CN113132457B

CN113132457B - Automatic method and system for converting Internet of things application program into RESTful service on cloud

Info

Publication number: CN113132457B
Application number: CN202110230383.1A
Authority: CN
Inventors: 沈玉龙; 绳金涛; 祝幸辉; 赵双睿; 程珂; 何吉
Original assignee: Xidian University
Current assignee: Xi'an Yinyuan Technology Co.,Ltd.
Priority date: 2021-03-02
Filing date: 2021-03-02
Publication date: 2022-06-14
Anticipated expiration: 2041-03-02
Also published as: CN113132457A

Abstract

The invention belongs to the technical field of Internet of things micro-services, and discloses an automatic method and system for converting an Internet of things application program into an RESTful service on a cloud, wherein the automatic method for converting the Internet of things application program into the RESTful service on the cloud comprises the following steps: analyzing a source code of an application program of the Internet of things, and determining an external method which can be controlled or accessed by an end user; extracting an interface specification of RESTful Internet of things service corresponding to an external method; providing a service protocol describing the specification of the service interface of the Internet of things, and determining data to be stored in the cloud by the Internet of things equipment through the service protocol; a RESTful internet of things service with a friendly user interface is instantiated using the service specification. The invention converts the application program of the Internet of things into the service of the Internet of things, provides the functions of the equipment of the Internet of things by using the architecture of the micro-service, has interoperability for the service of the Internet of things based on the micro-service system, and is easy to integrate with the existing application.

Description

Automatic method and system for converting Internet of things application program into RESTful service on cloud

Technical Field

The invention belongs to the technical field of Internet of things micro-services, and particularly relates to an automatic method and system for converting an Internet of things application program into a RESTful service on the cloud.

Background

At present, interconnected physical devices, i.e., internet of things (IoT) devices, are common in all aspects of life. For example, the internet of things device may sense the nearby environment (e.g., obtain temperature) and react to the end user's request to change the physical environment (e.g., turn on lights). The internet of things application is designed by an application developer to assist in the functionality of the internet of things device (e.g., obtaining temperature, turning on lights). In the meantime, the internet has become a global infrastructure carrying heterogeneous web services that end users can use to perform various online activities, such as online shopping and online entertainment. With the combination of web services and internet of things devices, the convenience of daily life has increased substantially. For example, by analyzing data read by refrigerator sensors, a food consumption alert may be triggered, thereby completing an online shopping order. However, such combinations are not without their limitations. For example, an end user must install a number of proprietary end user applications (e.g., mobile applications) on a smartphone or computer to access internet of things application information in an internet of things device. In addition, different end-user applications lack a standard interface that allows communication between various internet of things devices and web services. Therefore, it is not simple to integrate the internet of things devices with existing internet of things applications.

In order to simplify the integration of internet of things applications, some research work has been put into methods of providing internet of things services to end users. Most of these approaches run internet of things services on internet of things devices, which is not optimal because the internet of things devices typically have limited resources available, e.g., low battery capacity and limited processing power. Furthermore, the complexity of the microservice standards may result in additional effort by developers in designing services for the internet of things.

Through the above analysis, the problems and defects of the prior art are as follows:

(1) in the existing internet of things equipment, a terminal user must install a large number of special terminal user application programs on a smart phone or a computer to access the information of the internet of things application programs in the internet of things equipment.

(2) In existing internet of things devices, different end-user applications lack a standard interface that allows communication between various internet of things devices and web services. Therefore, it is not simple to integrate the internet of things devices with existing internet of things applications.

(3) Existing methods for providing internet of things services to end users mostly run internet of things services on internet of things devices, which is not optimal because the resources generally available for the internet of things devices are limited. Furthermore, the complexity of the microservice standards may result in additional effort by developers in designing services for the internet of things.

The difficulty in solving the above problems and defects is: in actual production, the internet of things equipment and the internet of things application programs of all manufacturers conform to the own standard, and various problems (such as non-adaption of an interaction protocol) can be caused by putting the equipment of different manufacturers together for cooperative service; the devices with different interaction protocols work cooperatively, so that a user can control all the devices through uniform Web service; and the equipment with limited resources is communicated with the cloud service through the interface standard provided by the invention.

The significance of solving the problems and the defects is as follows: aiming at the three problems, the automatic method and the system for converting the application program of the internet of things into the RESTful service on the cloud can conveniently process the integration of newly-added internet of things equipment and the existing internet of things service; the service program of the equipment of the Internet of things can be uploaded to the cloud, so that the resource-limited equipment can have longer cruising ability; meanwhile, the distance between the user and the service of the Internet of things is abstracted, the user does not need to install a special application program control device, and all the equipment of the Internet of things can be remotely controlled only by the Web service.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides an automatic method and system for converting an application program of the Internet of things into RESTful service on the cloud.

