exchange/src/include/taler_json_lib.h
2020-08-19 18:19:00 +02:00

352 lines
11 KiB
C

/*
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 <http://www.gnu.org/licenses/>
*/
/**
* @file include/taler_json_lib.h
* @brief helper functions for JSON processing using libjansson
* @author Sree Harsha Totakura <sreeharsha@totakura.in>
* @author Christian Grothoff
*/
#ifndef TALER_JSON_LIB_H_
#define TALER_JSON_LIB_H_
#include <jansson.h>
#include <gnunet/gnunet_json_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_util.h"
#include "taler_error_codes.h"
/**
* Print JSON parsing related error information
* @deprecated
*/
#define TALER_json_warn(error) \
GNUNET_log (GNUNET_ERROR_TYPE_WARNING, \
"JSON parsing failed at %s:%u: %s (%s)\n", \
__FILE__, __LINE__, error.text, error.source)
/**
* Convert a TALER amount to a JSON object.
*
* @param amount the amount
* @return a json object describing the amount
*/
json_t *
TALER_JSON_from_amount (const struct TALER_Amount *amount);
/**
* Convert a TALER amount to a JSON object.
*
* @param amount the amount
* @return a json object describing the amount
*/
json_t *
TALER_JSON_from_amount_nbo (const struct TALER_AmountNBO *amount);
/**
* Provide specification to parse given JSON object to an amount.
*
* @param name name of the amount field in the JSON
* @param[out] r_amount where the amount has to be written
*/
struct GNUNET_JSON_Specification
TALER_JSON_spec_amount (const char *name,
struct TALER_Amount *r_amount);
/**
* Provide specification to parse given JSON object to an amount
* in network byte order.
*
* @param name name of the amount field in the JSON
* @param[out] r_amount where the amount has to be written
*/
struct GNUNET_JSON_Specification
TALER_JSON_spec_amount_nbo (const char *name,
struct TALER_AmountNBO *r_amount);
/**
* Provide specification to parse given JSON object to an absolute time.
* The absolute time value is expected to be already rounded.
*
* @param name name of the time field in the JSON
* @param[out] r_time where the time has to be written
*/
struct GNUNET_JSON_Specification
TALER_JSON_spec_absolute_time (const char *name,
struct GNUNET_TIME_Absolute *r_time);
/**
* Provide specification to parse given JSON object to an absolute time
* in network byte order.
* The absolute time value is expected to be already rounded.
*
* @param name name of the time field in the JSON
* @param[out] r_time where the time has to be written
*/
struct GNUNET_JSON_Specification
TALER_JSON_spec_absolute_time_nbo (const char *name,
struct GNUNET_TIME_AbsoluteNBO *r_time);
/**
* Provide specification to parse given JSON object to a relative time.
* The absolute time value is expected to be already rounded.
*
* @param name name of the time field in the JSON
* @param[out] r_time where the time has to be written
*/
struct GNUNET_JSON_Specification
TALER_JSON_spec_relative_time (const char *name,
struct GNUNET_TIME_Relative *r_time);
/**
* Generate line in parser specification for denomination public key.
*
* @param field name of the field
* @param[out] pk key to initialize
* @return corresponding field spec
*/
struct GNUNET_JSON_Specification
TALER_JSON_spec_denomination_public_key (const char *field,
struct TALER_DenominationPublicKey *pk);
/**
* Generate line in parser specification for denomination signature.
*
* @param field name of the field
* @param sig the signature to initialize
* @return corresponding field spec
*/
struct GNUNET_JSON_Specification
TALER_JSON_spec_denomination_signature (const char *field,
struct TALER_DenominationSignature *sig);
/**
* Hash a JSON 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 to hash
* @param[out] hc resulting hash code
* @return #GNUNET_OK on success, #GNUNET_SYSERR on error
*/
int
TALER_JSON_contract_hash (const json_t *json,
struct GNUNET_HashCode *hc);
/**
* Mark part of a contract object as 'forgettable'.
*
* @param[in,out] json some JSON object to modify
* @param field name of the field to mark as forgettable
* @return #GNUNET_OK on success, #GNUNET_SYSERR on error
*/
int
TALER_JSON_contract_mark_forgettable (json_t *json,
const char *field);
/**
* Forget part of a contract object.
