First experience with PHP, first experience with love

First experience with PHP, first experience with love

1. Introduction to related content

1>Internet Development

• Internet: Traditional Internet, Mobile Internet

• Internet development: front-end development (front-end), back-end development (back-end, server)

• Front-end development: visual display (user interface), user interaction, collecting input information

• Backend development: manage and process data, develop interfaces to clients, control output

　2> Client server mode (C/S)

• Client: actively initiate communication (initiate request), such as browsers, mobile clients, etc.

• Server: passively waiting for communication (responding to requests), such as: web server, FTP server, mail server, etc.

　3> Web Server Development

Web Server: In a network environment, it provides response services to clients that initiate requests, mainly processing HTTP requests.

1> Environment setup

• Apache: Web server software, supports most computer operating systems, and is one of the most popular Web server software. Mac system comes with Apache.

• PHP: A scripting language suitable for Webserver development, cross-platform, supporting most databases and operating systems, mixed with C and Java language syntax, open source code.

• MySQL: Relational database management system, small in size and fast, widely used in small and medium-sized websites.

2> XAMPP and Coda

• XAMPP is a software package that integrates the Apache PHP MySQL installation environment. It can be installed with one click, which is convenient and fast.

Coda: a web programming tool for Mac computers with multi-language support (HTML, PHP, JavaScript, CSS, etc.)

3> Web Server Workflow

1> Principle

2> Local server path

3> Access server files

URL format: protocol://domain name/path/query

http://127.0.0.1

Access the root directory of the local web server and load the index file content by default

http://127.0.0.1/File path (including file name and suffix)

Access a file in the root directory of the local web server, such as pictures, php, html

4. Basic PHP syntax

1> PHP tag

<?<span>php

    </span><span>echo</span>("hello lanou")；<span>//</span><span> 输出函数</span>

    "<br/>"  <span>//</span><span> 换行</span>

    <span>echo</span> "iOS"; <span>//</span><span> 输出函数，可以不带括号        </span>
    
?>

Reference learning website: http://www.runoob.com/php/php-tutorial.html

2> Variables

Variable definition

Variables start with $, followed by the variable name

Variables are composed of letters, numbers, and underscores, and do not start with numbers

Variable names are case-sensitive

Define automatic type variables

<span>　　$int_value</span> = 10<span>;       
　　</span><span>$float_value</span> = 1.5<span>;    
　　</span><span>$name</span> = "hello lanou";

Get the variable type and return string

<span>　　gettype</span>(<span>$name</span>);

3> String

Connection string

    <span>$name</span> = 'iPhone'<span>;
    </span><span>$str</span> = '5'<span>;
    </span><span>$name</span> = <span>$name</span>.<span>$str</span><span>;
    </span><span>echo</span>(<span>$name</span>);

4> if branch

    <span>//</span><span>比较两个变量，输出最大值</span>
    
    <span>$a</span> = 3;<span>$b</span> = 5<span>;

    </span><span>if</span>(<span>$a</span>><span>$b</span><span>){
        </span><span>echo</span>(<span>$a</span><span>);
    }</span><span>else</span><span>{
        </span><span>echo</span>(<span>$b</span><span>);
    }</span>

5> for loop

<span>//</span><span>输出1~10之间所有的数</span>
<span>for</span>(<span>$i</span> = 1;<span>$i</span><=10;<span>$i</span>++<span>){
    </span><span>echo</span>(<span>$i</span>.'<br>'<span>);
}</span>

6> Random number

Generate a random number between a~b rand(a, b)

<span>//</span><span> 生成20~50之间的随机数，并输出</span>
<span>$num</span> = <span>rand</span>(20, 50<span>);
</span><span>echo</span> <span>$num</span>;

7> Array

In PHP, use the array() function to create an array

In PHP, there are three types of arrays:

Numeric array - array with numeric ID keys (similar to NSArray)

Associative array - an array with specified keys, each key is associated with a value (similar to NSDictionary)

