From b2c55c38dcc024f2ef3007843bf82f53841cbff4 Mon Sep 17 00:00:00 2001
From: nick-4711 <nick@airgradient.com>
Date: Thu, 25 Apr 2024 16:11:49 +0700
Subject: [PATCH] better handle the 304 and 400 case

---
 examples/OneOpenAir/OtaHandler.h | 50 +++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 17 deletions(-)

diff --git a/examples/OneOpenAir/OtaHandler.h b/examples/OneOpenAir/OtaHandler.h
index e26848f..5f75d8b 100644
--- a/examples/OneOpenAir/OtaHandler.h
+++ b/examples/OneOpenAir/OtaHandler.h
@@ -9,6 +9,13 @@
 #define OTA_BUF_SIZE 512
 #define URL_BUF_SIZE 256
 
+enum OtaUpdateOutcome {
+    UPDATE_PERFORMED,
+    ALREADY_UP_TO_DATE,
+    UPDATE_FAILED,
+    UDPATE_SKIPPED
+};
+
 
 class OtaHandler {
 public:
@@ -20,45 +27,54 @@ public:
         url += GIT_VERSION;
         char urlAsChar[URL_BUF_SIZE];
         url.toCharArray(urlAsChar, URL_BUF_SIZE);
-        Serial.printf("checking for new ota @ %s\n", urlAsChar);
+        Serial.printf("checking for new OTA update @ %s\n", urlAsChar);
 
         esp_http_client_config_t config = {};
         config.url = urlAsChar;
         esp_err_t ret = attemptToPerformOta(&config);
         Serial.println(ret);
-        if (ret == 0) {
-            Serial.println("OTA completed");
+        if (ret == OtaUpdateOutcome::UPDATE_PERFORMED) {
+            Serial.println("OTA update performed, restarting ...");
             esp_restart();
-        } else {
-            Serial.println("OTA failed, maybe already up to date");
-        }   
+        } 
     }
 
 private:
 
-    int attemptToPerformOta(const esp_http_client_config_t *config) {
+    OtaUpdateOutcome attemptToPerformOta(const esp_http_client_config_t *config) {
         esp_http_client_handle_t client = esp_http_client_init(config);
         if (client == NULL) {
             Serial.println("Failed to initialize HTTP connection");
-            return -1;
+            return OtaUpdateOutcome::UPDATE_FAILED;
         }
 
         esp_err_t err = esp_http_client_open(client, 0);
         if (err != ESP_OK) {
             esp_http_client_cleanup(client);
             Serial.printf("Failed to open HTTP connection: %s\n", esp_err_to_name(err));
-            return -1;
+            return OtaUpdateOutcome::UPDATE_FAILED;
         }
         esp_http_client_fetch_headers(client);
 
+        int httpStatusCode = esp_http_client_get_status_code(client);
+        if (httpStatusCode == 304) {
+            Serial.println("Firmware is already up to date");
+            cleanupHttp(client);
+            return OtaUpdateOutcome::ALREADY_UP_TO_DATE;
+        } else if (httpStatusCode != 200) {
+            Serial.printf("Firmware update skipped, the server returned %d\n", httpStatusCode);
+            cleanupHttp(client);
+            return OtaUpdateOutcome::UDPATE_SKIPPED;
+        }
+
         esp_ota_handle_t update_handle = 0;
         const esp_partition_t *update_partition = NULL;
-        Serial.println("Starting OTA ...");
+        Serial.println("Starting OTA update ...");
         update_partition = esp_ota_get_next_update_partition(NULL);
         if (update_partition == NULL) {
             Serial.println("Passive OTA partition not found");
             cleanupHttp(client);
-            return ESP_FAIL;
+            return OtaUpdateOutcome::UPDATE_FAILED;
         }
         Serial.printf("Writing to partition subtype %d at offset 0x%x\n",
                 update_partition->subtype, update_partition->address);
@@ -67,14 +83,14 @@ private:
         if (err != ESP_OK) {
             Serial.printf("esp_ota_begin failed, error=%d\n", err);
             cleanupHttp(client);
-            return err;
+            return OtaUpdateOutcome::UPDATE_FAILED;
         }
   
         esp_err_t ota_write_err = ESP_OK;
         char *upgrade_data_buf = (char *)malloc(OTA_BUF_SIZE);
         if (!upgrade_data_buf) {
             Serial.println("Couldn't allocate memory for data buffer");
-            return ESP_ERR_NO_MEM;
+            return OtaUpdateOutcome::UPDATE_FAILED;
         }
 
         int binary_file_len = 0;
@@ -104,18 +120,18 @@ private:
         esp_err_t ota_end_err = esp_ota_end(update_handle);
         if (ota_write_err != ESP_OK) {
             Serial.printf("Error: esp_ota_write failed! err=0x%d\n", err);
-            return ota_write_err;
+            return OtaUpdateOutcome::UPDATE_FAILED;
         } else if (ota_end_err != ESP_OK) {
             Serial.printf("Error: esp_ota_end failed! err=0x%d. Image is invalid", ota_end_err);
-            return ota_end_err;
+            return OtaUpdateOutcome::UPDATE_FAILED;
         }
 
         err = esp_ota_set_boot_partition(update_partition);
         if (err != ESP_OK) {
             Serial.printf("esp_ota_set_boot_partition failed! err=0x%d\n", err);
-            return err;
+            return OtaUpdateOutcome::UPDATE_FAILED;
         }
-        return 0;
+        return OtaUpdateOutcome::UPDATE_PERFORMED;
     }
 
     void cleanupHttp(esp_http_client_handle_t client) {