adaptations to latest exchange API

10 files changed, 121 insertions, 499 deletions

diff --git a/src/backend/taler-merchant-exchange.c b/src/backend/taler-merchant-exchange.c
index d8755ee7..5ce419d6 100644
--- a/src/backend/taler-merchant-exchange.c
+++ b/src/backend/taler-merchant-exchange.c
@@ -85,7 +85,12 @@ struct Exchange
   /**
    * A connection to this exchange
    */
-  struct TALER_EXCHANGE_Handle *conn;
+  struct TALER_EXCHANGE_GetKeysHandle *conn;
+
+  /**
+   * The keys of this exchange
+   */
+  struct TALER_EXCHANGE_Keys *keys;
 
   /**
    * Task where we retry fetching /keys from the exchange.
@@ -305,30 +310,27 @@ download_keys (void *cls);
 static void
 cert_cb (
   void *cls,
-  const struct TALER_EXCHANGE_KeysResponse *kr)
+  const struct TALER_EXCHANGE_KeysResponse *kr,
+  struct TALER_EXCHANGE_Keys *keys)
 {
   struct Exchange *e = cls;
-  struct GNUNET_TIME_Timestamp t;
   struct GNUNET_TIME_Absolute n;
 
+  e->conn = NULL;
   switch (kr->hr.http_status)
   {
   case MHD_HTTP_OK:
     e->ready = true;
+    TALER_EXCHANGE_keys_decref (e->keys);
+    e->keys = keys;
     launch_inquiries_at_exchange (e);
     /* Reset back-off */
     e->retry_delay = GNUNET_TIME_UNIT_ZERO;
     /* Success: rate limit at once per minute */
     e->first_retry = GNUNET_TIME_relative_to_absolute (
       GNUNET_TIME_UNIT_MINUTES);
-    /* Moreover usually only go after the current
-       response actually expired */
-    t = TALER_EXCHANGE_check_keys_current (e->conn,
-                                           TALER_EXCHANGE_CKF_NONE,
-                                           NULL,
-                                           NULL);
-    n = GNUNET_TIME_absolute_max (t.abs_time,
-                                  e->first_retry);
+    n = GNUNET_TIME_absolute_max (e->first_retry,
+                                  keys->key_data_expiration.abs_time);
     if (NULL != e->retry_task)
       GNUNET_SCHEDULER_cancel (e->retry_task);
     e->retry_task = GNUNET_SCHEDULER_add_at (n,
@@ -340,7 +342,6 @@ cert_cb (
       = GNUNET_TIME_STD_BACKOFF (e->retry_delay);
     e->first_retry
       = GNUNET_TIME_relative_to_absolute (e->retry_delay);
-
     if (NULL != e->retry_task)
       GNUNET_SCHEDULER_cancel (e->retry_task);
     e->retry_task = GNUNET_SCHEDULER_add_delayed (e->retry_delay,
@@ -364,17 +365,13 @@ download_keys (void *cls)
   e->retry_task = GNUNET_SCHEDULER_add_delayed (n,
                                                 &download_keys,
                                                 e);
-  if (NULL == e->conn)
-    e->conn = TALER_EXCHANGE_connect (ctx,
-                                      e->exchange_url,
-                                      &cert_cb,
-                                      e,
-                                      TALER_EXCHANGE_OPTION_END);
-  else
-    (void) TALER_EXCHANGE_check_keys_current (e->conn,
-                                              TALER_EXCHANGE_CKF_NONE,
-                                              NULL,
-                                              NULL);
+  if ( (NULL == e->keys) ||
+       (GNUNET_TIME_absolute_is_past (e->keys->key_data_expiration.abs_time)) )
+    e->conn = TALER_EXCHANGE_get_keys (ctx,
+                                       e->exchange_url,
+                                       e->keys,
+                                       &cert_cb,
+                                       e);
 }
 
 
@@ -516,7 +513,11 @@ shutdown_task (void *cls)
       end_inquiry (w);
     }
     GNUNET_free (e->exchange_url);
-    TALER_EXCHANGE_disconnect (e->conn);
+    if (NULL != e->conn)
+    {
+      TALER_EXCHANGE_get_keys_cancel (e->conn);
+      e->conn = NULL;
+    }
     if (NULL != e->retry_task)
     {
       GNUNET_SCHEDULER_cancel (e->retry_task);
@@ -568,7 +569,7 @@ check_wire_fee (struct Inquiry *w,
                 const struct TALER_Amount *wire_fee)
 {
   struct Exchange *e = w->exchange;
-  const struct TALER_EXCHANGE_Keys *keys;
+  const struct TALER_EXCHANGE_Keys *keys = e->keys;
   struct TALER_WireFeeSet fees;
   struct TALER_MasterSignatureP master_sig;
   struct GNUNET_TIME_Timestamp start_date;
@@ -576,7 +577,6 @@ check_wire_fee (struct Inquiry *w,
   enum GNUNET_DB_QueryStatus qs;
   char *wire_method;
 
-  keys = TALER_EXCHANGE_get_keys (e->conn);
   if (NULL == keys)
   {
     GNUNET_break (0);
@@ -943,7 +943,7 @@ exchange_request (void *cls)
   w->wdh = TALER_EXCHANGE_transfers_get (
     ctx,
     e->exchange_url,
-    TALER_EXCHANGE_get_keys (e->conn),
+    e->keys,
     &w->wtid,
     &wire_transfer_cb,
     w);
diff --git a/src/backend/taler-merchant-httpd_exchanges.c b/src/backend/taler-merchant-httpd_exchanges.c
index c0138537..665607c1 100644
--- a/src/backend/taler-merchant-httpd_exchanges.c
+++ b/src/backend/taler-merchant-httpd_exchanges.c
@@ -64,46 +64,6 @@
 
