JP6086490B2 - Information processing apparatus, information processing method, and information processing program - Google Patents

Description

  The present invention relates to a technique for handling asynchronous processing.

  In order to make Web content more dynamic, it is known to write a script called JavaScript (registered trademark) in Web content. In JavaScript, in order to describe the operation according to the state, it is possible to obtain a value indicating the state, such as calling an object method or obtaining a property value of the object. For example, an object that refers to an element for playing a movie is assigned to a variable called video, and a method (canPlayType) for checking whether or not the element can play a particular type of movie, or a property value of the current playback position (CurrentTime) can be acquired. 7 and 8 show an example of JavaScript. In the example of FIG. 7, the return value of the canPlayType method of the video element is assigned to the variable ty. A value obtained from an element can be described in a conditional statement without being assigned to a variable, or can be used as a part of an expression such as addition, subtraction, multiplication, and division as in the currentTime property in the example of FIG.

  Non-Patent Document 1 proposes that a part of Web content is displayed on browsers of a plurality of devices. In Non-Patent Document 1, an intermediate browser is arranged between a Web server and a device, and the intermediate browser executes communication between devices and JavaScript to link a plurality of devices. By displaying a part of Web content on the browsers of multiple devices, for example, when the Web content includes a part for displaying a moving image and a part for operating the moving image, the moving image is displayed on the TV browser, and the moving image is displayed. Can be performed with the browser of the smartphone. In this case, an operation on the smartphone is sent to the intermediate browser, and the intermediate browser causes the television to execute an operation corresponding to the operation content.

Yasuhiro Nakamoge and 4 others, “Proposal of multi-device collaboration technology using an intermediate browser”, 87th GN Research Conference, Information Processing Society of Japan, March 2013, 2013-GN-87, No. 6, p.1-6

  In the technique of Non-Patent Document 1, in order to acquire the state of an element deployed in a browser (hereinafter referred to as “remote browser”) on a device with a different intermediate browser, communication with the device is indispensable. Specifically, the JavaScript shown in FIG. 7 is executed by the intermediate browser. However, when the video element is expanded in the remote browser, it is the remote browser that starts the canPlayType method. Therefore, a communication message REQ1 for starting the canPlayType method on the remote browser and a communication message RES1 for notifying the return value of the method are determined in advance, and when the canPlayType method is executed in the intermediate browser, REQ1 is transmitted from the browser to the remote browser, the return value is extracted from RES1 returned from the remote browser to the intermediate browser, and is set as the return value of the canPlayType method. Similarly, in the example of FIG. 8, when the communication message REQ2 for referring to the currentTime property and the communication message RES2 for notifying the value of the currentTime property are determined in advance, and the currentTime property is referred to by the intermediate browser Then, REQ2 is transmitted from the intermediate browser to the remote browser, the return value is extracted from RES2 returned from the remote browser to the intermediate browser, and is set as the value of the currentTime property.

  In Non-Patent Document 1, WebSocket is used for communication between an intermediate browser and a remote browser. In order to process WebSocket communication with JavaScript, it is necessary to define in advance a callback function that is called when a communication message is received. Therefore, it is necessary to write a callback function that retrieves the return value when invoking a method of an element expanded in a remote browser and acquiring a property value. Specifically, since the variable ty in the third line in FIG. 7 is substituted at the timing when RES1 is received from the remote browser, the part that outputs the value of the variable ty in the fourth line in FIG. It is necessary to execute at the timing of receiving. Therefore, in the example of FIG. 7, as shown in FIG. 9, it is necessary to separately describe the callback function that is executed when RES1 is received from the remote browser. Note that request_canPlayType on the third line in FIG. 9 specifies that instead of invoking the canPlayType method on the intermediate browser, REQ1 is sent to the remote browser, and the function callback1 specified by the second argument is called when REQ1 is received. Method. Furthermore, the example of FIG. 8 shows console.console on the eighth line according to the value of flag. The timing for executing log (flag) changes. Specifically, when the flag value is 1 and the currentTime property is referenced, the time when the RES2 is received from the remote browser and the value of the currentTime property is acquired is console. log (flag) is executed. When the value of flag is other than 1 and the currentTime property is not referred to, the time when sapple2 is called is console. It is the timing to execute log (flag). Therefore, there is a problem that it is difficult to simply rewrite JavaScript in FIG. 8 so as to correspond to the intermediate browser.

