esp_http_server: Expose low level socket send/recv APIs

For some advanced use cases, the low level APIs may be useful.

components/esp_http_server/include/esp_http_server.h

@@ -1292,6 +1292,53 @@ static inline esp_err_t httpd_resp_send_500(httpd_req_t *r) {
  */
 int httpd_send(httpd_req_t *r, const char *buf, size_t buf_len);
 
+/**
+ * A low level API to send data on a given socket
+ *
+ * @note This API is not recommended to be used in any request handler.
+ * Use this only for advanced use cases, wherein some asynchronous
+ * data is to be sent over a socket.
+ *
+ * This internally calls the default send function, or the function registered by
+ * httpd_sess_set_send_override().
+ *
+ * @param[in] hd        server instance
+ * @param[in] sockfd    session socket file descriptor
+ * @param[in] buf       buffer with bytes to send
+ * @param[in] buf_len   data size
+ * @param[in] flags     flags for the send() function
+ * @return
+ *  - Bytes : The number of bytes sent successfully
+ *  - HTTPD_SOCK_ERR_INVALID  : Invalid arguments
+ *  - HTTPD_SOCK_ERR_TIMEOUT  : Timeout/interrupted while calling socket send()
+ *  - HTTPD_SOCK_ERR_FAIL     : Unrecoverable error while calling socket send()
+ */
+int httpd_socket_send(httpd_handle_t hd, int sockfd, const char *buf, size_t buf_len, int flags);
+
+/**
+ * A low level API to receive data from a given socket
+ *
+ * @note This API is not recommended to be used in any request handler.
+ * Use this only for advanced use cases, wherein some asynchronous
+ * communication is required.
+ *
+ * This internally calls the default recv function, or the function registered by
+ * httpd_sess_set_recv_override().
+ *
+ * @param[in] hd        server instance
+ * @param[in] sockfd    session socket file descriptor
+ * @param[in] buf       buffer with bytes to send
+ * @param[in] buf_len   data size
+ * @param[in] flags     flags for the send() function
+ * @return
+ *  - Bytes : The number of bytes received successfully
+ *  - 0     : Buffer length parameter is zero / connection closed by peer
+ *  - HTTPD_SOCK_ERR_INVALID  : Invalid arguments
+ *  - HTTPD_SOCK_ERR_TIMEOUT  : Timeout/interrupted while calling socket recv()
+ *  - HTTPD_SOCK_ERR_FAIL     : Unrecoverable error while calling socket recv()
+ */
+int httpd_socket_recv(httpd_handle_t hd, int sockfd, char *buf, size_t buf_len, int flags);
+
 /** End of Request / Response
  * @}
  */

components/esp_http_server/src/httpd_txrx.c

@@ -599,3 +599,27 @@ int httpd_default_recv(httpd_handle_t hd, int sockfd, char *buf, size_t buf_len,
     }
     return ret;
 }
+
+int httpd_socket_send(httpd_handle_t hd, int sockfd, const char *buf, size_t buf_len, int flags)
+{
+    struct sock_db *sess = httpd_sess_get(hd, sockfd);
+    if (!sess) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    if (!sess->send_fn) {
+        return ESP_ERR_INVALID_STATE;
+    }
+    return sess->send_fn(hd, sockfd, buf, buf_len, flags);
+}
+
+int httpd_socket_recv(httpd_handle_t hd, int sockfd, char *buf, size_t buf_len, int flags)
+{
+    struct sock_db *sess = httpd_sess_get(hd, sockfd);
+    if (!sess) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    if (!sess->recv_fn) {
+        return ESP_ERR_INVALID_STATE;
+    }
+    return sess->recv_fn(hd, sockfd, buf, buf_len, flags);
+}