Changing configuration structure to enable multiple accounts.

This change enables using multiple wire plugins at the same time.
Also, we now distinguish between the wire plugin (i.e. EBICS or
taler_bank) and the wire method (i.e. SEPA or x-taler-bank) that
the wire plugin is implementing.  The "taler-bank" wire method
was renamed from "test" to "x-taler-bank".

This also changes the format of the /wire response of the exchange,
as we now need to return multiple accounts.  Note that wire fees
are specified per wire method, not per wire account.

taler-exchange-keyup now automatically signs all of the /wire
responses in the location specified by the configuration.

Account identification in wire plugins was changed to use
payto://-URLs instead of method-specific JSON fields.  Signing
and validation of /wire responses was moved from each wire
plugin to a generic validation method in libtalerutil (crypto)
or libtalerjson (for JSON-formatted inputs).
Convenience methods were added to generate JSON for wire accounts
(salting, signing).

Various section and option names were adjusted to streamline the
configuration and make it more consistent overall.  Documentation
was updated as well.

1 files changed, 141 insertions, 0 deletions

diff --git a/src/exchangedb/exchangedb_accounts.c b/src/exchangedb/exchangedb_accounts.c
new file mode 100644
index 000000000..275e92674
--- /dev/null
+++ b/src/exchangedb/exchangedb_accounts.c
@@ -0,0 +1,141 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2018 Taler Systems SA
+
+  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 exchangedb/exchangedb_accounts.c
+ * @brief Logic to parse account information from the configuration
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "taler_exchangedb_lib.h"
+
+
+/**
+ * Closure of #check_for_account.
+ */
+struct FindAccountContext
+{
+  /**
+   * Configuration we are usign.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Callback to invoke.
+   */
+  TALER_EXCHANGEDB_AccountCallback cb;
+
+  /**
+   * Closure for @e cb.
+   */
+  void *cb_cls;
+};
+
+
+/**
+ * Check if @a section begins with "exchange-wire-", and if
+ * so if the "ENABLE" option is set to "YES".  If both are
+ * true, call the callback from the context with the
+ * rest of the section name.
+ *
+ * @param cls our `struct FindEnabledWireContext`
+ * @param section name of a section in the configuration
+ */
+static void
+check_for_account (void *cls,
+                   const char *section)
+{
+  struct FindAccountContext *ctx = cls;
+  char *plugin_name;
+  char *payto_url;
+  char *wire_response_filename;
+  struct TALER_EXCHANGEDB_AccountInfo ai;
+
+  if (0 != strncasecmp (section,
+                        "account-",
+                        strlen ("account-")))
+    return;
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_string (ctx->cfg,
+                                             section,
+                                             "URL",
+                                             &payto_url))
+  {
+    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_WARNING,
+                               section,
+                               "URL");
+    return;
+  }
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_string (ctx->cfg,
+                                             section,
+                                             "PLUGIN",
+                                             &plugin_name))
+  {
+    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_WARNING,
+                               section,
+                               "PLUGIN");
+    GNUNET_free (payto_url);
+    return;
+  }
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_filename (ctx->cfg,
+                                               section,
+                                               "WIRE_RESPONSE",
+                                               &wire_response_filename))
+    wire_response_filename = NULL;
+  ai.section_name = section;
+  ai.plugin_name = plugin_name;
+  ai.payto_url = payto_url;
+  ai.wire_response_filename = wire_response_filename;
+  ai.debit_enabled = (GNUNET_YES ==
+                      GNUNET_CONFIGURATION_get_value_yesno (ctx->cfg,
+                                                            section,
+                                                            "ENABLE_DEBIT"));
+  ai.credit_enabled = (GNUNET_YES ==
+                       GNUNET_CONFIGURATION_get_value_yesno (ctx->cfg,
+                                                             section,
+                                                             "ENABLE_CREDIT"));
+  ctx->cb (ctx->cb_cls,
+           &ai);
+  GNUNET_free (payto_url);
+  GNUNET_free (plugin_name);
+  GNUNET_free_non_null (wire_response_filename);
+}
+
+
+/**
+ * Parse the configuration to find account information.
+ *
+ * @param cfg configuration to use
+ * @param cb callback to invoke
+ * @param cb_cls closure for @a cb
+ */
+void
+TALER_EXCHANGEDB_find_accounts (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                                TALER_EXCHANGEDB_AccountCallback cb,
+                                void *cb_cls)
+{
+  struct FindAccountContext ctx;
+
+  ctx.cfg = cfg;
+  ctx.cb = cb;
+  ctx.cb_cls = cb_cls;
+  GNUNET_CONFIGURATION_iterate_sections (cfg,
+                                         &check_for_account,
+                                         &ctx);
+}
+
+/* end of exchangedb_accounts.c */