 
 /**
- * Information we keep for a pending #MMH_EXCHANGES_find_exchange() operation.
- */
-struct TMH_EXCHANGES_FindOperation
-{
-
-  /**
-   * Kept in a DLL.
-   */
-  struct TMH_EXCHANGES_FindOperation *next;
-
-  /**
-   * Kept in a DLL.
-   */
-  struct TMH_EXCHANGES_FindOperation *prev;
-
-  /**
-   * Function to call with the result.
-   */
-  TMH_EXCHANGES_FindContinuation fc;
-
-  /**
-   * Closure for @e fc.
-   */
-  void *fc_cls;
-
-  /**
-   * Exchange we wait for the /keys for.
-   */
-  struct TMH_Exchange *my_exchange;
-
-  /**
-   * Task scheduled to asynchronously return the result to
-   * the find continuation.
-   */
-  struct GNUNET_SCHEDULER_Task *at;
-
-};
-
-
-/**
  * Information we keep for a pending #MMH_EXCHANGES_keys4exchange() operation.
  */
 struct TMH_EXCHANGES_Find2Operation
@@ -312,16 +272,6 @@ struct TMH_Exchange
   /**
    * Head of FOs pending for this exchange.
    */
-  struct TMH_EXCHANGES_FindOperation *fo_head;
-
-  /**
-   * Tail of FOs pending for this exchange.
-   */
-  struct TMH_EXCHANGES_FindOperation *fo_tail;
-
-  /**
-   * Head of FOs pending for this exchange.
-   */
   struct TMH_EXCHANGES_Find2Operation *fo2_head;
 
   /**
@@ -357,7 +307,12 @@ struct TMH_Exchange
   /**
    * A connection to this exchange
    */
-  struct TALER_EXCHANGE_Handle *conn;
+  struct TALER_EXCHANGE_GetKeysHandle *conn;
+
+  /**
+   * The keys of this exchange
+   */
+  struct TALER_EXCHANGE_Keys *keys;
 
   /**
    * Active /wire request to the exchange, or NULL.
@@ -391,11 +346,6 @@ struct TMH_Exchange
   struct GNUNET_TIME_Absolute first_retry;
 
   /**
-   * How soon should we re-download /keys?
-   */
-  struct GNUNET_TIME_Timestamp keys_expiration;
-
-  /**
    * How long should we wait between the next retry?
    */
   struct GNUNET_TIME_Relative retry_delay;
@@ -411,13 +361,6 @@ struct TMH_Exchange
   struct GNUNET_SCHEDULER_Task *retry_task;
 
   /**
-   * Falsoe to indicate that there is a /keys request
-   * we are waiting for.
-   * True to indicate that /keys data is up-to-date.
-   */
-  bool have_keys;
-
-  /**
    * true if this exchange is from our configuration and
    * explicitly trusted, false if we need to check each
    * key to be sure it is trusted.
@@ -466,18 +409,14 @@ static int trusted_exchange_count;
  * Function called with information about who is auditing
  * a particular exchange and what key the exchange is using.
  *
- * @param cls closure, will be `struct TMH_Exchange` so that
- *   when this function gets called, it will change the flag 'have_keys'
- *   to 'true'. Note: 'keys' is automatically saved inside the exchange's
- *   handle, which is contained inside 'struct TMH_Exchange', when
- *   this callback is called. Thus, once 'have_keys' turns 'true',
- *   it is safe to call 'TALER_EXCHANGE_get_keys()' on the exchange's handle,
- *   in order to get the "good" keys.
+ * @param cls closure, will be `struct TMH_Exchange`
  * @param kr response details
+ * @param[in] keys keys object returned
  */
 static void
 keys_mgmt_cb (void *cls,
-              const struct TALER_EXCHANGE_KeysResponse *kr);
+              const struct TALER_EXCHANGE_KeysResponse *kr,
+              struct TALER_EXCHANGE_Keys *keys);
 
 
 /**
@@ -544,9 +483,10 @@ purge_exchange_accounts (struct TMH_Exchange *exchange)
  * @return #GNUNET_OK on success
  */
 static enum GNUNET_GenericReturnValue
-set_exchange_accounts (struct TMH_Exchange *exchange,
-                       unsigned int accounts_len,
-                       const struct TALER_EXCHANGE_WireAccount *accounts)
+set_exchange_accounts (
+  struct TMH_Exchange *exchange,
+  unsigned int accounts_len,
+  const struct TALER_EXCHANGE_WireAccount accounts[static accounts_len])
 {
   purge_exchange_accounts (exchange);
   for (unsigned int i = 0; i<accounts_len; i++)
@@ -608,32 +548,19 @@ retry_exchange (void *cls)
 
   /* might be a scheduled reload and not our first attempt */
   exchange->retry_task = NULL;
+  if (NULL != exchange->conn)
+    return;
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Connecting to exchange %s in retry_exchange()\n",
               exchange->url);
-  if (NULL == exchange->conn)
-  {
-    exchange->conn = TALER_EXCHANGE_connect (merchant_curl_ctx,
-                                             exchange->url,
-                                             &keys_mgmt_cb,
-                                             exchange,
-                                             TALER_EXCHANGE_OPTION_END);
-  }
-  else
-  {
-    struct GNUNET_TIME_Timestamp next;
-
-    next = TALER_EXCHANGE_check_keys_current (exchange->conn,
-                                              TALER_EXCHANGE_CKF_NONE,
-                                              NULL,
-                                              NULL);
-    if (! GNUNET_TIME_absolute_is_zero (next.abs_time))
-    {
-      exchange->retry_task = GNUNET_SCHEDULER_add_at (next.abs_time,
-                                                      &retry_exchange,
-                                                      exchange);
-    }
-  }
+  if ( (NULL == exchange->keys) ||
+       (GNUNET_TIME_absolute_is_past (
+          exchange->keys->key_data_expiration.abs_time)) )
+    exchange->conn = TALER_EXCHANGE_get_keys (merchant_curl_ctx,
+                                              exchange->url,
+                                              exchange->keys,
+                                              &keys_mgmt_cb,
+                                              exchange);
   /* Note: while the API spec says 'returns NULL on error', the implementation
      actually never returns NULL. */
   GNUNET_break (NULL != exchange->conn);
@@ -652,10 +579,11 @@ retry_exchange (void *cls)
  * @return #TALER_EC_NONE on success
  */
 static enum TALER_ErrorCode
-process_wire_fees (struct TMH_Exchange *exchange,
-                   const struct TALER_MasterPublicKeyP *master_pub,
-                   unsigned int num_methods,
-                   const struct TALER_EXCHANGE_WireFeesByMethod *fbm)
+process_wire_fees (
+  struct TMH_Exchange *exchange,
+  const struct TALER_MasterPublicKeyP *master_pub,
+  unsigned int num_methods,
+  const struct TALER_EXCHANGE_WireFeesByMethod fbm[static num_methods])
 {
   for (unsigned int i = 0; i<num_methods; i++)
   {
@@ -990,7 +918,6 @@ get_wire_fees (struct TMH_Exchange *exchange,
 static bool
 process_find_operations (struct TMH_Exchange *exchange)
 {
-  struct TMH_EXCHANGES_FindOperation *fn;
   struct TMH_EXCHANGES_Find2Operation *fn2;
   struct TMH_EXCHANGES_WireOperation *wn;
   struct GNUNET_TIME_Timestamp now;
@@ -1001,7 +928,7 @@ process_find_operations (struct TMH_Exchange *exchange)
        fo = fn2)
   {
     fo->fc (fo->fc_cls,
-            TALER_EXCHANGE_get_keys (exchange->conn));
+            exchange->keys);
     fn2 = fo->next;
     TMH_EXCHANGES_keys4exchange_cancel (fo);
   }
@@ -1053,22 +980,6 @@ process_find_operations (struct TMH_Exchange *exchange)
 
