Python 如何使用scala process utility发送EOF

我想从scala程序内部启动一个python程序，该程序必须接收可能无限长的字符串。因此，不可能将其作为cmd参数传递

我的解决方案是通过STDStream传输数据。但是，我找不到工作bash代码的scala版本：

#/bin/bash
var="SOME REALLY LONG STRING THAT IS SEND TO THE PYTHON PROGRAM"
echo "$var" | ./readUntilEOF.py

bash代码：

#/bin/bash
var="SOME REALLY LONG STRING THAT IS SEND TO THE PYTHON PROGRAM"
echo "$var" | ./readUntilEOF.py

scala代码：

import sys.process._
 
object main {

       def main(args : Array[String]) : Unit = {
           val cmd = "./readUntilEOF.py"
           val string = "SOME REALLY LONG STRING THAT IS SEND TO THE PYTHON PROGRAM"
           print("I am starting to send stuff...")
           val resultString = (string #| cmd.!!).!!
           print(resultString)
       }
 
}

#> scala scala.sc
I am starting to send stuff...
/* and then it never terminates */

readUntilEOF.py：

#!/usr/bin/python3

import sys

if __name__ == "__main__":
    read = sys.stdin.read()
    print(read)

运行bash命令的输出：

#> ./scalaBashEquivalent.sh 
SOME REALLY LONG STRING THAT IS SEND TO THE PYTHON PROGRAM

运行scala代码的输出：

import sys.process._
 
object main {

       def main(args : Array[String]) : Unit = {
           val cmd = "./readUntilEOF.py"
           val string = "SOME REALLY LONG STRING THAT IS SEND TO THE PYTHON PROGRAM"
           print("I am starting to send stuff...")
           val resultString = (string #| cmd.!!).!!
           print(resultString)
       }
 
}

#> scala scala.sc
I am starting to send stuff...
/* and then it never terminates */

---

这确实比预期的要复杂一些。但下面的代码似乎有效

import java.io.PrintWriter

object main {

       def main(args : Array[String]) : Unit = {
           val cmd = "./readUntilEOF.py"
           val string = "SOME REALLY LONG STRING THAT IS SEND TO THE PYTHON PROGRAM"
           println("I am starting to send stuff...")
           val processOutput : StringBuilder = new StringBuilder()
           val process = Process(cmd).run(new ProcessIO(
               in => {
                  val writer = new PrintWriter(in)
                  writer.write(string)
                  writer.close()
               },
               out => {
                   processOutput.addAll(scala.io.Source.fromInputStream(out))
                   out.close()
               },
               _.close()
           ))
           assert(process.exitValue() == 0)
           print(processOutput.toString)
       }

}

---

这确实比预期的要复杂一些。但下面的代码似乎有效

import java.io.PrintWriter

object main {

       def main(args : Array[String]) : Unit = {
           val cmd = "./readUntilEOF.py"
           val string = "SOME REALLY LONG STRING THAT IS SEND TO THE PYTHON PROGRAM"
           println("I am starting to send stuff...")
           val processOutput : StringBuilder = new StringBuilder()
           val process = Process(cmd).run(new ProcessIO(
               in => {
                  val writer = new PrintWriter(in)
                  writer.write(string)
                  writer.close()
               },
               out => {
                   processOutput.addAll(scala.io.Source.fromInputStream(out))
                   out.close()
               },
               _.close()
           ))
           assert(process.exitValue() == 0)
           print(processOutput.toString)
       }

}

可以接受

InputStream

，因此请尝试

(cmd #< new ByteArrayInputStream(string.getBytes)).!!

（cmd#

可以接受

输入流

所以请尝试

(cmd #< new ByteArrayInputStream(string.getBytes)).!!

（cmd#

---

不幸的是，这比你想象的要复杂一些。不幸的是，这个问题的答案比你想象的要复杂得多。请查看“是”的答案，该答案同样有效，并且比我的尝试更详细。我在底部添加了工作程序。是的，它也可以工作，并且比我的尝试更详细。我在底部添加了工作程序。