, if any.
+   */
+  enum TALER_ErrorCode ec;
+
+  union
+  {
+
+    /**
+     * KYC is OK, affirmation returned by the exchange.
+     */
+    struct
+    {
+
+      /**
+       * Time of the affirmation.
+       */
+      struct GNUNET_TIME_Absolute timestamp;
+
+      /**
+       * The signing public key used for @e exchange_sig.
+       */
+      struct TALER_ExchangePublicKeyP exchange_pub;
+
+      /**
+       * Signature of purpose
+       * #TALER_SIGNATURE_ACCOUNT_SETUP_SUCCESS affirming
+       * the successful KYC process.
+       */
+      struct TALER_ExchangeSignatureP exchange_sig;
+
+    } kyc_ok;
+
+    /**
+     * URL the user should open in a browser if
+     * the KYC process is to be run. Returned if
+     * @e http_status is #MHD_HTTP_ACCEPTED.
+     */
+    const char *kyc_url;
+
+  } details;
+
+};
+
+/**
+ * Function called with the result of a KYC check.
+ *
+ * @param cls closure
+ * @param ks the account's KYC status details
+ */
+typedef void
+(*TALER_EXCHANGE_KycStatusCallback)(
+  void *cls,
+  const struct TALER_EXCHANGE_KycStatus *ks);
+
+
+/**
+ * Run interaction with exchange to check KYC status
+ * of a merchant.
+ *
+ * @param eh exchange handle to use
+ * @param payment_target number identifying the target
+ * @param h_payto hash of the payto:// URI at @a payment_target
+ * @param timeout how long to wait for a positive KYC status
+ * @param cb function to call with the result
+ * @param cb_cls closure for @a cb
+ * @return NULL on error
+ */
+struct TALER_EXCHANGE_KycCheckHandle *
+TALER_EXCHANGE_kyc_check (struct TALER_EXCHANGE_Handle *eh,
+                          uint64_t payment_target,
+                          const struct GNUNET_HashCode *h_wire,
+                          struct GNUNET_TIME_Relative timeout,
+                          TALER_EXCHANGE_KycStatusCallback cb,
+                          void *cb_cls);
+
+
+/**
+ * Cancel KYC check operation.
+ *
+ * @param kyc handle for operation to cancel
+ */
+void
+TALER_EXCHANGE_kyc_check_cancel (struct TALER_EXCHANGE_KycCheckHandle *kyc);
+
+
 /* *********************  /management *********************** */
 
 

src/lib/Makefile.am

@@ -27,6 +27,7 @@ libtalerexchange_la_SOURCES = \
   exchange_api_handle.c exchange_api_handle.h \
   exchange_api_deposit.c \
   exchange_api_deposits_get.c \
+  exchange_api_kyc_check.c \
   exchange_api_link.c \
   exchange_api_management_auditor_disable.c \
   exchange_api_management_auditor_enable.c \

