我无法做到一件事。 RFC 2616 in 4.4.5表示Message Length可以确定＆＃34; By the server closing the connection.＆＃34;。
这意味着服务器响应（例如返回一个大图像）的响应是有效的，它在标题中没有Content-Length，但客户端应该继续获取直到连接已关闭，然后假设已下载所有数据。
但客户如何确定连接是否被服务器故意关闭？服务器应用程序可能在发送数据的过程中崩溃，服务器的操作系统很可能会发送FIN数据包以正常关闭与客户端的TCP连接。
答案 0 :(得分：3)
You are absolutely right, that mechanism is totally unreliable. This is covered in RFC 7230:
Since there is no way to distinguish a successfully completed, close-delimited message from a partially received message interrupted by network failure, a server SHOULD generate encoding or length-delimited messages whenever possible. The close-delimiting feature exists primarily for backwards compatibility with HTTP/1.0.
Fortunately most of HTTP traffic today are HTTP/1.1, with Content-Length or "Transfer-Encoding" to explicitly define the end of message.
The lesson is that, a message must have it own way of termination; we cannot repurpose the underlying transport layer's EOF as the message's EOF.
On that note, a (well-formed) require 'vendor/autoload.php';
use Facebook\FacebookSession;
use Facebook\FacebookRequest;
use Facebook\GraphUser;
use Facebook\FacebookRequestException;
use Facebook\FacebookRedirectLoginHelper;
FacebookSession::setDefaultApplication(123456,'a1b2c3d4e5');
$helper = new FacebookRedirectLoginHelper('http://domain.com/login.php');
try {
# success
$session = $helper->getSessionFromRedirect();
} catch(FacebookRequestException $ex) {
# when Facebook returns an error
} catch(\Exception $ex) {
# when validation fails or other local issues
}
if($session) {
# do something with user data
$me = (new FacebookRequest($session, 'GET', '/me'))->execute()->getGraphObject(GraphUser::className());
# redirect to user profile page
header('Location: http://domain.com/profile.php');
exit();
} else {
# $session is always NULL with this code :(
}
document, or a html, .gif etc, does define its own termination; we will know if we received an incomplete document. Therefore it is not so much of a problem to transmit it over HTTP/1.0 without Content-Length.
However, for plain text document, .avi, javascript etc. EOF is used to marked the end of the document, therefore it's problematic over HTTP/1.0.