implement /exchanges API in libtalerauditor

3 files changed, 318 insertions, 1 deletions

diff --git a/src/auditor-lib/Makefile.am b/src/auditor-lib/Makefile.am
index 1e7c87a4..1d3810fd 100644
--- a/src/auditor-lib/Makefile.am
+++ b/src/auditor-lib/Makefile.am
@@ -15,7 +15,8 @@ libtalerauditor_la_LDFLAGS = \
 libtalerauditor_la_SOURCES = \
   curl_defaults.c \
   auditor_api_handle.c auditor_api_handle.h \
-  auditor_api_deposit_confirmation.c
+  auditor_api_deposit_confirmation.c \
+  auditor_api_exchanges.c
 libtalerauditor_la_LIBADD = \
   $(top_builddir)/src/json/libtalerjson.la \
   $(top_builddir)/src/util/libtalerutil.la \
diff --git a/src/auditor-lib/auditor_api_exchanges.c b/src/auditor-lib/auditor_api_exchanges.c
new file mode 100644
index 00000000..2ddd2e5b
--- /dev/null
+++ b/src/auditor-lib/auditor_api_exchanges.c
@@ -0,0 +1,245 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2018 GNUnet e.V.
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU 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 auditor-lib/auditor_api_exchanges.c
+ * @brief Implementation of the /exchanges request of the auditor's HTTP API
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <jansson.h>
+#include <microhttpd.h> /* just for HTTP status codes */
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_json_lib.h>
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_json_lib.h"
+#include "taler_auditor_service.h"
+#include "auditor_api_handle.h"
+#include "taler_signatures.h"
+#include "curl_defaults.h"
+
+/**
+ * How many exchanges do we allow a single auditor to
+ * audit at most?
+ */
+#define MAX_EXCHANGES 1024
+
+
+/**
+ * @brief A ListExchanges Handle
+ */
+struct TALER_AUDITOR_ListExchangesHandle
+{
+
+  /**
+   * The connection to auditor this request handle will use
+   */
+  struct TALER_AUDITOR_Handle *auditor;
+
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * Handle for the request.
+   */
+  struct GNUNET_CURL_Job *job;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_AUDITOR_ListExchangesResultCallback cb;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+};
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /deposit-confirmation request.
+ *
+ * @param cls the `struct TALER_AUDITOR_ListExchangesHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param djson parsed JSON result, NULL on error
+ */
+static void
+handle_exchanges_finished (void *cls,
+                           long response_code,
+                           const void *djson)
+{
+  const json_t *json = djson;
+  const json_t *ja;
+  unsigned int ja_len;
+  struct TALER_AUDITOR_ListExchangesHandle *leh = cls;
+
+  leh->job = NULL;
+  switch (response_code)
+  {
+  case 0:
+    break;
+  case MHD_HTTP_OK:
+    ja = json_object_get (json,
+                          "exchanges");
+    if ( (NULL == ja) ||
+         (! json_is_array (ja)) )
+    {
+      GNUNET_break (0);
+      response_code = 0;
+      break;
+    }
+
+    ja_len = json_array_size (ja);
+    if (ja_len > MAX_EXCHANGES)
+    {
+      GNUNET_break (0);
+      response_code = 0;
+      break;
+    }
+    {
+      struct TALER_AUDITOR_ExchangeInfo ei[ja_len];
+      int ok;
+
+      ok = GNUNET_YES;
+      for (unsigned int i=0;i<ja_len;i++)
+      {
+        struct GNUNET_JSON_Specification spec[] = {
+          GNUNET_JSON_spec_fixed_auto ("master_pub", &ei[i].master_pub),
+          GNUNET_JSON_spec_string ("exchange_url", &ei[i].exchange_url),
+          GNUNET_JSON_spec_end()
+        };
+
+        if (GNUNET_OK !=
+            GNUNET_JSON_parse (json_array_get (ja,
+                                               i),
+                               spec,
+                               NULL, NULL))
+        {
+          GNUNET_break_op (0);
+          ok = GNUNET_NO;
+          break;
+        }
+      }
+      if (GNUNET_YES != ok)
+        break;
+      leh->cb (leh->cb_cls,
+               response_code,
+               TALER_EC_NONE,
+               ja_len,
+               ei,
+               json);
+      leh->cb = NULL;
+    }
+    break;
+  case MHD_HTTP_BAD_REQUEST:
+    /* This should never happen, either us or the auditor is buggy
+       (or API version conflict); just pass JSON reply to the application */
+    break;
+  case MHD_HTTP_NOT_FOUND:
+    /* Nothing really to verify, this should never
+       happen, we should pass the JSON reply to the application */
+    break;
+  case MHD_HTTP_INTERNAL_SERVER_ERROR:
+    /* Server had an internal issue; we should retry, but this API
+       leaves this to the application */
+    break;
+  default:
+    /* unexpected response code */
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u\n",
+                (unsigned int) response_code);
+    GNUNET_break (0);
+    response_code = 0;
+    break;
+  }
+  if (NULL != leh->cb)
+    leh->cb (leh->cb_cls,
+             response_code,
+             TALER_JSON_get_error_code (json),
+             0,
+             NULL,
+             json);
+  TALER_AUDITOR_list_exchanges_cancel (leh);
+}
+
+
+/**
+ * Submit an /exchanges request to the auditor and get the
+ * auditor's response.  If the auditor's reply is not
+ * well-formed, we return an HTTP status code of zero to @a cb.
+ *
+ * @param auditor the auditor handle; the auditor must be ready to operate
+ * @param cb the callback to call when a reply for this request is available
+ * @param cb_cls closure for the above callback
+ * @return a handle for this request; NULL if the inputs are invalid (i.e.
+ *         signatures fail to verify).  In this case, the callback is not called.
+ */
+struct TALER_AUDITOR_ListExchangesHandle *
+TALER_AUDITOR_list_exchanges (struct TALER_AUDITOR_Handle *auditor,
+                              TALER_AUDITOR_ListExchangesResultCallback cb,
+                              void *cb_cls)
+{
+  struct TALER_AUDITOR_ListExchangesHandle *leh;
+  struct GNUNET_CURL_Context *ctx;
+  CURL *eh;
+
+  GNUNET_assert (GNUNET_YES ==
+		 MAH_handle_is_ready (auditor));
+
+  leh = GNUNET_new (struct TALER_AUDITOR_ListExchangesHandle);
+  leh->auditor = auditor;
+  leh->cb = cb;
+  leh->cb_cls = cb_cls;
+  leh->url = MAH_path_to_url (auditor, "/exchanges");
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "URL for list-exchanges: `%s'\n",
+              leh->url);
+  eh = TAL_curl_easy_get (leh->url);
+  ctx = MAH_handle_to_context (auditor);
+  leh->job = GNUNET_CURL_job_add (ctx,
+                                  eh,
+                                  GNUNET_NO,
+                                  &handle_exchanges_finished,
+                                  leh);
+  return leh;
+}
+
+
+/**
+ * Cancel a deposit-confirmation permission request.  This function cannot be used
+ * on a request handle if a response is already served for it.
+ *
+ * @param deposit-confirmation the deposit-confirmation permission request handle
+ */
+void
+TALER_AUDITOR_list_exchanges_cancel (struct TALER_AUDITOR_ListExchangesHandle *leh)
+{
+  if (NULL != leh->job)
+  {
+    GNUNET_CURL_job_cancel (leh->job);
+    leh->job = NULL;
+  }
+  GNUNET_free (leh->url);
+  GNUNET_free (leh);
+}
+
+
+/* end of auditor_api_exchanges.c */
diff --git a/src/include/taler_auditor_service.h b/src/include/taler_auditor_service.h
index a494a931..6f9fef5a 100644
--- a/src/include/taler_auditor_service.h
+++ b/src/include/taler_auditor_service.h
@@ -240,4 +240,75 @@ TALER_AUDITOR_deposit_confirmation (struct TALER_AUDITOR_Handle *auditor,
 void
 TALER_AUDITOR_deposit_confirmation_cancel (struct TALER_AUDITOR_DepositConfirmationHandle *deposit_confirmation);
 
