Headers invalid argument in addHeaderLine method

[necromant2005]

Headers failing by sending empty "user-agent"
The main issue in Headers::addHeaders

if (is_string($value)) {
   $this->addHeaderLine($value);

But below in method addHeaderLine signature

    public function addHeaderLine($headerFieldNameOrLine, $fieldValue = null)
    {
        $matches = null;
        if (preg_match('/^(?P<name>[^()><@,;:\"\\/\[\]?=}{ \t]+):.*$/', $headerFieldNameOrLine, $matches)
            && $fieldValue === null) {
            // is a header
            $headerName = $matches['name'];
            $headerKey  = static::createKey($matches['name']);
            $line = $headerFieldNameOrLine;
        } elseif ($fieldValue === null) {
            throw new Exception\InvalidArgumentException('A field name was provided without a field value');
        }

Witch is wrong typing NULL on string only fields

[Xerkus]

Headers without value are invalid.
https://tools.ietf.org/html/rfc7230#section-3.2

What is trying to send empty user-agent?

[weierophinney]

@necromant2005 —

I'm unclear what you expect to occur. If the idea is to unset the header, you would need to use:

if ($headers->has($header)) {
    $headers->removeHeader($headers->get($name));
}

If the idea is to set an empty value, as @Xerkus notes, that's invalid per the HTTP specifications. You could do something like this:

$headers->addHeaderLine($header, '');

Both of the above would require that you validate the value being provided before you try and create the header, which is likely a good idea anyways.

We do not intend to support the usage $headers->addHeaderLine($value) where the value is not a fully-formed header line, but just the header name, as its purpose would be too vague:

• Should it remove such a header, if it's already present?
• Or set a header with an empty string as a value (invalid by the specification)?

Neither feels like a valid option.

[necromant2005]

I'm getting error on production because some bots comes with empty "user-agent" headers

file:vendor/zendframework/zend-servicemanager/src/ServiceManager.php | 
ln:765 | 
msg: message => 'Uncaught Zend\\Http\\Exception\\InvalidArgumentException: A field name was provided without a field value in vendor/zendframework/zend-http/src/Headers.php:192

Stack trace:
#0 vendor/zendframework/zend-http/src/Headers.php(155): Zend\\Http\\Headers->addHeaderLine(\'User-Agent\')
#1 vendor/zendframework/zend-http/src/PhpEnvironment/Request.php(238): Zend\\Http\\Headers->addHeaders(Array)
#2 vendor/zendframework/zend-http/src/PhpEnvironment/Request.php(86): Zend\\Http\\PhpEnvironment\\Request->setServer(Object(Zend\\Stdlib\\Parameters))
#3 vendor/zendframework/zend-mvc/src/Service/RequestFactory.php(29): Zend\\Http\\PhpEnvironment\\Request->__construct()
#4 vendor/zendframework/zend-servicemanager/src/ServiceManager.php(758): Zend\\Mvc\\Service\\RequestFactory->__invoke(Object(Zend\\ServiceManage',
  'file' => 'vendor/zendframework/zend-servicemanager/src/ServiceManager.php',
  'line' => 765,
) => array (
)

You're right, there shouldn't be requests with empty value, but they are. It's incorrect zf behaviour to fail on every request, I'm expecting something simpler - "skip it and move forward"

[Xerkus]

@weierophinney may be he is on to something here, it is actually zend-mvc related issue, exception in request factory will result in uncaught exception and error log entry while it should be normal abort with 400 Bad Request