Add support for creating a NimBLEClient from a NimBLEServer peer.

This allows the NimBLEServer instance to create a NimBLEClient instance to read/write form/to a connected peer.
Only one instance is supported subsequent calls will overwrite the previous client connection information and data.

Author: h2zero

src/NimBLEClient.cpp

@@ -551,62 +551,6 @@ uint16_t NimBLEClient::getConnHandle() const {
     return m_connHandle;
 } // getConnHandle
 
-/**
- * @brief Clear the connection information for this client.
- * @note This is designed to be used to reset the connection information after
- * calling setConnection(), and should not be used to disconnect from a peer.
- * To disconnect from a peer, use disconnect().
- */
-void NimBLEClient::clearConnection() {
-    m_connHandle  = BLE_HS_CONN_HANDLE_NONE;
-    m_peerAddress = NimBLEAddress{};
-} // clearConnection
-
-/**
- * @brief Set the connection information for this client.
- * @param [in] connInfo The connection information.
- * @return True on success.
- * @note Sets the connection established flag to true.
- * @note If the client is already connected to a peer, this will return false.
- * @note This is designed to be used when a connection is made outside of the
- * NimBLEClient class, such as when a connection is made by the
- * NimBLEServer class and the client is passed the connection info.
- * This enables the GATT Server to read the attributes of the client connected to it.
- */
-bool NimBLEClient::setConnection(const NimBLEConnInfo& connInfo) {
-    if (isConnected()) {
-        NIMBLE_LOGE(LOG_TAG, "Already connected");
-        return false;
-    }
-
-    m_peerAddress = connInfo.getAddress();
-    m_connHandle  = connInfo.getConnHandle();
-    return true;
-} // setConnection
-
-/**
- * @brief Set the connection information for this client.
- * @param [in] connHandle The connection handle.
- * @note Sets the connection established flag to true.
- * @note This is designed to be used when a connection is made outside of the
- * NimBLEClient class, such as when a connection is made by the
- * NimBLEServer class and the client is passed the connection handle.
- * This enables the GATT Server to read the attributes of the client connected to it.
- * @note If the client is already connected to a peer, this will return false.
- * @note This will look up the peer address using the connection handle.
- */
-bool NimBLEClient::setConnection(uint16_t connHandle) {
-    // we weren't provided the peer address, look it up using ble_gap_conn_find
-    NimBLEConnInfo connInfo;
-    int            rc = ble_gap_conn_find(connHandle, &connInfo.m_desc);
-    if (rc != 0) {
-        NIMBLE_LOGE(LOG_TAG, "Connection info not found");
-        return false;
-    }
-
-    return setConnection(connInfo);
-} // setConnection
-
 /**
  * @brief Retrieve the address of the peer.
  * @return A NimBLEAddress instance with the peer address data.

src/NimBLEClient.h

@@ -60,9 +60,6 @@ class NimBLEClient {
     void           setClientCallbacks(NimBLEClientCallbacks* pClientCallbacks, bool deleteCallbacks = true);
     std::string    toString() const;
     uint16_t       getConnHandle() const;
-    void           clearConnection();
-    bool           setConnection(const NimBLEConnInfo& connInfo);
-    bool           setConnection(uint16_t connHandle);
     uint16_t       getMTU() const;
     bool           exchangeMTU();
     bool           secureConnection(bool async = false) const;
@@ -140,6 +137,7 @@ class NimBLEClient {
     ble_gap_conn_params m_connParams;
 
     friend class NimBLEDevice;
+    friend class NimBLEServer;
 }; // class NimBLEClient
 
 /**
@@ -155,7 +153,7 @@ class NimBLEClientCallbacks {
      */
     virtual void onConnect(NimBLEClient* pClient);
 
-        /**
+    /**
      * @brief Called when a connection attempt fails.
      * @param [in] pClient A pointer to the connecting client object.
      * @param [in] reason Contains the reason code for the connection failure.

src/NimBLEServer.cpp

@@ -19,6 +19,10 @@
 # include "NimBLEDevice.h"
 # include "NimBLELog.h"
 
+# if defined(CONFIG_BT_NIMBLE_ROLE_CENTRAL)
+#  include "NimBLEClient.h"
+# endif
+
 # if defined(CONFIG_NIMBLE_CPP_IDF)
 #  include "services/gap/ble_svc_gap.h"
 #  include "services/gatt/ble_svc_gatt.h"
@@ -63,6 +67,10 @@ NimBLEServer::~NimBLEServer() {
     if (m_deleteCallbacks) {
         delete m_pServerCallbacks;
     }
+
+    if (m_pClient != nullptr) {
+        delete m_pClient;
+    }
 }
 
 /**
@@ -169,7 +177,7 @@ void NimBLEServer::serviceChanged() {
  */
 void NimBLEServer::start() {
     if (m_gattsStarted) {
-        return; //already started
+        return; // already started
     }
 
     int rc = ble_gatts_start();
@@ -497,6 +505,11 @@ int NimBLEServer::handleGapEvent(ble_gap_event* event, void* arg) {
                 }
             }
 
