插入需要最少字符数的语句

Question

这里我有一个将数据插入db的代码.它现在工作正常,但我希望标题至少有4个字符,身体最少500个.

这是我的代码:

<?php
if(isset($_POST['submit'])) {
  //get blog data
$title=strip_tags($_POST['title']);
$body=strip_tags($_POST['body']);
$posted_by = $first_name;
$category=$_POST['category'];
$bio = $bio;
$userid=$_COOKIE['user'];
$date = date ('d-M-Y');
if ($title && $body && $category) {
$query = "INSERT INTO blogs (userid, title, body, posted_by, bio, category_id, posted) VALUES ('$userid', '$title', '$body', '$posted_by','$bio', '$category', '$date')";
 $run = mysqli_query($con,$query);
 if($query) {
    echo "posted";
  }
  else {
    echo "error";
  }
  }else {
    echo "data missing";
  }
  }
  ?>

我尝试使用下面的代码来为标题和正文添加最低要求,但是即使标题包含超过5个字符,它也会在您提交数据时回显标题错误消息.

  <?php
  if(isset($_POST['submit'])) {
   //get blog data
   $title=strip_tags($_POST['title']);
   $body=strip_tags($_POST['body']);
   $posted_by = $first_name;
   $category=$_POST['category'];
   $bio = $bio;
   $userid=$_COOKIE['user'];
   $date = date ('d-M-Y');
   if (strlen($title<5)) {
   echo "Title must be of minimum 5 characters";
   }
   else {
   if (strlen($body<500)) {
    echo "Title must be of minimum 500 characters";
    }
    else {
    $query = "INSERT INTO blogs (userid, title, body, posted_by, bio, category_id, posted) VALUES ('$userid', '$title', '$body', '$posted_by','$bio', '$category', '$date')";
    $run = mysqli_query($con,$query);
    if($query) {
    echo "posted";
    }
    else {
     echo "error";
    }
    }
    }
    }
   ?> 

Answer 1

这样的问题值得对未来读者解释这个问题.

您的代码失败的原因是:

if (strlen($title<5))

评估为:

function($string conditional)

当语法是:

function($string) conditional

手册说明:

int strlen(string $ string)

• http://php.net/manual/en/function.strlen.php

从手册中拉出的示例:

if (strlen($foo) === 0) echo 'Null length is Zero <br>';

另外,正如评论中所述.您的查询受SQL注入.最好使用准备好的声明.

请参考以下链接:

• 如何在PHP中阻止SQL注入？

• https://en.wikipedia.org/wiki/Prepared_statement