*
* @param[in,out] json some JSON object to modify
* @param field name of the field to forget
* @return #GNUNET_OK on success, #GNUNET_SYSERR on error
*/
int
TALER_JSON_contract_part_forget (json_t *json,
const char *field);
/**
* Called for each path found after expanding a path.
*
* @param cls the closure.
* @param object_id the name of the object that is pointed to.
* @param parent the parent of the object at @e object_id.
*/
typedef void
(*TALER_JSON_ExpandPathCallback) (
void *cls,
const char *object_id,
json_t *parent);
/**
* Expands a path for a json object. May call the callback several times
* if the path contains a wildcard.
*
* @param json the json object the path references.
* @param path the path to expand. Must begin with "$." and follow dot notation,
* and may include array indices and wildcards.
* @param cb the callback.
* @param cb_cls closure for the callback.
* @return #GNUNET_OK on success, #GNUNET_SYSERR if @e path is invalid.
*/
int
TALER_JSON_expand_path (json_t *json,
const char *path,
TALER_JSON_ExpandPathCallback cb,
void *cb_cls);
/**
* 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);
/**
* Extract the Taler error hint from the given @a json object.
* Note that NULL is returned if no "hint" is present.
*
* @param json response to extract the error hint from
* @return the "hint" value from @a json; only valid as long as @a json is valid
*/
const char *
TALER_JSON_get_error_hint (const json_t *json);
/**
* 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);
/* **************** /wire account offline signing **************** */
/**
* Compute the hash of the given wire details. The resulting
* hash is what is put into the contract. Also performs rudimentary
* checks on the account data *if* supported.
*
* @param wire_s wire details to hash
* @param[out] hc set to the hash
* @return #GNUNET_OK on success, #GNUNET_SYSERR if @a wire_s is malformed
*/
int
TALER_JSON_merchant_wire_signature_hash (const json_t *wire_s,
struct GNUNET_HashCode *hc);
/**
* Check the signature in @a wire_s. Also performs rudimentary
* checks on the account data *if* supported.
*
* @param wire_s signed wire information of an exchange
* @param master_pub master public key of the exchange
* @return #GNUNET_OK if signature is valid
*/
int
TALER_JSON_exchange_wire_signature_check (
const json_t *wire_s,
const struct TALER_MasterPublicKeyP *master_pub);
/**
* Create a signed wire statement for the given account.
*
* @param payto_uri account specification
* @param master_priv private key to sign with
* @return NULL if @a payto_uri is malformed
*/
json_t *
TALER_JSON_exchange_wire_signature_make (
const char *payto_uri,
const struct TALER_MasterPrivateKeyP *master_priv);
/**
* Extract a string from @a object under the field @a field, but respecting
* the Taler i18n rules and the language preferences expressed in @a
* language_pattern.
*
* Basically, the @a object may optionally contain a sub-object
* "${field}_i18n" with a map from IETF BCP 47 language tags to a localized
* version of the string. If this map exists and contains an entry that
* matches the @a language pattern, that object (usually a string) is
* returned. If the @a language_pattern does not match any entry, or if the
* i18n sub-object does not exist, we simply return @a field of @a object
* (also usually a string).
*
* If @a object does not have a member @a field we return NULL (error).
*
* @param object the object to extract internationalized
* content from
* @param language_pattern a language preferences string
* like "fr-CH, fr;q=0.9, en;q=0.8, *;q=0.1", following
* https://tools.ietf.org/html/rfc7231#section-5.3.1
* @param field name of the field to extract
* @return NULL on error, otherwise the member from
* @a object. Note that the reference counter is
* NOT incremented.
*/
const json_t *
TALER_JSON_extract_i18n (const json_t *object,
const char *language_pattern,
const char *field);
/**
* Obtain the wire method associated with the given
* wire account details. @a wire_s must contain a payto://-URL
* under 'url'.
*
* @return NULL on error
*/
char *
TALER_JSON_wire_to_method (const json_t *wire_s);
/**
* Obtain the payto://-URL associated with the given
* wire account details. @a wire_s must contain a payto://-URL
* under 'payto_uri'.
*
* @return NULL on error
*/
char *
TALER_JSON_wire_to_payto (const json_t *wire_s);
#endif /* TALER_JSON_LIB_H_ */
/* End of taler_json_lib.h */