+
+/**
+ * Handle for /exchanges API returned by
+ * #TALER_AUDITOR_list_exchanges() so that the operation can be
+ * cancelled with #TALER_AUDITOR_list_exchanges_cancel()
+ */
+struct TALER_AUDITOR_ListExchangesHandle;
+
+
+/**
+ * Information about an exchange kept by the auditor.
+ */
+struct TALER_AUDITOR_ExchangeInfo
+{
+  /**
+   * Master public key of the exchange.
+   */
+  struct TALER_MasterPublicKeyP master_pub;
+
+  /**
+   * Base URL of the exchange's API.
+   */
+  const char *exchange_url;
+};
+
+
+/**
+ * Function called with the result from /exchagnes.
+ *
+ * @param cls closure
+ * @param http_status the HTTP status code, 200 on success
+ * @param ec detailed Taler error status code, #TALER_EC_NONE on success
+ * @param num_exchanges length of array at @a ei
+ * @param ei information about exchanges returned by the auditor
+ * @param raw_response raw JSON response
+ */
+typedef void
+(*TALER_AUDITOR_ListExchangesResultCallback)(void *cls,
+                                             unsigned int http_status,
+                                             enum TALER_ErrorCode ec,
+                                             unsigned int num_exchanges,
+                                             const struct TALER_AUDITOR_ExchangeInfo *ei,
+                                             const json_t *raw_response);
+
+/**
+ * Submit an /exchanges request to the auditor and get the
+ * auditor's response.  If the auditor's reply is not
+ * well-formed, we return an HTTP status code of zero to @a cb.
+ *
+ * @param auditor the auditor handle; the auditor must be ready to operate
+ * @param cb the callback to call when a reply for this request is available
+ * @param cb_cls closure for the above callback
+ * @return a handle for this request; NULL if the inputs are invalid (i.e.
+ *         signatures fail to verify).  In this case, the callback is not called.
+ */
+struct TALER_AUDITOR_ListExchangesHandle *
+TALER_AUDITOR_list_exchanges (struct TALER_AUDITOR_Handle *auditor,
+                              TALER_AUDITOR_ListExchangesResultCallback cb,
+                              void *cb_cls);
+
+
+/**
+ * Cancel a deposit-confirmation permission request.  This function cannot be used
+ * on a request handle if a response is already served for it.
+ *
+ * @param deposit-confirmation the deposit-confirmation permission request handle
+ */
+void
+TALER_AUDITOR_list_exchanges_cancel (struct TALER_AUDITOR_ListExchangesHandle *leh);
+
+
 #endif  /* _TALER_AUDITOR_SERVICE_H */