osd-contiki/apps/json-resource/generic_resource.c

/*
 * Copyright (c) 2014-15, Ralf Schlatterbeck Open Source Consulting
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/**
 * \addtogroup Generic CoAP Resource Handler
 *
 * @{
 */


/**
 * \file
 *      Generic CoAP Resource Handler
 * \author
 *      Ralf Schlatterbeck <rsc@runtux.com>
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "contiki.h"
#include "jsonparse.h"
#include "er-coap.h"
#include "generic_resource.h"

/* Error-handling macro */
# define BYE(_exp, _tag) \
   do {                                  \
     PRINTF("Expect "_exp": %d\n",_tag); \
     return -1;                          \
   } while(0)

#define DEBUG 1
#if DEBUG
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif

int8_t
json_parse_variable
  (const uint8_t *bytes, size_t len, char *name, char *buf, size_t buflen)
{
  int tag = 0;
  struct jsonparse_state state;
  struct jsonparse_state *parser = &state;
  PRINTF ("PUT: len: %d, %s\n", len, (const char *)bytes);
  jsonparse_setup (parser, (const char *)bytes, len);
  if ((tag = jsonparse_next (parser)) != JSON_TYPE_OBJECT) {
    BYE ("OBJECT", tag);
  }
  if ((tag = jsonparse_next (parser)) != JSON_TYPE_PAIR_NAME) {
    BYE ("PAIR_NAME", tag);
  }
  while (jsonparse_strcmp_value (parser, name) != 0) {
    tag = jsonparse_next (parser);
    if (tag != JSON_TYPE_PAIR) {
      BYE ("PAIR", tag);
    }
    tag = jsonparse_next (parser);
    tag = jsonparse_next (parser);
    if (tag != ',') {
      BYE (",", tag);
    }
    tag = jsonparse_next (parser);
    if (tag != JSON_TYPE_PAIR_NAME) {
      BYE ("PAIR_NAME", tag);
    }
  }
  tag = jsonparse_next (parser);
  if (tag != JSON_TYPE_PAIR) {
    BYE ("PAIR", tag);
  }
  tag = jsonparse_next (parser);
  if (tag != JSON_TYPE_STRING) {
    BYE ("STRING", tag);
  }
  jsonparse_copy_value (parser, buf, buflen);
  return 0;
}

static const char *get_uri (void *request)
{
  static char buf [MAX_URI_STRING_LENGTH];
  const char *uri;
  size_t len = coap_get_header_uri_path (request, &uri);
  if (len > sizeof (buf) - 1) {
    *buf = '\0';
  } else {
    strncpy (buf, uri, len);
    buf [len] = '\0';
  }
  return buf;
}

void generic_get_handler
  ( void *request
  , void *response
  , uint8_t *buffer
  , uint16_t preferred_size
  , int32_t *offset
  , char *name
  , int is_str
  , size_t (*to_str)(const char *name, const char *uri, char *buf, size_t bsize)
  )
{
  int success = 1;
  char temp [MAX_GET_STRING_LENGTH];
  size_t len = 0;
  unsigned int accept = -1;
  const char *uri = get_uri (request);

  REST.get_header_accept (request, &accept);
  if (  accept != -1
     && accept != REST.type.TEXT_PLAIN
     && accept != REST.type.APPLICATION_JSON
     )
  {
    success = 0;
    REST.set_response_status (response, REST.status.NOT_ACCEPTABLE);
    return;
  }

  // TEXT format
  if (accept == REST.type.APPLICATION_JSON) {
    len += snprintf
      ( temp + len
      , sizeof (temp) - len
      , "{\n \"%s\" : %s"
      , name
      , is_str ? "\"" : ""
      );
    if (len > sizeof (temp)) {
      success = 0;
      goto out;
    }
    len += to_str (name, uri, temp + len, sizeof (temp) - len);
    if (len > sizeof (temp)) {
      success = 0;
      goto out;
    }
    len += snprintf 
      ( temp + len
      , sizeof (temp) - len
      , "%s\n}\n"
      , is_str ? "\"" : ""
      );
    if (len > sizeof (temp)) {
      success = 0;
      goto out;
    }
  } else { // TEXT Format
    len += to_str (name, uri, temp + len, sizeof (temp) - len);
    if (len > sizeof (temp)) {
      success = 0;
      goto out;
    }
    len += snprintf (temp + len, sizeof (temp) - len, "\n");
    if (len > sizeof (temp)) {
      success = 0;
      goto out;
    }
  }
  memcpy (buffer, temp, len);
  REST.set_header_content_type (response, accept);
  REST.set_response_payload (response, buffer, len);
out :
  if (!success) {
    REST.set_response_status (response, REST.status.BAD_REQUEST);
  }
}

void generic_put_handler
  ( void *request
  , void *response
  , uint8_t *buffer
  , uint16_t preferred_size
  , int32_t *offset
  , char *name
  , int (*from_str)(const char *name, const char *uri, const char *s)
  )
{
  int success = 1;
  char temp [100];
  size_t len = 0;
  const uint8_t  *bytes  = NULL;
  unsigned int c_ctype;
  const char *uri = get_uri (request);
  REST.get_header_content_type (request, &c_ctype);

  if (from_str && (len = coap_get_payload (request, &bytes))) {
    if (c_ctype == REST.type.TEXT_PLAIN) {
      int l = MIN (len, sizeof (temp) - 1);
      temp [sizeof (temp) - 1] = 0;
      strncpy (temp, (const char *)bytes, l);
      temp [l] = 0;
    } else { // jSON Format
      if (json_parse_variable (bytes, len, name, temp, sizeof (temp)) < 0) {
        success = 0;
        goto out;
      }
    }
    if (from_str (name, uri, temp) < 0) {
      success = 0;
    } else {
      REST.set_response_status (response, REST.status.CHANGED);
    }
  } else {
    success = 0;
  }
out:
  if (!success) {
    REST.set_response_status (response, REST.status.BAD_REQUEST);
  }
}

/*
 * VI settings, see coding style
 * ex:ts=8:et:sw=2
 */

/** @} */