[taler-exchange] branch master updated: implement libtalerexchange:reserve_close API

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grothoff pushed a commit to branch master
in repository exchange.

The following commit(s) were added to refs/heads/master by this push:
     new 0de4db77 implement libtalerexchange:reserve_close API
0de4db77 is described below

commit 0de4db77551458ad338bda8a76ec2c70484550f8
Author: Christian Grothoff <christian@grothoff.org>
AuthorDate: Tue Sep 27 15:21:51 2022 +0200

    implement libtalerexchange:reserve_close API
---
 src/include/taler_crypto_lib.h        |  40 +++-
 src/include/taler_exchange_service.h  |  23 ++
 src/lib/Makefile.am                   |   1 +
 src/lib/exchange_api_reserves_close.c | 385 ++++++++++++++++++++++++++++++++++
 src/lib/exchange_api_reserves_open.c  |   7 +
 5 files changed, 452 insertions(+), 4 deletions(-)

diff --git a/src/include/taler_crypto_lib.h b/src/include/taler_crypto_lib.h
index 2977ccf3..4ad9eed0 100644
--- a/src/include/taler_crypto_lib.h
+++ b/src/include/taler_crypto_lib.h
@@ -3059,7 +3059,16 @@ TALER_wallet_account_merge_verify (
 
 
 /**
- * FIXME.
+ * Sign a request to keep a reserve open.
+ *
+ * @param reserve_payment how much to pay from the
+ *        reserve's own balance for opening the reserve
+ * @param request_timestamp when was the request created
+ * @param reserve_expiration desired expiration time for the reserve
+ * @param purse_limit minimum number of purses the client
+ *       wants to have concurrently open for this reserve
+ * @param reserve_priv key identifying the reserve
+ * @param[out] reserve_sig resulting signature
  */
 void
 TALER_wallet_reserve_open_sign (
@@ -3072,7 +3081,17 @@ TALER_wallet_reserve_open_sign (
 
 
 /**
- * FIXME.
+ * Verify a request to keep a reserve open.
+ *
+ * @param reserve_payment how much to pay from the
+ *        reserve's own balance for opening the reserve
+ * @param request_timestamp when was the request created
+ * @param reserve_expiration desired expiration time for the reserve
+ * @param purse_limit minimum number of purses the client
+ *       wants to have concurrently open for this reserve
+ * @param reserve_pub key identifying the reserve
+ * @param reserve_sig resulting signature
+ * @return #GNUNET_OK if the signature is valid
  */
 enum GNUNET_GenericReturnValue
 TALER_wallet_reserve_open_verify (
@@ -3085,7 +3104,13 @@ TALER_wallet_reserve_open_verify (
 
 
 /**
- * FIXME.
+ * Sign to deposit coin to pay for keeping a reserve open.
+ *
+ * @param coin_contribution how much the coin should contribute
+ * @param reserve_pub public key of the reserve
+ * @param request_timestamp time of the open request
+ * @param coin_priv private key of the coin
+ * @param[out] coin_sig signature by the coin
  */
 void
 TALER_wallet_reserve_open_deposit_sign (
@@ -3097,7 +3122,14 @@ TALER_wallet_reserve_open_deposit_sign (
 
 
 /**
- * FIXME.
+ * Verify signature that deposits coin to pay for keeping a reserve open.
+ *
+ * @param coin_contribution how much the coin should contribute
+ * @param reserve_pub public key of the reserve
+ * @param request_timestamp time of the open request
+ * @param coin_pub public key of the coin
+ * @param coin_sig signature by the coin
+ * @return #GNUNET_OK if the signature is valid
  */
 enum GNUNET_GenericReturnValue
 TALER_wallet_reserve_open_deposit_verify (
diff --git a/src/include/taler_exchange_service.h 
b/src/include/taler_exchange_service.h
index d59fcaef..7949dbbf 100644
--- a/src/include/taler_exchange_service.h
+++ b/src/include/taler_exchange_service.h
@@ -5538,8 +5538,31 @@ struct TALER_EXCHANGE_ReserveCloseResult
     struct
     {
 
+      /**
+       * Amount wired to the target account.
+       */
+      struct TALER_Amount wire_amount;
     } ok;
 
