This is an example of BLE GATT Client, which receives broadcast data from BLE_Server_BME280 ( a GATT server) , then transfers values up to mbed Device Connector (cloud).

Please refer details about BLEClient_mbedDevConn below. https://github.com/soramame21/BLEClient_mbedDevConn

The location of required BLE GATT server, BLE_Server_BME280, is at here. https://developer.mbed.org/users/edamame22/code/BLE_Server_BME280/

Revision:
0:29983394c6b6
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-client/source/m2mdevice.cpp	Thu Apr 13 04:48:11 2017 +0000
@@ -0,0 +1,568 @@
+/*
+ * Copyright (c) 2015 ARM Limited. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mbed-client/m2mdevice.h"
+#include "mbed-client/m2mconstants.h"
+#include "mbed-client/m2mobject.h"
+#include "mbed-client/m2mobjectinstance.h"
+#include "mbed-client/m2mresource.h"
+#include "mbed-trace/mbed_trace.h"
+
+#define BUFFER_SIZE 21
+#define TRACE_GROUP "mClt"
+
+M2MDevice* M2MDevice::_instance = NULL;
+
+M2MDevice* M2MDevice::get_instance()
+{
+    if(_instance == NULL) {
+        // ownership of this path is transferred to M2MBase.
+        // Since this object is a singleton, we could use the C-structs to avoid heap
+        // allocation on a lot of M2MDevice -objects data.
+        char *path = stringdup(M2M_DEVICE_ID);
+        if (path) {
+            _instance = new M2MDevice(path);
+        }
+    }
+    return _instance;
+}
+
+void M2MDevice::delete_instance()
+{
+    delete _instance;
+    _instance = NULL;
+}
+
+M2MDevice::M2MDevice(char *path)
+: M2MObject(M2M_DEVICE_ID, path)
+{
+    M2MBase::set_register_uri(false);
+    M2MBase::set_operation(M2MBase::GET_ALLOWED);
+
+    _device_instance = M2MObject::create_object_instance();
+    if(_device_instance) {
+        _device_instance->set_operation(M2MBase::GET_ALLOWED);
+        _device_instance->set_register_uri(true);
+        _device_instance->set_coap_content_type(COAP_CONTENT_OMA_TLV_TYPE);
+        M2MResource* res = _device_instance->create_dynamic_resource(DEVICE_REBOOT,
+                                                                     OMA_RESOURCE_TYPE,
+                                                                     M2MResourceInstance::OPAQUE,
+                                                                     false);
+        if(res) {
+            res->set_operation(M2MBase::POST_ALLOWED);
+            res->set_register_uri(false);
+        }
+
+        M2MResourceInstance* instance = _device_instance->create_dynamic_resource_instance(DEVICE_ERROR_CODE,
+                                                                 OMA_RESOURCE_TYPE,
+                                                                 M2MResourceInstance::INTEGER,
+                                                                 true,0);
+        if(instance) {
+            M2MResource * dev_res = _device_instance->resource(DEVICE_ERROR_CODE);
+            if(dev_res) {
+                dev_res->set_register_uri(false);
+            }
+            instance->set_operation(M2MBase::GET_ALLOWED);
+
+            instance->set_value(0);
+
+            instance->set_register_uri(false);
+        }
+        res = _device_instance->create_dynamic_resource(DEVICE_SUPPORTED_BINDING_MODE,
+                                                        OMA_RESOURCE_TYPE,
+                                                        M2MResourceInstance::STRING,
+                                                        true);
+        if(res) {
+            res->set_operation(M2MBase::GET_ALLOWED);
+            res->set_value((const uint8_t*)BINDING_MODE_UDP,sizeof(BINDING_MODE_UDP)-1);
+            res->set_register_uri(false);
+        }
+    }
+}
+
+M2MDevice::~M2MDevice()
+{
+}
+
+M2MResource* M2MDevice::create_resource(DeviceResource resource, const String &value)
+{
+    M2MResource* res = NULL;
