Comparison of curl, fsocket, file_get_content functions in php

When I was working on a web thief program recently, I discovered that file_get_content could no longer meet the needs. I think that when reading remote content, file_get_content is not as good as curl except for being more convenient to use than curl

To capture remote content, I have been using the file_get_content function before. In fact, I have known about the existence of such a good thing as curl, but after taking a look, I felt that it is quite complicated to use. It is not as simple as file_get_content, and the demand is not big. So I didn't learn to use curl.

Some comparisons between curl and file_get_content in php Main differences: Curl supports many protocols, including FTP, FTPS, HTTP, HTTPS, GOPHER, TELNET, DICT, FILE and LDAP. In other words, it can do many things that file_get_content cannot do. Curl can achieve remote acquisition and collection of content in PHP; implement FTP upload and download of PHP web version; implement simulated login; implement interface docking (API), data transmission; implement simulated cookies; download file breakpoint resume transfer, etc., the function is very powerful . After understanding some basic uses of curl, I found that it is not difficult. It is just a little difficult to remember some of the setting parameters, but we can just remember a few commonly used ones. Turn on curl: Because PHP does not support the curl function by default, if you want to use curl, you first need to enable this function in php.ini, that is, remove the semicolon in front of ;extension= php_curl.dll, then save and restart apache/iis . Basic syntax:

$my_curl = curl_init(); //Initialize a curl object
curl_setopt($my_curl, CURLOPT_URL, "http://bbs.it-home.org"); //Set what you need to crawl URL
curl_setopt($my_curl,CURLOPT_RETURNTRANSFER,1); //Set whether to save the result to a string or output it to the screen. 1 means saving the result to a string
$str = curl_exec($curl); //Execute Request
echo $str; //Output the crawled results
curl_close($curl); //Close the url request

Recently, I need to obtain music data from other people's websites. I used the file_get_contents function, but I always encountered the problem of failure to obtain it. Although I set the timeout according to the examples in the manual, it does not work most of the time:

$config['context'] = stream_context_create(array('http' => array('method' => "GET",
'timeout' => 5//This timeout period is not Stable, often doesn't work
)
));

At this time, if I look at the server's connection pool, I will find a bunch of similar errors, which gives me a huge headache: file_get_contents(http://***): failed to open stream… Now I use the curl library instead and write a function replacement:

function curl_file_get_contents($durl){
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $durl);
curl_setopt($ch, CURLOPT_TIMEOUT, 5);
curl_setopt($ch, Curlopt_useragent, _Userager _); exec ($ ch);
CURL_CLOSE ($ ch);
Ereturn $ r;
 }



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Speaking of the usage of curl and file_get_contents, they have been mentioned in previous articles. Here are a few good articles recommended for your reference:

How to set up PHP file_get_contents timeout processing

Solution to php file_get_contents grabbing garbled Gzip web pages
Solution to file_get_contents timeout problem in php
How to set PHP file_get_contents timeout
Example of php file_get_content compatibility detection
php file_get_contents code to capture page information
php file_get_contents function code to capture page information
• Method 1: Use file_get_contents to get the content in get mode

$url='http://www.domain.com/';

$html = file_get_contents($url);

echo $html;

?>

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Method 2: Open the url with fopen and get the content with get method

$fp = fopen($url, 'r');
stream_get_meta_data($fp);
while(!feof($fp)) {
$result .= fgets($ fp, 1024);
}
echo "url body: $result";
fclose($fp);
?>

Method 3: Use the file_get_contents function to get the url in post mode

$data = array ('foo' => 'bar');
$data = http_build_query($data);
$opts = array (
'http' => array (
'method' => 'POST',
'header'=> "Content-type: application/x-www-form-urlencodedrn" .
"Content-Length: " . strlen($data) . "rn",
'content' => $data
)
);
$context = stream_context_create($opts);
$html = file_get_contents('http://localhost/e/admin/test.html', false, $context);
echo $html;
?>

