# KWS Plug-in 1. Add the API of the KWS plug-in to the **//foundation/ai/engine/services/server/plugin** directory. This API is used to call AI capabilities. The following code snippet is an example API implementation of the KWS plug-in. The reference code is available at the **//foundation/ai/engine/services/server/plugin/asr/keyword\_spotting** directory. ``` #include "plugin/i_plugin.h class KWSPlugin : public IPlugin { public: KWSPlugin(); ~KWSPlugin(); const long long GetVersion() const override; const char* GetName() const override; const char* GetInferMode() const override; int32_t Prepare(long long transactionId, const DataInfo &inputInfo, DataInfo &outputInfo) override; int32_t SetOption(int optionType, const DataInfo &inputInfo) override; int32_t GetOption(int optionType, const DataInfo &inputInfo, DataInfo &outputInfo) override; int32_t SyncProcess(IRequest *request, IResponse *&response) override; int32_t AsyncProcess(IRequest *request, IPluginCallback*callback) override; int32_t Release(bool isFullUnload, long long transactionId, const DataInfo &inputInfo) override; }; ``` The preceding code implements the **IPlugin** API provided by the server. [Table 1](#table567211582104) shows the mapping between the client APIs and the plug-in APIs. **Table 1** Mapping between the client APIs and the plug-in APIs

Client API	Plug-in API	Description
AieClientPrepare	Prepare	Initializes the inference algorithm plug-in. For KWS, this API loads the KWS model from the fixed location (/sdcard/wenwen_inst.wk) to the memory.
AieClientSyncProcess	SyncProcess	Executes the inference algorithm synchronously. For KWS, this API synchronously executes the audio inference algorithm to determine whether the specified wakeup keyword exists in the audio.
AieClientAsyncProcess	AsyncProcess	Executes the inference algorithm asynchronously. Currently, this API is not used in KWS. However, you can implement the API based on your use case.
AieClientSetOption	SetOption	Sets algorithm-related configuration items, such as the confidence threshold and delay. Currently, this API is not used in KWS. However, you can implement the API based on your use case.
AieClientGetOption	GetOption	Obtains algorithm-related configuration items. For KWS, this API can obtain the input and output scale of the KWS model. The input scale is the MFCC feature (fixed value: 4000) required by the KWS model, and the output scale is the confidence (fixed value: 2) of the result.
AieClientRelease	Release	Releases the algorithm model. For KWS, this API releases the specified algorithm model and clears the dynamic memory in the feature processor.

Note: 1. The **AieClientInit** and **AieClientDestroy** APIs are used to connect to and disconnect from the server, respectively. They are not called in the plug-in algorithm and therefore do not need to be defined in the plug-in. 2. The KWS plug-in needs to use the **PLUGIN\_INTERFACE\_IMPL** statement to expose the function pointer. Otherwise, the plug-in cannot be properly loaded. ``` PLUGIN_INTERFACE_IMPL(KWSPlugin); ```