diff options
Diffstat (limited to 'contrib/examples/httpd/fs_example/fs_example.c')
| -rw-r--r-- | contrib/examples/httpd/fs_example/fs_example.c | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/contrib/examples/httpd/fs_example/fs_example.c b/contrib/examples/httpd/fs_example/fs_example.c new file mode 100644 index 00000000000..e3552b12ea8 --- /dev/null +++ b/contrib/examples/httpd/fs_example/fs_example.c @@ -0,0 +1,324 @@ +/** + * @file + * HTTPD custom file system example + * + * This file demonstrates how to add support for an external file system to httpd. + * It provides access to the specified root directory and uses stdio.h file functions + * to read files. + * + * ATTENTION: This implementation is *not* secure: no checks are added to ensure + * files are only read below the specified root directory! + */ + + /* + * 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 "fs_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_CUSTOMFILES to 1 to enable this file system */ +#ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES +#define LWIP_HTTPD_EXAMPLE_CUSTOMFILES 0 +#endif + +/** define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED to 1 to delay open and read + * as if e.g. reading from external SPI flash */ +#ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED +#define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED 1 +#endif + +/** define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ to the number of bytes + * to read to emulate limited transfer buffers and don't read whole files in + * one chunk. + * WARNING: lowering this slows down the connection! + */ +#ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ +#define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ 0 +#endif + +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES + +#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 +#if !LWIP_HTTPD_DYNAMIC_FILE_READ +#error This wants to demonstrate read-after-open, so LWIP_HTTPD_DYNAMIC_FILE_READ is required! +#endif +#if !LWIP_HTTPD_FS_ASYNC_READ +#error This needs LWIP_HTTPD_FS_ASYNC_READ +#endif +#if !LWIP_HTTPD_FILE_EXTENSION +#error This needs LWIP_HTTPD_FILE_EXTENSION +#endif + +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED +#include "lwip/tcpip.h" +#endif + +struct fs_custom_data { + FILE *f; +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED + int delay_read; + fs_wait_cb callback_fn; + void *callback_arg; +#endif +}; + +const char* fs_ex_root_dir; + +void +fs_ex_init(const char *httpd_root_dir) +{ + fs_ex_root_dir = strdup(httpd_root_dir); +} + +#if LWIP_HTTPD_CUSTOM_FILES +int +fs_open_custom(struct fs_file *file, const char *name) +{ + char full_filename[256]; + FILE *f; + + snprintf(full_filename, 255, "%s%s", fs_ex_root_dir, name); + full_filename[255] = 0; + + f = fopen(full_filename, "rb"); + if (f != NULL) { + if (!fseek(f, 0, SEEK_END)) { + int len = (int)ftell(f); + if(!fseek(f, 0, SEEK_SET)) { + struct fs_custom_data *data = (struct fs_custom_data *)mem_malloc(sizeof(struct fs_custom_data)); + LWIP_ASSERT("out of memory?", data != NULL); + memset(file, 0, sizeof(struct fs_file)); +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED + file->len = 0; /* read size delayed */ + data->delay_read = 3; + LWIP_UNUSED_ARG(len); +#else + file->len = len; +#endif + file->flags = FS_FILE_FLAGS_HEADER_PERSISTENT; + data->f = f; + file->pextension = data; + return 1; + } + } + fclose(f); + } + return 0; +} + +void +fs_close_custom(struct fs_file *file) +{ + if (file && file->pextension) { + struct fs_custom_data *data = (struct fs_custom_data *)file->pextension; + if (data->f != NULL) { + fclose(data->f); + data->f = NULL; + } + mem_free(data); + } +} + +#if LWIP_HTTPD_FS_ASYNC_READ +u8_t +fs_canread_custom(struct fs_file *file) +{ + /* This function is only necessary for asynchronous I/O: + If reading would block, return 0 and implement fs_wait_read_custom() to call the + supplied callback if reading works. */ +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED + struct fs_custom_data *data; + LWIP_ASSERT("file != NULL", file != NULL); + data = (struct fs_custom_data *)file->pextension; + if (data == NULL) { + /* file