mirror of
https://github.com/oliverschmidt/contiki.git
synced 2024-11-19 18:40:17 +00:00
98 lines
3.8 KiB
C
98 lines
3.8 KiB
C
/*
|
|
* Copyright (c) 2013, Institute for Pervasive Computing, ETH Zurich
|
|
* 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.
|
|
*
|
|
* This file is part of the Contiki operating system.
|
|
*/
|
|
|
|
/**
|
|
* \file
|
|
* Example resource
|
|
* \author
|
|
* Matthias Kovatsch <kovatsch@inf.ethz.ch>
|
|
*/
|
|
|
|
#include <string.h>
|
|
#include "rest-engine.h"
|
|
|
|
static void res_get_handler(void *request, void *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset);
|
|
|
|
/*
|
|
* For data larger than REST_MAX_CHUNK_SIZE (e.g., when stored in flash) resources must be aware of the buffer limitation
|
|
* and split their responses by themselves. To transfer the complete resource through a TCP stream or CoAP's blockwise transfer,
|
|
* the byte offset where to continue is provided to the handler as int32_t pointer.
|
|
* These chunk-wise resources must set the offset value to its new position or -1 of the end is reached.
|
|
* (The offset for CoAP's blockwise transfer can go up to 2'147'481'600 = ~2047 M for block size 2048 (reduced to 1024 in observe-03.)
|
|
*/
|
|
RESOURCE(res_chunks,
|
|
"title=\"Blockwise demo\";rt=\"Data\"",
|
|
res_get_handler,
|
|
NULL,
|
|
NULL,
|
|
NULL);
|
|
|
|
#define CHUNKS_TOTAL 2050
|
|
|
|
static void
|
|
res_get_handler(void *request, void *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset)
|
|
{
|
|
int32_t strpos = 0;
|
|
|
|
/* Check the offset for boundaries of the resource data. */
|
|
if(*offset >= CHUNKS_TOTAL) {
|
|
REST.set_response_status(response, REST.status.BAD_OPTION);
|
|
/* A block error message should not exceed the minimum block size (16). */
|
|
|
|
const char *error_msg = "BlockOutOfScope";
|
|
REST.set_response_payload(response, error_msg, strlen(error_msg));
|
|
return;
|
|
}
|
|
|
|
/* Generate data until reaching CHUNKS_TOTAL. */
|
|
while(strpos < preferred_size) {
|
|
strpos += snprintf((char *)buffer + strpos, preferred_size - strpos + 1, "|%ld|", *offset);
|
|
}
|
|
|
|
/* snprintf() does not adjust return value if truncated by size. */
|
|
if(strpos > preferred_size) {
|
|
strpos = preferred_size;
|
|
/* Truncate if above CHUNKS_TOTAL bytes. */
|
|
}
|
|
if(*offset + (int32_t)strpos > CHUNKS_TOTAL) {
|
|
strpos = CHUNKS_TOTAL - *offset;
|
|
}
|
|
REST.set_response_payload(response, buffer, strpos);
|
|
|
|
/* IMPORTANT for chunk-wise resources: Signal chunk awareness to REST engine. */
|
|
*offset += strpos;
|
|
|
|
/* Signal end of resource representation. */
|
|
if(*offset >= CHUNKS_TOTAL) {
|
|
*offset = -1;
|
|
}
|
|
}
|