   if (! exchange->have_wire)
     return true; /* need /wire response to continue */
-  fn = NULL;
-  for (struct TMH_EXCHANGES_FindOperation *fo = exchange->fo_head;
-       NULL != fo;
-       fo = fn)
-  {
-    struct TALER_EXCHANGE_HttpResponse hr = {
-      .http_status = MHD_HTTP_OK,
-    };
-
-    fo->fc (fo->fc_cls,
-            &hr,
-            exchange->conn,
-            exchange);
-    fn = fo->next;
-    TMH_EXCHANGES_find_exchange_cancel (fo);
-  }
   wn = NULL;
   for (struct TMH_EXCHANGES_WireOperation *w = exchange->w_head;
        NULL != w;
@@ -1094,8 +1005,7 @@ wire_task_cb (void *cls);
  * If the request fails to generate a valid response from the
  * exchange, @a http_status will also be zero.
  *
- * Must only be called if 'exchange->have_keys' is true.
- * that is #TALER_EXCHANGE_get_keys() will succeed.
+ * Must only be called if 'exchange->keys' is non-NULL.
  *
  * @param cls closure, a `struct TMH_Exchange`
  * @param wr response details
@@ -1113,7 +1023,6 @@ handle_wire_data (void *cls,
               "Received /wire response\n");
   if (MHD_HTTP_OK != wr->hr.http_status)
   {
-    struct TMH_EXCHANGES_FindOperation *fo;
     struct TMH_EXCHANGES_WireOperation *w;
 
     exchange->have_wire = false;
@@ -1122,14 +1031,6 @@ handle_wire_data (void *cls,
                 exchange->url,
                 wr->hr.http_status,
                 wr->hr.ec);
-    while (NULL != (fo = exchange->fo_head))
-    {
-      fo->fc (fo->fc_cls,
-              &wr->hr,
-              exchange->conn,
-              false);
-      TMH_EXCHANGES_find_exchange_cancel (fo);
-    }
     while (NULL != (w = exchange->w_head))
     {
       w->fc (w->fc_cls,
@@ -1138,7 +1039,7 @@ handle_wire_data (void *cls,
     }
     return;
   }
-  keys = TALER_EXCHANGE_get_keys (exchange->conn);
+  keys = exchange->keys;
   GNUNET_assert (NULL != keys);
   ecx = process_wire_accounts (exchange,
                                &keys->master_pub,
@@ -1152,24 +1053,10 @@ handle_wire_data (void *cls,
   if (TALER_EC_NONE != ecx)
   {
     /* Report hard failure to all callbacks! */
-    struct TMH_EXCHANGES_FindOperation *fo;
     struct TMH_EXCHANGES_Find2Operation *fo2;
-    struct TALER_EXCHANGE_HttpResponse hrx = {
-      .ec = ecx,
-      .http_status = 0,
-      .reply = wr->hr.reply
-    };
 
     GNUNET_break_op (0);
     exchange->have_wire = false;
-    while (NULL != (fo = exchange->fo_head))
-    {
-      fo->fc (fo->fc_cls,
-              &hrx,
-              NULL,
-              false);
-      TMH_EXCHANGES_find_exchange_cancel (fo);
-    }
     while (NULL != (fo2 = exchange->fo2_head))
     {
       fo2->fc (fo2->fc_cls,
@@ -1210,8 +1097,7 @@ handle_wire_data (void *cls,
  * the callback.  If requests without /wire data remain,
  * retry the /wire request after some delay.
  *
- * Must only be called if 'exchange->have_keys' is true,
- * that is #TALER_EXCHANGE_get_keys() will succeed.
+ * Must only be called if 'exchange->keys' is non-NULL.
  *
  * @param cls a `struct TMH_Exchange` to check
  */
@@ -1221,7 +1107,6 @@ wire_task_cb (void *cls)
   struct TMH_Exchange *exchange = cls;
 
