ESP32使用SPIFFS文件系统笔记

1 #include <stdio.h>
2 #include <string.h>
3 #include <sys/unistd.h>
4 #include <sys/stat.h>
5 #include "esp_err.h"
6 #include "esp_log.h"
7 #include "esp_spiffs.h"
8
9 static const char *TAG = "example";
10
11 void app_main(void)
12 {
13 ESP_LOGI(TAG, "Initializing SPIFFS");
14
15 esp_vfs_spiffs_conf_t conf = {
16 .base_path = "/spiffs",
17 .partition_label = NULL,
18 .max_files = 5,
19 .format_if_mount_failed = true
20 };
21
22 //使用上面定义的设置来初始化和挂在spiffs文件系统
23 esp_err_t ret = esp_vfs_spiffs_register(&conf);
24
25 if (ret != ESP_OK) {
26 if (ret == ESP_FAIL) {
27 ESP_LOGE(TAG, "Failed to mount or format filesystem");
28 } else if (ret == ESP_ERR_NOT_FOUND) {
29 ESP_LOGE(TAG, "Failed to find SPIFFS partition");
30 } else {
31 ESP_LOGE(TAG, "Failed to initialize SPIFFS (%s)", esp_err_to_name(ret));
32 }
33 return;
34 }
35
36 size_t total = 0, used = 0;
37 ret = esp_spiffs_info(conf.partition_label, &total, &used);
38 if (ret != ESP_OK) {
39 ESP_LOGE(TAG, "Failed to get SPIFFS partition information (%s)", esp_err_to_name(ret));
40 } else {
41 ESP_LOGI(TAG, "Partition size: total: %d, used: %d", total, used);
42 }
43
44 //使用POSIX和C标准库函数操作文件
45 //创建一个文件
46 ESP_LOGI(TAG, "Opening file");
47 FILE* f = fopen("/spiffs/hello.txt", "w"); // 打开只写文件，若文件存在则文件长度清为0，即该文件内容会消失。若文件不存在则建立该文件。
48 if (f == NULL) {
49 ESP_LOGE(TAG, "Failed to open file for writing");
50 return;
51 }
52 fprintf(f, "Hello World!\n");
53 fclose(f);
54 ESP_LOGI(TAG, "File written");
55
56 //重命名前检查目标文件是否存在
57 struct stat st;
58 if (stat("/spiffs/foo.txt", &st) == 0) {
59 // 如果存在则删除
60 unlink("/spiffs/foo.txt");
61 }
62
63 // 重命名原始文件
64 ESP_LOGI(TAG, "Renaming file");
65 if (rename("/spiffs/hello.txt", "/spiffs/foo.txt") != 0) {
66 ESP_LOGE(TAG, "Rename failed");
67 return;
68 }
69
70 // 打开重命名的文件
71 ESP_LOGI(TAG, "Reading file");
72 f = fopen("/spiffs/foo.txt", "r"); // 以只读方式打开文件
73 if (f == NULL) {
74 ESP_LOGE(TAG, "Failed to open file for reading");
75 return;
76 }
77 char line[64];
78 //从指定的流 f 读取一行，并把它存储在 line 所指向的字符串内
79 fgets(line, sizeof(line), f);
80 fclose(f);
81 // 查找换行符
82 char* pos = strchr(line, '\n');
83 if (pos) {
84 *pos = '\0'; //放置一个空字符串
85 }
86 ESP_LOGI(TAG, "Read from file: '%s'", line);
87
88 // 卸载分区并禁用SPIFFS
89 esp_vfs_spiffs_unregister(conf.partition_label);
90 ESP_LOGI(TAG, "SPIFFS unmounted");
91 }