如何使用PHP制作API [关闭]

Question

I have been using file_get_contents and curl to fetch data from other web sites .But we all know what happens if the owner of that site changes its html .So many people say we might make an API inorder to avoid these things .(1)My first qeustion is can we do this with any kind of web site or is this only for big web sites such as youtube twitter facebook ?? (2) second question is how to make this ? can somebody explain this briefly or please give me the guides
I am so sorry i know this is just a stupid question to ask here ,but after searching for few days still I dont have proper idea about API

Answer 1

For who? For what?

Anyone. Anywhere. Anything.

How to make it

There is many way to make an API.
First, you need to know some things:

• Return values method or Content-Type (JSON, XML..)
• Allowed websites origins

To explain how to create an API,
I'll use JSON. To define Content Type use the header() function :

header('Content-Type: application/json');

To define allowed websites origins (only if another website gonna use this API):

header('Access-Control-Allow-Origin: http://yourwebsite.com');

Once this is done, you can begin your API.
It's like any PHP code, here's an example:

First, you'll maybe need to get all $_GET variables.
As for me, I save them all like this:

if(!empty($_GET)) {
  foreach($_GET as $eachKey => $eachValue) {
    ${'param_' . $eachKey} = $eachValue;
  }
}

Example : $_GET['hello'] => 'world' gonna be $param_hello = 'hello'

Then, your code.
First, you need to set the response var. For JSON, it's gonna be an array.

$response = [];

For example, I'll use mt_rand() function.
This value gonna be saved in $response array as ['result'] key.

$reponse['result'] = mt_rand($param_min, $param_max);

Now, the API is finished, so we need to write down response:

echo json_encode($response);
die(); // Then end the script

This method is recommended and very efficient with AJAX requests (most used with APIs)

Using file_get_contents

Forget $response and json functions.
The best Content-Type for this way is this:

header('Content-Type: text/plain');

And just echo the result:

echo mt_rand($param_min, $param_max);

I'm here for questions. And you have Internet, or PHP Manual for more info.