  In addition, it is assumed that conventional Web content is browsed by a single browser, and there is no need to asynchronously process a process for referring to an element property value. When displaying Web content on a remote browser using the technology of Non-Patent Document 1, considering that JavaScript is executed by an intermediate browser, JavaScript must be described in correspondence with processing that is performed asynchronously by the remote browser. There was a problem that had to be done.

  The present invention has been made in view of the above, and an object of the present invention is to make it possible to describe a program without being aware of processing performed asynchronously.

  An information processing apparatus according to a first aspect of the present invention is an information processing apparatus that executes a script including a process that is performed asynchronously. The execution unit that executes the script and the process that the execution unit executes are different from each other. When using the return value of the process executed in the apparatus, an ID is generated, a communication message including the ID is transmitted to the other apparatus to perform the process, and the execution of the script is resumed using the ID as a key. When receiving the communication message including the ID and the return value from the other device, and the execution interruption means for interrupting the execution of the script by the execution means after registering the data necessary to do The ID and the return value are extracted from the communication message, and the data necessary to resume execution of the script is acquired from the table using the ID as a key. Passing said return value to the execution unit and having a an execution resumption means for resuming the execution of the script.

  In the information processing apparatus, the process executed in the other apparatus is such that a method included in an element accessed by an execution unit that executes the script causes the other apparatus to perform the process. The execution of the script is interrupted.

  An information processing method according to a second aspect of the present invention is an information processing method by an information processing apparatus that executes a script including processing that is performed asynchronously, and includes a step of executing the script and a processing executed in the step When using a return value of processing executed in another device, an ID is generated and a communication message including the ID is transmitted to the other device to perform processing, and the script is executed using the ID as a key. When the communication message including the ID and the return value is received from the other device, the step of interrupting the execution of the script after registering the data necessary for restarting the table in the table, from the communication message The ID and the return value are extracted, and the data necessary to resume execution of the script is acquired from the table using the ID as a key. Characterized by having the steps of: resuming execution of the script by passing the return value.

  In the information processing method, the processing executed in the other device is a method provided in an element accessed in the step of executing the script, causing the other device to perform processing. And the execution of the script is interrupted.

An information processing program according to a third aspect of the present invention causes a computer to function as each unit of the information processing apparatus.

  According to the present invention, it is possible to describe a program without being aware of processing performed asynchronously.

It is a functional block diagram which shows the structure of the content display apparatus in this Embodiment. It is a figure which shows the example of DOM memorize | stored in a DOM data storage part. It is a figure which shows the implementation example of the dispatchEvent function rewritten so that execution of JavaScript could be suspended and resumed explicitly. FIG. 10 is a sequence diagram showing a flow of processing for interrupting and resuming execution of JavaScript. It is a figure which shows the example of mounting of the method performed asynchronously. It is a figure which shows the implementation example of the Getter function which acquires the value of a property from a remote browser. It is a figure which shows the example of JavaScript contained in a web content. It is a figure which shows the example of JavaScript contained in a web content. FIG. 8 is a diagram illustrating an example in which JavaScript shown in FIG. 7 is described in association with a method that is performed asynchronously.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a functional block diagram showing the configuration of the content display device in the present embodiment. The content display apparatus 1 according to the present embodiment acquires WEB content, divides the acquired WEB content, transmits it to the remote browsers 2A and 2B, and displays a part of the WEB content on each of the remote browsers 2A and 2B. . For example, by receiving WEB content for displaying a moving image, displaying the moving image on a remote browser 2A such as a television, and displaying an operation button on the remote browser 2B such as a smartphone, the user can operate with the smartphone at hand. It will be possible to watch videos on TV. In FIG. 1, two remote browsers 2A and 2B are shown as an example, but the present invention is not limited to this.