The invention is realized in such a way, and an automatic method for converting an internet of things application program into an RESTful service on a cloud comprises the following steps:

(1) analyzing a source code of an application program of the Internet of things, and determining an external method which can be controlled or accessed by an end user, wherein the source code of the analysis program is used for determining an interaction mode of the method and equipment or the user, and the interaction mode of a service interface can be inferred to be a GET mode or a POST mode or other modes through a weight calculation formula;

(2) extracting an interface specification of RESTful Internet of things service corresponding to an external method; the interface specification describes an interface of the service of the Internet of things, and consists of a service name, an HTTP method and input or output parameters, wherein the interface specification is an interface specification which is a standard to be followed by interaction between other equipment and cloud or a user;

(3) providing a service protocol describing the specification of the service interface of the Internet of things, and determining data to be stored in the cloud by the Internet of things equipment through the service protocol; the service protocol is service content and a service mode of the service, and comprises information such as a data format and data content of the internet of things equipment stored in the cloud;

(4) and instantiating RESTful Internet of things service with a friendly user interface by using the service protocol, wherein the user interface is Web service for uniformly controlling all Internet of things equipment by a user, and the working state, the operation record, the management equipment and the like of the Internet of things equipment can be clearly and conveniently checked.

Further, the automatic method for converting the internet of things application program into the RESTful service on the cloud comprises the following steps:

step one, identifying an external method;

step two, extracting the SERVICE _ specific of the external method;

step three, describing an external method by using SERVICE _ SCHEMA;

and step four, converting the external method into the service of the Internet of things.

Further, in step one, the identifying an external method includes:

(1) analyzing a source code of the method, and identifying the structural form of the method: analyzing an abstract syntax tree AST of the source code, the AST being a tree structure representing syntax of the source code, each node in the tree describing a construct present in the source code; traversing the tree, and identifying the structural form of the method in a function method: method name, input parameter, return value, method call in the method body, if-else statement;

(2) the internal method of filtration: identifying the internal method according to the method structure extracted in the step (1), and filtering out the internal method;

(3) the name of the processing method is as follows: the method name is used to convey the intent of the method, distinguishing external methods from internal methods. The names are normalized using the following steps: splitting a hump word; removing punctuation marks; deleting suffixes containing numbers; removing stop words; identifying part-of-speech tags for each word using Natural Language Processing (NLP) techniques; performing a stem analysis to find a root word, the word being used to extract features to identify external methods;

(4) finding characteristics of external methods: determining an external method characteristic EF according to the method construction form determined in the step (1);

(5) determining an external method according to the external characteristics; if a method has at least two characteristics determined in step (4), it is assumed that the method is an external method.

Further, in step (2), a method having the following internal characteristics is considered as an internal method:

IF 1: the method name containing the keywords "init, setup, debug, test"; the method name containing the keywords "init" and "setup" is an initialization method for configuring initial settings; the method comprising the keywords 'debug' and 'test' is named as a test method and is used for testing different functions of the Internet of things equipment, and the test method is an internal method of the Internet of things equipment;

IF 2: the method name starts with "_"; the leading underline of the method name indicates that the method is for internal use or retention to the programming language;

IF 3: a method called in an internal method or defined in an internal file; the file names containing the keywords "init, setup, debug, test" or beginning with "_" are all internal files; methods called in internal methods or defined in internal files are used for initialization and testing.

Further, in the step (3), the internal method and the external method include:

methods in the source code of the application program of the internet of things can be divided into two types: internal methods and external methods. The internal method is related to the setting of the Internet of things equipment and is only used by the Internet of things equipment; the external method is used as an interface of the Internet of things equipment and can be communicated with the cloud. The input parameters of the external method may represent input commands of the actuator, and the return values of the method may represent sensory data of the sensor. Because the external method allows the terminal user to control the internet of things equipment or acquire information from the internet of things equipment, the method is converted into RESTful internet of things service.

Further, in step (4), the finding characteristics of the external method includes:

EF 1: the method comprises the following steps: if the method called in the method body contains the related keywords for sending in the name of the method body, the method sends the data to the cloud;

EF 2: if-else statement: a method is an external method if it contains an if-else statement that reacts to an input variable of the method when receiving a command from the cloud;

EF 3: semantics of verbs: verbs in the method name represent operations performed in the method, and external methods are inferred by recognizing the semantics of the verbs;

EF 4: the semantics of nouns: nouns in the method names represent objects in which the methods are interested, and if the nouns are matched with the service names of the Internet of things, the respective method is an external method; acquiring a large number of names of the internet of things services from an iot co website, and extracting nouns from the acquired internet of things service names by using the method described in the step (1) to form a word packet containing the nouns; it is determined whether the method has the characteristics of an external method by matching the nouns found in the method name with the words in the noun package.

Further, in step two, the SERVICE _ specific represents a RESTful internet of things SERVICE interface specification, which is a description of a SERVICE name, an HTTP method, and an input or output parameter.

Further, in step two, the extracting the SERVICE _ specific of the external method includes:

(1) using the method name as a service name;

(2) determining an HTTP method GET/POST of the RESTful Internet of things service interface according to the described external characteristics;

(3) extracting a method parameter of RESTful Internet of things service according to the HTTP method GET/POST identified in the step (2); extracting a return value of an external method of the HTTP GET as an output parameter of the corresponding RESTful Internet of things service; the input variables of the external method that extracts HTTP POST are extracted as input parameters for the corresponding RESTful internet of things service.

