implement POST /products//lock

1 files changed, 274 insertions, 0 deletions

diff --git a/src/lib/merchant_api_lock_product.c b/src/lib/merchant_api_lock_product.c
new file mode 100644
index 00000000..ddd5e8e3
--- /dev/null
+++ b/src/lib/merchant_api_lock_product.c
@@ -0,0 +1,274 @@
+/*
+  This file is part of TALER
+  Copyright (C) 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_lock_product.c
+ * @brief Implementation of the POST /products/$ID/lock request
+ *        of the merchant's HTTP API
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <curl/curl.h>
+#include <jansson.h>
+#include <microhttpd.h> /* just for HTTP status codes */
+#include <gnunet/gnunet_util_lib.h>
+#include "taler_merchant_service.h"
+#include <taler/taler_json_lib.h>
+#include <taler/taler_curl_lib.h>
+
+
+/**
+ * Handle for a POST /products/$ID/lock operation.
+ */
+struct TALER_MERCHANT_ProductLockHandle
+{
+
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * Handle for the request.
+   */
+  struct GNUNET_CURL_Job *job;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_MERCHANT_ProductLockCallback cb;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+  /**
+   * Reference to the execution context.
+   */
+  struct GNUNET_CURL_Context *ctx;
+
+  /**
+   * Minor context that holds body and headers.
+   */
+  struct TALER_CURL_PostContext post_ctx;
+
+};
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP POST /products/$ID/lock request.
+ *
+ * @param cls the `struct TALER_MERCHANT_ProductLockHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param json response body, NULL if not in JSON
+ */
+static void
+handle_lock_product_finished (void *cls,
+                              long response_code,
+                              const void *response)
+{
+  struct TALER_MERCHANT_ProductLockHandle *plh = cls;
+  const json_t *json = response;
+  struct TALER_MERCHANT_HttpResponse hr = {
+    .http_status = (unsigned int) response_code,
+    .reply = json
+  };
+
+  plh->job = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "LOCK /products/$ID completed with response code %u\n",
+              (unsigned int) response_code);
+  switch (response_code)
+  {
+  case 0:
+    hr.ec = TALER_EC_INVALID_RESPONSE;
+    break;
+  case MHD_HTTP_NO_CONTENT:
+    break;
+  case MHD_HTTP_BAD_REQUEST:
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    GNUNET_break_op (0);
+    /* This should never happen, either us
+     * or the merchant is buggy (or API version conflict);
+     * just pass JSON reply to the application */
+    break;
+  case MHD_HTTP_FORBIDDEN:
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    /* Nothing really to verify, merchant says we tried to abort the payment
+     * after it was successful. We should pass the JSON reply to the
+     * application */
+    break;
+  case MHD_HTTP_NOT_FOUND:
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    break;
+  case MHD_HTTP_GONE:
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    break;
+  case MHD_HTTP_INTERNAL_SERVER_ERROR:
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    /* Server had an internal issue; we should retry,
+       but this API leaves this to the application */
+    break;
+  default:
+    TALER_MERCHANT_parse_error_details_ (json,
+                                         response_code,
+                                         &hr);
+    /* unexpected response code */
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u/%d\n",
+                (unsigned int) response_code,
+                (int) hr.ec);
+    GNUNET_break_op (0);
+    break;
+  }
+  plh->cb (plh->cb_cls,
+           &hr);
+  TALER_MERCHANT_product_lock_cancel (plh);
+}
+
+
+/**
+ * Make a POST /products/$ID/lock request to reserve a certain
+ * amount of product in inventory to a reservation UUID.
+ *
+ * @param ctx the context
+ * @param backend_url HTTP base URL for the backend
+ * @param instance_id instance to query about its products,
+ *                    NULL to query the default instance
+ * @param product_id identifier of the product
+ * @param uuid UUID that identifies the client holding the lock
+ * @param duration how long should the lock be held
+ * @param quantity how much product should be locked
+ * @param cb function to call with the backend's lock status
+ * @param cb_cls closure for @a cb
+ * @return the request handle; NULL upon error
+ */
+struct TALER_MERCHANT_ProductLockHandle *
+TALER_MERCHANT_product_lock (
+  struct GNUNET_CURL_Context *ctx,
+  const char *backend_url,
+  const char *instance_id,
+  const char *product_id,
+  const struct GNUNET_Uuid *uuid,
+  struct GNUNET_TIME_Relative duration,
+  uint32_t quantity,
+  TALER_MERCHANT_ProductLockCallback cb,
+  void *cb_cls)
+{
+  struct TALER_MERCHANT_ProductLockHandle *plh;
+  json_t *req_obj;
+
+  req_obj = json_pack ("{s:o, s:o, s:I}",
+                       "lock_uuid",
+                       GNUNET_JSON_from_data_auto (uuid),
+                       "duration",
+                       GNUNET_JSON_from_time_rel (duration),
+                       "quantity",
+                       (json_int_t) quantity);
+  if (NULL == req_obj)
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  plh = GNUNET_new (struct TALER_MERCHANT_ProductLockHandle);
+  plh->ctx = ctx;
+  plh->cb = cb;
+  plh->cb_cls = cb_cls;
+  {
+    char *path;
+
+    if (NULL == instance_id)
+      GNUNET_asprintf (&path,
+                       "products/%s/lock",
+                       product_id);
+    else
+      GNUNET_asprintf (&path,
+                       "instances/%s/products/%s/lock",
+                       instance_id,
+                       product_id);
+    plh->url = TALER_url_join (backend_url,
+                               path,
+                               NULL);
+    GNUNET_free (path);
+  }
+  if (NULL == plh->url)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Could not construct request URL.\n");
+    json_decref (req_obj);
+    GNUNET_free (plh);
+    return NULL;
+  }
+  {
+    CURL *eh;
+
+    eh = curl_easy_init ();
+    if (GNUNET_OK !=
+        TALER_curl_easy_post (&plh->post_ctx,
+                              eh,
+                              req_obj))
+    {
+      GNUNET_break (0);
+      json_decref (req_obj);
+      GNUNET_free (plh);
+      return NULL;
+    }
+
+    json_decref (req_obj);
+    GNUNET_assert (CURLE_OK == curl_easy_setopt (eh,
+                                                 CURLOPT_URL,
+                                                 plh->url));
+    plh->job = GNUNET_CURL_job_add2 (ctx,
+                                     eh,
+                                     plh->post_ctx.headers,
+                                     &handle_lock_product_finished,
+                                     plh);
+  }
+  return plh;
+}
+
+
+/**
+ * Cancel POST /products/$ID/lock request.  Must not be called by clients after
+ * the callback was invoked.
+ *
+ * @param plh request to cancel.
+ */
+void
+TALER_MERCHANT_product_lock_cancel (
+  struct TALER_MERCHANT_ProductLockHandle *plh)
+{
+  if (NULL != plh->job)
+  {
+    GNUNET_CURL_job_cancel (plh->job);
+    plh->job = NULL;
+  }
+  TALER_curl_easy_post_finished (&plh->post_ctx);
+  GNUNET_free (plh->url);
+  GNUNET_free (plh);
+}
+
+
+/* end of merchant_api_lock_product.c */