+    const char* device_id_ptr = "";
+    M2MBase::Operation operation = M2MBase::GET_ALLOWED;
+    if(!is_resource_present(resource) && value.size() <= MAX_ALLOWED_STRING_LENGTH) {
+        switch(resource) {
+            case Manufacturer:
+               device_id_ptr = DEVICE_MANUFACTURER;
+               break;
+            case DeviceType:
+                device_id_ptr = DEVICE_DEVICE_TYPE;
+                break;
+            case ModelNumber:
+                device_id_ptr = DEVICE_MODEL_NUMBER;
+                break;
+            case SerialNumber:
+                device_id_ptr = DEVICE_SERIAL_NUMBER;
+                break;
+            case HardwareVersion:
+                device_id_ptr = DEVICE_HARDWARE_VERSION;
+                break;
+            case FirmwareVersion:
+                device_id_ptr = DEVICE_FIRMWARE_VERSION;
+                break;
+            case SoftwareVersion:
+                device_id_ptr = DEVICE_SOFTWARE_VERSION;
+                break;
+            case UTCOffset:
+                device_id_ptr = DEVICE_UTC_OFFSET;
+                operation = M2MBase::GET_PUT_ALLOWED;
+                break;
+            case Timezone:
+                device_id_ptr = DEVICE_TIMEZONE;
+                operation = M2MBase::GET_PUT_ALLOWED;
+                break;
+            default:
+                break;
+        }
+    }
+    const String device_id(device_id_ptr);
+
+    if(!device_id.empty()) {
+        if(_device_instance) {
+            res = _device_instance->create_dynamic_resource(device_id,
+                                                            OMA_RESOURCE_TYPE,
+                                                            M2MResourceInstance::STRING,
+                                                            true);
+
+            if(res ) {
+                res->set_operation(operation);
+                if (value.empty()) {
+                    res->clear_value();
+                } else {
+                    res->set_value((const uint8_t*)value.c_str(),
+                                   (uint32_t)value.length());
+                }
+                res->set_register_uri(false);
+            }
+        }
+    }
+    return res;
+}
+
+M2MResource* M2MDevice::create_resource(DeviceResource resource, int64_t value)
+{
+    M2MResource* res = NULL;
+    const char* device_id_ptr = "";
+    M2MBase::Operation operation = M2MBase::GET_ALLOWED;
+    if(!is_resource_present(resource)) {
+        switch(resource) {
+        case BatteryLevel:
+            if(check_value_range(resource, value)) {
+                device_id_ptr = DEVICE_BATTERY_LEVEL;
+            }
+            break;
+        case BatteryStatus:
+            if(check_value_range(resource, value)) {
+                device_id_ptr = DEVICE_BATTERY_STATUS;
+            }
+            break;
+        case MemoryFree:
+            device_id_ptr = DEVICE_MEMORY_FREE;
+            break;
+        case MemoryTotal:
+            device_id_ptr = DEVICE_MEMORY_TOTAL;
+            break;
+        case CurrentTime:
+            device_id_ptr = DEVICE_CURRENT_TIME;
+            operation = M2MBase::GET_PUT_ALLOWED;
+            break;
+        default:
+            break;
+        }
+    }
+
+    const String device_id(device_id_ptr);
+
+    if(!device_id.empty()) {
+        if(_device_instance) {
+            res = _device_instance->create_dynamic_resource(device_id,
+                                                            OMA_RESOURCE_TYPE,
+                                                            M2MResourceInstance::INTEGER,
+                                                            true);
+
+            if(res) {
+
+
+                res->set_operation(operation);
+                res->set_value(value);
+
+                res->set_register_uri(false);
+            }
+        }
+    }
+    return res;
+}
+