   exchange->wire_task = NULL;
-  GNUNET_assert (exchange->have_keys);
   if (! process_find_operations (exchange))
     return; /* no more need */
   GNUNET_assert (NULL == exchange->wire_request);
@@ -1230,7 +1115,7 @@ wire_task_cb (void *cls)
   exchange->wire_request
     = TALER_EXCHANGE_wire (merchant_curl_ctx,
                            exchange->url,
-                           TALER_EXCHANGE_get_keys (exchange->conn),
+                           exchange->keys,
                            &handle_wire_data,
                            exchange);
 }
@@ -1277,16 +1162,16 @@ free_exchange_entry (struct TMH_Exchange *exchange)
   }
   if (NULL != exchange->conn)
   {
-    TALER_EXCHANGE_disconnect (exchange->conn);
+    TALER_EXCHANGE_get_keys_cancel (exchange->conn);
     exchange->conn = NULL;
   }
+  TALER_EXCHANGE_keys_decref (exchange->keys);
+  exchange->keys = NULL;
   if (NULL != exchange->retry_task)
   {
     GNUNET_SCHEDULER_cancel (exchange->retry_task);
     exchange->retry_task = NULL;
   }
-  GNUNET_assert (NULL == exchange->fo_head);
-  GNUNET_assert (NULL == exchange->fo_tail);
   GNUNET_assert (NULL == exchange->fo2_head);
   GNUNET_assert (NULL == exchange->fo2_tail);
   GNUNET_assert (NULL == exchange->w_head);
@@ -1307,11 +1192,9 @@ static void
 fail_and_retry (struct TMH_Exchange *exchange,
                 const struct TALER_EXCHANGE_HttpResponse *hr)
 {
-  struct TMH_EXCHANGES_FindOperation *fo;
   struct TMH_EXCHANGES_Find2Operation *fo2;
   struct TMH_EXCHANGES_WireOperation *w;
 
-  exchange->have_keys = false;
   if (NULL != exchange->wire_request)
   {
     TALER_EXCHANGE_wire_cancel (exchange->wire_request);
@@ -1322,14 +1205,6 @@ fail_and_retry (struct TMH_Exchange *exchange,
     GNUNET_SCHEDULER_cancel (exchange->wire_task);
     exchange->wire_task = NULL;
   }
-  while (NULL != (fo = exchange->fo_head))
-  {
-    fo->fc (fo->fc_cls,
-            hr,
-            NULL,
-            false);
-    TMH_EXCHANGES_find_exchange_cancel (fo);
-  }
   while (NULL != (fo2 = exchange->fo2_head))
   {
     fo2->fc (fo2->fc_cls,
@@ -1342,8 +1217,7 @@ fail_and_retry (struct TMH_Exchange *exchange,
            NULL);
     TMH_EXCHANGES_wire4exchange_cancel (w);
   }
-  if ( (NULL == exchange->fo_head) &&
-       (TALER_EC_GENERIC_CONFIGURATION_INVALID == hr->ec) )
+  if (TALER_EC_GENERIC_CONFIGURATION_INVALID == hr->ec)
   {
     /* This can NEVER work, so don't retry */
     free_exchange_entry (exchange);
@@ -1369,19 +1243,21 @@ fail_and_retry (struct TMH_Exchange *exchange,
 
 static void
 keys_mgmt_cb (void *cls,
-              const struct TALER_EXCHANGE_KeysResponse *kr)
+              const struct TALER_EXCHANGE_KeysResponse *kr,
+              struct TALER_EXCHANGE_Keys *keys)
 {
   struct TMH_Exchange *exchange = cls;
   struct GNUNET_TIME_Relative delay;
-  const struct TALER_EXCHANGE_Keys *keys;
 
+  exchange->conn = NULL;
   if (MHD_HTTP_OK != kr->hr.http_status)
   {
     fail_and_retry (exchange,
                     &kr->hr);
     return;
   }
-  keys = kr->details.ok.keys;
+  TALER_EXCHANGE_keys_decref (exchange->keys);
+  exchange->keys = keys;
   if ( (exchange->trusted) &&
        (0 != GNUNET_memcmp (&exchange->master_pub,
                             &keys->master_pub)) )
@@ -1436,17 +1312,12 @@ keys_mgmt_cb (void *cls,
 
   exchange->first_retry
     = GNUNET_TIME_relative_to_absolute (MIN_RELOAD_DELAY);
-  exchange->keys_expiration
-    = TALER_EXCHANGE_check_keys_current (exchange->conn,
-                                         TALER_EXCHANGE_CKF_NONE,
-                                         NULL,
-                                         NULL);
   delay = GNUNET_TIME_absolute_get_remaining (
-    exchange->keys_expiration.abs_time);
+    keys->key_data_expiration.abs_time);
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "/keys response from expires at %s! Retrying at that time!\n",
               GNUNET_TIME_absolute2s (
-                exchange->keys_expiration.abs_time));
+                keys->key_data_expiration.abs_time));
   delay = GNUNET_TIME_relative_max (delay,
                                     MIN_RELOAD_DELAY);
   exchange->retry_delay = GNUNET_TIME_UNIT_ZERO;
@@ -1456,7 +1327,6 @@ keys_mgmt_cb (void *cls,
     = GNUNET_SCHEDULER_add_delayed (delay,
                                     &retry_exchange,
                                     exchange);
-  exchange->have_keys = true;
   if ( (process_find_operations (exchange)) &&
        (NULL == exchange->wire_request) &&
        (NULL == exchange->wire_task) )
@@ -1467,7 +1337,7 @@ keys_mgmt_cb (void *cls,
       = TALER_EXCHANGE_wire (
           merchant_curl_ctx,
           exchange->url,
-          TALER_EXCHANGE_get_keys (exchange->conn),
+          exchange->keys,
           &handle_wire_data,
           exchange);
   }
@@ -1477,36 +1347,6 @@ keys_mgmt_cb (void *cls,
 /**
  * Task to return find operation result asynchronously to caller.
  *
- * @param cls a `struct TMH_EXCHANGES_FindOperation`
- */
-static void
-return_result (void *cls)
-{
-  struct TMH_EXCHANGES_FindOperation *fo = cls;
-  struct TMH_Exchange *exchange = fo->my_exchange;
-
-  fo->at = NULL;
-  if ( (process_find_operations (exchange)) &&
-       (NULL == exchange->wire_request) &&
-       (exchange->have_keys) &&
-       (NULL != exchange->wire_task) )
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "Do not have current wire data. Will re-request /wire in %s\n",
-                GNUNET_STRINGS_relative_time_to_string (
-                  exchange->wire_retry_delay,
-                  true));
-    exchange->wire_task
-      = GNUNET_SCHEDULER_add_delayed (exchange->wire_retry_delay,
-                                      &wire_task_cb,
-                                      exchange);
-  }
-}
-
-
-/**
- * Task to return find operation result asynchronously to caller.
- *
  * @param cls a `struct TMH_EXCHANGES_Find2Operation`
  */
 static void
@@ -1555,124 +1395,6 @@ lookup_exchange (const char *exchange_url)
 }
 
