[taler-merchant] 60/277: GET /orders logic

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grothoff pushed a commit to branch master
in repository merchant.

commit 68c440b0eb385ad80dec73843e021039b91b913c
Author: Christian Grothoff <christian@grothoff.org>
AuthorDate: Sun Apr 26 23:32:57 2020 +0200

    GET /orders logic
---
 .../taler-merchant-httpd_private-get-orders.c      | 548 +++++++++++++++++++++
 .../taler-merchant-httpd_private-get-orders.h      |  71 +++
 2 files changed, 619 insertions(+)

diff --git a/src/backend/taler-merchant-httpd_private-get-orders.c 
b/src/backend/taler-merchant-httpd_private-get-orders.c
new file mode 100644
index 0000000..e835151
--- /dev/null
+++ b/src/backend/taler-merchant-httpd_private-get-orders.c
@@ -0,0 +1,548 @@
+/*
+  This file is part of TALER
+  (C) 2019, 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 backend/taler-merchant-httpd_private-get-orders.c
+ * @brief implement GET /orders
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "taler-merchant-httpd_private-get-orders.h"
+
+
+/**
+ * A pending GET /orders request that is in long polling mode.
+ */
+struct PendingOrder
+{
+
+  /**
+   * Kept in a DLL.
+   */
+  struct PendingOrder *prev;
+
+  /**
+   * Kept in a DLL.
+   */
+  struct PendingOrder *next;
+
+  /**
+   * Which connection was suspended.
+   */
+  struct MHD_Connection *con;
+
+  /**
+   * Associated heap node.
+   */
+  struct GNUNET_CONTAINER_HeapNode *hn;
+
+  /**
+   * Which instance is this client polling?
+   */
+  char *instance_id;
+
+  /**
+   * At what time does this request expire? If set in the future, we
+   * may wait this long for a payment to arrive before responding.
+   */
+  struct GNUNET_TIME_Absolute long_poll_timeout;
+
+  /**
+   * Array where we append matching orders. Must be
+   * json_decref()'ed when done with the `struct PendingOrder`!
+   */
+  json_t *pa;
+
+  /**
+   * Filter to apply.
+   */
+  struct TALER_MERCHANTDB_OrderFilter of;
+};
+
+
+/**
+ * Head of DLL of long-polling GET /orders requests.
+ */
+static struct PendingOrder *po_head;
+
+/**
+ * Tail of DLL of long-polling GET /orders requests.
+ */
+static struct PendingOrder *po_tail;
+
+/**
+ * Task to timeout pending orders.
+ */
+static struct GNUNET_SCHEDULER_Task *order_timeout_task;
+
+/**
+ * Heap for orders in long polling awaiting timeout.
+ */
+static struct GNUNET_CONTAINER_Heap *order_timeout_heap;
+
+
+/**
+ * We are shutting down, force resume of all GET /orders requests.
+ */
+void
+TMH_force_get_orders_resume ()
+{
+  struct PendingOrder *po;
+
+  while (NULL != (po = po_head))
+  {
+    GNUNET_CONTAINER_DLL_remove (po_head,
+                                 po_tail,
+                                 po);
+    GNUNET_assert (po ==
+                   GNUNET_CONTAINER_heap_remove_root (order_timeout_heap));
+    MHD_resume_connection (po->con);
+    json_decref (po->pa);
+    GNUNET_free (po->instance_id);
+    GNUNET_free (po);
+  }
+  if (NULL != order_timeout_task)
+  {
+    GNUNET_SCHEDULER_cancel (order_timeout_task);
+    order_timeout_task = NULL;
+  }
+  if (NULL != order_timeout_heap)
+  {
+    GNUNET_CONTAINER_heap_destroy (order_timeout_heap);
+    order_timeout_heap = NULL;
+  }
+}
+
+
+/**
+ * Task run to trigger timeouts on GET /orders requests with long polling.
+ *
+ * @param cls unused
+ */
+static void
+order_timeout (void *cls)
+{
+  struct PendingOrder *po;
+
+  (void) cls;
+  order_timeout_task = NULL;
+  while (1)
+  {
+    po = GNUNET_CONTAINER_heap_peek (order_timeout_heap);
+    if (NULL == po)
+    {
+      /* release data structure, we don't need it right now */
+      GNUNET_CONTAINER_heap_destroy (order_timeout_heap);
+      order_timeout_heap = NULL;
+      return;
+    }
+    if  (0 !=
+         GNUNET_TIME_absolute_get_remaining (
+           po->long_poll_timeout).rel_value_us)
+      break;
+    GNUNET_assert (po ==
+                   GNUNET_CONTAINER_heap_remove_root (order_timeout_heap));
+    po->hn = NULL;
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                "Resuming long polled job due to timeout\n");
+    GNUNET_CONTAINER_DLL_remove (po_head,
+                                 po_tail,
+                                 po);
+    json_decref (po->pa);
+    MHD_resume_connection (po->con);
+    GNUNET_free (po->instance_id);
+    GNUNET_free (po);
+  }
+  order_timeout_task = GNUNET_SCHEDULER_add_at (po->long_poll_timeout,
+                                                &order_timeout,
+                                                NULL);
+}
+
+
+/**
+ * Cleanup our "context", where we stored the JSON array
+ * we are building for the response.