Further, in step (2), each HTTP method is associated with two external properties. In the external features, the semantics of the verb are respectively divided into sending semantics based on a GET method and receiving semantics based on a POST method; an HTTP GET method associated with sending semantics and characteristics of a method call; the verb in the sending semantic representation method name contains keywords related to sending, namely "push, post, publish, send, notify, get, send"; sending the data to the cloud, wherein the GET-based RESTful Internet of things service can identify and retrieve the data; an HTTP POST method associated with receiving semantics and characteristics of an if-else statement; the verb in the name of the receiving semantic representation method comprises keywords relevant to receiving, namely 'set, receive, control, script'; the internet of things device receives a command from a POST-based RESTful internet of things service.

The external method is determined which HTTP method should be associated with by calculating a score for the external characteristic of the external method. If the external method has a given characteristic, the counter for that characteristic is incremented by 1. Calculating a score S of the HTTP GET method using equation (1)_getCalculating the score S of the HTTP POST method using equation (2)_post。

S_get＝C_{semantic of send}+C_{method calls} (1)

S_post＝C_{semantic of receive}+G_{if-else statements} (2)

By S_getAnd S_postThe size of the score determines whether the HTTP method should be GET or POST, i.e., which score is high and which method is used. At S_getIs equal to S_postThe Fan-in and Fan-out Fan-in of the external method need to be calculated. Fan-in represents the number of input variables for an external method and Fan-out represents the number of return values for an external method. When the fan-in-fan-out ratio is greater than 1, the POST function is selected because such a ratio indicates that an external method is written to receive data, while the GET function is selected.

Further, in step three, the SERVICE _ SCHEMA includes:

the extracted SERVICE _ specific is specified by a structured data format, called SERVICE _ SCHEMA, whose attributes are defined by an XML SCHEMA. In SERVICE _ SCHEMA, the SERVICE name, HTTP method, and parameters of the identified SERVICE _ capabilities are pre-populated. A developer may verify, modify, and complete SERVICE _ SCHEMA. This SERVICE _ SCHEMA may be used to generate an internet of things SERVICE. SERVICE _ SCHEMA is composed of four main components: class, individual, relationship, and attribute. A class represents a group of objects with similar properties. Relationships are used to connect components of SERVICE _ SCHEMA. Classes can be inherited by subclasses. An individual is an example of a class. Finally, the attributes declare the attributes of the class. device _ type groups many internet of things devices that provide similar functionality. The internet-of-things devices with the same device type correspond to a unique SERVICE _ SCHEMA, and the SCHEMA is used for describing respective internet-of-things SERVICEs. The device _ id attribute is unique for each internet of things device and is used for distinguishing one internet of things device from another internet of things device. The MAC address of the internet of things device may be used to represent the device _ id.

Resource: some functions of internet of things devices are to publish a single scalar value stream to a channel on the cloud. Scalar value flows are considered a resource of the internet of things service. The resource is stored in a resource database on the cloud.

The operation is as follows: the internet of things service provides various operations to execute different operations on resources, and determines six operations of the internet of things service, namely reading, profile, sampling parameter, formatting, status and context. The reading operation is used to obtain the latest value of the resource. This operation listens to the resources of the internet of things service until a new value for the resource is received. The intercepted value and the timestamp of the value update are returned to the end user. Status operation returns the Status of a given internet of things service. For the executor, the end user can send a POST request to the state operation, so as to change the physical state of the internet of things equipment. These operations are predefined in SERVICE _ SCHEMA for the developer to choose from.

Further, in step three, the describing the external method by SERVICE _ SCHEMA includes:

the extracted external methods and the extracted SERVICE _ capabilities are normalized by SERVICE _ SCHEMA, i.e. each external method needs to be represented by a SERVICE _ SCHEMA file.

Further, in the fourth step, the converting the external method into the service of the internet of things includes:

(1) and (3) generating a Web form: automatically generating a web form by using the proposed SERVICE _ SCHEMA and the form template; generating text output by using data of SERVICE _ SCHEMA used by the template, wherein the generated form is used for sending a POST request to the SERVICE of the Internet of things; designing a form template by using a Freemarker template engine, wherein the basic components of a web form comprise an HTTP method, an operation URL and parameters to be filled by an end user;

(2) instantiating the service of the Internet of things: automatically generating source codes by using the related information filling code template of the proposed SERVICE _ SCHEMA to instantiate the SERVICE of the Internet of things; the required information is the HTTP method, the action URL, the request media type, the response media type, and the fill parameters from the web form; the instantiated internet of things service conforms to the Jersey grammar standard. The invention provides a code template for each operation;

(3) accessing RESTful Internet of things service: and after calling the instantiated Operation, the end user accesses the source code generated by the Operation according to the specified Operation URL and HTTP method, and the data transmitted between the equipment of the Internet of things and the cloud conforms to the JSON standard.

Another object of the present invention is to provide an automatic system for converting an internet of things application program into a RESTful service on a cloud, using the automatic method for converting an internet of things application program into a RESTful service on a cloud, the automatic system for converting an internet of things application program into a RESTful service on a cloud, including:

an external identification module for identifying an external method;

an external method extracting module for extracting the SERVICE _ specific of the external method;

an external method description module for describing an external method through SERVICE _ SCHEMA;

and the Internet of things service conversion module is used for converting the external method into the Internet of things service.

It is another object of the present invention to provide a computer program product stored on a computer readable medium, comprising a computer readable program for providing a user input interface to implement the automatic method of converting an internet of things application into a RESTful service on the cloud when executed on an electronic device.