  The content display device 1 shown in FIG. 1 includes a WEB content evaluation unit 11, a DOM data storage unit 12, a DOM data transmission unit 13, an execution unit 14, a DOM access unit 15, a browser communication unit 16, and an event reception unit 17. Each unit included in the content display device 1 may be configured by a computer including an arithmetic processing device, a storage device, and the like, and the processing of each unit may be executed by a program. This program is stored in a storage device included in the content display device 1, and can be recorded on a recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, or provided through a network. Hereinafter, each part of the content display device 1 will be described.

  The WEB content evaluation unit 11 acquires the WEB content from a Web server (not shown), etc., sends HTML data and CSS (Cascading Style Sheet) data included in the WEB content to the DOM data storage unit 12, and generates a JavaScript code. The data is sent to the execution unit 14.

  The DOM data storage unit 12 analyzes the HTML data, expands and stores it in a DOM (Document Object Model) that is a tree-like data structure. One tag of HTML data constitutes one element of DOM, and a portion surrounded by the tags is a child element. The DOM data storage unit 12 also stores CSS data that designates a mode for displaying DOM elements.

  The DOM data transmission unit 13 determines a partial tree corresponding to a part of the WEB content to be displayed on each of the remote browsers 2A and 2B from the DOM stored in the DOM data storage unit 12, and corresponds to each of the remote browsers 2A and 2B. Send a subtree. As a method for determining a subtree to be transmitted to the remote browsers 2A and 2B, for example, an attribute “device” is provided in HTML data, and the determination is made based on the value of the device attribute. FIG. 2 shows an example of the DOM stored in the DOM data storage unit 12. In the DOM shown in the figure, there is an element in which “TV” and “phone” are set in the device attribute. A subtree A whose root is an element having a device attribute “TV” is transmitted to the remote browser 2A, and a subtree B whose root is an element whose device attribute is “phone” is transmitted to the remote browser 2B. To do.

  As a method of configuring the DOM data storage unit 12 and the DOM data transmission unit 13, a node.node known as Java Script execution environment on the server side is used. A platform called js can be used. node. A software library called JSDOM that operates DOM with JavaScript is known as js.

  The execution unit 14 executes the JavaScript code included in the Web content. When an event occurs in a DOM element, the corresponding event listener is executed. The event listener is a program written in JavaScript that is executed when an event occurs.

  When the execution unit 14 accesses the DOM element, the DOM access unit 15 notifies the remote browsers 2A and 2B that hold the DOM (partial tree) to be accessed, and holds the DOM itself in the remote browsers 2A and 2B. To get the return value. When a return value is received from the remote browsers 2A and 2B, such as when an element method is called and there is a return value, or when an element property is referenced, the remote browser 2A or 2B has its own DOM After transmitting the communication message for executing the access, the execution unit 14 interrupts the execution of JavaScript, receives the return value from the remote browsers 2A and 2B, and then restarts the execution of JavaScript. Details of the processing for interrupting and resuming execution of JavaScript will be described later.

  The browser communication unit 16 communicates with the remote browsers 2A and 2B, transmits DOM data to be changed, a communication message for requesting execution of a method, a communication message including a return value of a method and a property value, and the like. Receive. The browser communication unit 16 is constructed as a WebSocket server, for example, and establishes a WebSocket connection with the remote browsers 2A and 2B to transmit and receive data.

