[taler-merchant] 09/277: implement instances_get in library

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grothoff pushed a commit to branch master
in repository merchant.

commit b03f6cf5044193931b028e867642f13ee9a24f3b
Author: Christian Grothoff <christian@grothoff.org>
AuthorDate: Fri Apr 17 21:06:20 2020 +0200

    implement instances_get in library
---
 src/include/taler_merchant_service.h               | 117 ++++++---
 src/lib/Makefile.am                                |   3 +-
 ...hant_api_config.c => merchant_api_config_get.c} |   8 +-
 src/lib/merchant_api_instances_get.c               | 292 +++++++++++++++++++++
 4 files changed, 382 insertions(+), 38 deletions(-)

diff --git a/src/include/taler_merchant_service.h 
b/src/include/taler_merchant_service.h
index 4c24882..324ed40 100644
--- a/src/include/taler_merchant_service.h
+++ b/src/include/taler_merchant_service.h
@@ -176,38 +176,6 @@ enum TALER_MERCHANT_VersionCompatibility
 };
 
 
-/**
- * @brief Information about a merchant instance.
- */
-struct TALER_MERCHANT_InstanceInformation
-{
-  /**
-   * URL of this instance.  The URL can be relative to the current domain
-   * (i.e. "/PizzaShop/") or include a schema and fully qualified domain name
-   * (i.e. "https://backend.example.com/PS/";). The latter can be used to 
redirect
-   * clients to a different server in case the deployment location changes.
-   */
-  const char *instance_baseurl;
-
-  /**
-   * Legal name of the merchant/instance.
-   */
-  const char *name;
-
-  /**
-   * Base URL of the exchange this instance uses for tipping, or NULL if this
-   * instance does not support tipping.
-   */
-  const char *tipping_exchange_baseurl;
-
-  /**
-   * Public key of the instance.
-   */
-  struct TALER_MerchantPublicKeyP merchant_pub;
-
-};
-
-
 /**
  * @brief Config information we get from the backend.
  */
@@ -280,6 +248,91 @@ void
 TALER_MERCHANT_config_get_cancel (struct TALER_MERCHANT_ConfigGetHandle *vgh);
 
 
+/* ********************* /instances *********************** */
+
+
+/**
+ * @brief Information about a merchant instance.
+ */
+struct TALER_MERCHANT_InstanceInformation
+{
+  /**
+   * Id of this instance.  This $ID can be used to construct the URL of the
+   * instance, by combining it using "$MERCHANT_BASEURL/instances/$ID/".
+   */
+  const char *id;
+
+  /**
+   * Legal name of the merchant/instance.
+   */
+  const char *name;
+
+  /**
+   * Public key of the instance.
+   */
+  struct TALER_MerchantPublicKeyP merchant_pub;
+
+  /**
+   * JSON array of payment targets (strings) supported by this backend
+   * instance.
+   */
+  json_t *payment_targets;
+
+};
+
+
+/**
+ * Handle for a GET /instances operation.
+ */
+struct TALER_MERCHANT_InstancesGetHandle;
+
+
+/**
+ * Function called with the result of the GET /instances operation.
+ *
+ * @param cls closure
+ * @param hr HTTP response data
+ * @param iis_length length of the @a iis array
+ * @param iis array with instance information of length @a iis_length
+ */
+typedef void
+(*TALER_MERCHANT_InstancesCallback)(
+  void *cls,
+  const struct TALER_MERCHANT_HttpResponse *hr,
+  unsigned int iis_length,
+  const struct TALER_MERCHANT_InstanceInformation iis[]);
+
+
+/**
+ * Get the instance data of a backend. Will connect to the merchant backend
+ * and obtain information about the instances.  The respective information will
+ * be passed to the @a instances_cb once available.
+ *
+ * @param ctx the context
+ * @param backend_url HTTP base URL for the backend
+ * @param instances_cb function to call with the
+ *        backend's instances information
+ * @param instances_cb_cls closure for @a config_cb
+ * @return the instances handle; NULL upon error
+ */
+struct TALER_MERCHANT_InstancesGetHandle *
+TALER_MERCHANT_instances_get (struct GNUNET_CURL_Context *ctx,
+                              const char *backend_url,
+                              TALER_MERCHANT_InstancesCallback instances_cb,
+                              void *instances_cb_cls);
+
+
+/**
+ * Cancel /instances request.  Must not be called by clients after
+ * the callback was invoked.
+ *
+ * @param igh request to cancel.
+ */
+void
+TALER_MERCHANT_instances_get_cancel (
+  struct TALER_MERCHANT_InstancesGetHandle *igh);
+
+
 /* ********************* /refund ************************** */
 
