implement /refund handling

1 files changed, 226 insertions, 0 deletions

diff --git a/src/lib/merchant_api_post_order_refund.c b/src/lib/merchant_api_post_order_refund.c
new file mode 100644
index 00000000..7143e5ba
--- /dev/null
+++ b/src/lib/merchant_api_post_order_refund.c
@@ -0,0 +1,226 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014, 2015, 2016, 2017, 2019, 2020 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Lesser General Public License as published by the Free Software
+  Foundation; either version 2.1, 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 Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License along with
+  TALER; see the file COPYING.LGPL.  If not, see
+  <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file lib/merchant_api_post_order_refund.c
+ * @brief Implementation of the POST /orders/ID/refund request
+ * @author Christian Grothoff
+ * @author Marcello Stanisci
+ */
+#include "platform.h"
+#include <curl/curl.h>
+#include <jansson.h>
+#include <microhttpd.h> /* just for HTTP status codes */
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_merchant_service.h"
+#include <taler/taler_json_lib.h>
+#include <taler/taler_signatures.h>
+#include <taler/taler_curl_lib.h>
+
+
+/**
+ * Handle for a POST /orders/ID/refund operation.
+ */
+struct TALER_MERCHANT_OrderRefundHandle
+{
+  /**
+   * Complete URL where the backend offers /refund
+   */
+  char *url;
+
+  /**
+   * Minor context that holds body and headers.
+   */
+  struct TALER_CURL_PostContext post_ctx;
+
+  /**
+   * The CURL context to connect to the backend
+   */
+  struct GNUNET_CURL_Context *ctx;
+
+  /**
+   * The callback to pass the backend response to
+   */
+  TALER_MERCHANT_RefundCallback cb;
+
+  /**
+   * Clasure to pass to the callback
+   */
+  void *cb_cls;
+
+  /**
+   * Handle for the request
+   */
+  struct GNUNET_CURL_Job *job;
+};
+
+
+/**
+ * Callback to process POST /orders/ID/refund response
+ *
+ * @param cls the `struct TALER_MERCHANT_OrderRefundHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param json response body, NULL if not JSON
+ */
+static void
+handle_refund_finished (void *cls,
+                        long response_code,
+                        const void *response)
+{
+  struct TALER_MERCHANT_OrderRefundHandle *orh = cls;
+  const json_t *json = response;
+  struct TALER_MERCHANT_HttpResponse hr = {
+    .http_status = (unsigned int) response_code,
+    .reply = json
+  };
+
+  orh->job = NULL;
+  switch (response_code)
+  {
+  case 0:
+    hr.ec = TALER_EC_INVALID_RESPONSE;
+    orh->cb (orh->cb_cls,
+             &hr);
+    break;
+  case MHD_HTTP_OK:
+    orh->cb (orh->cb_cls,
+             &hr);
+    break;
+  case MHD_HTTP_CONFLICT:
+  case MHD_HTTP_NOT_FOUND:
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    orh->cb (orh->cb_cls,
+             &hr);
+    break;
+  default:
+    GNUNET_break_op (0); /* unexpected status code */
+    TALER_MERCHANT_parse_error_details_ (json,
+                                         response_code,
+                                         &hr);
+    orh->cb (orh->cb_cls,
+             &hr);
+    break;
+  }
+  TALER_MERCHANT_post_order_refund_cancel (orh);
+}
+
+
+/**
+ * Cancel a POST /orders/ID/refund request.
+ *
+ * @param orh the refund increasing operation to cancel
+ */
+void
+TALER_MERCHANT_post_order_refund_cancel (
+  struct TALER_MERCHANT_OrderRefundHandle *orh)
+{
+  if (NULL != orh->job)
+  {
+    GNUNET_CURL_job_cancel (orh->job);
+    orh->job = NULL;
+  }
+  TALER_curl_easy_post_finished (&orh->post_ctx);
+  GNUNET_free (orh->url);
+  GNUNET_free (orh);
+}
+
+
+/**
+ * Increase the refund granted for an order
+ *
+ * @param ctx the CURL context used to connect to the backend
+ * @param backend_url backend's base URL, including final "/"
+ * @param order_id id of the order whose refund is to be increased
+ * @param refund amount to which increase the refund
+ * @param reason human-readable reason justifying the refund
+ * @param cb callback processing the response from /refund
+ * @param cb_cls closure for cb
+ */
+struct TALER_MERCHANT_OrderRefundHandle *
+TALER_MERCHANT_order_refund (struct GNUNET_CURL_Context *ctx,
+                             const char *backend_url,
+                             const char *order_id,
+                             const struct TALER_Amount *refund,
+                             const char *reason,
+                             TALER_MERCHANT_RefundCallback cb,
+                             void *cb_cls)
+{
+  struct TALER_MERCHANT_OrderRefundHandle *orh;
+  json_t *req;
+  CURL *eh;
+
+  orh = GNUNET_new (struct TALER_MERCHANT_OrderRefundHandle);
+  orh->ctx = ctx;
+  orh->cb = cb;
+  orh->cb_cls = cb_cls;
+  {
+    char *path;
+
+    GNUNET_asprintf (&path,
+                     "private/orders/%s/refund",
+                     order_id);
+    orh->url = TALER_url_join (backend_url,
+                               path,
+                               NULL);
+    GNUNET_free (path);
+  }
+  if (NULL == orh->url)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Could not construct request URL.\n");
+    GNUNET_free (orh);
+    return NULL;
+  }
+  req = json_pack ("{s:o, s:s}",
+                   "refund", TALER_JSON_from_amount (refund),
+                   "reason", reason);
+  GNUNET_assert (NULL != req);
+  eh = curl_easy_init ();
+  GNUNET_assert (NULL != eh);
+  if (GNUNET_OK !=
+      TALER_curl_easy_post (&orh->post_ctx,
+                            eh,
+                            req))
+  {
+    GNUNET_break (0);
+    json_decref (req);
+    GNUNET_free (orh->url);
+    GNUNET_free (orh);
+    return NULL;
+  }
+  json_decref (req);
+  GNUNET_assert (CURLE_OK ==
+                 curl_easy_setopt (eh,
+                                   CURLOPT_URL,
+                                   orh->url));
+  orh->job = GNUNET_CURL_job_add2 (ctx,
+                                   eh,
+                                   orh->post_ctx.headers,
+                                   &handle_refund_finished,
+                                   orh);
+  if (NULL == orh->job)
+  {
+    GNUNET_free (orh->url);
+    GNUNET_free (orh);
+    return NULL;
+  }
+  return orh;
+}
+
+
+/* end of merchant_api_post_order_refund.c */