+    /**
+     * Information returned if KYC is required to proceed, set if
+     * @e hr.http_status is #MHD_HTTP_UNAVAILABLE_FOR_LEGAL_REASONS.
+     */
+    struct
+    {
+      /**
+       * Requirement row that the merchant should use
+       * to check for its KYC status.
+       */
+      uint64_t requirement_row;
+
+      /**
+       * Hash of the payto-URI of the account to KYC;
+       */
+      struct TALER_PaytoHashP h_payto;
+
+    } unavailable_for_legal_reasons;
+
   } details;
 
 };
diff --git a/src/lib/Makefile.am b/src/lib/Makefile.am
index 959cdc7e..73ae3003 100644
--- a/src/lib/Makefile.am
+++ b/src/lib/Makefile.am
@@ -60,6 +60,7 @@ libtalerexchange_la_SOURCES = \
   exchange_api_refresh_common.c exchange_api_refresh_common.h \
   exchange_api_refreshes_reveal.c \
   exchange_api_refund.c \
+  exchange_api_reserves_close.c \
   exchange_api_reserves_get.c \
   exchange_api_reserves_history.c \
   exchange_api_reserves_open.c \
diff --git a/src/lib/exchange_api_reserves_close.c 
b/src/lib/exchange_api_reserves_close.c
new file mode 100644
index 00000000..278d1310
--- /dev/null
+++ b/src/lib/exchange_api_reserves_close.c
@@ -0,0 +1,385 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2022 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 lib/exchange_api_reserves_close.c
+ * @brief Implementation of the POST /reserves/$RESERVE_PUB/close requests
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <jansson.h>
+#include <microhttpd.h> /* just for HTTP close codes */
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_json_lib.h>
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_exchange_service.h"
+#include "taler_json_lib.h"
+#include "exchange_api_handle.h"
+#include "taler_signatures.h"
+#include "exchange_api_curl_defaults.h"
+
+
+/**
+ * @brief A /reserves/$RID/close Handle
+ */
+struct TALER_EXCHANGE_ReservesCloseHandle
+{
+
+  /**
+   * The connection to exchange this request handle will use
+   */
+  struct TALER_EXCHANGE_Handle *exchange;
+
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * Handle for the request.
+   */
+  struct GNUNET_CURL_Job *job;
+
+  /**
+   * Context for #TEH_curl_easy_post(). Keeps the data that must
+   * persist for Curl to make the upload.
+   */
+  struct TALER_CURL_PostContext post_ctx;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_EXCHANGE_ReservesCloseCallback cb;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+  /**
+   * Public key of the reserve we are querying.
+   */
+  struct TALER_ReservePublicKeyP reserve_pub;
+
+  /**
+   * Our signature.
+   */
+  struct TALER_ReserveSignatureP reserve_sig;
+
+  /**
+   * When did we make the request.
+   */
+  struct GNUNET_TIME_Timestamp ts;
+
+};
+
+
+/**
+ * We received an #MHD_HTTP_OK close code. Handle the JSON
+ * response.
+ *
+ * @param rch handle of the request
+ * @param j JSON response
+ * @return #GNUNET_OK on success
+ */
+static enum GNUNET_GenericReturnValue
+handle_reserves_close_ok (struct TALER_EXCHANGE_ReservesCloseHandle *rch,
+                          const json_t *j)
+{
+  struct TALER_EXCHANGE_ReserveCloseResult rs = {
+    .hr.reply = j,
+    .hr.http_status = MHD_HTTP_OK,
+  };
+  struct GNUNET_JSON_Specification spec[] = {
+    TALER_JSON_spec_amount_any ("wire_amount",
+                                &rs.details.ok.wire_amount),
+    GNUNET_JSON_spec_end ()
+  };
+
+  if (GNUNET_OK !=
+      GNUNET_JSON_parse (j,
+                         spec,
+                         NULL,
+                         NULL))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  rch->cb (rch->cb_cls,
+           &rs);
+  rch->cb = NULL;
+  GNUNET_JSON_parse_free (spec);
+  return GNUNET_OK;
+}
+
+
+/**
+ * We received an #MHD_HTTP_UNAVAILABLE_FOR_LEGAL_REASONS close code. Handle 
the JSON
+ * response.
+ *
+ * @param rch handle of the request
+ * @param j JSON response
+ * @return #GNUNET_OK on success
+ */
