Detailed explanation of precautions for using PHP curl function to send Post requests

Preface
I encountered a requirement at work a few days ago. When the user clicks a certain button, a post request is initiated to me in the background, and I accept the passed data. At first, my colleague sent it using the

http_request()

method encapsulated publicly in the company framework. The code is as follows:

public function http_request( $url, $post = '', $timeout = 5 ){ 
 if( empty( $url ) ){
  return ;
 }
 $ch = curl_init();
 curl_setopt($ch, CURLOPT_URL, $url);
 curl_setopt($ch, CURLOPT_HEADER, 0);
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
 curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
 
 if( $post != '' && !empty( $post ) ){
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json', 'Content-Length: ' . strlen($post)));
 }
 curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
 $result = curl_exec($ch);
 curl_close($ch);
 return $result;
 }

At first, I didn’t notice that the data passed was

application/json

Encoded json string, I directly use the data method that accepts the

application/x-www-form-urlencoded

encoding format to get the passed data in the background (that is, directly using the

$_POST

method), Of course, nothing was obtained. Later, my colleague directly changed the

http_request()

method and directly passed the data in the

application/x-www-form-urlencoded

encoding format. I did not make any changes.

Regarding the above question, I have always wondered why I didn’t get the data passed at that time.

The project is basically completed today, and the following has been studied. When the

curl()

makes a post request, the format of the data can be passed in the following ways:

(1): Spliced ​​by parameters The resulting

key=>value

key-value pair string. The format is as follows:

name=xxx&age=23$sex=1

This request parameter is encoded according to

application/x-www-form-urlencoded

by default.
(2): An array of

key=>value

key-value pairs composed of parameters (can only be a one-dimensional array, higher-dimensional arrays will report an error).

The format is as follows:

[ name="xxx" , age = 23 , sex = 男 ]

This request parameter is encoded according to the

multipart/form-data

format by default.

As mentioned above,

curl()

When making a post request, only one-dimensional arrays can be passed as parameters. So what should be done if you want to pass multi-dimensional arrays?

There are two ways to deal with it, namely method 3 and method 4 below.

(3): Process the multi-dimensional array

http_build_query()

and wait for a string in key=>value key-value pair format.

As shown below:

$data = [
          "msg"=>"这是一条测试数据",
          "xxx" => "yyyy",
          "msg_data" => [
                          "name"=>"sunms",
                          "age"=>23,
                          "sex"=>"男",
                          "content"=>[
                                 1,2,3
                                ]
                       ],
       ];

will get the following string:

msg=这是一条测试数据&xxx=yyyy&msg_data[name]=sunms&msg_data[age]=23&msg_data[sex]=男&msg_data[content][0]=1&msg_data[content][1]=2&msg_data[content][2]=3

This method is also encoded through the

application/x-www-form-urlencoded进

line, and can be obtained directly through $_POST on the receiving side.

(4): Convert the multi-dimensional array into a string in json format, encode the string in

application/json

format, and pass

file_get_contents(“php://input”)

or

$GLOBALS[‘HTTP_RAW_POST_DATA']

method to obtain the passed json format string, and then convert the json format string into an array for processing.

$data = [];
$data_string = json_encode($data);
.....
//设置header信息
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
               'Content-Type: application/json',
               'Content-Length: ' . strlen($data_string))
      );

Note: For data encoded in the

application/json

format,

$_POST

cannot be obtained directly. It needs to be obtained through

file_get_contents(“php://input”)

or

$GLOBALS[‘HTTP_RAW_POST_DATA']

.

Summary
The above is a detailed explanation of the precautions for using the curl function to send Post requests in PHP. For more related content, please pay attention to the PHP Chinese website (www.php.cn)!

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