Another object of the present invention is to provide a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the automatic method for converting an internet of things application program into RESTful service on the cloud.

By combining all the technical schemes, the invention has the advantages and positive effects that: according to the automatic method for converting the application program of the Internet of things into the RESTful service on the cloud, the application program of the Internet of things is converted into the service of the Internet of things, and the functions of the equipment of the Internet of things are provided by using the micro-service system structure. Internet of things services based on a microservice system have two main advantages: (1) interoperability, allowing internet of things services to exchange information with web services using structured data formats; (2) because of the uniform interface of the service of the Internet of things, the service is easy to integrate with the existing application.

The invention focuses on automatically converting the functions of the Internet of things equipment into Internet of things services. The internet of things services are designed using the RESTful paradigm, and use a cloud platform to host the internet of things services. Compared with the Internet of things equipment with limited resources, the cloud platform has the advantages of mass storage, high-speed network and huge computing capacity. In addition, the cloud platform has the potential to host a large number of internet of things services, connect internet of things devices and process internet of things data. The functionality of the internet of things devices may be managed through standard APIs on the cloud, which may be accessible to end users from anywhere.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of an automatic method for converting an application of the internet of things into a RESTful service on the cloud according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of an automatic method for converting an application of the internet of things into a RESTful service on the cloud according to an embodiment of the present invention.

Fig. 3 is a block diagram of an automatic system for converting an application of the internet of things into a RESTful service on the cloud according to an embodiment of the present invention;

in the figure: 1. an external identification module; 2. an external method extraction module; 3. an external method description module; 4. and the Internet of things service conversion module.

Fig. 4 is a schematic diagram of an example HTML form for controlling LEDs according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of an instantiated internet of things service according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides an automatic method and system for converting an application program of the internet of things into RESTful service on the cloud, and the invention is described in detail below with reference to the attached drawings.

As shown in fig. 1, the automatic method for converting an internet of things application program into a RESTful service on the cloud provided by the embodiment of the present invention includes the following steps:

s101, identifying an external method;

s102, extracting the SERVICE _ specific of the external method;

s103, describing an external method by using SERVICE _ SCHEMA;

and S104, converting an external method into an Internet of things service.

An automatic method schematic diagram for converting an internet of things application program into a RESTful service on the cloud provided by the embodiment of the invention is shown in fig. 2.

As shown in fig. 3, the automatic system for converting an application of the internet of things into a RESTful service on the cloud provided by the embodiment of the present invention includes:

an external identification module 1 for identifying an external method;

an external method extracting module 2 for extracting the SERVICE _ specific of the external method;

an external method description module 3, configured to describe an external method by SERVICE _ SCHEMA;

and the Internet of things service conversion module 4 is used for converting an external method into the Internet of things service.

The technical solution of the present invention is further described with reference to the following examples.

1. In order to simplify the integration of the application programs of the internet of things, the application programs of the internet of things are converted into the services of the internet of things, and the functions of the equipment of the internet of things are provided by using a micro-service architecture. In particular, internet of things services based on a microservice system have two main advantages: (1) interoperability, allowing internet of things services to exchange information with web services using structured data formats; (2) because of the uniform interface of the service of the Internet of things, the service is easy to integrate with the existing application.

The invention focuses on automatically converting the functions of the Internet of things equipment into Internet of things services. The internet of things services are designed using the RESTful paradigm and use a cloud platform to host the internet of things services. Compared with the Internet of things equipment with limited resources, the cloud platform has the advantages of mass storage, high-speed network and huge computing capacity. In addition, the cloud platform has the potential to host a large number of internet of things services, connect internet of things devices and process internet of things data. The functionality of the internet of things devices may be managed through standard APIs on the cloud, which may be accessible to end users from anywhere.

2. The invention provides a method for automatically generating RESTful Internet of things service on a cloud from an Internet of things application program. As shown in fig. 2, the present invention mainly comprises four activity steps:

first, the present invention analyzes the source code of the internet of things application to determine the external methods that the end user can control or access. Furthermore, the interface specification of RESTful Internet of things service corresponding to an external method is extracted; the interface specification describes an interface of the service of the internet of things, and the interface consists of a service name, an HTTP method and input (or output) parameters. In order to allow a developer to modify the generated service interface specification, the invention also provides a service protocol for describing the specification of the service interface of the Internet of things; the service convention determines which data of the internet of things device should be stored in the cloud. In addition, the present invention uses service conventions to instantiate RESTful internet of things services with a friendly user interface.

An automated method of converting an internet of things application to RESTful services on the cloud, comprising the steps and associated definitions of:

definition 1: internal methods and external methods. Methods in the source code of the application program of the internet of things can be divided into two types: internal methods and external methods. The internal method is related to the setting of the internet of things device and is only used by the internet of things device (e.g., an init method for initializing the setting of the internet of things device). The external method is used as an interface of the Internet of things equipment and can be communicated with the cloud. The input parameter of the external method may represent an input command to the actuator (e.g., turn on a light), while the return value of the method may represent sensed data from the sensor (e.g., sensed temperature). Since the external method allows the terminal user to control or acquire information from the internet of things device, such a method can be converted into RESTful internet of things service.