+ *
+ * @param ctx context to clean up, must be a `json_t *`
+ */
+static void
+json_cleanup (void *ctx)
+{
+  json_t *j = ctx;
+
+  json_decref (j);
+}
+
+
+/**
+ * Add order details to our JSON array.
+ *
+ * @param[in,out] cls a `json_t *` JSON array to build
+ * @param order_id ID of the order
+ * @param order_serial serial ID of the order
+ * @param creation_time when was the order created
+ */
+static void
+add_order (void *cls,
+           const char *order_id,
+           uint64_t order_serial,
+           struct GNUNET_TIME_Absolute creation_time)
+{
+  json_t *pa = cls;
+
+  GNUNET_assert (0 ==
+                 json_array_append_new (
+                   pa,
+                   json_pack (
+                     "{s:s, s:I, s:o}",
+                     "order_id",
+                     order_id,
+                     "row_id",
+                     (json_int_t) order_serial,
+                     "timestamp",
+                     GNUNET_JSON_from_time_abs (creation_time))));
+}
+
+
+/**
+ * There has been a change or addition of a new @a order_id.  Wake up
+ * long-polling clients that may have been waiting for this event.
+ *
+ * FIXME: Here we go over all long polling clients.  We should consider moving
+ * the global DLL into the *instance* data structure (note: that has then
+ * implications in case an instance is deleted, i.e. we would then need to
+ * trigger all the long pollers!).
+ *
+ * @param instance_id the instance where the order changed
+ * @param order_id the order that changed
+ * @param paid is the order paid by the customer?
+ * @param refunded was the order refunded?
+ * @param wire was the merchant paid via wire transfer?
+ * @param data execution date of the order
+ * @param order_serial_id serial ID of the order in the database
+ */
+void
+TMH_notify_order_change (const char *instance_id,
+                         const char *order_id,
+                         bool paid,
+                         bool refunded,
+                         bool wired,
+                         struct GNUNET_TIME_Absolute date,
+                         uint64_t order_serial_id)
+{
+  struct PendingOrder *pn;
+
+  for (struct PendingOrder *po = po_head;
+       NULL != po;
+       po = pn)
+  {
+    pn = po->next;
+    if (! ( ( ((TALER_MERCHANTDB_YNA_YES == po->of.paid) == paid) ||
+              (TALER_MERCHANTDB_YNA_ALL == po->of.paid) ) &&
+            ( ((TALER_MERCHANTDB_YNA_YES == po->of.refunded) == refunded) ||
+              (TALER_MERCHANTDB_YNA_ALL == po->of.refunded) ) &&
+            ( ((TALER_MERCHANTDB_YNA_YES == po->of.wired) == wired) ||
+              (TALER_MERCHANTDB_YNA_ALL == po->of.wired) ) ) )
+      continue;
+    if (0 != strcmp (instance_id,
+                     po->instance_id))
+      continue;
+    if (po->of.delta > 0)
+    {
+      if (order_serial_id < po->of.start_row)
+        continue;
+      if (date.abs_value_us < po->of.date.abs_value_us)
+        continue;
+      po->of.delta--;
+    }
+    else
+    {
+      if (order_serial_id > po->of.start_row)
+        continue;
+      if (date.abs_value_us > po->of.date.abs_value_us)
+        continue;
+      po->of.delta++;
+    }
+    add_order (po->pa,
+               order_id,
+               order_serial_id,
+               date);
+    GNUNET_CONTAINER_DLL_remove (po_head,
+                                 po_tail,
+                                 po);
+    GNUNET_assert (po ==
+                   GNUNET_CONTAINER_heap_remove_node (po->hn));
+    MHD_resume_connection (po->con);
+    json_decref (po->pa);
+    GNUNET_free (po->instance_id);
+    GNUNET_free (po);
+  }
+}
+
+
+/**
+ * Convert query argument to @a yna value.
