lwip/contrib/examples/httpd/genfiles_example/genfiles_example.c

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/**
* @file
* HTTPD custom file system example for runtime generated files
*
* This file demonstrates how to add support for generated files to httpd.
*/
/*
* Copyright (c) 2017 Simon Goldschmidt
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 lwIP TCP/IP stack.
*
* Author: Simon Goldschmidt <goldsimon@gmx.de>
*
*/
#include "lwip/opt.h"
#include "genfiles_example.h"
#include "lwip/apps/fs.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include <stdio.h>
#include <string.h>
/** define LWIP_HTTPD_EXAMPLE_GENERATEDFILES to 1 to enable this file system */
#ifndef LWIP_HTTPD_EXAMPLE_GENERATEDFILES
#define LWIP_HTTPD_EXAMPLE_GENERATEDFILES 0
#endif
#if LWIP_HTTPD_EXAMPLE_GENERATEDFILES
#if !LWIP_HTTPD_CUSTOM_FILES
#error This needs LWIP_HTTPD_CUSTOM_FILES
#endif
#if !LWIP_HTTPD_DYNAMIC_HEADERS
#error This needs LWIP_HTTPD_DYNAMIC_HEADERS
#endif
/* This is the page we send. It's not generated, as you see.
* Generating custom things instead of memcpy is left to your imagination :-)
*/
const char generated_html[] =
"<html>\n"
"<head><title>lwIP - A Lightweight TCP/IP Stack</title></head>\n"
" <body bgcolor=\"white\" text=\"black\">\n"
" <table width=\"100%\">\n"
" <tr valign=\"top\">\n"
" <td width=\"80\">\n"
" <a href=\"http://www.sics.se/\"><img src=\"/img/sics.gif\"\n"
" border=\"0\" alt=\"SICS logo\" title=\"SICS logo\"></a>\n"
" </td>\n"
" <td width=\"500\">\n"
" <h1>lwIP - A Lightweight TCP/IP Stack</h1>\n"
" <h2>Generated page</h2>\n"
" <p>This page might be generated in-memory at runtime</p>\n"
" </td>\n"
" <td>\n"
" &nbsp;\n"
" </td>\n"
" </tr>\n"
" </table>\n"
" </body>\n"
"</html>";
void
genfiles_ex_init(void)
{
/* nothing to do here yet */
}
int
fs_open_custom(struct fs_file *file, const char *name)
{
/* this example only provides one file */
if (!strcmp(name, "/generated.html")) {
/* initialize fs_file correctly */
memset(file, 0, sizeof(struct fs_file));
file->pextension = mem_malloc(sizeof(generated_html));
if (file->pextension != NULL) {
/* instead of doing memcpy, you would generate e.g. a JSON here */
memcpy(file->pextension, generated_html, sizeof(generated_html));
file->data = (const char *)file->pextension;
file->len = sizeof(generated_html) - 1; /* don't send the trailing 0 */
file->index = file->len;
/* allow persisteng connections */
file->flags = FS_FILE_FLAGS_HEADER_PERSISTENT;
return 1;
}
}
return 0;
}
void
fs_close_custom(struct fs_file *file)
{
if (file && file->pextension) {
mem_free(file->pextension);
file->pextension = NULL;
}
}
#if LWIP_HTTPD_FS_ASYNC_READ
u8_t
fs_canread_custom(struct fs_file *file)
{
LWIP_UNUSED_ARG(file);
/* This example does not use delayed/async reading */
return 1;
}
u8_t
fs_wait_read_custom(struct fs_file *file, fs_wait_cb callback_fn, void *callback_arg)
{
LWIP_ASSERT("not implemented in this example configuration", 0);
LWIP_UNUSED_ARG(file);
LWIP_UNUSED_ARG(callback_fn);
LWIP_UNUSED_ARG(callback_arg);
/* Return
- 1 if ready to read (at least one byte)
- 0 if reading should be delayed (call 'tcpip_callback(callback_fn, callback_arg)' when ready) */
return 1;
}
int
fs_read_async_custom(struct fs_file *file, char *buffer, int count, fs_wait_cb callback_fn, void *callback_arg)
{
LWIP_ASSERT("not implemented in this example configuration", 0);
LWIP_UNUSED_ARG(file);
LWIP_UNUSED_ARG(buffer);
LWIP_UNUSED_ARG(count);
LWIP_UNUSED_ARG(callback_fn);
LWIP_UNUSED_ARG(callback_arg);
/* Return
- FS_READ_EOF if all bytes have been read
- FS_READ_DELAYED if reading is delayed (call 'tcpip_callback(callback_fn, callback_arg)' when done) */
/* all bytes read already */
return FS_READ_EOF;
}
#else /* LWIP_HTTPD_FS_ASYNC_READ */
int
fs_read_custom(struct fs_file *file, char *buffer, int count)
{
LWIP_ASSERT("not implemented in this example configuration", 0);
LWIP_UNUSED_ARG(file);
LWIP_UNUSED_ARG(buffer);
LWIP_UNUSED_ARG(count);
/* Return
- FS_READ_EOF if all bytes have been read
- FS_READ_DELAYED if reading is delayed (call 'tcpip_callback(callback_fn, callback_arg)' when done) */
/* all bytes read already */
return FS_READ_EOF;
}
#endif /* LWIP_HTTPD_FS_ASYNC_READ */
#endif /* LWIP_HTTPD_EXAMPLE_GENERATEDFILES */