Multidimensional array - an array containing one or more arrays

<span>$array1</span> = <span>array</span>();  <span>//</span><span> 空数组</span>
<span>$array2</span> = <span>array</span>(99, 98, 97);  <span>//</span><span> 数值数组    </span>
<span>$array3</span> = <span>array</span>("name"=>"lishuai", "age"<span>=>40);  // 关联数组，键=>值
print_r(</span><span>$array3</span>); // 输出数组内容

8> Numeric array　

The count() function is used to return the number of array elements

<span>$count</span> = <span>count</span>(<span>$array</span><span>);

</span><span>echo</span> <span>$count</span>;

　Add array elements

<span>$array</span>[] = 96;  <span>//</span><span> 数组中最后一个元素</span>

Access array elements

$array[numeric ID key]

Traverse the numerical array

foreach(array as $value){
echo($value."
");
}

    <span>$array</span> = <span>array</span>(12, 13, 14, 15<span>);
    
    </span><span>foreach</span>(<span>$array</span> <span>as</span> <span>$value</span><span>){
　　　　</span><span>echo</span>(<span>$value</span>."<br/>"<span>);
    }</span> 

9> Associative array

      <span>$person</span> = <span>array</span>("name"=>"yihuiyun", &ldquo;age"=>"18"<span>)
      print_r(</span><span>$person</span>);  // 输出

Output result Array ( [name] => yihuiyun [age] => 18 )

<span>$person</span> = <span>array</span>("name"=>"yihuiyun", &ldquo;age"=>"18"<span>)

// count()函数用于返回数组元素的数量

</span><span>$count</span> = count(<span>$person</span><span>);
echo </span><span>$count</span><span>;

//添加键值对

</span><span>$person</span>["sex"] = "female"<span>;  

//根据键获取值

//</span><span>$person</span>[键]

Traverse associative array

　　　foreach(数组 as $key=>$value){
　　echo($key.":".$value."
");
　　　}

<span>$person</span> = <span>array</span>("name"=>"yihuiyun", &ldquo;age&rdquo;=>&rdquo;18"<span>);

foreach(</span><span>$person</span> as <span>$key</span>=><span>$value</span><span>){
    echo(</span><span>$key</span>.":".<span>$value</span>."<br/>"<span>);
}</span>

　10> json转换

<span>//</span><span> 数组转json字符串</span>
<span>$json</span> = json_encode(<span>$array</span><span>);

</span><span>//</span><span> json字符串转PHP对象</span>
<span>$array</span> = json_decode(<span>$json</span>);

5. PHP实现API接口开发（GET）

　1> 概述

　 在 PHP 中，预定义的 $_GET 变量用于收集来自 method="get" 的表单中的值。

　 从带有 GET 方法的表单发送的信息，对任何人都是可见的（会显示在浏览器的地址栏），并且对发送信息的量也有限制。

　 GET 传值的一个 URL：http://127.0.0.1/get.php?username=lanou&password=123

　　解析：http://127.0.0.1/get.php?参数名1=值1&参数名2=值2

　　　参数名通常由后台规定，前端根据接口文档填写

　 PHP文件接收数据代码：

    <span>//</span><span> 获取数据   key必须与参数名保持一致</span>
    <span>$name</span> = <span>$_GET</span>["username"<span>];
    </span><span>$password</span> = <span>$_GET</span>["password"];

　2> iOS网络编程

　　代码：

6. PHP实现API接口开发（POST）

　1> 概述

　　预定义的 $_POST 变量用于收集来自 method="post" 的表单中的值。

　　从带有 POST 方法的表单发送的信息，对任何人都是不可见的（不会显示在浏览器的地址栏），并且对发送信息的量也没有限制

　　http://127.0.0.1/post.php

　　URL中不需要携带参数，通过body上传参数
　 PHP文件接收数据代码：

    <span>//</span><span> 获取数据   key必须与参数名保持一致</span>
    <span>$name</span> = <span>$_POST</span>["username"<span>];
    </span><span>$password</span> = <span>$_POST</span>["password"];