Method 4: Use the fsockopen function to open the url and get the complete data in get mode, including header and body

function get_url ($url,$cookie=false)
{
$url = parse_url($url);
$query = $url[path]."?".$url [query];
echo "Query:".$query;
$fp = fsockopen( $url[host], $url[port]?$url[port]:80 , $errno, $errstr, 30);
 if (!$fp) {
return false;
} else {
$request = "GET $query HTTP/1.1rn";
$request .= "Host: $url[host]rn";
$request .= "Connection: Closern";
if($cookie) $request.="Cookie: $cookien";
$request.="rn";
fwrite($fp,$request);
while()) {
$ result .= @fgets($fp, 1024);
}
fclose($fp);
return $result;
}
}
//Get the html part of the url, remove the header
function GetUrlHTML($url,$cookie =false)
{
$rowdata = get_url($url,$cookie);
if($rowdata)
{
$body= stristr($rowdata,"rnrn");
$body=substr($body,4 ,strlen($body));
return $body;
}
return false;
}
?>

Method 5: Use the fsockopen function to open the url and get the complete data in POST mode , including header and body

function HTTP_Post($URL,$data,$cookie, $referrer="")
{
// parsing the given URL
$URL_Info=parse_url($URL);
/ / Building referrer
if($referrer=="") // if not given use this script as referrer
$referrer="111″;
// making string from $data
foreach($data as $key=> $value)
$values[]="$key=".urlencode($value);
$data_string=implode("&",$values);
// Find out which port is needed – if not given use standard (=80)
if(!isset($URL_Info["port"]))
$URL_Info["port"]=80;
// building POST-request:
$request.="POST ".$URL_Info[ "path"]." HTTP/1.1n";
$request.="Host: ".$URL_Info["host"]."n";
$request.="Referer: $referern";
$request. ="Content-type: application/x-www-form-urlencodedn";
$request.="Content-length: ".strlen($data_string)."n";
$request.="Connection: closen";
$request.="Cookie: $cookien";
$request.="n";
$request.=$data_string."n";
$fp = fsockopen($URL_Info["host"],$URL_Info[ "port"]);
fputs($fp, $request);
while(!feof($fp)) {
$result .= fgets($fp, 1024);
}
fclose($fp);
 return $result;
}
?>

Method 6: Use the curl library. Before using the curl library, you may need to check whether the curl extension has been turned on in php.ini

$ch = curl_init();
$timeout = 5;
curl_setopt ($ch, CURLOPT_URL, 'http://www.domain.com/');
curl_setopt ($ ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
$file_contents = curl_exec($ch);
curl_close($ch);
echo $file_contents;
?>

The three functions of curl, fsockopen and file_get_contents in php can all realize the collection of simulated speeches. What is the difference between the three, or is there anything to pay attention to? Zhao Yongbin: Sometimes when using file_get_contents() to call external files, it is easy to report an error due to timeout. Just change it to curl. The specific reason is not clear. The efficiency of curl is higher than file_get_contents() and fsockopen(). The reason is that CURL will automatically cache DNS information (the highlight is for me to test personally)

Fan Jiapeng: file_get_contents curl fsockopen Selective operations in the current requested environment, without generalization: Let’s look at the KBI application developed by our company: Just started using: file_get_contents Later adopted: fsockopen Last used till now: curl (Remotely) My personal understanding is as follows (please point out if it is wrong, please add if it is not correct) file_get_contents needs to enable allow_url_fopen in php.ini. When requesting http, http_fopen_wrapper is used. It is ok if you don't know keeplive.curl. file_get_contents() has high single execution efficiency and returns information without header. This is no problem when reading ordinary files, but problems will occur when reading remote files. If you want to make a continuous connection, request multiple pages multiple times. Then there will be problems with file_get_contents and fopen. The obtained content may also be incorrect. So when doing some similar collection work, there will definitely be a problem. Sock is relatively low-level, troublesome to configure, and difficult to operate. Return complete information.

Pan Shaoning-Tencent: Although file_get_contents can get the content of a certain URL, it cannot post get it. Curl can post and get. Head information can also be obtained Sockets are lower level. Can be set to interact based on UDP or TCP protocol If file_get_contents and curl can do it, socket can do it. What socket can do, curl may not be able to do. file_get_contents more often just pulls data. It is more efficient and simpler. I have also encountered Zhao's situation. I set the host through CURL and it was OK. This has something to do with the network environment.

That’s it. The above introduces the similarities and differences in the usage of url, fsocket, and file_get_content functions in PHP through examples. I hope it will be helpful to everyone.