Header Only Retrieval in PHP Via Curl

Header only retrieval in php via curl

You are passing $header to curl_getinfo(). It should be $curl (the curl handle). You can get just the filetime by passing CURLINFO_FILETIME as the second parameter to curl_getinfo(). (Often the filetime is unavailable, in which case it will be reported as -1).

Your class seems to be wasteful, though, throwing away a lot of information that could be useful. Here's another way it might be done:

class URIInfo 
{
    public $info;
    public $header;
    private $url;

    public function __construct($url)
    {
        $this->url = $url;
        $this->setData();
    }

    public function setData() 
    {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $this->url);
        curl_setopt($curl, CURLOPT_FILETIME, true);
        curl_setopt($curl, CURLOPT_NOBODY, true);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_HEADER, true);
        $this->header = curl_exec($curl);
        $this->info = curl_getinfo($curl);
        curl_close($curl);
    }

    public function getFiletime() 
    {
        return $this->info['filetime'];
    }

    // Other functions can be added to retrieve other information.
}

$uri_info = new URIInfo('http://www.codinghorror.com/blog/');
$filetime = $uri_info->getFiletime();
if ($filetime != -1) {
    echo date('Y-m-d H:i:s', $filetime);
} else {
    echo 'filetime not available';
}

Yes, the load will be lighter on the server, since it's only returning only the HTTP header (responding, after all, to a HEAD request). How much lighter will vary greatly.

Can PHP cURL retrieve response headers AND body in a single request?

One solution to this was posted in the PHP documentation comments: http://www.php.net/manual/en/function.curl-exec.php#80442

Code example:

$ch = curl_init();
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HEADER, 1);
// ...

$response = curl_exec($ch);

// Then, after your curl_exec call:
$header_size = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
$header = substr($response, 0, $header_size);
$body = substr($response, $header_size);

Warning: As noted in the comments below, this may not be reliable when used with proxy servers or when handling certain types of redirects. @Geoffrey's answer may handle these more reliably.

cURL request to a page to get headers without waiting for page contents to load

When you use cURL to access the headers of a page, the whole PHP file will be executed, even if there is long-running tasks inside. That's because HTTP headers may be overrided by the header function.

If you don't want to hang up, my suggestion is to use a command-line instead of a function to copy your file : instead of copy($source, $target), run the following if you're on a Linux system :

$source = escapeshellarg($source);
$target = escapeshellarg($target);
exec("cp $source $target &");

The & symbol will execute the command in background (so if the copy takes 3 secondes, it will be run in background and not hang your PHP file).

PHP Using cURL and GET request with a header

According to PHP documentation for CURLOPT_HEADER:

TRUE to include the header in the output.

Your $response will probably look like this:

HTTP/1.1 200 OK
Some: headers
More: header lines

{
    "real": "json content"
}

This is because you added the CURLOPT_HEADER option.

You don't need to set any options to let the curl request send your headers. As long as you set the CURLOPT_HTTPHEADER option, the headers will be sent.

If you really want to receive the response headers too, check existing questions like "Can PHP cURL retrieve response headers AND body in a single request?"

Get Header from PHP cURL response

It converts all headers into an array

// create curl resource
$ch = curl_init();

// set url
curl_setopt($ch, CURLOPT_URL, "example.com");

//return the transfer as a string
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
//enable headers
curl_setopt($ch, CURLOPT_HEADER, 1);
//get only headers
curl_setopt($ch, CURLOPT_NOBODY, 1);
// $output contains the output string
$output = curl_exec($ch);

// close curl resource to free up system resources
curl_close($ch);

$headers = [];
$output = rtrim($output);
$data = explode("\n",$output);
$headers['status'] = $data[0];
array_shift($data);

foreach($data as $part){

    //some headers will contain ":" character (Location for example), and the part after ":" will be lost, Thanks to @Emanuele
    $middle = explode(":",$part,2);

    //Supress warning message if $middle[1] does not exist, Thanks to @crayons
    if ( !isset($middle[1]) ) { $middle[1] = null; }

    $headers[trim($middle[0])] = trim($middle[1]);
}

// Print all headers as array
echo "<pre>";
print_r($headers);
echo "</pre>";

Retrieve the response code from header cURL php

I think you need to pass $curl to the curl_getinfo method, not the $response

$response = curl_exec($curl);
$theInfo = curl_getinfo($curl);
$http_code = $theInfo['http_code'];

You can see the doco here.. https://www.php.net/manual/en/function.curl-getinfo.php

Get Headers as part of CURL

The reason this was happening is because I was discarding the input of curl_exec. I changed that section of the code to:

$headers=curl_exec($info);

cURL - How to fetch page only if it has changed since last fetch?

I looked for answer for more than 2 days, and nobody could give me universal answer.

So I implemented etag and if-modified-since headers (as Matt Raines and sowa posts here), also to lower traffic I used compression like gzip.

Also there is request header Range, so that i could grap only part of the page as someone told me, but i think it is used only for files not web pages.

Thank you all for your time

How to get the headers from the last redirect with PHP's curl functions?

Search the output for "HTTP/1.1 200 OK" in the beginning of the line - this is where your last request will begin. All others will give other HTTP return codes.

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