php curl usage methods and steps

What’s special about this book is that it provides everyone with the core ideas of important operations. We take real steps in database, image, and file uploading. It also explains how the steps are organized into our code and implementation process.

We divide the steps of curl into the following 7 steps:

1. Initialize the curl resource

2. Parameter setting request protocol address

3. Whether the parameter setting returns the request result

4. Set the sending data (no need to set if there is no sending data)

5. Other parameter information settings (according to actual work needs Decision)

6. Execute or execute to get the return result

7. Close the curl resource

In order to better let everyone learn and get started, we will change steps 2 to 2. The 5 steps that should have been classified as one step were inserted into 4 steps.

The second to fifth steps should essentially be unified into curl parameter settings.

All curl setting parameter settings are completed through curl_setopt

curl_setopt This step is the most important, and all the secrets are here.

curl_setopt This step completes the detailed settings including connection, parameters and all requests. It can be difficult to read and understand them all at once, so we'll just try the more common and useful options.

We are here for a better introduction. And what we use most in php is http request. Therefore, we will not explain all the things that you do not need to use.

If you are interested, you can refer to the complex parameter settings in curl_setopt.

The address is as follows: http://php.net/manual/zh/function.curl-setopt.php

1. Initial use of curl resources

There is only one sentence, that is, the curl_init function is used. This parameter method requires any parameters to be passed in. Returns the curl operation resource.

Because, we later push data into curl's operating resource variables through curl_setopt.

Example:

$ch = curl_init();

2. Parameter setting request protocol address

The detailed usage of the curl_setopt function is as follows:

CURLOPT_URL This parameter option specifies the requested url address.

curl_setopt($ch, CURLOPT_URL, "http://www.php.cn");

3. Whether the parameter setting returns the request result

We hope that the curl request will return the corresponding result. If we want to get the corresponding result, we also need to set a parameter. This parameter is called: CURLOPT_RETURNTRANSFER.

If required, the return value is 1. The result returned after no request can be set to 0.

curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

4. Set the sending data

If it is a get request, we do not need to set the sending parameters. When posting and waiting for requests, we need to set the sending method to the post method. and set the data to be sent.

*CURLOPT_POST *Set the value to 1 to use the POST method, and 0 to not use the POST method

CURLOPT_POSTFIELDSSet the passed data

//声明使用POST方式来进行发送
    curl_setopt($ch, CURLOPT_POST, 1);
//发送什么数据呢
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

5. Other parameter information settings

If it is https, sometimes we need to ignore the security certificate of https.

CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST are changed to false to ignore the certificate.

curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);

CURLOPT_HEADER This parameter also determines whether to process http header information. If we do not want to receive processing, we can set this value to 0.

curl_setopt($ch, CURLOPT_HEADER, 0);

In addition, we can also set the timeout of the request, the parameter is: CURLOPT_TIMEOUT.

curl_setopt($ch, CURLOPT_TIMEOUT, 10);

There are many other parameters. We have talked about it before. If you want to know more, you can visit:
The address is as follows: http://php.net/manual/zh/function.curl -setopt.php

6. Execute or execute to get the return result

In our third step, set the value of the CURLOPT_RETURNTRANSFER parameter to 1. If the execution result has data. After execution using curl_exec, the result will be returned to the $output variable.

$output = curl_exec($ch);

7. Close curl resources

Close curl resources. Because of the resource type, we have repeatedly emphasized that if it is opened, it will be closed.

If you don’t need to use it, use curl_close to close it and release the memory immediately.

curl_close($ch);

8. Put the above together

<?php
//初始化
$ch = curl_init();
//设置选项，包括URL
curl_setopt($ch, CURLOPT_URL, "http://www.php.cn");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
//执行并获取HTML文档内容
$output = curl_exec($ch);
//释放curl句柄
curl_close($ch);
//打印获得的数据
print_r($output);
?>

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