 
-struct TMH_EXCHANGES_FindOperation *
-TMH_EXCHANGES_find_exchange (const char *chosen_exchange,
-                             bool force_reload,
-                             TMH_EXCHANGES_FindContinuation fc,
-                             void *fc_cls)
-{
-  struct TMH_Exchange *exchange;
-  struct TMH_EXCHANGES_FindOperation *fo;
-
-  if (NULL == merchant_curl_ctx)
-  {
-    GNUNET_break (0);
-    return NULL;
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Trying to find chosen exchange `%s'\n",
-              chosen_exchange);
-  /* Check if the exchange is known */
-  exchange = lookup_exchange (chosen_exchange);
-  if (NULL == exchange)
-  {
-    /* This is a new exchange */
-    exchange = GNUNET_new (struct TMH_Exchange);
-    exchange->url = GNUNET_strdup (chosen_exchange);
-    GNUNET_CONTAINER_DLL_insert (exchange_head,
-                                 exchange_tail,
-                                 exchange);
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "The exchange `%s' is new\n",
-                chosen_exchange);
-  }
-
-  fo = GNUNET_new (struct TMH_EXCHANGES_FindOperation);
-  fo->fc = fc;
-  fo->fc_cls = fc_cls;
-  fo->my_exchange = exchange;
-  GNUNET_CONTAINER_DLL_insert (exchange->fo_head,
-                               exchange->fo_tail,
-                               fo);
-
-  if ( (GNUNET_TIME_absolute_is_past (exchange->first_retry)) &&
-       (force_reload ||
-        (GNUNET_TIME_absolute_is_past (
-           exchange->keys_expiration.abs_time))) )
-  {
-    /* increment exponential-backoff */
-    exchange->retry_delay = RETRY_BACKOFF (exchange->retry_delay);
-    /* do not allow forced check until both backoff and #FORCED_RELOAD_DELAY
-       are satisfied again */
-    exchange->first_retry
-      = GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_max (
-                                            exchange->retry_delay,
-                                            FORCED_RELOAD_DELAY));
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "/keys retry forced, waiting until %s\n",
-                GNUNET_TIME_absolute2s (exchange->first_retry));
-    if (NULL == exchange->conn)
-    {
-      /* Not connected at all yet */
-      exchange->retry_task
-        = GNUNET_SCHEDULER_add_now (&retry_exchange,
-                                    exchange);
-    }
-    else
-    {
-      /* Use existing connection, but update /keys */
-      exchange->keys_expiration
-        = TALER_EXCHANGE_check_keys_current (exchange->conn,
-                                             TALER_EXCHANGE_CKF_FORCE_DOWNLOAD,
-                                             NULL,
-                                             NULL);
-    }
-    return fo;
-  }
-
-  if ( (exchange->have_keys) &&
-       (exchange->have_wire) )
-  {
-    /* We are not currently waiting for a reply, immediately
-       return result */
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "The exchange `%s' is ready\n",
-                exchange->url);
-    GNUNET_assert (NULL == fo->at);
-    fo->at = GNUNET_SCHEDULER_add_now (&return_result,
-                                       fo);
-    return fo;
-  }
-
-  /* If new or resumed, (re)try fetching /keys */
-  if ( (NULL == exchange->conn) &&
-       (NULL == exchange->retry_task) &&
-       (! exchange->have_keys) )
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Do not have current /keys data for `%s'. Will request /keys now\n",
-                exchange->url);
-    exchange->retry_task = GNUNET_SCHEDULER_add_now (&retry_exchange,
-                                                     exchange);
-    return fo;
-  }
-  if ( (exchange->have_keys) &&
-       (! exchange->have_wire) &&
-       (NULL == exchange->wire_task) &&
-       (NULL == exchange->wire_request) )
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "Do not have required /wire data. Will re-request %s/wire now\n",
-                exchange->url);
-    exchange->wire_task = GNUNET_SCHEDULER_add_now (&wire_task_cb,
-                                                    exchange);
-    return fo;
-  }
-  /* No activity to launch, we are already doing so */
-  return fo;
-}
-
-
 struct TMH_EXCHANGES_Find2Operation *
 TMH_EXCHANGES_keys4exchange (
   const char *chosen_exchange,
@@ -1726,26 +1448,15 @@ TMH_EXCHANGES_keys4exchange (
     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                 "/keys retry forced, waiting until %s\n",
                 GNUNET_TIME_absolute2s (exchange->first_retry));
-    if (NULL == exchange->conn)
-    {
-      /* Not connected at all yet */
+
+    if (NULL == exchange->retry_task)
       exchange->retry_task
         = GNUNET_SCHEDULER_add_now (&retry_exchange,
                                     exchange);
-    }
-    else
-    {
-      /* Use existing connection, but update /keys */
-      exchange->keys_expiration
-        = TALER_EXCHANGE_check_keys_current (exchange->conn,
-                                             TALER_EXCHANGE_CKF_FORCE_DOWNLOAD,
-                                             NULL,
-                                             NULL);
-    }
     return fo;
   }
 
-  if (exchange->have_keys)
+  if (NULL != exchange->keys)
   {
     /* We are not currently waiting for a reply, immediately
        return result */
@@ -1759,9 +1470,8 @@ TMH_EXCHANGES_keys4exchange (
   }
 
