/* This file is part of TALER Copyright (C) 2014, 2015, 2016 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 */ /** * @file json/json.c * @brief helper functions for JSON processing using libjansson * @author Sree Harsha Totakura */ #include "platform.h" #include #include "taler_util.h" #include "taler_json_lib.h" /** * Hash a JSON object for binary signing. * * See https://tools.ietf.org/html/draft-rundgren-json-canonicalization-scheme-15 * for fun JSON canonicalization problems. Callers must ensure that * those are avoided in the input. We will use libjanson's "JSON_COMPACT" * encoding for whitespace and "JSON_SORT_KEYS" to canonicalize as best * as we can. * * @param[in] json some JSON value * @param[out] hc resulting hash code * @return #GNUNET_OK on success, #GNUNET_SYSERR on error */ int TALER_JSON_hash (const json_t *json, struct GNUNET_HashCode *hc) { char *wire_enc; size_t len; if (NULL == (wire_enc = json_dumps (json, JSON_COMPACT | JSON_SORT_KEYS))) { GNUNET_break (0); return GNUNET_SYSERR; } len = strlen (wire_enc) + 1; GNUNET_CRYPTO_hash (wire_enc, len, hc); free (wire_enc); return GNUNET_OK; } /** * Extract the Taler error code from the given @a json object. * Note that #TALER_EC_NONE is returned if no "code" is present. * * @param json response to extract the error code from * @return the "code" value from @a json */ enum TALER_ErrorCode TALER_JSON_get_error_code (const json_t *json) { const json_t *jc; if (NULL == json) { GNUNET_break_op (0); return TALER_EC_INVALID_RESPONSE; } jc = json_object_get (json, "code"); /* The caller already knows that the JSON represents an error, so we are dealing with a missing error code here. */ if (NULL == jc) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Expected Taler error code `code' in JSON, but field does not exist!\n"); return TALER_EC_INVALID; } if (json_is_integer (jc)) return (enum TALER_ErrorCode) json_integer_value (jc); GNUNET_break_op (0); return TALER_EC_INVALID; } /** * Extract the Taler error code from the given @a data object, which is expected to be in JSON. * Note that #TALER_EC_INVALID is returned if no "code" is present or if @a data is not in JSON. * * @param data response to extract the error code from * @param data_size number of bytes in @a data * @return the "code" value from @a json */ enum TALER_ErrorCode TALER_JSON_get_error_code2 (const void *data, size_t data_size) { json_t *json; enum TALER_ErrorCode ec; json_error_t err; json = json_loads (data, data_size, &err); if (NULL == json) return TALER_EC_INVALID; ec = TALER_JSON_get_error_code (json); json_decref (json); if (ec == TALER_EC_NONE) return TALER_EC_INVALID; return ec; } /* End of json/json.c */