gcoap/fileserver: add event callbacks

makefiles/pseudomodules.inc.mk

@@ -67,6 +67,7 @@ PSEUDOMODULES += fatfs_vfs_format
 PSEUDOMODULES += fmt_%
 PSEUDOMODULES += gcoap_forward_proxy
 PSEUDOMODULES += gcoap_fileserver
+PSEUDOMODULES += gcoap_fileserver_callback
 PSEUDOMODULES += gcoap_fileserver_delete
 PSEUDOMODULES += gcoap_fileserver_put
 PSEUDOMODULES += gcoap_dtls

sys/include/net/gcoap/fileserver.h

@@ -90,6 +90,51 @@ extern "C" {
  */
 #define COAPFILESERVER_DIR_DELETE_ETAG (0x6ce88b56u)
 
+/**
+ * @brief   GCoAP fileserver event types
+ *
+ * @note This requires the gcoap_fileserver_callback module.
+ */
+typedef enum {
+    GCOAP_FILESERVER_GET_FILE_START,     /**< file download started   */
+    GCOAP_FILESERVER_GET_FILE_END,       /**< file download finished  */
+    GCOAP_FILESERVER_PUT_FILE_START,     /**< file upload started     */
+    GCOAP_FILESERVER_PUT_FILE_END,       /**< file upload finished    */
+    GCOAP_FILESERVER_DELETE_FILE,        /**< file deletion requested
+                                         (called before file is deleted) */
+} gcoap_fileserver_event_t;
+
+/**
+ * @brief   GCoAP fileserver event context
+ */
+typedef struct {
+    const char *path;               /**< VFS path of the affected file  */
+    void *user_ctx;                 /**< Optional user supplied context */
+} gcoap_fileserver_event_ctx_t;
+
+/**
+ * @brief   GCoAP fileserver event callback type
+ *
+ * @param[in] event     Type of the event
+ * @param[in] ctx       Event context information
+ *
+ */
+typedef void (*gcoap_fileserver_event_handler_t)(gcoap_fileserver_event_t event,
+                                                 gcoap_fileserver_event_ctx_t *ctx);
+
+/**
+ * @brief   Register a consumer for GCoAP fileserver events
+ *          Requires the `gcoap_fileserver_callback` module
+ *
+ *          The Callback is called on each fileserver event and executed
+ *          within the GCoAP thread.
+ *
+ * @param[in]   cb  The callback function to be called on events
+ * @param[in]  arg  Custom callback function context
+ *
+ */
+void gcoap_fileserver_set_event_cb(gcoap_fileserver_event_handler_t cb, void *arg);
+
 /**
  * @brief File server handler
  *

sys/net/application_layer/gcoap/fileserver.c

@@ -34,6 +34,21 @@
 /** Maximum length of an expressible path, including the trailing 0 character. */
 #define COAPFILESERVER_PATH_MAX (64)
 
+/**
+ * @brief   fileserver event callback, only used with `gcoap_fileserver_callback`
+ */
+static gcoap_fileserver_event_handler_t _event_cb;
+
+/**
+ * @brief   fileserver event callback context, only used with `gcoap_fileserver_callback`
+ */
+static void *_event_ctx;
+
+/**
+ * @brief   fileserver event mutex, protects event cb and event ctx from concurrent access
+ */
+static mutex_t _event_mtx;
+
 /**
  * @brief   Structure holding information about present options in a request
  */
@@ -146,6 +161,26 @@ static void _calc_szx2(coap_pkt_t *pdu, size_t reserve, coap_block1_t *block2)
     }
 }
 
+static inline void _event_file(gcoap_fileserver_event_t event, struct requestdata *request)
+{
+    if (!IS_USED(MODULE_GCOAP_FILESERVER_CALLBACK)) {
+        return;
+    }
+
+    mutex_lock(&_event_mtx);
+    gcoap_fileserver_event_ctx_t ctx = {
+        .path = request->namebuf,
+        .user_ctx = _event_ctx,
+    };
+
+    gcoap_fileserver_event_handler_t cb = _event_cb;
+    mutex_unlock(&_event_mtx);
+
+    if (cb) {
+        cb(event, &ctx);
+    }
+}
+
 static ssize_t _get_file(coap_pkt_t *pdu, uint8_t *buf, size_t len,
                          struct requestdata *request)
 {
@@ -193,6 +228,10 @@ static ssize_t _get_file(coap_pkt_t *pdu, uint8_t *buf, size_t len,
         goto late_err;
     }
 
+    if (block2.blknum == 0) {
+        _event_file(GCOAP_FILESERVER_GET_FILE_START, request);
+    }
+
     /* That'd only happen if the buffer is too small for even a 16-byte block,
      * or if the above calculations were wrong.
      *
@@ -218,6 +257,10 @@ static ssize_t _get_file(coap_pkt_t *pdu, uint8_t *buf, size_t len,
         read -= 1;
     }
 
+    if (!more) {
+        _event_file(GCOAP_FILESERVER_GET_FILE_END, request);
+    }
+
     return resp_len + read;
 
 late_err:
@@ -257,6 +300,8 @@ static ssize_t _put_file(coap_pkt_t *pdu, uint8_t *buf, size_t len,
             ret = COAP_CODE_PRECONDITION_FAILED;
             goto unlink_on_error;
         }
+
+        _event_file(GCOAP_FILESERVER_PUT_FILE_START, request);
     }
     if (request->options.exists.if_match) {
         stat_etag(&stat, &etag); /* Etag before write */
@@ -310,6 +355,9 @@ static ssize_t _put_file(coap_pkt_t *pdu, uint8_t *buf, size_t len,
                 goto unlink_on_error;
             }
         }
+
+        _event_file(GCOAP_FILESERVER_PUT_FILE_END, request);
+
         stat_etag(&stat, &etag); /* Etag after write */
         gcoap_resp_init(pdu, buf, len, create ? COAP_CODE_CREATED : COAP_CODE_CHANGED);
         coap_opt_add_opaque(pdu, COAP_OPT_ETAG, &etag, sizeof(etag));
@@ -347,6 +395,9 @@ static ssize_t _delete_file(coap_pkt_t *pdu, uint8_t *buf, size_t len,
             return gcoap_fileserver_error_handler(pdu, buf, len, COAP_CODE_PRECONDITION_FAILED);
         }
     }
+
+    _event_file(GCOAP_FILESERVER_DELETE_FILE, request);
+
     if ((ret = vfs_unlink(request->namebuf)) < 0) {
         return gcoap_fileserver_error_handler(pdu, buf, len, ret);
     }
@@ -644,4 +695,16 @@ error:
     return gcoap_response(pdu, buf, len, errorcode);
 }
 
+#ifdef MODULE_GCOAP_FILESERVER_CALLBACK
+void gcoap_fileserver_set_event_cb(gcoap_fileserver_event_handler_t cb, void *ctx)
+{
+    mutex_lock(&_event_mtx);
+
+    _event_cb = cb;
+    _event_ctx = ctx;
+
+    mutex_unlock(&_event_mtx);
+}
+#endif
+
 /** @} */