  The event receiving unit 17 receives event notifications such as button clicks generated on the remote browsers 2A and 2B, and generates pseudo-similar events with corresponding elements of the DOM stored in the DOM data storage unit 12. The event listener registered in the DOM element stored in the DOM data storage unit 12 is executed by the execution unit 14. By registering, as an event listener, a process for sending an event notification to the content display device 1 when an event occurs in the DOM element held by the remote browsers 2A and 2B, an event that has occurred in the remote browsers 2A and 2B is registered. It can be processed by the content display device 1.

  Next, processing for interrupting and resuming execution of JavaScript will be described.

  As a technique for explicitly interrupting and resuming a program, there is a technique called Fiber. In Fiber, when a program being executed makes an explicit interruption request, data necessary for continuing program execution is saved in a temporary storage area, and then execution is stopped. The stopped program makes an explicit restart request to restore data from the temporary storage area and resume execution. In this embodiment, Fiber is set to node. A library called node-fibers implemented on js was used. In node-fibers, a program that may be interrupted is executed in a Fiber object in node-fibers, and Fiber. Execution of the program is interrupted by calling the yield function. In addition, the suspended program is resumed by calling the run method for the Fiber object holding the suspended state.

  In the execution unit 14, the dispatchEvent function for starting the event listener is rewritten as shown in FIG. 3 so that the execution of JavaScript can be explicitly interrupted and resumed. When an event occurs, the event listener is set in the Fiber object. To be executed. As a result, the event listener is executed in the Fiber object, and the execution of the program can be explicitly interrupted and resumed.

  FIG. 4 is a sequence diagram showing a flow of processing for interrupting and resuming execution of JavaScript. Hereinafter, a process for interrupting and restarting the execution of JavaScript will be described with reference to an implementation example.

  When a method executed asynchronously in the remote browsers 2A and 2B is called by the execution unit 14, an ID used to identify a Fiber object that resumes execution is generated (step S11), and a request message in which the generated ID is embedded Is transmitted to the remote browsers 2A and 2B (step S12), and the Fiber object is registered in the table using the ID as a key (step S13), and then the execution unit 14 interrupts the execution of JavaScript (step S14). Through the processing so far, the request message is transmitted to the remote browsers 2A and 2B, and the JavaScript processing executed by the execution unit 14 is interrupted. For methods that are performed asynchronously in the remote browsers 2A and 2B, the DOM access unit 15 is implemented so as to interrupt the execution of the program after requesting the remote browsers 2A and 2B to perform processing. FIG. 5 shows an implementation example of the method performed asynchronously. In the implementation example shown in FIG. 5, an ID is generated in the second line, the processing content is transmitted to the remote browsers 2A and 2B in the third line, and a Fiber object is stored in association with the ID in the fourth line. Yes. REQ1 on the third line is a value indicating the contents to be processed by the remote browsers 2A and 2B. After requesting the processing to the remote browsers 2A and 2B, the Fiber. The execution of JavaScript that called the yield function and called the corresponding method is interrupted. At this point, the execution unit 14 stops the execution of JavaScript and performs other processes such as a process of waiting for an event to occur.

  When the remote browsers 2A and 2B receive the request message (step S21), the remote browsers 2A and 2B execute the process specified by the request message (step S22), and transmit the ID received together with the request and the obtained return value to the content display device 1. (Step S23). In the implementation example shown in FIG. 5, the communication message RES1 corresponding to REQ1 is embedded with an ID and a return value.

  When the content display apparatus 1 receives the ID and the return value from the remote browsers 2A and 2B (step S31), the content display apparatus 1 acquires a Fiber object from the table using the ID as a key (step S32), and specifies the Fiber specified by putting the return value in the argument. The execution of JavaScript that has been interrupted is resumed by calling the run method of the object (step S33). When execution of JavaScript is resumed, the return value is substituted into the variable ret on the fifth line in the implementation example of FIG. 5 and passed to the caller as the return value from the req_canPlayType function. If the req_canPlayType function shown in FIG. 5 is replaced with the original canPlayType function, the JavaScript code included in the WEB content does not need to wait for the processing of the remote browsers 2A and 2B, and only the canPlayType function is described. Thus, a process of receiving the return value by causing the remote browsers 2A and 2B to execute the process is executed.

