AI-on-the-edge-device/code/components/jomjol_fileserver_ota/server_help.cpp

#include "server_help.h"

#include <stdio.h>
#include <string.h>
#include <sys/param.h>
#include <sys/unistd.h>
#include <sys/stat.h>
#include <dirent.h>

#include "esp_err.h"
#include "esp_log.h"

#include "esp_http_server.h"


static const char *TAG = "serverhelp";

#define SCRATCH_BUFSIZE  8192 
char scratch[SCRATCH_BUFSIZE];


#define IS_FILE_EXT(filename, ext) \
    (strcasecmp(&filename[strlen(filename) - sizeof(ext) + 1], ext) == 0)


esp_err_t send_file(httpd_req_t *req, std::string filename,  struct stat * file_stat)
{
    FILE *fd = fopen(filename.c_str(), "r");
    if (!fd) {
        ESP_LOGE(TAG, "Failed to read existing file : %s", filename.c_str());
        /* Respond with 500 Internal Server Error */
        httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "Failed to read existing file");
        return ESP_FAIL;
    }

    ESP_LOGI(TAG, "Sending file : %s (%ld bytes)...", filename.c_str(), file_stat->st_size);
    set_content_type_from_file(req, filename.c_str());

    /* Retrieve the pointer to scratch buffer for temporary storage */
    char *chunk = scratch;
    size_t chunksize;
    do {
        /* Read file in chunks into the scratch buffer */
        chunksize = fread(chunk, 1, SCRATCH_BUFSIZE, fd);

        /* Send the buffer contents as HTTP response chunk */
        if (httpd_resp_send_chunk(req, chunk, chunksize) != ESP_OK) {
            fclose(fd);
            ESP_LOGE(TAG, "File sending failed!");
            /* Abort sending file */
            httpd_resp_sendstr_chunk(req, NULL);
            /* Respond with 500 Internal Server Error */
            httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "Failed to send file");
            return ESP_FAIL;
        }

        /* Keep looping till the whole file is sent */
    } while (chunksize != 0);

    /* Close file after sending complete */
    fclose(fd);
    ESP_LOGI(TAG, "File sending complete");    
    return ESP_OK;    
}



/* Copies the full path into destination buffer and returns
 * pointer to path (skipping the preceding base path) */
const char* get_path_from_uri(char *dest, const char *base_path, const char *uri, size_t destsize)
{
    const size_t base_pathlen = strlen(base_path);
    size_t pathlen = strlen(uri);

    const char *quest = strchr(uri, '?');
    if (quest) {
        pathlen = MIN(pathlen, quest - uri);
    }
    const char *hash = strchr(uri, '#');
    if (hash) {
        pathlen = MIN(pathlen, hash - uri);
    }

    if (base_pathlen + pathlen + 1 > destsize) {
        /* Full path string won't fit into destination buffer */
        return NULL;
    }

    /* Construct full path (base + path) */
    strcpy(dest, base_path);
    strlcpy(dest + base_pathlen, uri, pathlen + 1);

    /* Return pointer to path, skipping the base */
    return dest + base_pathlen;
}


/* Set HTTP response content type according to file extension */
esp_err_t set_content_type_from_file(httpd_req_t *req, const char *filename)
{
    if (IS_FILE_EXT(filename, ".pdf")) {
        return httpd_resp_set_type(req, "application/pdf");
    } else if (IS_FILE_EXT(filename, ".html")) {
        return httpd_resp_set_type(req, "text/html");
    } else if (IS_FILE_EXT(filename, ".jpeg")) {
        return httpd_resp_set_type(req, "image/jpeg");
    } else if (IS_FILE_EXT(filename, ".ico")) {
        return httpd_resp_set_type(req, "image/x-icon");
    }
    /* This is a limited set only */
    /* For any other type always set as plain text */
    return httpd_resp_set_type(req, "text/plain");
}