找出函数是否与php有任何输出 [英] Find out if function has any output with php

问题描述

为您量身定制的一款.

说我有一个输出字符串的函数:

Say I have a function that outputs a string:

function myString()
{
      echo 'Hello World';
}

我该如何测试该函数是否输出任何数据?

How would I go about testing to see if the function outputs any data?

if(myString() ==''){ 
      echo ''Empty function;  
}

推荐答案

使用输出缓冲区功能:

function testFunctionOutput($f, $p = array()){
    ob_start();
    call_user_func_array($f, $p);
    $s = ob_get_contents();
    ob_end_flush();
    return (bool)($s !== '');
}

所以说...

function testa(){
  echo 'test';
}

function testb($b){
  $i = 20 * $b;
  return $i;
}

var_dump(testFunctionOutput('testa'));
var_dump(testFunctionOutput('testb', array(10)));

Felix建议的替代版本:

Alternative version suggested by Felix:

function testFunctionOutput2($f, $p = array()){
    ob_start();
    call_user_func_array($f, $p);
    $l = ob_get_length();
    ob_end_clean();
    return (bool)($l > 0);
}

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