 /**
diff --git a/src/lib/Makefile.am b/src/lib/Makefile.am
index 1561f57..ccaaaea 100644
--- a/src/lib/Makefile.am
+++ b/src/lib/Makefile.am
@@ -21,7 +21,8 @@ libtalermerchanttesting_la_LDFLAGS = \
 libtalermerchant_la_SOURCES = \
   merchant_api_check_payment.c \
   merchant_api_common.c \
-  merchant_api_config.c \
+  merchant_api_config_get.c \
+  merchant_api_instances_get.c \
   merchant_api_history.c \
   merchant_api_proposal.c \
   merchant_api_proposal_lookup.c \
diff --git a/src/lib/merchant_api_config.c b/src/lib/merchant_api_config_get.c
similarity index 98%
rename from src/lib/merchant_api_config.c
rename to src/lib/merchant_api_config_get.c
index 7509150..2e3ac5d 100644
--- a/src/lib/merchant_api_config.c
+++ b/src/lib/merchant_api_config_get.c
@@ -15,7 +15,7 @@
   <http://www.gnu.org/licenses/>
 */
 /**
- * @file lib/merchant_api_config.c
+ * @file lib/merchant_api_config_get.c
  * @brief Implementation of the /config request of the merchant's HTTP API
  * @author Christian Grothoff
  */
@@ -214,11 +214,9 @@ TALER_MERCHANT_config_get (struct GNUNET_CURL_Context *ctx,
     GNUNET_free (vgh);
     return NULL;
   }
-
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Requesting URL '%s'\n",
               vgh->url);
-
   eh = curl_easy_init ();
   GNUNET_assert (CURLE_OK ==
                  curl_easy_setopt (eh,
@@ -253,4 +251,4 @@ TALER_MERCHANT_config_get_cancel (struct 
TALER_MERCHANT_ConfigGetHandle *vgh)
 }
 
