Merge branch 'bugfix/ota_failing_for_aws_signed_url_with_partial_download_enabled' into 'master'

fix(esp_http_client): Fix OTA failure with partial download enabled

Closes IDF-12590

See merge request espressif/esp-idf!37843

Author: mahavirj

components/esp_http_client/esp_http_client.c

@@ -67,6 +67,7 @@ typedef struct {
     int64_t             data_process;   /*!< data processed */
     int                 method;         /*!< http method */
     bool                is_chunked;
+    int64_t             content_range;  /*!< content range */
 } esp_http_data_t;
 
 typedef struct {
@@ -269,7 +270,29 @@ static int http_on_header_value(http_parser *parser, const char *at, size_t leng
     if (client->current_header_key == NULL) {
         return 0;
     }
-    if (strcasecmp(client->current_header_key, "Location") == 0) {
+    if (strcasecmp(client->current_header_key, "Content-Range") == 0) {
+        HTTP_RET_ON_FALSE_DBG(http_utils_append_string(&client->current_header_value, at, length), -1, TAG, "Failed to append string");
+
+        int64_t total_size = -1;
+        client->response->content_range = -1;
+        char *slash_pos = strchr(client->current_header_value, '/');
+
+        if (slash_pos) {
+            if (slash_pos[1] == '*') {
+                ESP_LOGE(TAG, "Content-Range header has unknown total size (bytes A-B/*)");
+            } else {
+                char *endptr;
+                total_size = strtol(slash_pos + 1, &endptr, 10);
+                if (total_size > 0 && *endptr == '\0') {
+                    client->response->content_range = total_size;
+                } else {
+                    ESP_LOGE(TAG, "Failed to extract total size from Content-Range");
+                }
+            }
+        } else {
+            ESP_LOGE(TAG, "Invalid Content-Range format (missing '/')");
+        }
+    } else if (strcasecmp(client->current_header_key, "Location") == 0) {
         HTTP_RET_ON_FALSE_DBG(http_utils_append_string(&client->location, at, length), -1, TAG, "Failed to append string");
     } else if (strcasecmp(client->current_header_key, "Transfer-Encoding") == 0
                && memcmp(at, "chunked", length) == 0) {
@@ -1817,6 +1840,11 @@ int64_t esp_http_client_get_content_length(esp_http_client_handle_t client)
     return client->response->content_length;
 }
 
+int64_t esp_http_client_get_content_range(esp_http_client_handle_t client)
+{
+    return client->response->content_range;
+}
+
 bool esp_http_client_is_chunked_response(esp_http_client_handle_t client)
 {
     return client->response->is_chunked;

components/esp_http_client/include/esp_http_client.h

@@ -232,6 +232,7 @@ typedef struct {
 typedef enum {
     /* 2xx - Success */
     HttpStatus_Ok                = 200,
+    HttpStatus_PartialContent    = 206,
 
     /* 3xx - Redirection */
     HttpStatus_MultipleChoices   = 300,
@@ -642,6 +643,19 @@ int esp_http_client_get_status_code(esp_http_client_handle_t client);
  */
 int64_t esp_http_client_get_content_length(esp_http_client_handle_t client);
 
+/**
+ * @brief      Get http response content range (from header Content-Range)
+ *             The returned value is valid only if this function is invoked after
+ *             a successful call to `esp_http_client_perform`.
+ *             Content-Range is set to -1 if parsing fails or if the Content-Range header is not present.
+ *
+ * @param[in]  client  The esp_http_client handle
+ *
+ * @return
+ *     - Content-Range value as bytes
+ */
+int64_t esp_http_client_get_content_range(esp_http_client_handle_t client);
+
 /**
  * @brief      Close http connection, still kept all http request resources
  *

components/esp_https_ota/src/esp_https_ota.c

@@ -365,20 +365,50 @@ esp_err_t esp_https_ota_begin(const esp_https_ota_config_t *ota_config, esp_http
 