+static enum GNUNET_GenericReturnValue
+handle_reserves_close_kyc (struct TALER_EXCHANGE_ReservesCloseHandle *rch,
+                           const json_t *j)
+{
+  struct TALER_EXCHANGE_ReserveCloseResult rs = {
+    .hr.reply = j,
+    .hr.http_status = MHD_HTTP_UNAVAILABLE_FOR_LEGAL_REASONS,
+  };
+  struct GNUNET_JSON_Specification spec[] = {
+    GNUNET_JSON_spec_fixed_auto (
+      "h_payto",
+      &rs.details.unavailable_for_legal_reasons.h_payto),
+    GNUNET_JSON_spec_uint64 (
+      "requirement_row",
+      &rs.details.unavailable_for_legal_reasons.requirement_row),
+    GNUNET_JSON_spec_end ()
+  };
+
+  if (GNUNET_OK !=
+      GNUNET_JSON_parse (j,
+                         spec,
+                         NULL,
+                         NULL))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  rch->cb (rch->cb_cls,
+           &rs);
+  rch->cb = NULL;
+  GNUNET_JSON_parse_free (spec);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /reserves/$RID/close request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_ReservesCloseHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param response parsed JSON result, NULL on error
+ */
+static void
+handle_reserves_close_finished (void *cls,
+                                long response_code,
+                                const void *response)
+{
+  struct TALER_EXCHANGE_ReservesCloseHandle *rch = cls;
+  const json_t *j = response;
+  struct TALER_EXCHANGE_ReserveCloseResult rs = {
+    .hr.reply = j,
+    .hr.http_status = (unsigned int) response_code
+  };
+
+  rch->job = NULL;
+  switch (response_code)
+  {
+  case 0:
+    rs.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
+    break;
+  case MHD_HTTP_OK:
+    if (GNUNET_OK !=
+        handle_reserves_close_ok (rch,
+                                  j))
+    {
+      GNUNET_break_op (0);
+      rs.hr.http_status = 0;
+      rs.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
+    }
+    break;
+  case MHD_HTTP_BAD_REQUEST:
+    /* This should never happen, either us or the exchange is buggy
+       (or API version conflict); just pass JSON reply to the application */
+    GNUNET_break (0);
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_FORBIDDEN:
+    /* This should never happen, either us or the exchange is buggy
+       (or API version conflict); just pass JSON reply to the application */
+    GNUNET_break (0);
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_NOT_FOUND:
+    /* Nothing really to verify, this should never
+       happen, we should pass the JSON reply to the application */
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_CONFLICT:
+    /* Insufficient balance to inquire for reserve close */
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_UNAVAILABLE_FOR_LEGAL_REASONS:
+    if (GNUNET_OK !=
+        handle_reserves_close_kyc (rch,
+                                   j))
+    {
+      GNUNET_break_op (0);
+      rs.hr.http_status = 0;
+      rs.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
+    }
+    break;
+  case MHD_HTTP_INTERNAL_SERVER_ERROR:
+    /* Server had an internal issue; we should retry, but this API
+       leaves this to the application */
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  default:
+    /* unexpected response code */
+    GNUNET_break_op (0);
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u/%d for reserves close\n",
+                (unsigned int) response_code,
+                (int) rs.hr.ec);
+    break;
+  }
+  if (NULL != rch->cb)
+  {
+    rch->cb (rch->cb_cls,
+             &rs);
+    rch->cb = NULL;
+  }
+  TALER_EXCHANGE_reserves_close_cancel (rch);
+}
+
+
+struct TALER_EXCHANGE_ReservesCloseHandle *
+TALER_EXCHANGE_reserves_close (
+  struct TALER_EXCHANGE_Handle *exchange,
+  const struct TALER_ReservePrivateKeyP *reserve_priv,
+  const char *target_payto_uri,
+  TALER_EXCHANGE_ReservesCloseCallback cb,
+  void *cb_cls)
+{