+            if (pServer->m_pClient->m_connHandle == event->disconnect.conn.conn_handle) {
+                // If this was also the client make sure it's flagged as disconnected.
+                pServer->m_pClient->m_connHandle = BLE_HS_CONN_HANDLE_NONE;
+            }
+
             if (pServer->m_svcChanged) {
                 pServer->resetGATT();
             }
@@ -705,8 +718,8 @@ int NimBLEServer::handleGattEvent(uint16_t connHandle, uint16_t attrHandle, ble_
     NIMBLE_LOGD(LOG_TAG,
                 "Gatt %s event",
                 (ctxt->op == BLE_GATT_ACCESS_OP_READ_CHR || ctxt->op == BLE_GATT_ACCESS_OP_READ_DSC) ? "Read" : "Write");
-    auto pAtt = static_cast<NimBLELocalValueAttribute*>(arg);
-    auto val  = pAtt->getAttVal();
+    auto           pAtt = static_cast<NimBLELocalValueAttribute*>(arg);
+    auto           val  = pAtt->getAttVal();
     NimBLEConnInfo peerInfo{};
     ble_gap_conn_find(connHandle, &peerInfo.m_desc);
 
@@ -1029,6 +1042,54 @@ void NimBLEServer::setDataLen(uint16_t connHandle, uint16_t octets) const {
 # endif
 } // setDataLen
 
+# if defined(CONFIG_BT_NIMBLE_ROLE_CENTRAL)
+/**
+ * @brief Create a client instance from the connection handle.
+ * @param [in] connHandle The connection handle to create a client instance from.
+ * @return A pointer to the NimBLEClient instance or nullptr if there was an error.
+ * @note Only one instance is supported subsequent calls will overwrite the previous
+ * client connection information and data.
+ */
+NimBLEClient* NimBLEServer::getClient(uint16_t connHandle) {
+    NimBLEConnInfo connInfo;
+    int            rc = ble_gap_conn_find(connHandle, &connInfo.m_desc);
+    if (rc != 0) {
+        NIMBLE_LOGE(LOG_TAG, "Client info not found");
+        return nullptr;
+    }
+
+    return getClient(connInfo);
+} // getClient
+
+/**
+ * @brief Create a client instance from the NimBLEConnInfo reference.
+ * @param [in] connInfo The connection info to create a client instance from.
+ * @return A pointer to the NimBLEClient instance or nullptr if there was an error.
+ * @note Only one instance is supported subsequent calls will overwrite the previous
+ * client connection information and data.
+ */
+NimBLEClient* NimBLEServer::getClient(const NimBLEConnInfo& connInfo) {
+    if (m_pClient == nullptr) {
+        m_pClient = new NimBLEClient(connInfo.getAddress());
+    }
+
+    m_pClient->deleteServices(); // Changed peer connection delete the database.
+    m_pClient->m_peerAddress = connInfo.getAddress();
+    m_pClient->m_connHandle  = connInfo.getConnHandle();
+    return m_pClient;
+} // getClient
+
+/**
+ * @brief Delete the NimBLEClient instance that was created with `getClient()`
+ */
+void NimBLEServer::deleteClient() {
+    if (m_pClient != nullptr) {
+        delete m_pClient;
+        m_pClient = nullptr;
+    }
+} // deleteClient
+# endif
+
 /** Default callback handlers */
 void NimBLEServerCallbacks::onConnect(NimBLEServer* pServer, NimBLEConnInfo& connInfo) {
     NIMBLE_LOGD("NimBLEServerCallbacks", "onConnect(): Default");

src/NimBLEServer.h

@@ -48,6 +48,9 @@ class NimBLEExtAdvertising;
 # else
 class NimBLEAdvertising;
 # endif
+# if defined(CONFIG_BT_NIMBLE_ROLE_CENTRAL)
+class NimBLEClient;
+# endif
 
 /**
  * @brief The model of a BLE server.
@@ -77,6 +80,12 @@ class NimBLEServer {
     void                  advertiseOnDisconnect(bool enable);
     void                  setDataLen(uint16_t connHandle, uint16_t tx_octets) const;
 
+# if defined(CONFIG_BT_NIMBLE_ROLE_CENTRAL)
+    NimBLEClient* getClient(uint16_t connHandle);
+    NimBLEClient* getClient(const NimBLEConnInfo& connInfo);
+    void          deleteClient();
+# endif
+
 # if CONFIG_BT_NIMBLE_EXT_ADV
     NimBLEExtAdvertising* getAdvertising() const;
     bool                  startAdvertising(uint8_t instanceId, int duration = 0, int maxEvents = 0) const;
@@ -115,6 +124,10 @@ class NimBLEServer {
     std::vector<NimBLEService*>                            m_svcVec;
     std::array<uint16_t, CONFIG_BT_NIMBLE_MAX_CONNECTIONS> m_connectedPeers;
 
+# if defined(CONFIG_BT_NIMBLE_ROLE_CENTRAL)
+    NimBLEClient* m_pClient{nullptr};
+# endif
+
     static int  handleGapEvent(struct ble_gap_event* event, void* arg);
     static int  handleGattEvent(uint16_t connHandle, uint16_t attrHandle, ble_gatt_access_ctxt* ctxt, void* arg);
     static int  peerNameCB(uint16_t connHandle, const ble_gatt_error* error, ble_gatt_attr* attr, void* arg);