Definition 2: internal Features (IF) and External Features (EF). Some features of the internal method are referred to as internal features. Also, some features of the external method are referred to as external features. Conversely, a method may be characterized as either an internal method or an external method based on internal characteristics versus external characteristics.

Step 1: an external method is identified. The specific steps involved in code analysis of step 1 are as follows:

step 1.1: and analyzing the method source code and identifying the structural form of the method. To identify external methods, an Abstract Syntax Tree (AST) of the source code is first analyzed. AST is a tree structure representing the source code syntax. Each node in the tree describes a construct (e.g., a method name) that exists in the source code. The invention traverses the tree, and identifies the construction form of the method in a function method: method name, input parameters, return values, method calls in the method body, if-else statements.

Step 1.2: the internal process is filtered. The internal methods can be identified according to the method configuration extracted in step 1.1. A process having the following internal characteristics is considered an internal process. The internal methods were filtered out and not further investigated.

IF 1: the method name including the keywords "init, setup, debug, test". The method containing the keywords "init" and "setup" is named as an initialization method for configuring initial settings, such as setting the voltage level of the GPIO pin. The method name containing the keywords "debug" and "test" is a test method, which is used to test different functions of an internet of things device. These testing methods are internal methods of the internet of things devices.

IF 2: the method name starts with "_". The leading underline of the method name indicates that the method is for internal use or retention to the programming language (e.g., the _ init __ method).

IF 3: methods called in internal methods or defined in internal files. The file names containing the key "init, setup, debug, test" or beginning with "_" are all internal files. Methods called in internal methods or defined in internal files are used for initialization and testing.

Step 1.3: the name of the process. The method name may convey the intent of the method, and may be used to distinguish between external and internal methods. To identify the semantics of method names, the names are normalized using the following steps. Split hump words (e.g., getTemperature split into get and temperature). Punctuation marks such as "_" and "-" are removed. Suffixes containing numbers are deleted (e.g., led1 is normalized to led). Stop words (e.g., "a," "the," and "is") are removed. The part-of-speech tag for each word is identified using Natural Language Processing (NLP) techniques. For example, "get" is marked as a verb and "temperature" is marked as a noun. Finally, stemming analysis is performed to find the root word (e.g., "reduced," "reducing," and "reduces" are normalized to "reduce"). These words are used to extract features to identify external methods.

Step 1.4: look for characteristics of the external method. The external method features (EF) are determined from the method configuration determined in step 1.1.

EF 1: and (6) calling a method. If a method called in the method body contains a send-related key in its name, such as "push, post, publish, send, notify," these methods may send data onto the cloud. Such as the send (temperature) method, is considered an external method.

EF 2: an if-else statement. If a method contains if-else statements that react to the method's input variables when receiving commands from the cloud, then such a method is likely to be an external method. If the led _ control method contains an if-else statement, it reacts to a change in the state variable.

EF 3: semantics of verbs. Verbs in the method name may represent operations performed in the method. External methods can be inferred by recognizing the semantics of verbs. For example, if a verb has a keyword associated with sending and receiving a message (e.g., "push, post, publish, send, notify, subscribe, get, sense, set, receive, control"), it can be inferred that its respective method is transmitting data to the cloud. These methods are likely external methods.

EF 4: the semantics of nouns. Nouns in the method names represent objects of interest to the methods, and if the nouns match the internet of things service name, their respective method may be an external method. According to the method, a large number of names of the internet of things services are obtained from an iot. Whether the method has the characteristics of an external method is determined by matching the nouns found in the method name with the words in the noun package.

Step 1.5: an external method is determined based on the external characteristic. If a method has at least two characteristics determined in step 1.4, it is assumed that the method is an external method.

Definition 3: SERVICE _ specific. SERVICE _ capabilities represents a RESTful internet of things SERVICE interface specification, which is a description of the SERVICE name, HTTP method, and input (or output) parameters (see table 1 for example).

Table 1 service interface specification example extracted from external methods

Name of method	Service name	HTTP method	Inputting parameters	Output parameter
					led_control	ledControl	POST	status
getTemperature	getTemperature	GET		Temp

Step 2: the external method, SERVICE _ specific, is extracted. Based on the external methods analyzed in step 1, the invention extracts the SERVICE _ SPECIFICATIONS corresponding to each external method. The specific steps involved in extracting SERVICE _ specific in step 2 are as follows:

step 2.1: the method name is used as the service name. For example, led _ control in table 1 is denoted as ledControl as a service name.

Step 2.2: the HTTP method (GET/POST) of the RESTful internet of things service interface is determined from using the external characteristics described in step 1.4.

Each HTTP method is associated with two external properties. Among these external features, the semantics of verbs are divided into a GET method-based sending semantics and a POST method-based receiving semantics, respectively. The HTTP GET method is associated with sending semantics and properties of the method call. The verb in the sending semantic representation method name contains the key words related to sending, namely "push, post, publish, send, notify, get, send". These methods send data to the cloud so that GET-based RESTful internet of things services can identify and retrieve these data. The HTTP POST method is associated with receiving semantics and properties of the if-else statement. The verb in the received semantic representation method name contains the key words "set, receive, control, describe" associated with the reception. The internet of things device receives a command from a POST-based RESTful internet of things service.