   /* If new or resumed, (re)try fetching /keys */
-  if ( (NULL == exchange->conn) &&
-       (NULL == exchange->retry_task) &&
-       (! exchange->have_keys) )
+  if ( (NULL == exchange->keys) &&
+       (NULL == exchange->retry_task) )
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Do not have current /keys data for `%s'. Will request /keys now\n",
@@ -1834,11 +1544,11 @@ TMH_EXCHANGES_wire4exchange (
       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                   "Requesting /keys from `%s' to connect\n",
                   exchange->url);
-      exchange->conn = TALER_EXCHANGE_connect (merchant_curl_ctx,
-                                               exchange->url,
-                                               &keys_mgmt_cb,
-                                               exchange,
-                                               TALER_EXCHANGE_OPTION_END);
+      exchange->conn = TALER_EXCHANGE_get_keys (merchant_curl_ctx,
+                                                exchange->url,
+                                                exchange->keys,
+                                                &keys_mgmt_cb,
+                                                exchange);
     }
     else
     {
@@ -1848,7 +1558,7 @@ TMH_EXCHANGES_wire4exchange (
       exchange->wire_request
         = TALER_EXCHANGE_wire (merchant_curl_ctx,
                                exchange->url,
-                               TALER_EXCHANGE_get_keys (exchange->conn),
+                               exchange->keys,
                                &handle_wire_data,
                                exchange);
     }
@@ -1858,23 +1568,6 @@ TMH_EXCHANGES_wire4exchange (
 
 
 void
-TMH_EXCHANGES_find_exchange_cancel (struct TMH_EXCHANGES_FindOperation *fo)
-{
-  struct TMH_Exchange *exchange = fo->my_exchange;
-
-  if (NULL != fo->at)
-  {
-    GNUNET_SCHEDULER_cancel (fo->at);
-    fo->at = NULL;
-  }
-  GNUNET_CONTAINER_DLL_remove (exchange->fo_head,
-                               exchange->fo_tail,
-                               fo);
-  GNUNET_free (fo);
-}
-
-
-void
 TMH_EXCHANGES_keys4exchange_cancel (struct TMH_EXCHANGES_Find2Operation *fo)
 {
   struct TMH_Exchange *exchange = fo->my_exchange;
@@ -2045,6 +1738,11 @@ TMH_EXCHANGES_init (const struct GNUNET_CONFIGURATION_Handle *cfg)
     return GNUNET_SYSERR;
   }
   merchant_curl_rc = GNUNET_CURL_gnunet_rc_create (merchant_curl_ctx);
+  /* Disable 100 continue processing */
+  GNUNET_break (GNUNET_OK ==
+                GNUNET_CURL_append_header (merchant_curl_ctx,
+                                           MHD_HTTP_HEADER_EXPECT ":"));
+
   GNUNET_CURL_enable_async_scope_header (merchant_curl_ctx,
                                          "Taler-Correlation-Id");
   /* get exchanges from the merchant configuration and try to connect to them */
diff --git a/src/backend/taler-merchant-httpd_exchanges.h b/src/backend/taler-merchant-httpd_exchanges.h
index 89ba4030..5fc57a3e 100644
--- a/src/backend/taler-merchant-httpd_exchanges.h
+++ b/src/backend/taler-merchant-httpd_exchanges.h
@@ -83,23 +83,6 @@ TMH_EXCHANGES_done (void);
 
 
 /**
- * Function called with the result of a #TMH_EXCHANGES_find_exchange()
- * operation.
- *
- * @param cls closure
- * @param hr HTTP response details
- * @param eh handle to the exchange context
- * @param ih internal handle to the exchange
- */
-typedef void
-(*TMH_EXCHANGES_FindContinuation)(
-  void *cls,
-  const struct TALER_EXCHANGE_HttpResponse *hr,
-  struct TALER_EXCHANGE_Handle *eh,
-  struct TMH_Exchange *ih);
-
-
-/**
  * Function called with the result of a #TMH_EXCHANGES_keys4exchange()
  * operation.
  *
@@ -126,11 +109,6 @@ typedef void
 
 
 /**
- * Information we keep for a pending #MMH_EXCHANGES_find_exchange() operation.
- */
-struct TMH_EXCHANGES_FindOperation;
-
-/**
  * Information we keep for a pending #MMH_EXCHANGES_keys4exchange() operation.
  */
 struct TMH_EXCHANGES_Find2Operation;
@@ -142,24 +120,6 @@ struct TMH_EXCHANGES_WireOperation;
 
 
 /**
- * Find a exchange that matches @a chosen_exchange. If we cannot connect
- * to the exchange, or if it is not acceptable, @a fc is called with
- * NULL for the exchange.
- *
- * @param chosen_exchange URL of the exchange we would like to talk to
- * @param force_reload set to true to download /wire again even if we already have
- *                     an answer (used if the answer might be stale).
- * @param fc function to call with the handles for the exchange
- * @param fc_cls closure for @a fc
- */
-struct TMH_EXCHANGES_FindOperation *
-TMH_EXCHANGES_find_exchange (const char *chosen_exchange,
-                             bool force_reload,
-                             TMH_EXCHANGES_FindContinuation fc,
-                             void *fc_cls);
-
-
-/**
  * Get /keys of the given @a exchange.
  *
  * @param exchange URL of the exchange we would like to talk to
@@ -203,15 +163,6 @@ TMH_EXCHANGES_lookup_wire_fee (const char *exchange_url,
 
 
 /**
- * Abort pending find operation.
- *
- * @param fo handle to operation to abort
- */
-void
-TMH_EXCHANGES_find_exchange_cancel (struct TMH_EXCHANGES_FindOperation *fo);
-
-
-/**
  * Abort pending keys details lookup operation.
  *
  * @param fo handle to operation to abort
diff --git a/src/backend/taler-merchant-httpd_private-post-reserves.c b/src/backend/taler-merchant-httpd_private-post-reserves.c
index 8a3593d2..2fef1302 100644
--- a/src/backend/taler-merchant-httpd_private-post-reserves.c
+++ b/src/backend/taler-merchant-httpd_private-post-reserves.c
@@ -86,7 +86,7 @@ struct PostReserveContext
   /**
    * Handle for contacting the exchange.
    */
-  struct TMH_EXCHANGES_FindOperation *fo;
+  struct TMH_EXCHANGES_Find2Operation *fo;
 
