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/*
This file is part of TALER
(C) 2014 GNUnet e.V.
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU Affero 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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License along with
TALER; see the file COPYING. If not, If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file taler-mint-httpd_parsing.h
* @brief functions to parse incoming requests
* @author Florian Dold
* @author Benedikt Mueller
* @author Christian Grothoff
*/
#ifndef TALER_MICROHTTPD_LIB_H_
#define TALER_MICROHTTPD_LIB_H_
#include <microhttpd.h>
#include <jansson.h>
/**
* Process a POST request containing a JSON object. This
* function realizes an MHD POST processor that will
* (incrementally) process JSON data uploaded to the HTTP
* server. It will store the required state in the
* "connection_cls", which must be cleaned up using
* #TALER_MINT_parse_post_cleanup_callback().
*
* @param connection the MHD connection
* @param con_cs the closure (points to a `struct Buffer *`)
* @param upload_data the POST data
* @param upload_data_size number of bytes in @a upload_data
* @param json the JSON object for a completed request
* @returns
* GNUNET_YES if json object was parsed or at least
* may be parsed in the future (call again);
* `*json` will be NULL if we need to be called again,
* and non-NULL if we are done.
* GNUNET_NO is request incomplete or invalid
* (error message was generated)
* GNUNET_SYSERR on internal error
* (we could not even queue an error message,
* close HTTP session with MHD_NO)
*/
int
TALER_MINT_parse_post_json (struct MHD_Connection *connection,
void **con_cls,
const char *upload_data,
size_t *upload_data_size,
json_t **json);
/**
* Function called whenever we are done with a request
* to clean up our state.
*
* @param con_cls value as it was left by
* #TALER_MINT_parse_post_json(), to be cleaned up
*/
void
TALER_MINT_parse_post_cleanup_callback (void *con_cls);
/**
* Constants for JSON navigation description.
*/
enum TALER_MINT_JsonNavigationCommand
{
/**
* Access a field.
* Param: const char *
*/
JNAV_FIELD,
/**
* Access an array index.
* Param: int
*/
JNAV_INDEX,
/**
* Return base32crockford encoded data of
* constant size.
* Params: (void *, size_t)
*/
JNAV_RET_DATA,
/**
* Return base32crockford encoded data of
* variable size.
* Params: (void **, size_t *)
*/
JNAV_RET_DATA_VAR,
/**
* Return a json object, which must be
* of the given type (JSON_* type constants,
* or -1 for any type).
* Params: (int, json_t **)
*/
JNAV_RET_TYPED_JSON
};
/**
* Navigate through a JSON tree.
*
* Sends an error response if navigation is impossible (i.e.
* the JSON object is invalid)
*
* @param connection the connection to send an error response to
* @param root the JSON node to start the navigation at.
* @param ... navigation specification (see `enum TALER_MINT_JsonNavigationCommand`)
* @return
* #GNUNET_YES if navigation was successful
* #GNUNET_NO if json is malformed, error response was generated
* #GNUNET_SYSERR on internal error
*/
int
GNUNET_MINT_parse_navigate_json (struct MHD_Connection *connection,
const json_t *root,
...);
/**
* Specification for how to parse a JSON field.
*/
struct GNUNET_MINT_ParseFieldSpec
{
/**
* Name of the field. NULL only to terminate array.
*/
const char *field_name;
/**
* Where to store the result. Must have exactly
* @e destination_size bytes, except if @e destination_size is zero.
* NULL to skip assignment (but check presence of the value).
*/
void *destination;
/**
* How big should the result be, 0 for variable size. In
* this case, @e destination must be a "void **", pointing
* to a location that is currently NULL and is to be allocated.
*/
size_t destination_size_in;
/**
* @e destination_size_out will then be set to the size of the
* value that was stored in @e destination (useful for
* variable-size allocations).
*/
size_t destination_size_out;
};
/**
* Parse JSON object into components based on the given field
* specification.
*
* @param connection the connection to send an error response to
* @param root the JSON node to start the navigation at.
* @param spec field specification for the parser
* @return
* #GNUNET_YES if navigation was successful (caller is responsible
* for freeing allocated variable-size data using
* #TALER_MINT_release_parsed_data() when done)
* #GNUNET_NO if json is malformed, error response was generated
* #GNUNET_SYSERR on internal error
*/
int
TALER_MINT_parse_json_data (struct MHD_Connection *connection,
const json_t *root,
struct GNUNET_MINT_ParseFieldSpec *spec);
/**
* Release all memory allocated for the variable-size fields in
* the parser specification.
*
* @param spec specification to free
*/
void
TALER_MINT_release_parsed_data (struct GNUNET_MINT_ParseFieldSpec *spec);
/**
* Generate line in parser specification for fixed-size value.
*
* @param field name of the field
* @param value where to store the value
*/
#define TALER_MINT_PARSE_FIXED(field,value) { field, value, sizeof (*value), 0 }
/**
* Generate line in parser specification for variable-size value.
*
* @param field name of the field
* @param value where to store the value
*/
#define TALER_MINT_PARSE_VARIABLE(field,value) { field, &value, 0, 0 }
/**
* Generate line in parser specification indicating the end of the spec.
*/
#define TALER_MINT_PARSE_END { NULL, NULL, 0, 0 }
/**
* Extraxt base32crockford encoded data from request.
*
* Queues an error response to the connection if the parameter is missing or
* invalid.
*
* @param connection the MHD connection
* @param param_name the name of the parameter with the key
* @param[out] out_data pointer to store the result
* @param out_size expected size of @a out_data
* @return
* #GNUNET_YES if the the argument is present
* #GNUNET_NO if the argument is absent or malformed
* #GNUNET_SYSERR on internal error (error response could not be sent)
*/
int
TALER_MINT_mhd_request_arg_data (struct MHD_Connection *connection,
const char *param_name,
void *out_data,
size_t out_size);
#endif /* TALER_MICROHTTPD_LIB_H_ */
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