src/lib/exchange_api_kyc_check.c

@@ -0,0 +1,215 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2021 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_kyc_check.c
+ * @brief Implementation of the /kyc-check request
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <microhttpd.h> /* just for HTTP check codes */
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_exchange_service.h"
+#include "taler_json_lib.h"
+#include "exchange_api_handle.h"
+#include "taler_signatures.h"
+#include "exchange_api_curl_defaults.h"
+
+
+/**
+ * @brief A ``/kyc-check`` handle
+ */
+struct TALER_EXCHANGE_KycCheckHandle
+{
+
+  /**
+   * The connection to exchange this request handle will use
+   */
+  struct TALER_EXCHANGE_Handle *exchange;
+
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * Handle for the request.
+   */
+  struct GNUNET_CURL_Job *job;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_EXCHANGE_KycStatusCallback cb;
+
+  /**
+   * Closure for @e cb.
+   */
+  void *cb_cls;
+
+};
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /kyc-check request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_KycCheckHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param response parsed JSON result, NULL on error
+ */
+static void
+handle_kyc_check_finished (void *cls,
+                           long response_code,
+                           const void *response)
+{
+  struct TALER_EXCHANGE_KycCheckHandle *kch = cls;
+  const json_t *j = response;
+  struct TALER_EXCHANGE_KycStatus ks = {
+    .http_status = (unsigned int) response_code
+  };
+
+  kch->job = NULL;
+  switch (response_code)
+  {
+  case 0:
+    ks.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
+    break;
+  case MHD_HTTP_OK:
+    GNUNET_break (0); // FIXME
+    TALER_EXCHANGE_kyc_check_cancel (kch);
+    return;
+  case MHD_HTTP_ACCEPTED:
+    GNUNET_break (0); // FIXME
+    TALER_EXCHANGE_kyc_check_cancel (kch);
+    return;
+  case MHD_HTTP_NO_CONTENT:
+    GNUNET_break (0); // FIXME
+    TALER_EXCHANGE_kyc_check_cancel (kch);
+    return;
+  case MHD_HTTP_BAD_REQUEST:
+    ks.ec = TALER_JSON_get_error_code (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_UNAUTHORIZED:
+    GNUNET_break (0); // FIXME
+    TALER_EXCHANGE_kyc_check_cancel (kch);
+    return;
+  case MHD_HTTP_NOT_FOUND:
+    ks.ec = TALER_JSON_get_error_code (j);
+    TALER_EXCHANGE_kyc_check_cancel (kch);
+    return;
+  case MHD_HTTP_INTERNAL_SERVER_ERROR:
+    ks.ec = TALER_JSON_get_error_code (j);
+    /* Server had an internal issue; we should retry, but this API
+       leaves this to the application */
+    break;
+  default:
+    /* unexpected response code */
+    GNUNET_break_op (0);
+    ks.ec = TALER_JSON_get_error_code (j);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u/%d for exchange kyc_check\n",
+                (unsigned int) response_code,
+                (int) ks.ec);
+    break;
+  }
+  TALER_EXCHANGE_kyc_check_cancel (kch);
+}
+
+
+/**
+ * Submit a kyc_check request to the exchange and get the exchange's response.
+ *
+ * This API is typically not used by anyone, it is more a threat against those
+ * trying to receive a funds transfer by abusing the refresh protocol.
+ *
+ * @param exchange the exchange handle; the exchange must be ready to operate
+ * @param coin_priv private key to request kyc_check data for
+ * @param kyc_check_cb the callback to call with the useful result of the
+ *        refresh operation the @a coin_priv was involved in (if any)
+ * @param kyc_check_cb_cls closure for @a kyc_check_cb
+ * @return a handle for this request
+ */
+struct TALER_EXCHANGE_KycCheckHandle *
+TALER_EXCHANGE_kyc_check (struct TALER_EXCHANGE_Handle *exchange,
+                          uint64_t payment_target,
+                          const struct GNUNET_HashCode *h_wire,
+                          struct GNUNET_TIME_Relative timeout,
+                          TALER_EXCHANGE_KycStatusCallback cb,
+                          void *cb_cls)
+{
+  struct TALER_EXCHANGE_KycCheckHandle *kch;
+  CURL *eh;
+  struct GNUNET_CURL_Context *ctx;
+
+  if (GNUNET_YES !=
+      TEAH_handle_is_ready (exchange))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+
+  kch = GNUNET_new (struct TALER_EXCHANGE_KycCheckHandle);
+  kch->exchange = exchange;
+  kch->cb = cb;
+  kch->cb_cls = cb_cls;
+  kch->url = TEAH_path_to_url (exchange,
+                               "FIXME");
+  if (NULL == kch->url)
+  {
+    GNUNET_free (kch);
+    return NULL;
+  }
+  eh = TALER_EXCHANGE_curl_easy_get_ (kch->url);
+  if (NULL == eh)
+  {
+    GNUNET_break (0);
+    GNUNET_free (kch->url);
+    GNUNET_free (kch);
+    return NULL;
+  }
+  ctx = TEAH_handle_to_context (exchange);
+  kch->job = GNUNET_CURL_job_add_with_ct_json (ctx,
+                                               eh,
+                                               &handle_kyc_check_finished,
+                                               kch);
+  return kch;
+}
+
+
+/**
+ * Cancel a kyc_check request.  This function cannot be used
+ * on a request handle if the callback was already invoked.
+ *
+ * @param kch the kyc_check handle
+ */
+void
+TALER_EXCHANGE_kyc_check_cancel (struct TALER_EXCHANGE_KycCheckHandle *kch)
+{
+  if (NULL != kch->job)
+  {
+    GNUNET_CURL_job_cancel (kch->job);
+    kch->job = NULL;
+  }
+  GNUNET_free (kch->url);
+  GNUNET_free (kch);
+}
+
+
+/* end of exchange_api_kyc_check.c */