+M2MResourceInstance* M2MDevice::create_resource_instance(DeviceResource resource, int64_t value,
+                                                 uint16_t instance_id)
+{
+    M2MResourceInstance* res = NULL;
+    const char* device_id_ptr = "";
+    // For these resources multiple instance can exist
+    if(AvailablePowerSources == resource) {
+        if(check_value_range(resource, value)) {
+            device_id_ptr = DEVICE_AVAILABLE_POWER_SOURCES;
+        }
+    } else if(PowerSourceVoltage == resource) {
+        device_id_ptr = DEVICE_POWER_SOURCE_VOLTAGE;
+    } else if(PowerSourceCurrent == resource) {
+        device_id_ptr = DEVICE_POWER_SOURCE_CURRENT;
+    } else if(ErrorCode == resource) {
+        if(check_value_range(resource, value)) {
+            device_id_ptr = DEVICE_ERROR_CODE;
+        }
+    }
+
+    const String device_id(device_id_ptr);
+
+    if(!device_id.empty()) {
+        if(_device_instance) {
+            res = _device_instance->create_dynamic_resource_instance(device_id,OMA_RESOURCE_TYPE,
+                                                                     M2MResourceInstance::INTEGER,
+                                                                     true, instance_id);
+
+            M2MResource *resource = _device_instance->resource(device_id);
+            if(resource) {
+                resource->set_register_uri(false);
+            }
+            if(res) {
+                res->set_value(value);
+                // Only read operation is allowed for above resources
+                res->set_operation(M2MBase::GET_ALLOWED);
+
+                res->set_register_uri(false);
+            }
+        }
+    }
+    return res;
+}
+M2MResource* M2MDevice::create_resource(DeviceResource resource)
+{
+    M2MResource* res = NULL;
+    if(!is_resource_present(resource)) {
+        const char* device_Id_ptr = "";
+        if(FactoryReset == resource) {
+            device_Id_ptr = DEVICE_FACTORY_RESET;
+        } else if(ResetErrorCode == resource) {
+            device_Id_ptr = DEVICE_RESET_ERROR_CODE;
+        }
+        const String device_Id(device_Id_ptr);
+
+        if(_device_instance && !device_Id.empty()) {
+            res = _device_instance->create_dynamic_resource(device_Id,
+                                                            OMA_RESOURCE_TYPE,
+                                                            M2MResourceInstance::OPAQUE,
+                                                            true);
+            M2MResource *resource = _device_instance->resource(device_Id);
+            if(resource) {
+                resource->set_register_uri(false);
+            }
+            if(res) {
+                res->set_operation(M2MBase::POST_ALLOWED);
+                res->set_register_uri(false);
+            }
+        }
+    }
+    return res;
+}
+
+bool M2MDevice::delete_resource(DeviceResource resource)
+{
+    bool success = false;
+    if(M2MDevice::Reboot != resource             &&
+       M2MDevice::ErrorCode != resource          &&
+       M2MDevice::SupportedBindingMode != resource) {
+        if(_device_instance) {
+            success = _device_instance->remove_resource(resource_name(resource));
+        }
+    }
+    return success;
+}
+
+bool M2MDevice::delete_resource_instance(DeviceResource resource,
+                                         uint16_t instance_id)
+{
+    bool success = false;
+    if(M2MDevice::Reboot != resource             &&
+       M2MDevice::ErrorCode != resource          &&
+       M2MDevice::SupportedBindingMode != resource) {
+        if(_device_instance) {
+            success = _device_instance->remove_resource_instance(resource_name(resource),instance_id);
+        }
+    }
+    return success;
+}
+
+bool M2MDevice::set_resource_value(DeviceResource resource,
+                                   const String &value,
