This article mainly introduces how to call RScript scripts in PHP. It has certain reference value. Interested friends can refer to it. I hope it will be helpful to you!

For some reason, R voice needs to be called in PHP to draw images. After many searches on Baidu, most of the current solutions are: using system command functions in PHP such as exec, system, shell_exec, etc. to call RScript scripts. There are two common command lines:

The first one:

exec("RScript " . $your_script_dir . "$your_RScript_file " . $args);    // 里面有printf某个变量
// echo ("RScript " . $your_script_dir . "$your_RScript_file " . $args);

Second Two types:

 system("R --slave < " . $your_RScript_dir . "$your_RScript_file" . " --args " . $args); // 里面有printf某个变量
// echo ("R --slave < " . $your_RScript_dir . "$your_RScript_file" . " --args " . $args);

Next, when we run PHP with confidence, we will find that the value returned by the system command we executed is 1, which means failure. However, we took the echo statement and executed it in the cmd window, and found that we could printf the result, and the image I wanted was also generated. Why is this? After many attempts on Baidu, I finally found a solution. For your reference and you are welcome to post in the comment area if you have better methods, so that we can work together to make progress.

1. Take a brief look at the failed call situation

This is the statement of the R script I called in PHP. The following is the result of calling it in the browser.

We will execute the echoed statement in cmd. The result is as follows:

The generated file is as follows:

As you can see, the $plotName I want to get finally is null, which means that the execution is not successful, or the file information printed in cmd is not obtained.

2. Solution

provides a PHP plug-in called RServe. If you use Java to call R language, you must be familiar with this. Now that the PHP version is out, we can use it. Download address: Rserve-php

3. How to use

Of course, the plug-in also has some simple examples, you can refer to it and understand it by yourself. Here is my solution: I implemented it based on the ThinkPHP5 framework.

1. We first need to add it to our project. I put the plug-in in my vendor. Add the following code:

require_once ROOT_PATH . 'vendor/rserve/autoload.php';

2. Use some of the classes according to your own needs

use Sentiweb\Rserve\Connection;            // 连接R服务的类
use Sentiweb\Rserve\Evaluator;             // 简单的理解为：建立连接后返回的处理器
use Sentiweb\Rserve\REXP\Vector;           // 内置的存储容器

3. Write an RScript script

We need to modify the previously written script into a function in R language. The format is as follows:

RScript <- function(arg1, ...， argN) {
    # code... 请无视这种注释方式，R语言没有注释
    return output    # 该函数的返回值
}

We will use the Rserve plug-in to call it later.

4. Write our PHP function

In order to make it easier to call later, we unified the function of calling RScript scripts into a function, which is easy to read and easy to maintain.

class Common {
    // $source 表示自己编写的R语言函数文件
    // $file, $cancer：本R函数所需要参数
    function RScript($source, $file, $cancer) {
        $cnx = new Connection(RSERVE_HOST);                    // 与RSERVE_HOST建立连接，一般为自己服务器地址，如果本地，则为localhost
        $eval = new Evaluator($cnx, Evaluator::PARSER_REXP);   // 通过连接，生成处理器，后一个参数决定连接失败时返回错误信息
        $eval->evaluate("source('$source')");                  // 类似library，将函数载入R的编程环境中；evaluate计算括号内的R命令
        // 同理，执行R命令，注意括号内是字符串的形式，由于返回的是RServe的Rstring类，为了拿到我想要的信息，通过Vector类的toHTML转为含return信息的标签语言
        $RString = $eval->evaluate("RScript('$file', '$cancer')")->toHTML();    
        preg_match("/$cancer.+.pdf/", $RString, $fileName);    // 提炼信息
        return $fileName[0];                                   // 返回结果
    }
}

5. Successful implementation

I won’t show my final results here, students who need this can try it themselves.

4. Reasons for failure

Due to the tight project schedule and low familiarity with PHP and R languages, I don’t understand why the result of directly calling the command execution fails. Friends who know this can reply to me in the comments. The above is all my solutions on how to call R language scripts in PHP. Thank you all for reading.

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