+ *
+ * @param connection connection to take query argument from
+ * @param arg argument to try for
+ * @param[out] value to set
+ * @return true on success, false if the parameter was malformed
+ */
+static bool
+arg_to_yna (struct MHD_Connection *connection,
+            const char *arg,
+            enum TALER_MERCHANTDB_YesNoAll *yna)
+{
+  const char *str;
+
+  str = MHD_lookup_connection_value (connection,
+                                     MHD_GET_ARGUMENT_KIND,
+                                     arg);
+  if (NULL == str)
+  {
+    *yna = TALER_MERCHANTDB_YNA_ALL;
+    return true;
+  }
+  if (0 == strcasecmp (str, "yes"))
+  {
+    *yna = TALER_MERCHANTDB_YNA_YES;
+    return true;
+  }
+  if (0 == strcasecmp (str, "no"))
+  {
+    *yna = TALER_MERCHANTDB_YNA_NO;
+    return true;
+  }
+  if (0 == strcasecmp (str, "all"))
+  {
+    *yna = TALER_MERCHANTDB_YNA_ALL;
+    return true;
+  }
+  return false;
+}
+
+
+/**
+ * Handle a GET "/orders" request.
+ *
+ * @param rh context of the handler
+ * @param connection the MHD connection to handle
+ * @param[in,out] hc context with further information about the request
+ * @return MHD result code
+ */
+MHD_RESULT
+TMH_private_get_orders (const struct TMH_RequestHandler *rh,
+                        struct MHD_Connection *connection,
+                        struct TMH_HandlerContext *hc)
+{
+  json_t *pa;
+  enum GNUNET_DB_QueryStatus qs;
+  struct TALER_MERCHANTDB_OrderFilter of;
+
+  if (NULL != hc->ctx)
+  {
+    /* resumed from long-polling, return answer we already have
+       in 'hc->ctx' */
+    return TALER_MHD_reply_json_pack (connection,
+                                      MHD_HTTP_OK,
+                                      "{s:O}",
+                                      "orders", hc->ctx);
+  }
+
+  if (! (arg_to_yna (connection,
+                     "paid",
+                     &of.paid)) )
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_PARAMETER_MALFORMED,
+                                       "paid");
+  if (! (arg_to_yna (connection,
+                     "refunded",
+                     &of.refunded)) )
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_PARAMETER_MALFORMED,
+                                       "refunded");
+  if (! (arg_to_yna (connection,
+                     "wired",
+                     &of.wired)) )
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_PARAMETER_MALFORMED,
+                                       "wired");
+  {
+    const char *start_row_str;
+
+    start_row_str = MHD_lookup_connection_value (connection,
+                                                 MHD_GET_ARGUMENT_KIND,
+                                                 "start");
+    if (NULL == start_row_str)
+    {
+      of.start_row = UINT64_MAX;
+    }
+    else
+    {
+      char dummy[2];
+      unsigned long long ull;
+
+      if (1 !=
+          sscanf (start_row_str,
+                  "%llu%1s",
+                  &ull,
+                  dummy))
+        return TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_BAD_REQUEST,
+                                           TALER_EC_PARAMETER_MALFORMED,
+                                           "date");
+      of.start_row = (uint64_t) ull;
+    }
+  }
+  {
+    const char *delta_str;
+
+    delta_str = MHD_lookup_connection_value (connection,
+                                             MHD_GET_ARGUMENT_KIND,
+                                             "delta");
+    if (NULL == delta_str)
+    {
+      of.delta = -20;
+    }
+    else
+    {
+      char dummy[2];
+      long long ll;
+
+      if (1 !=
+          sscanf (delta_str,
+                  "%lld%1s",
+                  &ll,
+                  dummy))
+        return TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_BAD_REQUEST,
+                                           TALER_EC_PARAMETER_MALFORMED,
+                                           "delta");
+      of.delta = (uint64_t) ll;
+    }
+  }
+  {
+    const char *date_str;
+
+    date_str = MHD_lookup_connection_value (connection,
+                                            MHD_GET_ARGUMENT_KIND,
+                                            "date");
+    if (NULL == date_str)
+    {
+      if (of.delta > 0)
+        of.date = GNUNET_TIME_UNIT_ZERO_ABS;
+      else
+        of.date = GNUNET_TIME_UNIT_FOREVER_ABS;
+    }
+    else
+    {
+      if (GNUNET_OK !=
+          GNUNET_STRINGS_fancy_time_to_absolute (date_str,
+                                                 &of.date))
+        return TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_BAD_REQUEST,
+                                           TALER_EC_PARAMETER_MALFORMED,
+                                           "date");
+    }
+  }
+  {
+    const char *timeout_ms_str;
+
+    timeout_ms_str = MHD_lookup_connection_value (connection,
+                                                  MHD_GET_ARGUMENT_KIND,
