[Examples] [Async Handlers] simplify code

examples/protocols/http_server/async_handlers/main/main.c

@@ -38,7 +38,7 @@ static const char *TAG = "example";
 
 // Async requests are queued here while they wait to
 // be processed by the workers
-static QueueHandle_t async_req_queue;
+static QueueHandle_t request_queue;
 
 // Track the number of free workers at any given time
 static SemaphoreHandle_t worker_ready_count;
@@ -53,22 +53,8 @@ typedef struct {
     httpd_req_handler_t handler;
 } httpd_async_req_t;
 
-
+// queue an HTTP req to the worker queue
-static bool is_on_async_worker_thread(void)
+static esp_err_t queue_request(httpd_req_t *req, httpd_req_handler_t handler)
-{
-    // is our handle one of the known async handles?
-    TaskHandle_t handle = xTaskGetCurrentTaskHandle();
-    for (int i = 0; i < CONFIG_EXAMPLE_MAX_ASYNC_REQUESTS; i++) {
-        if (worker_handles[i] == handle) {
-            return true;
-        }
-    }
-    return false;
-}
-
-
-// Submit an HTTP req to the async worker queue
-static esp_err_t submit_async_req(httpd_req_t *req, httpd_req_handler_t handler)
 {
     // must create a copy of the request that we own
     httpd_req_t* copy = NULL;
@@ -97,7 +83,7 @@ static esp_err_t submit_async_req(httpd_req_t *req, httpd_req_handler_t handler)
 
     // Since worker_ready_count > 0 the queue should already have space.
     // But lets wait up to 100ms just to be safe.
-    if (xQueueSend(async_req_queue, &async_req, pdMS_TO_TICKS(100)) == false) {
+    if (xQueueSend(request_queue, &async_req, pdMS_TO_TICKS(100)) == false) {
         ESP_LOGE(TAG, "worker queue is full");
         httpd_req_async_handler_complete(copy); // cleanup
         return ESP_FAIL;
@@ -106,25 +92,10 @@ static esp_err_t submit_async_req(httpd_req_t *req, httpd_req_handler_t handler)
     return ESP_OK;
 }
 
-
+/* handle long request (on async thread) */
-/* A long running HTTP GET handler */
+static esp_err_t long_async(httpd_req_t *req)
-static esp_err_t long_async_handler(httpd_req_t *req)
 {
-    ESP_LOGI(TAG, "uri: /long");
+    ESP_LOGI(TAG, "running: /long");
-    // This handler is first invoked on the httpd thread.
-    // In order to free the httpd thread to handle other requests,
-    // we must resubmit our request to be handled on an async worker thread.
-    if (is_on_async_worker_thread() == false) {
-
-        // submit
-        if (submit_async_req(req, long_async_handler) == ESP_OK) {
-            return ESP_OK;
-        } else {
-            httpd_resp_set_status(req, "503 Busy");
-            httpd_resp_sendstr(req, "<div> no workers available. server busy.</div>");
-            return ESP_OK;
-        }
-    }
 
     // track the number of long requests
     static uint8_t req_count = 0;
@@ -154,7 +125,8 @@ static esp_err_t long_async_handler(httpd_req_t *req)
     return ESP_OK;
 }
 
-static void async_req_worker_task(void *p)
+// each worker thread loops forever, processing requests
+static void worker_task(void *p)
 {
     ESP_LOGI(TAG, "starting async req task worker");
 
@@ -166,7 +138,7 @@ static void async_req_worker_task(void *p)
 
         // wait for a request
         httpd_async_req_t async_req;
-        if (xQueueReceive(async_req_queue, &async_req, portMAX_DELAY)) {
+        if (xQueueReceive(request_queue, &async_req, portMAX_DELAY)) {
 
             ESP_LOGI(TAG, "invoking %s", async_req.req->uri);
 
@@ -185,7 +157,8 @@ static void async_req_worker_task(void *p)
     vTaskDelete(NULL);
 }
 
-static void start_async_req_workers(void)
+// start worker threads
+static void start_workers(void)
 {
 
     // counting semaphore keeps track of available workers
@@ -198,9 +171,9 @@ static void start_async_req_workers(void)
     }
 
     // create queue
-    async_req_queue = xQueueCreate(1, sizeof(httpd_async_req_t));
+    request_queue = xQueueCreate(1, sizeof(httpd_async_req_t));
-    if (async_req_queue == NULL){
+    if (request_queue == NULL){
-        ESP_LOGE(TAG, "Failed to create async_req_queue");
+        ESP_LOGE(TAG, "Failed to create request_queue");
         vSemaphoreDelete(worker_ready_count);
         return;
     }
@@ -208,7 +181,7 @@ static void start_async_req_workers(void)
     // start worker tasks
     for (int i = 0; i < CONFIG_EXAMPLE_MAX_ASYNC_REQUESTS; i++) {
 
-        bool success = xTaskCreate(async_req_worker_task, "async_req_worker",
+        bool success = xTaskCreate(worker_task, "async_req_worker",
                                     ASYNC_WORKER_TASK_STACK_SIZE, // stack size
                                     (void *)0, // argument
                                     ASYNC_WORKER_TASK_PRIORITY, // priority
@@ -221,6 +194,20 @@ static void start_async_req_workers(void)
     }
 }
 
+/* adds /long request to the request queue */
+static esp_err_t long_handler(httpd_req_t *req)
+{
+    ESP_LOGI(TAG, "uri: /long");
+
+    // add to the async request queue
+    if (queue_request(req, long_async) == ESP_OK) {
+        return ESP_OK;
+    } else {
+        httpd_resp_set_status(req, "503 Busy");
+        httpd_resp_sendstr(req, "<div> no workers available. server busy.</div>");
+        return ESP_OK;
+    }
+}
 
 /* A quick HTTP GET handler, which does not
    use any asynchronous features */
@@ -271,7 +258,7 @@ static httpd_handle_t start_webserver(void)
     const httpd_uri_t long_uri = {
         .uri       = "/long",
         .method    = HTTP_GET,
-        .handler   = long_async_handler,
+        .handler   = long_handler,
     };
 
     const httpd_uri_t quick_uri = {
@@ -346,7 +333,7 @@ void app_main(void)
 #endif // CONFIG_EXAMPLE_CONNECT_ETHERNET
 
     // start workers
-    start_async_req_workers();
+    start_workers();
 
     /* Start the server for the first time */
     server = start_webserver();