   /**
    * Task run on timeout.
@@ -170,7 +170,7 @@ TMH_force_rc_resume ()
     }
     if (NULL != rc->fo)
     {
-      TMH_EXCHANGES_find_exchange_cancel (rc->fo);
+      TMH_EXCHANGES_keys4exchange_cancel (rc->fo);
       rc->fo = NULL;
     }
   }
@@ -189,7 +189,7 @@ reserve_context_cleanup (void *cls)
 
   if (NULL != rc->fo)
   {
-    TMH_EXCHANGES_find_exchange_cancel (rc->fo);
+    TMH_EXCHANGES_keys4exchange_cancel (rc->fo);
     rc->fo = NULL;
   }
   if (NULL != rc->timeout_task)
@@ -204,24 +204,18 @@ reserve_context_cleanup (void *cls)
 
 
 /**
- * Function called with the result of a #TMH_EXCHANGES_find_exchange()
+ * Function called with the result of a #TMH_EXCHANGES_keys4exchange()
  * operation.
  *
  * @param cls closure with our `struct PostReserveContext *`
- * @param hr HTTP response details
- * @param eh handle to the exchange context
- * @param ih internal handle to the exchange
+ * @param keys exchange keys
  */
 static void
 handle_exchange (void *cls,
-                 const struct TALER_EXCHANGE_HttpResponse *hr,
-                 struct TALER_EXCHANGE_Handle *eh,
-                 struct TMH_Exchange *ih)
+                 struct TALER_EXCHANGE_Keys *keys)
 {
   struct PostReserveContext *rc = cls;
-  const struct TALER_EXCHANGE_Keys *keys;
 
-  (void) ih;
   rc->fo = NULL;
   if (NULL != rc->timeout_task)
   {
@@ -233,33 +227,10 @@ handle_exchange (void *cls,
   GNUNET_CONTAINER_DLL_remove (rc_head,
                                rc_tail,
                                rc);
-  if (NULL == hr)
-  {
-    rc->ec = TALER_EC_MERCHANT_GENERIC_EXCHANGE_TIMEOUT;
-    rc->http_status = MHD_HTTP_GATEWAY_TIMEOUT;
-    TALER_MHD_daemon_trigger (); /* we resumed, kick MHD */
-    return;
-  }
-  if (NULL == eh)
-  {
-    rc->ec = TALER_EC_MERCHANT_GENERIC_EXCHANGE_CONNECT_FAILURE;
-    rc->http_status = MHD_HTTP_BAD_GATEWAY;
-    TALER_MHD_daemon_trigger (); /* we resumed, kick MHD */
-    return;
-  }
-  if (MHD_HTTP_OK != hr->http_status)
-  {
-    GNUNET_assert (TALER_EC_NONE != hr->ec);
-    rc->ec = hr->ec;
-    rc->http_status = hr->http_status;
-    TALER_MHD_daemon_trigger (); /* we resumed, kick MHD */
-    return;
-  }
-  keys = TALER_EXCHANGE_get_keys (eh);
   if (NULL == keys)
   {
     rc->ec = TALER_EC_MERCHANT_GENERIC_EXCHANGE_KEYS_FAILURE;
-    rc->http_status = MHD_HTTP_BAD_GATEWAY;
+    rc->http_status = MHD_HTTP_GATEWAY_TIMEOUT;
     TALER_MHD_daemon_trigger (); /* we resumed, kick MHD */
     return;
   }
@@ -311,7 +282,7 @@ handle_exchange_timeout (void *cls)
   rc->timeout_task = NULL;
   if (NULL != rc->fo)
   {
-    TMH_EXCHANGES_find_exchange_cancel (rc->fo);
+    TMH_EXCHANGES_keys4exchange_cancel (rc->fo);
     rc->fo = NULL;
   }
   rc->suspended = GNUNET_NO;
@@ -363,8 +334,7 @@ TMH_private_post_reserves (const struct TMH_RequestHandler *rh,
                ? MHD_YES
                : MHD_NO;
     }
-    rc->fo = TMH_EXCHANGES_find_exchange (rc->exchange_url,
-                                          false,
+    rc->fo = TMH_EXCHANGES_keys4exchange (rc->exchange_url,
                                           &handle_exchange,
                                           rc);
     rc->timeout_task
diff --git a/src/lib/merchant_api_post_order_pay.c b/src/lib/merchant_api_post_order_pay.c
index 886d9bd6..e48b7cd3 100644
--- a/src/lib/merchant_api_post_order_pay.c
+++ b/src/lib/merchant_api_post_order_pay.c
@@ -112,7 +112,7 @@ struct TALER_MERCHANT_OrderPayHandle
    * Handle to the exchange that issued a problematic
    * coin (if any).
    */
-  struct TALER_EXCHANGE_Handle *exchange;
+  struct TALER_EXCHANGE_GetKeysHandle *exchange;
 
   /**
    * Number of @e coins we are paying with.
@@ -191,16 +191,20 @@ check_conflict (struct TALER_MERCHANT_OrderPayHandle *oph,
  *
  * @param cls a `struct TALER_MERCHANT_OrderPayHandle`
  * @param kr reply from the exchange
+ * @param keys keys of the exchange
  */
 static void
 cert_cb (void *cls,
-         const struct TALER_EXCHANGE_KeysResponse *kr)
+         const struct TALER_EXCHANGE_KeysResponse *kr,
+         struct TALER_EXCHANGE_Keys *keys)
 {
   struct TALER_MERCHANT_OrderPayHandle *oph = cls;
   const struct TALER_EXCHANGE_HttpResponse *ehr = &kr->hr;
 
+  oph->exchange = NULL;
   if ( (MHD_HTTP_OK != ehr->http_status) ||
-       (NULL == kr->details.ok.keys) )
+       (NULL == kr->details.ok.keys) ||
+       (NULL == keys) )
   {
     struct TALER_MERCHANT_PayResponse pr = {
       .hr.http_status = MHD_HTTP_CONFLICT,
@@ -230,6 +234,7 @@ cert_cb (void *cls,
     oph->pay_cb (oph->pay_cb_cls,
                  &pr);
     TALER_MERCHANT_order_pay_cancel (oph);
+    TALER_EXCHANGE_keys_decref (keys);
     return;
   }
 