     if (https_ota_handle->partial_http_download) {
         esp_http_client_set_method(https_ota_handle->http_client, HTTP_METHOD_HEAD);
+
         err = esp_http_client_perform(https_ota_handle->http_client);
         if (err == ESP_OK) {
             int status = esp_http_client_get_status_code(https_ota_handle->http_client);
             if (status != HttpStatus_Ok) {
-                ESP_LOGE(TAG, "Received incorrect http status %d", status);
-                err = ESP_FAIL;
-                goto http_cleanup;
+                // If server doesn't support HEAD request, we need to get image length from GET request
+                // using Range header
+                esp_http_client_set_header(https_ota_handle->http_client, "Range", "bytes=0-0");
+                esp_http_client_set_method(https_ota_handle->http_client, HTTP_METHOD_GET);
+
+                err = esp_http_client_perform(https_ota_handle->http_client);
+                if (err == ESP_OK) {
+                    status = esp_http_client_get_status_code(https_ota_handle->http_client);
+                    if (status != HttpStatus_Ok && status != HttpStatus_PartialContent) {
+                        ESP_LOGE(TAG, "Received incorrect http status %d", status);
+                        err = ESP_FAIL;
+                        goto http_cleanup;
+                    }
+                } else {
+                    ESP_LOGE(TAG, "ESP HTTP client perform failed: %d", err);
+                    goto http_cleanup;
+                }
+                esp_http_client_set_header(https_ota_handle->http_client, "Range", NULL);
+
+                if (status == HttpStatus_Ok) {
+                    // If server responds with 200 OK, we can get image length from content-length header
+                    https_ota_handle->image_length = esp_http_client_get_content_length(https_ota_handle->http_client);
+                } else {
+                    // If server responds with 206 Partial Content, we can get image length from content-range header
+                    https_ota_handle->image_length = esp_http_client_get_content_range(https_ota_handle->http_client);
+                }
+            } else {
+                https_ota_handle->image_length = esp_http_client_get_content_length(https_ota_handle->http_client);
             }
         } else {
             ESP_LOGE(TAG, "ESP HTTP client perform failed: %d", err);
             goto http_cleanup;
         }
 
-        https_ota_handle->image_length = esp_http_client_get_content_length(https_ota_handle->http_client);
+        if (https_ota_handle->image_length == -1) {
+            ESP_LOGE(TAG, "Failed to get image length from http response");
+            err = ESP_FAIL;
+            goto http_cleanup;
+        }
 #if CONFIG_ESP_HTTPS_OTA_DECRYPT_CB
         /* In case of pre ecnrypted OTA, actual image size of OTA binary includes header size
          * which stored in variable enc_img_header_size */

docs/en/api-reference/system/esp_https_ota.rst

@@ -47,6 +47,9 @@ This option is useful while fetching image from a service like AWS S3, where mbe
 
 Default value of mbedTLS Rx buffer size is set to 16 KB. By using ``partial_http_download`` with ``max_http_request_size`` of 4 KB, size of mbedTLS Rx buffer can be reduced to 4 KB. With this configuration, memory saving of around 12 KB is expected.
 
+.. note::
+    If the server uses chunked transfer encoding, partial downloads are not feasible because the total content length is not known in advance.
+
 OTA Resumption
 --------------
 

docs/zh_CN/api-reference/system/esp_https_ota.rst

@@ -47,6 +47,9 @@ ESP HTTPS OTA 升级
 
 mbedTLS Rx buffer 的默认大小为 16 KB，但如果将 ``partial_http_download`` 的 ``max_http_request_size`` 设置为 4 KB，便能将 mbedTLS Rx 的 buffer 减小到 4 KB。使用这一配置方式预计可以节省约 12 KB 内存。
 
+.. note::
+    如果服务器使用分块传输编码，则无法进行部分下载，因为无法预先获知总内容长度。
+
 OTA 恢复
 --------