S_get＝C_{semantic of send}+C_{method calls} (1)

S_post＝C_{semantic of receive}+C_{if-else statements} (2)

By S_getAnd S_postThe size of the score determines whether the HTTP method should be GET or POST, i.e., which score is high and which method is used. At S_getIs equal to S_postIn the case of (2), the Fan-in (Fan-in) and Fan-out (Fan-in) of the external method need to be calculated. Fan-in represents the number of input variables for an external method and Fan-out represents the number of return values for an external method. When the fan-in-fan-out ratio is greater than 1, the POST function is selected because such a ratio indicates that an external method is written to receive data, while the GET function is selected.

Step 2.3: and (3) extracting the parameters of the RESTful Internet of things service according to the HTTP method (GET/POST) identified in the step 2.2. And extracting a return value of an external method of the HTTP GET as an output parameter of the corresponding RESTful Internet of things service. The input variables of the external method that extracts HTTP POST are extracted as input parameters for the corresponding RESTful internet of things service.

Definition 4: SERVICE _ SCHEMA. In order to convert an external method into RESTful internet of things SERVICE, a structured data format is needed to specify and describe the extracted SERVICE _ specific, and the structured data format is called SERVICE _ SCHEMA, and the attribute of the SERVICE _ specific is defined by XML SCHEMA. In SERVICE _ SCHEMA, the SERVICE name, HTTP method, and parameters of the identified SERVICE _ capabilities are pre-populated. A developer may verify, modify, and complete SERVICE _ SCHEMA. This SERVICE _ SCHEMA may be used to generate an internet of things SERVICE. SERVICE _ SCHEMA is composed of four main components: class, individual, relationship, and attribute. A class represents a group of objects with similar properties. For example, internet of things devices are a class. Relationships are used to connect components of SERVICE _ SCHEMA (e.g., the internet of things SERVICE has some operations). A class may be inherited by a subclass. For example, a read operation for obtaining the latest value of a sensor is a subclass of operations. An individual is an example of a class. Finally, the attributes declare the attributes of the class. For example, the internet of things device class has device type device _ type and device _ id attributes. device _ type groups many internet of things devices that provide similar functionality. The internet-of-things devices with the same device type correspond to a unique SERVICE _ SCHEMA, and the SCHEMA is used for describing respective internet-of-things SERVICEs. For example, the temperature sensor may be a type of device. The device _ id attribute is unique for each internet of things device and is used for distinguishing one internet of things device from another internet of things device. The MAC address of the internet of things device may be used to represent the device _ id.

Definition 5: and (4) resources. Some functions of internet of things devices are to publish a single scalar value stream (e.g., temperature values) to channels on the cloud. Scalar value flows are considered a resource of the internet of things service. The resource is stored in a resource database on the cloud.

Definition 6: and (5) operating. Internet of things services provide a variety of operations to perform different operations on resources. For example, a "temperature-aware" internet of things service may obtain up-to-date data for temperature and modify the frequency at which the temperature should be sensed. The invention determines six operations of the Internet of things service, namely reading, profile, sampling parameter, formatting, status and context. Table 2 summarizes these six operations of the internet of things service. For example, the reading operation is used to obtain the latest value of the resource. This operation listens to the resources of the internet of things service until a new value for the resource is received. The intercepted value and the timestamp of the value update are then returned to the end user. Status operation returns the Status of a given internet of things service (e.g., whether it is on or off). For the executor, the end user may send a POST request to the status operation, thereby changing the physical status of the internet of things device (e.g., turning on a light). These operations are predefined in SERVICE _ SCHEMA for the developer to choose from.

Table 2 summary of commonly used operations for internet of things services

And 3, step 3: the external method is described by SERVICE _ SCHEMA. The external methods extracted in step 1.4 and the SERVICE _ capabilities extracted in the corresponding step 2 are normalized and represented by SERVICE _ SCHEMA, i.e. each external method needs to be represented by a SERVICE _ SCHEMA file. Each external method corresponds to one of the operations specified in table 2.

And 4, step 4: and converting an external method into the service of the Internet of things. This step describes how the method of the present invention automatically converts external methods into internet of things services.

Step 4.1: and generating the Web form. Since the end user may not be familiar with RESTful internet of things services, it is important to provide a friendly user interface for accessing and controlling internet of things services. In this regard, the web form is automatically generated by using the proposed SERVICE _ SCHEMA and the form template. The data of SERVICE _ SCHEMA used by the template generates a textual output, such as source code or HTML form. These generated forms are used to send POST requests to the internet of things service. The method uses a FreeMarker template engine to design form templates. The basic components of a web form are the HTTP method, the action URL, and the parameters to be filled in by the end user. Fig. 4 shows an example HTML form for controlling LEDs, where the text circled in boxes is data extracted from SERVICE _ SCHEMA. Upon the end user clicking the "Submit" button, a POST request is submitted to the action URL. The Operation URL is formed as "< Device Type >/< Device ID >/< Service Name >/< Operation Name >".

Step 4.2: and instantiating the service of the Internet of things. The invention uses the related information of the proposed SERVICE _ SCHEMA to fill a code template to automatically generate source codes to instantiate the SERVICE of the Internet of things. The required information is the HTTP method, the action URL, the request media type, the response media type, and the fill parameters from the web form. The instantiated internet of things service conforms to the Jersey grammar standard. The present invention provides a code template for each operation. Fig. 5 shows an example of an instantiated profile operation, where the information of the part enclosed by the blocks originates from SERVICE _ SCHEMA. The resources of a given internet of things service are located by the service name, device type, and device id extracted from the URL of the corresponding service request. Once the profile operation is requested, the internet of things service will obtain the last N values of the resource from the database. The value of N is specified by the end user as a URL parameter.

