Can't send massive data from http server

[nikolos]

I want to send 5000 byte data as response for GET request. When I send small respond all goes right but once I increase sending data it crashes. How to fix it?

[WiFive]

Sorry we are not psychic you have to post your code and crash/backtrace output.

[nikolos]

The main task is to get 5000 kilobytes every 0.1 seconds from esp32. Is there better way to make it ?

Code: [Select all] [Expand/Collapse]

1. ***ERROR*** A stack overflow in task httpd has been detected.
2. abort() was called at PC 0x40087e4c on core 0
3. 0x40087e4c: vApplicationStackOverflowHook at /home/niko/esp/esp-idf/components/esp32/panic.c:716
4.  
5.  
6. ELF file SHA256: 440ac70c88f935f625f5a612dda1df6f7698a6ba9d730597e52b392de6b9b17e
7.  
8. Backtrace: 0x40087be8:0x3ffc3ed0 0x40087e35:0x3ffc3ef0 0x40087e4c:0x3ffc3f10 0x4008c944:0x3ffc3f30 0x4008e3e8:0x3ffc3f50 0x4008e39e:0x4e45454b
9. 0x40087be8: invoke_abort at /home/niko/esp/esp-idf/components/esp32/panic.c:716
10.  
11. 0x40087e35: abort at /home/niko/esp/esp-idf/components/esp32/panic.c:716
12.  
13. 0x40087e4c: vApplicationStackOverflowHook at /home/niko/esp/esp-idf/components/esp32/panic.c:716
14.  
15. 0x4008c944: vTaskSwitchContext at /home/niko/esp/esp-idf/components/freertos/tasks.c:3538
16.  
17. 0x4008e3e8: _frxt_dispatch at /home/niko/esp/esp-idf/components/freertos/portasm.S:406
18.  
19. 0x4008e39e: _frxt_int_exit at /home/niko/esp/esp-idf/components/freertos/portasm.S:206

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Code: [Select all] [Expand/Collapse]

1. #include <esp_wifi.h>
2. #include <esp_event_loop.h>
3. #include <esp_log.h>
4. #include <esp_system.h>
5. #include <nvs_flash.h>
6. #include <sys/param.h>
7.  
8.  
9. #include <esp_http_server.h>
10.  
11. #include <stdio.h>
12. #include <string.h>
13. #include "driver/gpio.h"
14. #include "freertos/FreeRTOS.h"
15.  
16. #define LED1 12
17.  
18. static const char *TAG="APP";
19. esp_err_t data_get_handler(httpd_req_t *req)
20. {
21.     // example of big data
22.     char tmp_buff[10000] = "";
23.     for (int i = 0; i < 9000; i++) {
24.         tmp_buff[i] = 'a';
25.     }
26.  
27.     httpd_resp_send(req, tmp_buff, strlen(tmp_buff));
28.  
29.     if (httpd_req_get_hdr_value_len(req, "Host") == 0) {
30.         ESP_LOGI(TAG, "Request headers lost");
31.     }
32.     return ESP_OK;
33. }
34.  
35. httpd_uri_t data = {
36.     .uri = "/data",
37.     .method = HTTP_GET,
38.     .handler = data_get_handler,
39.     .user_ctx = "ESP32 data"
40. };
41.  
42.  
43. httpd_handle_t start_webserver(void)
44. {
45.     httpd_handle_t server = NULL;
46.     httpd_config_t config = HTTPD_DEFAULT_CONFIG();
47.  
48.     ESP_LOGI(TAG, "Starting server on port: '%d'", config.server_port);
49.     if (httpd_start(&server, &config) == ESP_OK) {
50.         ESP_LOGI(TAG, "Registering URI handlers");
51.    
52.         httpd_register_uri_handler(server, &data);
53.         return server;
54.     }
55.  
56.     ESP_LOGI(TAG, "Error starting server!");
57.     return NULL;
58. }
59.  
60. void stop_webserver(httpd_handle_t server)
61. {
62.     httpd_stop(server);
63. }
64.  
65. static esp_err_t event_handler(void *ctx, system_event_t *event)
66. {
67.     httpd_handle_t *server = (httpd_handle_t *) ctx;
68.  
69.     switch(event->event_id) {
70.     case SYSTEM_EVENT_STA_START:
71.         ESP_LOGI(TAG, "SYSTEM_EVENT_STA_START");
72.         ESP_ERROR_CHECK(esp_wifi_connect());
73.         break;
74.     case SYSTEM_EVENT_STA_GOT_IP:
75.         ESP_LOGI(TAG, "SYSTEM_EVENT_STA_GOT_IP");
76.         ESP_LOGI(TAG, "Got IP: '%s'", ip4addr_ntoa(&event->event_info.got_ip.ip_info.ip));
77.  
78.         if (*server == NULL) {
79.             *server = start_webserver();
80.         }
81.         break;
82.     case SYSTEM_EVENT_STA_DISCONNECTED:
83.         ESP_LOGI(TAG, "SYSTEM_EVENT_STA_DISCONNECTED");
84.         ESP_ERROR_CHECK(esp_wifi_connect());
85.  
86.         if (*server) {
87.             stop_webserver(*server);
88.             *server = NULL;
89.         }
90.         break;
91.     default:
92.         break;
93.     }
94.  
95.     return ESP_OK;
96. }
97.  
98. static void initialize_wifi(void *arg)
99. {
100.     tcpip_adapter_init();
101.     ESP_ERROR_CHECK(esp_event_loop_init(event_handler, arg));
102.     wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
103.     ESP_ERROR_CHECK(esp_wifi_init(&cfg));
104.     ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));
105.     wifi_config_t wifi_config = {
106.         .sta = {
107.             .ssid = "ZyXEL_KEENETIC_LITE_3EC257",
108.             .password = "zyxel-009-tqt",
109.         },
110.     };
111.     ESP_LOGI(TAG, "Setting WiFi configuration SSID %s PASSWORD %s", wifi_config.sta.ssid, wifi_config.sta.password);
112.     ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
113.     ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config));
114.     ESP_ERROR_CHECK(esp_wifi_start());
115. }
116.  
117.  
118. static void initialize_gpio(){
119.     gpio_pad_select_gpio(LED1);
120.     gpio_set_direction(LED1, GPIO_MODE_OUTPUT);
121. }
122.  
123. void app_main()
124. {
125.     static httpd_handle_t server = NULL;
126.     ESP_ERROR_CHECK(nvs_flash_init());
127.     initialize_gpio();
128.     initialize_wifi(&server);
129. }
130.  

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[ESP_Sprite]

Line 22 allocates an 10K buffer on the stack. The default esp-http-server stack size is only 4K, so that leads to a stack overflow, as you've seen. The easy way would be to increase the webservers stack; you could e.g. add 'config.stack_size=20480' to line 47.