164 lines
5.2 KiB
C
164 lines
5.2 KiB
C
/* HTTPS GET Example using plain mbedTLS sockets
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*
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* Contacts the howsmyssl.com API via TLS v1.2 and reads a JSON
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* response.
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*
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* Adapted from the ssl_client1 example in mbedtls.
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*
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* Original Copyright (C) 2006-2016, ARM Limited, All Rights Reserved, Apache 2.0 License.
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* Additions Copyright (C) Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD, Apache 2.0 License.
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*
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <string.h>
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#include <stdlib.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "freertos/event_groups.h"
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#include "esp_wifi.h"
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#include "esp_event.h"
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#include "esp_log.h"
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#include "esp_system.h"
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#include "nvs_flash.h"
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#include "protocol_examples_common.h"
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#include "tcpip_adapter.h"
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#include "lwip/err.h"
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#include "lwip/sockets.h"
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#include "lwip/sys.h"
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#include "lwip/netdb.h"
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#include "lwip/dns.h"
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#include "esp_tls.h"
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/* Constants that aren't configurable in menuconfig */
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#define WEB_SERVER "www.howsmyssl.com"
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#define WEB_PORT "443"
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#define WEB_URL "https://www.howsmyssl.com/a/check"
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static const char *TAG = "example";
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static const char *REQUEST = "GET " WEB_URL " HTTP/1.0\r\n"
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"Host: "WEB_SERVER"\r\n"
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"User-Agent: esp-idf/1.0 esp32\r\n"
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"\r\n";
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/* Root cert for howsmyssl.com, taken from server_root_cert.pem
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The PEM file was extracted from the output of this command:
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openssl s_client -showcerts -connect www.howsmyssl.com:443 </dev/null
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The CA root cert is the last cert given in the chain of certs.
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To embed it in the app binary, the PEM file is named
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in the component.mk COMPONENT_EMBED_TXTFILES variable.
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*/
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extern const uint8_t server_root_cert_pem_start[] asm("_binary_server_root_cert_pem_start");
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extern const uint8_t server_root_cert_pem_end[] asm("_binary_server_root_cert_pem_end");
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static void https_get_task(void *pvParameters)
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{
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char buf[512];
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int ret, len;
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while(1) {
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esp_tls_cfg_t cfg = {
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.cacert_buf = server_root_cert_pem_start,
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.cacert_bytes = server_root_cert_pem_end - server_root_cert_pem_start,
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};
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struct esp_tls *tls = esp_tls_conn_http_new(WEB_URL, &cfg);
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if(tls != NULL) {
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ESP_LOGI(TAG, "Connection established...");
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} else {
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ESP_LOGE(TAG, "Connection failed...");
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goto exit;
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}
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size_t written_bytes = 0;
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do {
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ret = esp_tls_conn_write(tls,
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REQUEST + written_bytes,
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strlen(REQUEST) - written_bytes);
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if (ret >= 0) {
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ESP_LOGI(TAG, "%d bytes written", ret);
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written_bytes += ret;
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} else if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
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ESP_LOGE(TAG, "esp_tls_conn_write returned 0x%x", ret);
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goto exit;
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}
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} while(written_bytes < strlen(REQUEST));
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ESP_LOGI(TAG, "Reading HTTP response...");
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do
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{
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len = sizeof(buf) - 1;
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bzero(buf, sizeof(buf));
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ret = esp_tls_conn_read(tls, (char *)buf, len);
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if(ret == MBEDTLS_ERR_SSL_WANT_WRITE || ret == MBEDTLS_ERR_SSL_WANT_READ)
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continue;
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if(ret < 0)
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{
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ESP_LOGE(TAG, "esp_tls_conn_read returned -0x%x", -ret);
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break;
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}
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if(ret == 0)
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{
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ESP_LOGI(TAG, "connection closed");
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break;
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}
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len = ret;
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ESP_LOGD(TAG, "%d bytes read", len);
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/* Print response directly to stdout as it is read */
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for(int i = 0; i < len; i++) {
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putchar(buf[i]);
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}
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} while(1);
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exit:
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esp_tls_conn_delete(tls);
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putchar('\n'); // JSON output doesn't have a newline at end
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static int request_count;
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ESP_LOGI(TAG, "Completed %d requests", ++request_count);
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for(int countdown = 10; countdown >= 0; countdown--) {
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ESP_LOGI(TAG, "%d...", countdown);
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vTaskDelay(1000 / portTICK_PERIOD_MS);
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}
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ESP_LOGI(TAG, "Starting again!");
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}
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}
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void app_main(void)
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{
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ESP_ERROR_CHECK( nvs_flash_init() );
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tcpip_adapter_init();
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ESP_ERROR_CHECK(esp_event_loop_create_default());
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/* This helper function configures Wi-Fi or Ethernet, as selected in menuconfig.
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* Read "Establishing Wi-Fi or Ethernet Connection" section in
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* examples/protocols/README.md for more information about this function.
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*/
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ESP_ERROR_CHECK(example_connect());
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xTaskCreate(&https_get_task, "https_get_task", 8192, NULL, 5, NULL);
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}
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