  video. For accessing property values of elements held by the remote browsers 2A and 2B such as currentTime, a method of defining a JavaScript Getter function is used. FIG. 6 shows an example of a Getter function for obtaining a property value. The processing content of the implementation example of FIG. 6 is almost the same as the processing content of the implementation example of FIG. 5. After sending REQ2 to the remote browsers 2A and 2B and inquiring the property value, the remote browsers 2A and 2B The execution of JavaScript is suspended until the value of the property is obtained by receiving RES2.

  Note that it is not necessary to suspend / restart the above-described program execution for all methods or property value references that return values defined as DOM APIs. For example, the element has a property “id” for referring to the ID, but the value of this id property does not cause a difference between the DOM data storage unit 12 and the remote browsers 2A and 2B. Reference may be made on the data storage unit 12. Since no delay occurs when referring to the DOM data storage unit 12, it is not necessary to perform processing for interrupting the execution of JavaScript until a value is obtained. Therefore, in the DOM access unit 15, if the above req_XXXX and get_XXXX are implemented only for those that require the method activation and property value reference on the remote browsers 2A and 2B for each DOM API. Good.

  As described above, according to the present embodiment, when it is necessary to wait for a return value transmitted from the remote browsers 2A and 2B, the execution of the JavaScript by the execution unit 14 is interrupted and the remote browsers 2A and 2B are interrupted. By restarting the execution when the return value is obtained from, the JavaScript code of the WEB content can be described without being aware of the asynchronous processing between the content display device 1 and the remote browsers 2A and 2B. As a result, even when a part of the WEB content is transmitted to the remote browser, the JavaScript code included in the WEB content can be described in the same manner of synchronization processing as when the WEB content is displayed by one browser.

DESCRIPTION OF SYMBOLS 1 ... Content display apparatus 11 ... WEB content evaluation part 12 ... DOM data storage part 13 ... DOM data transmission part 14 ... Execution part 15 ... DOM access part 16 ... Browser communication part 17 ... Event reception part 2A, 2B ... Remote browser

Claims (5)

An information processing apparatus that executes a script including processing performed asynchronously,
Execution means for executing the script;
When the process executed by the execution unit uses a return value of a process executed in another device, an ID is generated and a communication message including the ID is transmitted to the other device to perform the process. Execution interrupting means for causing the execution means to interrupt the execution of the script after registering data necessary for resuming the execution of the script with the ID as a key;
When the communication message including the ID and the return value is received from the other device, the ID and the return value are extracted from the communication message, and the execution of the script is resumed from the table using the ID as a key. Execution resumption means for obtaining data necessary for the execution, passing the return value to the execution means, and resuming execution of the script;
An information processing apparatus comprising:   The process executed in the other apparatus is a method in which a method included in an element accessed by an execution unit that executes the script causes the other apparatus to perform the process, and the execution of the script is performed in the method. The information processing apparatus according to claim 1, wherein the information processing apparatus is interrupted. An information processing method by an information processing apparatus that executes a script including processing performed asynchronously,
Executing the script;
When the process executed in the step uses a return value of the process executed in another device, an ID is generated and a communication message including the ID is transmitted to the other device to perform the process. Suspending the execution of the script after registering the data necessary for resuming the execution of the script in the table using as a key;
When the communication message including the ID and the return value is received from the other device, the ID and the return value are extracted from the communication message, and the execution of the script is resumed from the table using the ID as a key. Obtaining necessary data, passing the return value and resuming execution of the script;
An information processing method characterized by comprising:   The processing executed in the other device is a method in which the method provided in the element accessed in the step of executing the script causes the other device to perform processing, and the execution of the script is executed in the method. 4. The information processing method according to claim 3, wherein the information processing is interrupted. An information processing program for causing a computer to function as each unit of the information processing apparatus according to claim 1.

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