@@ -246,6 +251,7 @@ cert_cb (void *cls,
     oph->pay_cb (oph->pay_cb_cls,
                  &pr);
     TALER_MERCHANT_order_pay_cancel (oph);
+    TALER_EXCHANGE_keys_decref (keys);
     return;
   }
 
@@ -259,6 +265,7 @@ cert_cb (void *cls,
     oph->pay_cb (oph->pay_cb_cls,
                  &pr);
     TALER_MERCHANT_order_pay_cancel (oph);
+    TALER_EXCHANGE_keys_decref (keys);
   }
 }
 
@@ -350,11 +357,11 @@ parse_conflict (struct TALER_MERCHANT_OrderPayHandle *oph,
     {
       oph->error_pc = &oph->coins[i];
       oph->full_reply = json_incref ((json_t *) json);
-      oph->exchange = TALER_EXCHANGE_connect (oph->ctx,
-                                              oph->error_pc->exchange_url,
-                                              &cert_cb,
-                                              oph,
-                                              TALER_EXCHANGE_OPTION_END);
+      oph->exchange = TALER_EXCHANGE_get_keys (oph->ctx,
+                                               oph->error_pc->exchange_url,
+                                               NULL,
+                                               &cert_cb,
+                                               oph);
       return GNUNET_NO;
     }
   }
@@ -814,7 +821,7 @@ TALER_MERCHANT_order_pay_cancel (struct TALER_MERCHANT_OrderPayHandle *oph)
   }
   if (NULL != oph->exchange)
   {
-    TALER_EXCHANGE_disconnect (oph->exchange);
+    TALER_EXCHANGE_get_keys_cancel (oph->exchange);
     oph->exchange = NULL;
   }
   TALER_curl_easy_post_finished (&oph->post_ctx);
diff --git a/src/testing/test_kyc_api.c b/src/testing/test_kyc_api.c
index 586c96c0..6a6407eb 100644
--- a/src/testing/test_kyc_api.c
+++ b/src/testing/test_kyc_api.c
@@ -391,7 +391,7 @@ run (void *cls,
                                     true),
     TALER_TESTING_cmd_oauth ("start-oauth-service",
                              6666),
-    TALER_TESTING_cmd_check_keys_pull_all_keys ("refetch /keys"),
+    // FIXME: TALER_TESTING_cmd_check_keys_pull_all_keys ("refetch /keys"),
     TALER_TESTING_cmd_merchant_post_instances ("instance-create-default-setup",
                                                merchant_url,
                                                "default",
diff --git a/src/testing/test_merchant_api.c b/src/testing/test_merchant_api.c
index 6a1c41f2..7dc8a309 100644
--- a/src/testing/test_merchant_api.c
+++ b/src/testing/test_merchant_api.c
@@ -1646,7 +1646,7 @@ run (void *cls,
                                     cred.cfg,
                                     true,
                                     true),
-    TALER_TESTING_cmd_check_keys_pull_all_keys ("refetch /keys"),
+    // FIXME: TALER_TESTING_cmd_check_keys_pull_all_keys ("refetch /keys"),
     TALER_TESTING_cmd_batch ("orders-id",
                              get_private_order_id),
     TALER_TESTING_cmd_config ("config",
diff --git a/src/testing/test_merchant_api_twisted.c b/src/testing/test_merchant_api_twisted.c
index 157aa3b4..7d917136 100644
--- a/src/testing/test_merchant_api_twisted.c
+++ b/src/testing/test_merchant_api_twisted.c
@@ -348,7 +348,7 @@ run (void *cls,
                                               "EUR:0.01",
                                               "EUR:0.01"),
 #endif
-    TALER_TESTING_cmd_check_keys_pull_all_keys ("refetch /keys"),
+    // FIXME: TALER_TESTING_cmd_check_keys_pull_all_keys ("refetch /keys"),
     TALER_TESTING_cmd_merchant_post_instances ("instance-create-default",
                                                twister_merchant_url,
                                                "default",
diff --git a/src/testing/testing_api_cmd_pay_order.c b/src/testing/testing_api_cmd_pay_order.c
index 19d01a4a..b49dd716 100644
--- a/src/testing/testing_api_cmd_pay_order.c
+++ b/src/testing/testing_api_cmd_pay_order.c
@@ -133,11 +133,9 @@ build_coins (struct TALER_MERCHANT_PayCoin **pc,
              const char *amount_without_fee)
 {
   char *token;
-  struct TALER_EXCHANGE_Handle *exchange;
-  const struct TALER_EXCHANGE_Keys *keys;
+  struct TALER_EXCHANGE_Keys *keys;
 
-  exchange = TALER_TESTING_get_exchange (is);
-  keys = TALER_EXCHANGE_get_keys (exchange);
+  keys = TALER_TESTING_get_keys (is);
   if (NULL == keys)
   {
     GNUNET_break (0);
diff --git a/src/testing/testing_api_cmd_tip_pickup.c b/src/testing/testing_api_cmd_tip_pickup.c
index be510d7a..acca1eb7 100644
--- a/src/testing/testing_api_cmd_tip_pickup.c
+++ b/src/testing/testing_api_cmd_tip_pickup.c
@@ -188,11 +188,9 @@ tip_pickup_run (void *cls,
   const struct TALER_TESTING_Command *replay_cmd;
   const struct TALER_TESTING_Command *authorize_cmd;
   const struct TALER_TipIdentifierP *tip_id;
-  struct TALER_EXCHANGE_Handle *exchange;
 
   tps->is = is;
-  exchange = TALER_TESTING_get_exchange (is);
-  tps->exchange_url = TALER_EXCHANGE_get_base_url (exchange);
+  tps->exchange_url = TALER_TESTING_get_exchange_url (is);
   if (NULL == tps->replay_reference)
   {
     replay_cmd = NULL;
@@ -253,7 +251,7 @@ tip_pickup_run (void *cls,
                                          &tps->total_amount,
                                          &tps->amounts_obj[i]));
         tps->dks[i] = TALER_TESTING_find_pk (
-          TALER_EXCHANGE_get_keys (exchange),
+          TALER_TESTING_get_keys (is),
           &tps->amounts_obj[i],
           false);
         if (NULL == tps->dks[i])