+                                   uint16_t instance_id)
+{
+    bool success = false;
+    M2MResourceInstance* res = get_resource_instance(resource,instance_id);
+    if(res && value.size() <= MAX_ALLOWED_STRING_LENGTH) {
+        if(M2MDevice::Manufacturer == resource          ||
+           M2MDevice::ModelNumber == resource           ||
+           M2MDevice::DeviceType == resource            ||
+           M2MDevice::SerialNumber == resource          ||
+           M2MDevice::HardwareVersion == resource       ||
+           M2MDevice::FirmwareVersion == resource       ||
+           M2MDevice::SoftwareVersion == resource       ||
+           M2MDevice::UTCOffset == resource             ||
+           M2MDevice::Timezone == resource) {
+                if (value.empty()) {
+                    res->clear_value();
+                    success = true;
+                } else {
+                    success = res->set_value((const uint8_t*)value.c_str(),(uint32_t)value.length());
+                }
+        }
+    }
+    return success;
+}
+
+bool M2MDevice::set_resource_value(DeviceResource resource,
+                                       int64_t value,
+                                       uint16_t instance_id)
+{
+    bool success = false;
+    M2MResourceInstance* res = get_resource_instance(resource,instance_id);
+    if(res) {
+        if(M2MDevice::BatteryLevel == resource          ||
+           M2MDevice::BatteryStatus == resource         ||
+           M2MDevice::MemoryFree == resource            ||
+           M2MDevice::MemoryTotal == resource           ||
+           M2MDevice::ErrorCode == resource             ||
+           M2MDevice::CurrentTime == resource           ||
+           M2MDevice::AvailablePowerSources == resource ||
+           M2MDevice::PowerSourceVoltage == resource    ||
+           M2MDevice::PowerSourceCurrent == resource) {
+            // If it is any of the above resource
+            // set the value of the resource.
+            if (check_value_range(resource, value)) {
+
+                success = res->set_value(value);
+            }
+        }
+    }
+    return success;
+}
+
+String M2MDevice::resource_value_string(DeviceResource resource,
+                                        uint16_t instance_id) const
+{
+    String value = "";
+    M2MResourceInstance* res = get_resource_instance(resource,instance_id);
+    if(res) {
+        if(M2MDevice::Manufacturer == resource          ||
+           M2MDevice::ModelNumber == resource           ||
+           M2MDevice::DeviceType == resource            ||
+           M2MDevice::SerialNumber == resource          ||
+           M2MDevice::HardwareVersion == resource       ||
+           M2MDevice::FirmwareVersion == resource       ||
+           M2MDevice::SoftwareVersion == resource       ||
+           M2MDevice::UTCOffset == resource             ||
+           M2MDevice::Timezone == resource) {
+
+
+            value = res->get_value_string();
+        }
+    }
+    return value;
+}
+
+int64_t M2MDevice::resource_value_int(DeviceResource resource,
+                                      uint16_t instance_id) const
+{
+    int64_t value = -1;
+    M2MResourceInstance* res = get_resource_instance(resource,instance_id);
+    if(res) {
+        if(M2MDevice::BatteryLevel == resource          ||
+           M2MDevice::BatteryStatus == resource         ||
+           M2MDevice::MemoryFree == resource            ||
+           M2MDevice::MemoryTotal == resource           ||
+           M2MDevice::ErrorCode == resource             ||
+           M2MDevice::CurrentTime == resource           ||
+           M2MDevice::AvailablePowerSources == resource ||
+           M2MDevice::PowerSourceVoltage == resource    ||
+           M2MDevice::PowerSourceCurrent == resource) {
+
+            // note: the value may be 32bit int on 32b archs.