 
-/* end of merchant_api_config.c */
+/* end of merchant_api_config_get.c */
diff --git a/src/lib/merchant_api_instances_get.c 
b/src/lib/merchant_api_instances_get.c
new file mode 100644
index 0000000..437911d
--- /dev/null
+++ b/src/lib/merchant_api_instances_get.c
@@ -0,0 +1,292 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2018, 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_instances_get.c
+ * @brief Implementation of the GET /instances 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 <gnunet/gnunet_curl_lib.h>
+#include "taler_merchant_service.h"
+#include <taler/taler_json_lib.h>
+#include <taler/taler_signatures.h>
+
+
+/**
+ * Handle for a GET /instances operation.
+ */
+struct TALER_MERCHANT_InstancesGetHandle
+{
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * Handle for the request.
+   */
+  struct GNUNET_CURL_Job *job;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_MERCHANT_InstancesCallback cb;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+  /**
+   * Reference to the execution context.
+   */
+  struct GNUNET_CURL_Context *ctx;
+
+};
+
+
+/**
+ * Parse instance information from @a ia.
+ *
+ * @param ia JSON array (or NULL!) with instance data
+ * @param igh operation handle
+ * @return #GNUNET_OK on success
+ */
+static int
+parse_instances (const json_t *ia,
+                 struct TALER_MERCHANT_InstancesGetHandle *igh)
+{
+  unsigned int iis_len = json_array_size (ia);
+  struct TALER_MERCHANT_InstanceInformation iis[iis_len];
+  size_t index;
+  json_t *value;
+  int ret;
+
+  ret = GNUNET_OK;
+  json_array_foreach (ia, index, value) {
+    struct TALER_MERCHANT_InstanceInformation *ii = &iis[index];
+    struct GNUNET_JSON_Specification spec[] = {
+      GNUNET_JSON_spec_string ("name",
+                               &ii->name),
+      GNUNET_JSON_spec_string ("instance",
+                               &ii->id),
+      GNUNET_JSON_spec_fixed_auto ("merchant_pub",
+                                   &ii->merchant_pub),
+      GNUNET_JSON_spec_json ("payment_targets",
+                             &ii->payment_targets),
+      GNUNET_JSON_spec_end ()
+    };
+
+    if (GNUNET_OK !=
+        GNUNET_JSON_parse (value,
+                           spec,
+                           NULL, NULL))
+    {
+      GNUNET_break_op (0);
+      ret = GNUNET_SYSERR;
+      continue;
+    }
+    if (! json_is_array (ii->payment_targets))
+    {
+      GNUNET_break_op (0);
+      ret = GNUNET_SYSERR;
+      break;
+    }
+    for (unsigned int i = 0; i<json_array_size (ii->payment_targets); i++)
+    {
+      if  (! json_is_string (json_array_get (ii->payment_targets,
+                                             i)))
+      {
+        GNUNET_break_op (0);
+        ret = GNUNET_SYSERR;
+        break;
+      }
+    }
+    if (GNUNET_SYSERR == ret)
+      break;
+  }
+  if (GNUNET_OK == ret)
+  {
+    struct TALER_MERCHANT_HttpResponse hr = {
+      .http_status = MHD_HTTP_OK
+    };
+
+    igh->cb (igh->cb_cls,
+             &hr,
+             iis_len,
+             iis);
+    igh->cb = NULL; /* just to be sure */
+  }
+  for (unsigned int i = 0; i<iis_len; i++)
+    if (NULL != iis[i].payment_targets)
+      json_decref (iis[i].payment_targets);
+  return ret;
+}
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /instances request.
+ *
+ * @param cls the `struct TALER_MERCHANT_InstancesGetHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param json response body, NULL if not in JSON
+ */
+static void
+handle_instances_finished (void *cls,
+                           long response_code,
+                           const void *response)
+{
+  struct TALER_MERCHANT_InstancesGetHandle *igh = cls;
+  const json_t *json = response;
+  struct TALER_MERCHANT_HttpResponse hr = {
+    .http_status = (unsigned int) response_code,
+    .reply = json
+  };
+
+  igh->job = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Got /instances response with status code %u\n",
+              (unsigned int) response_code);
+  switch (response_code)
+  {
+  case MHD_HTTP_OK:
+    {
+      json_t *instances;
+      struct GNUNET_JSON_Specification spec[] = {
+        GNUNET_JSON_spec_json ("instances",
+                               &instances),
+        GNUNET_JSON_spec_end ()
+      };
+
+      if (GNUNET_OK !=
+          GNUNET_JSON_parse (json,
+                             spec,
+                             NULL, NULL))
+      {
+        hr.http_status = 0;
+        hr.ec = TALER_EC_INVALID_RESPONSE;
+      }
+      else
+      {
+        if ( (! json_is_array (instances)) ||
+             (GNUNET_OK ==
+              parse_instances (instances,
+                               igh)) )
+        {
+          GNUNET_JSON_parse_free (spec);
+          TALER_MERCHANT_instances_get_cancel (igh);
+          return;
+        }
+        else
+        {
+          hr.http_status = 0;
+          hr.ec = TALER_EC_INVALID_RESPONSE;
+        }
+      }
+      GNUNET_JSON_parse_free (spec);
+      break;
+    }
+  default:
+    /* unexpected response code */
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u/%d\n",
+                (unsigned int) response_code,
+                (int) hr.ec);
+    break;
+  }
+  igh->cb (igh->cb_cls,
+           &hr,
+           0,
+           NULL);
+  TALER_MERCHANT_instances_get_cancel (igh);
+}
+
+
+/**
+ * Get the instance data of a backend. Will connect to the merchant backend
+ * and obtain information about the instances.  The respective information will
+ * be passed to the @a instances_cb once available.
+ *
+ * @param ctx the context
+ * @param backend_url HTTP base URL for the backend
+ * @param instances_cb function to call with the
+ *        backend's instances information
+ * @param instances_cb_cls closure for @a config_cb
+ * @return the instances handle; NULL upon error
+ */
+struct TALER_MERCHANT_InstancesGetHandle *
+TALER_MERCHANT_instances_get (struct GNUNET_CURL_Context *ctx,
+                              const char *backend_url,
+                              TALER_MERCHANT_InstancesCallback instances_cb,
+                              void *instances_cb_cls)
+{
+  struct TALER_MERCHANT_InstancesGetHandle *igh;
+  CURL *eh;
+
+  igh = GNUNET_new (struct TALER_MERCHANT_InstancesGetHandle);
+  igh->ctx = ctx;
+  igh->cb = instances_cb;
+  igh->cb_cls = instances_cb_cls;
+  igh->url = TALER_url_join (backend_url,
+                             "instances",
+                             NULL);
+  if (NULL == igh->url)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Could not construct request URL.\n");
+    GNUNET_free (igh);
+    return NULL;
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Requesting URL '%s'\n",
+              igh->url);
+  eh = curl_easy_init ();
+  GNUNET_assert (CURLE_OK ==
+                 curl_easy_setopt (eh,
+                                   CURLOPT_URL,
+                                   igh->url));
+  igh->job = GNUNET_CURL_job_add (ctx,
+                                  eh,
+                                  GNUNET_YES,
+                                  &handle_instances_finished,
+                                  igh);
+  return igh;
+}
+
+
+/**
+ * Cancel /instances request.  Must not be called by clients after
+ * the callback was invoked.
+ *
+ * @param igh request to cancel.
+ */
+void
+TALER_MERCHANT_instances_get_cancel (
+  struct TALER_MERCHANT_InstancesGetHandle *igh)
+{
+  if (NULL != igh->job)
+    GNUNET_CURL_job_cancel (igh->job);
+  GNUNET_free (igh->url);
+  GNUNET_free (igh);
+}

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