+                                                  "timeout_ms");
+    if (NULL == timeout_ms_str)
+    {
+      of.timeout = GNUNET_TIME_UNIT_ZERO;
+    }
+    else
+    {
+      char dummy[2];
+      unsigned long long ull;
+
+      if (1 !=
+          sscanf (timeout_ms_str,
+                  "%lld%1s",
+                  &ull,
+                  dummy))
+        return TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_BAD_REQUEST,
+                                           TALER_EC_PARAMETER_MALFORMED,
+                                           "timeout_ms");
+      of.timeout = GNUNET_TIME_relative_multiply 
(GNUNET_TIME_UNIT_MILLISECONDS,
+                                                  ull);
+    }
+  }
+
+  pa = json_array ();
+  GNUNET_assert (NULL != pa);
+  qs = TMH_db->lookup_orders (TMH_db->cls,
+                              hc->instance->settings.id,
+                              &of,
+                              &add_order,
+                              pa);
+  if (0 > qs)
+  {
+    GNUNET_break (0);
+    json_decref (pa);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_ORDERS_GET_DB_LOOKUP_ERROR,
+                                       "failed to lookup orders in database");
+  }
+  if ( (0 == qs) &&
+       (of.timeout.rel_value_us > 0) )
+  {
+    struct PendingOrder *po;
+
+    /* setup timeout heap (if not yet exists) */
+    if (NULL == order_timeout_heap)
+      order_timeout_heap
+        = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
+    hc->ctx = pa;
+    hc->cc = &json_cleanup;
+    po = GNUNET_new (struct PendingOrder);
+    po->instance_id = GNUNET_strdup (hc->instance->settings.id);
+    po->con = connection;
+    po->pa = json_incref (pa);
+    po->hn = GNUNET_CONTAINER_heap_insert (order_timeout_heap,
+                                           po,
+                                           po->long_poll_timeout.abs_value_us);
+    po->long_poll_timeout = GNUNET_TIME_relative_to_absolute (of.timeout);
+    po->of = of;
+    GNUNET_CONTAINER_DLL_insert (po_head,
+                                 po_tail,
+                                 po);
+    MHD_suspend_connection (connection);
+    /* start timeout task */
+    po = GNUNET_CONTAINER_heap_peek (order_timeout_heap);
+    if (NULL != order_timeout_task)
+      GNUNET_SCHEDULER_cancel (order_timeout_task);
+    order_timeout_task = GNUNET_SCHEDULER_add_at (po->long_poll_timeout,
+                                                  &order_timeout,
+                                                  NULL);
+    return MHD_YES;
+  }
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o}",
+                                    "orders", pa);
+}
+
+
+/* end of taler-merchant-httpd_private-get-orders.c */
diff --git a/src/backend/taler-merchant-httpd_private-get-orders.h 
b/src/backend/taler-merchant-httpd_private-get-orders.h
new file mode 100644
index 0000000..7bb6324
--- /dev/null
+++ b/src/backend/taler-merchant-httpd_private-get-orders.h
@@ -0,0 +1,71 @@
+/*
+  This file is part of TALER
+  (C) 2019, 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 backend/taler-merchant-httpd_private-get-orders.h
+ * @brief implement GET /orders
+ * @author Christian Grothoff
+ */
+#ifndef TALER_MERCHANT_HTTPD_PRIVATE_GET_ORDERS_H
+#define TALER_MERCHANT_HTTPD_PRIVATE_GET_ORDERS_H
+
+#include "taler-merchant-httpd.h"
+
+
+/**
+ * Handle a GET "/orders" request.
+ *
+ * @param rh context of the handler
+ * @param connection the MHD connection to handle
+ * @param[in,out] hc context with further information about the request
+ * @return MHD result code
+ */
+MHD_RESULT
+TMH_private_get_orders (const struct TMH_RequestHandler *rh,
+                        struct MHD_Connection *connection,
+                        struct TMH_HandlerContext *hc);
+
+
+/**
+ * There has been a change or addition of a new @a order_id.  Wake up
+ * long-polling clients that may have been waiting for this event.
+ *
+ * @param instance_id the instance where the order changed
+ * @param order_id the order that changed
+ * @param paid is the order paid by the customer?
+ * @param refunded was the order refunded?
+ * @param wire was the merchant paid via wire transfer?
+ * @param data execution date of the order
+ * @param order_serial_id serial ID of the order in the database
+ */
+void
+TMH_notify_order_change (const char *instance_id,
+                         const char *order_id,
+                         bool paid,
+                         bool refunded,
+                         bool wired,
+                         struct GNUNET_TIME_Absolute date,
+                         uint64_t order_serial_id);
+
+
+/**
+ * We are shutting down, force resume of all GET /orders requests.
+ */
+void
+TMH_force_get_orders_resume (void);
+
+
+/* end of taler-merchant-httpd_private-get-orders.h */
+#endif

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