transfer has been completed already */ + LWIP_ASSERT("transfer complete", file->index == file->len); + return 1; + } + LWIP_ASSERT("data != NULL", data != NULL); + /* This just simulates a simple delay. This delay would normally come e.g. from SPI transfer */ + if (data->delay_read == 3) { + /* delayed file size mode */ + data->delay_read = 1; + LWIP_ASSERT("", file->len == 0); + if (!fseek(data->f, 0, SEEK_END)) { + int len = (int)ftell(data->f); + if(!fseek(data->f, 0, SEEK_SET)) { + file->len = len; /* read size delayed */ + data->delay_read = 1; + return 0; + } + } + /* if we come here, something is wrong with the file */ + LWIP_ASSERT("file error", 0); + } + if (data->delay_read == 1) { + /* tell read function to delay further */ + } +#endif + LWIP_UNUSED_ARG(file); + return 1; +} + +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED +static void +fs_example_read_cb(void *arg) +{ + struct fs_custom_data *data = (struct fs_custom_data *)arg; + fs_wait_cb callback_fn = data->callback_fn; + void *callback_arg = data->callback_arg; + data->callback_fn = NULL; + data->callback_arg = NULL; + + LWIP_ASSERT("no callback_fn", callback_fn != NULL); + + callback_fn(callback_arg); +} +#endif + +u8_t +fs_wait_read_custom(struct fs_file *file, fs_wait_cb callback_fn, void *callback_arg) +{ +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED + err_t err; + struct fs_custom_data *data = (struct fs_custom_data *)file->pextension; + LWIP_ASSERT("data not set", data != NULL); + data->callback_fn = callback_fn; + data->callback_arg = callback_arg; + err = tcpip_try_callback(fs_example_read_cb, data); + LWIP_ASSERT("out of queue elements?", err == ERR_OK); + LWIP_UNUSED_ARG(err); +#else + LWIP_ASSERT("not implemented in this example configuration", 0); +#endif + LWIP_UNUSED_ARG(file); + LWIP_UNUSED_ARG(callback_fn); + LWIP_UNUSED_ARG(callback_arg); + /* Return + - 0 if ready to read (at least one byte) + - 1 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) +{ + struct fs_custom_data *data = (struct fs_custom_data *)file->pextension; + FILE *f; + int len; + int read_count = count; + LWIP_ASSERT("data not set", data != NULL); + +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED + /* This just simulates a delay. This delay would normally come e.g. from SPI transfer */ + LWIP_ASSERT("invalid state", data->delay_read >= 0 && data->delay_read <= 2); + if (data->delay_read == 2) { + /* no delay next time */ + data->delay_read = 0; + return FS_READ_DELAYED; + } else if (data->delay_read == 1) { + err_t err; + /* execute requested delay */ + data->delay_read = 2; + LWIP_ASSERT("duplicate callback request", data->callback_fn == NULL); + data->callback_fn = callback_fn; + data->callback_arg = callback_arg; + err = tcpip_try_callback(fs_example_read_cb, data); + LWIP_ASSERT("out of queue elements?", err == ERR_OK); + LWIP_UNUSED_ARG(err); + return FS_READ_DELAYED; + } + /* execute this read but delay the next one */ + data->delay_read = 1; +#endif + +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ + read_count = LWIP_MIN(read_count, LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ); +#endif + + f = data->f; + len = (int)fread(buffer, 1, read_count, f); + + LWIP_UNUSED_ARG(callback_fn); + LWIP_UNUSED_ARG(callback_arg); + + file->index += len; + + /* 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) */ + if (len == 0) { + /* all bytes read already */ + return FS_READ_EOF; + } + return len; +} + +#else /* LWIP_HTTPD_FS_ASYNC_READ */ +int +fs_read_custom(struct fs_file *file, char *buffer, int count) +{ + struct fs_custom_data *data = (struct fs_custom_data *)file->pextension; + FILE *f; + int len; + int read_count = count; + LWIP_ASSERT("data not set", data != NULL); + +#if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ + read_count = LWIP_MIN(read_count, LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ); +#endif + + f = data->f; + len = (int)fread(buffer, 1, read_count, f); + + file->index += len; + + /* Return FS_READ_EOF if all bytes have been read */ + return len; +} + +#endif /* LWIP_HTTPD_FS_ASYNC_READ */ +#endif /* LWIP_HTTPD_CUSTOM_FILES */ + +#endif /* LWIP_HTTPD_EXAMPLE_CUSTOMFILES */ |