+  struct TALER_EXCHANGE_ReservesCloseHandle *rch;
+  struct GNUNET_CURL_Context *ctx;
+  CURL *eh;
+  char arg_str[sizeof (struct TALER_ReservePublicKeyP) * 2 + 32];
+  struct TALER_PaytoHashP h_payto;
+
+  if (GNUNET_YES !=
+      TEAH_handle_is_ready (exchange))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  rch = GNUNET_new (struct TALER_EXCHANGE_ReservesCloseHandle);
+  rch->exchange = exchange;
+  rch->cb = cb;
+  rch->cb_cls = cb_cls;
+  rch->ts = GNUNET_TIME_timestamp_get ();
+  GNUNET_CRYPTO_eddsa_key_get_public (&reserve_priv->eddsa_priv,
+                                      &rch->reserve_pub.eddsa_pub);
+  {
+    char pub_str[sizeof (struct TALER_ReservePublicKeyP) * 2];
+    char *end;
+
+    end = GNUNET_STRINGS_data_to_string (
+      &rch->reserve_pub,
+      sizeof (rch->reserve_pub),
+      pub_str,
+      sizeof (pub_str));
+    *end = '\0';
+    GNUNET_snprintf (arg_str,
+                     sizeof (arg_str),
+                     "/reserves/%s/close",
+                     pub_str);
+  }
+  rch->url = TEAH_path_to_url (exchange,
+                               arg_str);
+  if (NULL == rch->url)
+  {
+    GNUNET_free (rch);
+    return NULL;
+  }
+  eh = TALER_EXCHANGE_curl_easy_get_ (rch->url);
+  if (NULL == eh)
+  {
+    GNUNET_break (0);
+    GNUNET_free (rch->url);
+    GNUNET_free (rch);
+    return NULL;
+  }
+  if (NULL != target_payto_uri)
+    TALER_payto_hash (target_payto_uri,
+                      &h_payto);
+  TALER_wallet_reserve_close_sign (rch->ts,
+                                   (NULL != target_payto_uri)
+                                   ? &h_payto
+                                   : NULL,
+                                   reserve_priv,
+                                   &rch->reserve_sig);
+  {
+    json_t *close_obj = GNUNET_JSON_PACK (
+      GNUNET_JSON_pack_allow_null (
+        GNUNET_JSON_pack_string ("payto_uri",
+                                 target_payto_uri)),
+      GNUNET_JSON_pack_timestamp ("request_timestamp",
+                                  rch->ts),
+      GNUNET_JSON_pack_data_auto ("reserve_sig",
+                                  &rch->reserve_sig));
+
+    if (GNUNET_OK !=
+        TALER_curl_easy_post (&rch->post_ctx,
+                              eh,
+                              close_obj))
+    {
+      GNUNET_break (0);
+      curl_easy_cleanup (eh);
+      json_decref (close_obj);
+      GNUNET_free (rch->url);
+      GNUNET_free (rch);
+      return NULL;
+    }
+    json_decref (close_obj);
+  }
+  ctx = TEAH_handle_to_context (exchange);
+  rch->job = GNUNET_CURL_job_add2 (ctx,
+                                   eh,
+                                   rch->post_ctx.headers,
+                                   &handle_reserves_close_finished,
+                                   rch);
+  return rch;
+}
+
+
+void
+TALER_EXCHANGE_reserves_close_cancel (
+  struct TALER_EXCHANGE_ReservesCloseHandle *rch)
+{
+  if (NULL != rch->job)
+  {
+    GNUNET_CURL_job_cancel (rch->job);
+    rch->job = NULL;
+  }
+  TALER_curl_easy_post_finished (&rch->post_ctx);
+  GNUNET_free (rch->url);
+  GNUNET_free (rch);
+}
+
+
+/* end of exchange_api_reserves_close.c */
diff --git a/src/lib/exchange_api_reserves_open.c 
b/src/lib/exchange_api_reserves_open.c
index 8f3fab17..eb63f8fe 100644
--- a/src/lib/exchange_api_reserves_open.c
+++ b/src/lib/exchange_api_reserves_open.c
@@ -278,6 +278,13 @@ handle_reserves_open_finished (void *cls,
     rs.hr.ec = TALER_JSON_get_error_code (j);
     rs.hr.hint = TALER_JSON_get_error_hint (j);
     break;
+  case MHD_HTTP_CONFLICT:
+    // FIXME: not yet specified, but needed in
+    // case of double-spending or insufficient
+    // reserve balance!
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
   case MHD_HTTP_UNAVAILABLE_FOR_LEGAL_REASONS:
     if (GNUNET_OK !=
         handle_reserves_open_kyc (roh,

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