+            value = res->get_value_int();
+        }
+    }
+    return value;
+}
+
+bool M2MDevice::is_resource_present(DeviceResource resource) const
+{
+    bool success = false;
+    M2MResourceInstance* res = get_resource_instance(resource,0);
+    if(res) {
+        success = true;
+    }
+    return success;
+}
+
+uint16_t M2MDevice::per_resource_count(DeviceResource res) const
+{
+    uint16_t count = 0;
+    if(_device_instance) {
+        count = _device_instance->resource_count(resource_name(res));
+    }
+    return count;
+}
+
+uint16_t M2MDevice::total_resource_count() const
+{
+    uint16_t count = 0;
+    if(_device_instance) {
+        count = _device_instance->resources().size();
+    }
+    return count;
+}
+
+M2MResourceInstance* M2MDevice::get_resource_instance(DeviceResource dev_res,
+                                                      uint16_t instance_id) const
+{
+    M2MResource* res = NULL;
+    M2MResourceInstance* inst = NULL;
+    if(_device_instance) {
+        res = _device_instance->resource(resource_name(dev_res));
+        if(res) {
+            if(res->supports_multiple_instances()) {
+               inst = res->resource_instance(instance_id);
+            } else {
+                inst = res;
+            }
+        }
+    }
+    return inst;
+}
+
+const char* M2MDevice::resource_name(DeviceResource resource)
+{
+    const char* res_name = "";
+    switch(resource) {
+        case Manufacturer:
+            res_name = DEVICE_MANUFACTURER;
+            break;
+        case DeviceType:
+            res_name = DEVICE_DEVICE_TYPE;
+            break;
+        case ModelNumber:
+            res_name = DEVICE_MODEL_NUMBER;
+            break;
+        case SerialNumber:
+            res_name = DEVICE_SERIAL_NUMBER;
+            break;
+        case HardwareVersion:
+            res_name = DEVICE_HARDWARE_VERSION;
+            break;
+        case FirmwareVersion:
+            res_name = DEVICE_FIRMWARE_VERSION;
+            break;
+        case SoftwareVersion:
+            res_name = DEVICE_SOFTWARE_VERSION;
+            break;
+        case Reboot:
+            res_name = DEVICE_REBOOT;
+            break;
+        case FactoryReset:
+            res_name = DEVICE_FACTORY_RESET;
+            break;
+        case AvailablePowerSources:
+            res_name = DEVICE_AVAILABLE_POWER_SOURCES;
+            break;
+        case PowerSourceVoltage:
+            res_name = DEVICE_POWER_SOURCE_VOLTAGE;
+            break;
+        case PowerSourceCurrent:
+            res_name = DEVICE_POWER_SOURCE_CURRENT;
+            break;
+        case BatteryLevel:
+            res_name = DEVICE_BATTERY_LEVEL;
+            break;
+        case BatteryStatus:
+            res_name = DEVICE_BATTERY_STATUS;
+            break;
+        case MemoryFree:
+            res_name = DEVICE_MEMORY_FREE;
+            break;
+        case MemoryTotal:
+            res_name = DEVICE_MEMORY_TOTAL;
+            break;
+        case ErrorCode:
+            res_name = DEVICE_ERROR_CODE;
+            break;
+        case ResetErrorCode:
+            res_name = DEVICE_RESET_ERROR_CODE;
+            break;
+        case CurrentTime:
+            res_name = DEVICE_CURRENT_TIME;
+            break;
+        case UTCOffset:
+            res_name = DEVICE_UTC_OFFSET;
+            break;
+        case Timezone:
+            res_name = DEVICE_TIMEZONE;
+            break;
+        case SupportedBindingMode:
+            res_name = DEVICE_SUPPORTED_BINDING_MODE;
+            break;
+    }
+    return res_name;
+}
+
+bool M2MDevice::check_value_range(DeviceResource resource, int64_t value) const
+{
+    bool success = false;
+    switch (resource) {
+        case AvailablePowerSources:
+            if(value >= 0 && value <= 7) {
+                success = true;
+            }
+            break;
+        case BatteryLevel:
+            if (value >= 0 && value <= 100) {
+                success = true;
+            }
+            break;
+        case BatteryStatus:
+            if (value >= 0 && value <= 6) {
+                success = true;
+            }
+            break;
+        case ErrorCode:
+            if (value >= 0 && value <= 8) {
+                success = true;
+            }
+            break;
+    default:
+        success = true;
+        break;
+    }
+    return success;
+}
+