webhook backend

1 files changed, 214 insertions, 0 deletions

diff --git a/src/backend/taler-merchant-httpd_private-post-webhooks.c b/src/backend/taler-merchant-httpd_private-post-webhooks.c
new file mode 100644
index 00000000..ab076924
--- /dev/null
+++ b/src/backend/taler-merchant-httpd_private-post-webhooks.c
@@ -0,0 +1,214 @@
+/*
+  This file is part of TALER
+  (C) 2020 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Affero 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 taler-merchant-httpd_private-post-webhooks.c
+ * @brief implementing POST /webhooks request handling
+ * @author Priscilla HUANG
+ */
+#include "platform.h"
+#include "taler-merchant-httpd_private-post-webhooks.h"
+#include "taler-merchant-httpd_helper.h"
+#include <taler/taler_json_lib.h>
+
+
+/**
+ * How often do we retry the simple INSERT database transaction?
+ */
+#define MAX_RETRIES 3
+
+
+/**
+ * Check if the two webhooks are identical.
+ *
+ * @param w1 webhook to compare
+ * @param w2 other webhook to compare
+ * @return true if they are 'equal', false if not or of payto_uris is not an array
+ */
+static bool
+webhooks_equal (const struct TALER_MERCHANTDB_WebhookDetails *w1,
+                const struct TALER_MERCHANTDB_WebhookDetails *w2)
+{
+  return ( (0 == strcmp (w1->event_type,
+                         w2->event_type)) &&
+           (0 == strcmp (w1->url,
+                         w2->url)) &&
+           (0 == strcmp (w1->http_method,
+                         w2->http_method)) &&
+           (0 == strcmp (w1->header_template,
+                         w2->header_template)) &&
+           (0 == strcmp (w1->body_template,
+                         w2->body_template)));
+}
+
+
+MHD_RESULT
+TMH_private_post_webhooks (const struct TMH_RequestHandler *rh,
+                           struct MHD_Connection *connection,
+                           struct TMH_HandlerContext *hc)
+{
+  struct TMH_MerchantInstance *mi = hc->instance;
+  struct TALER_MERCHANTDB_WebhookDetails wb = { 0 };
+  const char *webhook_id;
+  enum GNUNET_DB_QueryStatus qs;
+  struct GNUNET_JSON_Specification spec[] = {
+    GNUNET_JSON_spec_string ("webhook_id",
+                             &webhook_id),
+    GNUNET_JSON_spec_string ("event_type",
+                             (const char **) &wb.event_type),
+    GNUNET_JSON_spec_string ("url",
+                             (const char **) &wb.url),
+    GNUNET_JSON_spec_string ("http_method",
+                             (const char **) &wb.http_method),
+    GNUNET_JSON_spec_string ("header_template",
+                             (const char **) &wb.header_template),
+    GNUNET_JSON_spec_string ("body_template",
+                             (const char **) &wb.body_template),
+    GNUNET_JSON_spec_end ()
+  };
+
+  GNUNET_assert (NULL != mi);
+  {
+    enum GNUNET_GenericReturnValue res;
+
+    res = TALER_MHD_parse_json_data (connection,
+                                     hc->request_body,
+                                     spec);
+    if (GNUNET_OK != res)
+    {
+      GNUNET_break_op (0);
+      return (GNUNET_NO == res)
+             ? MHD_YES
+             : MHD_NO;
+    }
+  }
+
+
+  if (! TMH_url_valid (wb.url))
+  {
+    GNUNET_break_op (0);
+    GNUNET_JSON_parse_free (spec);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_GENERIC_PARAMETER_MALFORMED,
+                                       "url");
+  }
+
+
+  /* finally, interact with DB until no serialization error */
+  for (unsigned int i = 0; i<MAX_RETRIES; i++)
+  {
+    /* Test if a webhook of this id is known */
+    struct TALER_MERCHANTDB_WebhookDetails ewb;
+
+    if (GNUNET_OK !=
+        TMH_db->start (TMH_db->cls,
+                       "/post webhooks"))
+    {
+      GNUNET_break (0);
+      GNUNET_JSON_parse_free (spec);
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                         TALER_EC_GENERIC_DB_START_FAILED,
+                                         NULL);
+    }
+    qs = TMH_db->lookup_webhook (TMH_db->cls,
+                                 mi->settings.id,
+                                 webhook_id,
+                                 &ewb);
+    switch (qs)
+    {
+    case GNUNET_DB_STATUS_HARD_ERROR:
+      /* Clean up and fail hard */
+      GNUNET_break (0);
+      TMH_db->rollback (TMH_db->cls);
+      GNUNET_JSON_parse_free (spec);
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                         TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                         NULL);
+    case GNUNET_DB_STATUS_SOFT_ERROR:
+      /* restart transaction */
+      goto retry;
+    case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
+      /* Good, we can proceed! */
+      break;
+    case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
+      /* idempotency check: is ewb == wb? */
+      {
+        bool eq;
+
+        eq = webhooks_equal (&wb,
+                             &ewb);
+        TALER_MERCHANTDB_webhook_details_free (&ewb);
+        TMH_db->rollback (TMH_db->cls);
+        GNUNET_JSON_parse_free (spec);
+        return eq
+          ? TALER_MHD_reply_static (connection,
+                                    MHD_HTTP_NO_CONTENT,
+                                    NULL,
+                                    NULL,
+                                    0)
+          : TALER_MHD_reply_with_error (connection,
+                                        MHD_HTTP_CONFLICT,
+                                        TALER_EC_MERCHANT_PRIVATE_POST_WEBHOOKS_CONFLICT_WEBHOOK_EXISTS,
+                                        webhook_id);
+      }
+    } /* end switch (qs) */
+
+    qs = TMH_db->insert_webhook (TMH_db->cls,
+                                 mi->settings.id,
+                                 webhook_id,
+                                 &wb);
+    if (GNUNET_DB_STATUS_HARD_ERROR == qs)
+    {
+      TMH_db->rollback (TMH_db->cls);
+      break;
+    }
+    if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs)
+    {
+      qs = TMH_db->commit (TMH_db->cls);
+      if (GNUNET_DB_STATUS_SOFT_ERROR != qs)
+        break;
+    }
+retry:
+    GNUNET_assert (GNUNET_DB_STATUS_SOFT_ERROR == qs);
+    TMH_db->rollback (TMH_db->cls);
+  } /* for RETRIES loop */
+  GNUNET_JSON_parse_free (spec);
+  if (qs < 0)
+  {
+    GNUNET_break (0);
+    return TALER_MHD_reply_with_error (
+      connection,
+      MHD_HTTP_INTERNAL_SERVER_ERROR,
+      (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+      ? TALER_EC_GENERIC_DB_SOFT_FAILURE
+      : TALER_EC_GENERIC_DB_COMMIT_FAILED,
+      NULL);
+  }
+  return TALER_MHD_reply_static (connection,
+                                 MHD_HTTP_NO_CONTENT,
+                                 NULL,
+                                 NULL,
+                                 0);
+}
+
+
+/* end of taler-merchant-httpd_private-post-webhooks.c */