Step 4.3: and accessing RESTful Internet of things service. Once the end user invokes the instantiated Operation, the source code generated by the Operation is accessed according to the specified Operation URL and HTTP method. Data transmitted between the internet of things device and the cloud conforms to the JSON standard.

To measure the effectiveness of the method of the present invention, 376 methods were randomly selected from the 17,178 extracted python methods with a confidence level of 95% and a confidence interval of 5%. The present invention applies the method of the present invention to identify external methods and extract service specifications from the sampled 376 methods. The present invention uses accuracy and recall as shown in the equation. (3) And (4) to evaluate the method of the present invention. The accuracy measures the proportion of external methods (or service specification parts) that are correctly retrieved from a set of external methods (or service specification parts) retrieved by the method of the invention. Recall, on the other hand, measures the proportion of external methods (or service specification parts) that the method of the present invention can retrieve from a data set. The results of the present invention show that the average accuracy of the method of the present invention to the identification of external methods is 75% and the recall rate is 72%. For the service specification, the average accuracy of the method of the invention is 82% and the recall rate is 81%.

To evaluate the accuracy of generating internet of things services, the present invention uses 190 extract networking services. The invention designs an external method on the RPi according to the type of the service of the Internet of things. For example, the present invention designs four possible external methods for sensor generated internet of things services. These methods are reading, sampling parameters, formats and contexts. For the service of the Internet of things generated for the executor, two external methods, namely a state and a context, are designed. The present invention does not design an external method for the summary operation because the summary operation is instantiated to get the resource from the resource database. The present invention generates a service pattern using the external method designed above. The method provided by the invention is used for automatically generating the service of the Internet of things. Equation 5 shows how the present invention measures the accuracy of the method. Accuracy is the ratio of the number of correctly generated internet of things services to the total number of internet of things services. Since the internet of things service consists of several operations, the present invention evaluates whether an operation is instantiated correctly. An internet of things service is correctly generated when all operations of the internet of things service are correctly instantiated. The method of the invention achieves 96% accuracy in generating the internet of things services (182 out of 190 internet of things services).

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When used in whole or in part, can be implemented in a computer program product that includes one or more computer instructions. When loaded or executed on a computer, cause the flow or functions according to embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL), or wireless (e.g., infrared, wireless, microwave, etc.)). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.

Claims

1. An automatic method for converting an internet of things application program into a RESTful service on a cloud, the automatic method for converting the internet of things application program into the RESTful service on the cloud comprising the following steps:

step one, identifying an external method;

step two, extracting the SERVICE _ specific of the external method; the SERVICE _ specific represents RESTful Internet of things SERVICE interface specification, which is the specification of a SERVICE name, an HTTP method and input or output parameters;

step three, describing an external method by using SERVICE _ SCHEMA;

the external method is described by SERVICE _ SCHEMA, and comprises the following steps: the extracted external methods and the extracted SERVICE _ specific are normalized and represented by SERVICE _ SCHEMA, that is, each external method needs to be represented by a SERVICE _ SCHEMA file;

the SERVICE _ SCHEMA, comprising:

the extracted SERVICE _ specific is specified and described by a structured data format, called SERVICE _ SCHEMA, the attribute of which is defined by XML SCHEMA; pre-populating a SERVICE name, an HTTP method and parameters of the identified SERVICE _ SPECIFICATIONS in a SERVICE _ SCHEMA; a developer can verify, modify, and complete SERVICE _ SCHEMA; the SERVICE _ SCHEMA can be used for generating the SERVICE of the Internet of things; SERVICE _ SCHEMA is composed of four main components: class, individual, relationship and attribute; a class represents a group of objects with similar properties; relationships are used to connect components of SERVICE _ SCHEMA; classes can be inherited by subclasses; an individual is an example of a class; finally, attribute declaring the attributes of the class; device _ type groups many internet of things devices that provide similar functionality; the internet of things devices with the same device type correspond to a unique SERVICE _ SCHEMA, and the SCHEMA is used for describing respective internet of things SERVICEs; the device _ id attribute is unique to each piece of Internet of things equipment and is used for distinguishing one piece of Internet of things equipment from another piece of Internet of things equipment; the MAC address of the equipment of the Internet of things can be used as device _ id;

resource: some functions of the internet of things device are to publish a single scalar value stream to a channel on the cloud; a scalar value stream is considered a resource of the internet of things service; the resources are stored in a resource database on the cloud;

the operation is as follows: the method comprises the steps that the Internet of things service provides multiple operations to execute different operations on resources, and six operations of the Internet of things service, namely reading, profile, sampling parameter, formatting, status and context are determined; the reading operation is used for acquiring the latest value of the resource; this operation listens to the resources of the internet of things service until a new value of the resources is received; returning the intercepted value and the timestamp of the value update to the end user; the Status operation returns the state of the given internet of things service; for the actuator, the terminal user can send a POST request to the state operation, so that the physical state of the equipment of the Internet of things is changed; these operations are predefined in SERVICE _ SCHEMA for the developer to choose from;

step four, converting the external method into the service of the Internet of things, wherein the step of converting the external method into the service of the Internet of things comprises the following steps:

1) and (3) generating a Web form: automatically generating a web form by using the proposed SERVICE _ SCHEMA and the form template; generating text output by using data of SERVICE _ SCHEMA used by the template, wherein the generated form is used for sending a POST request to the SERVICE of the Internet of things; designing a form template by using a Freemarker template engine, wherein the basic components of a web form comprise an HTTP method, an operation URL and parameters to be filled by an end user;

2) instantiating the service of the Internet of things: automatically generating source codes by using the related information filling code template of the proposed SERVICE _ SCHEMA to instantiate the SERVICE of the Internet of things; the required information is the HTTP method, the action URL, the request media type, the response media type, and the fill parameters from the web form; the instantiated IOT service conforms to Jersey grammar standard and provides a code template for each operation;

3) accessing RESTful Internet of things service: and after calling the instantiated Operation, the end user accesses the source code generated by the Operation according to the specified Operation URL and HTTP method, and the data transmitted between the equipment of the Internet of things and the cloud conforms to the JSON standard.

2. The automated method of converting an internet of things application to RESTful services on the cloud of claim 1, wherein in step one, the identifying an external method comprises:

(3) the name of the processing method is as follows: the method name is used to convey the intent of the method, distinguishing external methods from internal methods; the names are normalized using the following steps: splitting a hump word; removing punctuation marks; deleting suffixes containing numbers; removing the stop word; identifying part-of-speech tags for each word using Natural Language Processing (NLP) techniques; performing a stem analysis to find root words, the root words used to extract features to identify external methods;

3. The automated method of converting an internet of things application to a RESTful service on the cloud of claim 2, wherein in step (2), a method having the following internal characteristics is considered an internal method:

IF 1: the method name containing the keywords "init, setup, debug, test"; the method name including the keywords "init" and "setup" is an initialization method for configuring initial settings; the method comprising the keywords 'debug' and 'test' is named as a test method and is used for testing different functions of the Internet of things equipment, and the test method is an internal method of the Internet of things equipment;

4. The automated method of converting an internet of things application into a RESTful service on the cloud of claim 2, wherein in step (3), the internal method and the external method comprise: methods in the source code of the application program of the internet of things can be divided into two types: internal and external methods; the internal method is related to the setting of the Internet of things equipment and is only used by the Internet of things equipment; the external method serves as an interface of the Internet of things equipment and can be communicated with the cloud; the input parameters of the external method may represent input commands of the actuator, and the return values of the method may represent sensory data of the sensor; because the external method allows the terminal user to control the internet of things equipment or acquire information from the internet of things equipment, the method is converted into RESTful internet of things service.

5. The automated method for converting an internet of things application into a RESTful service on the cloud as claimed in claim 2, wherein in step (4), the finding characteristics of the external method comprises:

6. The automated method for converting an internet of things application into a RESTful SERVICE on the cloud as claimed in claim 1, wherein in step two, the extracting the SERVICE _ specific of the external method comprises:

(1) using the method name as a service name;

7. The automated method of converting an internet of things application to a RESTful service on the cloud of claim 6, wherein in step (2), each HTTP method is associated with two external properties; in the external features, the semantics of the verb are respectively divided into sending semantics based on a GET method and receiving semantics based on a POST method; an HTTP GET method associated with a property that sends semantics and method calls; the verb in the sending semantic representation method name contains keywords related to sending, namely "push, post, publish, send, notify, get, send"; sending data to the cloud, wherein GET-based RESTful Internet of things services can identify and retrieve the data; an HTTP POST method associated with receiving semantics and characteristics of an if-else statement; the verb in the name of the receiving semantic representation method comprises keywords relevant to receiving, namely 'set, receive, control, script'; the method comprises the steps that the IOT equipment receives a command from a RESTful IOT service based on POST;

determining which HTTP method the external method should be associated with by calculating a score for an external characteristic of the external method; if the external method has a given characteristic, the counter for that characteristic is incremented by 1; calculating a score S of the HTTP GET method using equation (1)_getThe score S of the HTTP POST method is calculated using equation (2)_post；

S_get＝C_{semanticofsend}+C_methodcalls (1)

S_post＝C_{semanticofreceive}+C_{if-elsestatements} (2)

By S_getAnd S_postThe score size to determine whether the HTTP method should be GET or POST, i.e., which score is high and which method is used; at S_getIs equal to S_postUnder the condition (2), Fan-in Fan-in and Fan-out Fan-in of an external method need to be calculated; fan-in represents the number of input variables of an external method, Fan-out represents the number of return values of an external method; when the fan-in-fan-out ratio is greater than 1, the POST function is selected because such a ratio indicates that an external method is written to receive data, while the GET function is selected.

8. An automatic system for converting an internet of things application program into a RESTful service on the cloud according to any one of claims 1 to 7, wherein the automatic system for converting an internet of things application program into a RESTful service on the cloud comprises:

an external identification module for identifying an external method;

an external method extracting module for extracting SERVICE _ specific of the external method;

9. A computer readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the automated method of converting an internet of things application to RESTful services on the cloud as claimed in any one of claims 1 to 7.