The Headers Class

Overview

The Zend\Http\Headers class is a container for HTTP headers. It is typically accessed as part of a Zend\Http\Request or Zend\Http\Response getHeaders() call. The Headers container will lazily load actual Header objects as to reduce the overhead of header specific parsing.

The Zend\Http\Header\* classes are the domain specific implementations for the various types of Headers that one might encounter during the typical HTTP request. If a header of unknown type is encountered, it will be implemented as a Zend\Http\Header\GenericHeader instance. See the below table for a list of the various HTTP headers and the API that is specific to each header type.

Quick Start

The quickest way to get started interacting with header objects is by getting an already populated Headers container from a request or response object.

// $client is an instance of Zend\Http\Client

// You can retrieve the request headers by first retrieving
// the Request object and then calling getHeaders on it
$requestHeaders  = $client->getRequest()->getHeaders();

// The same method also works for retrieving Response headers
$responseHeaders = $client->getResponse()->getHeaders();

Zend\Http\Headers can also extract headers from a string:

$headerString = <<<EOB
Host: www.example.com
Content-Type: text/html
Content-Length: 1337
EOB;

$headers = Zend\Http\Headers::fromString($headerString);
// $headers is now populated with three objects
//   (1) Zend\Http\Header\Host
//   (2) Zend\Http\Header\ContentType
//   (3) Zend\Http\Header\ContentLength

Now that you have an instance of Zend\Http\Headers you can manipulate the individual headers it contains using the provided public API methods outlined in the “Available Methods” section.

Configuration Options

No configuration options are available.

Available Methods

Headers::fromString

Headers::fromString(string $string)

Populates headers from string representation

Parses a string for headers, and aggregates them, in order, in the current instance, primarily as strings until they are needed (they will be lazy loaded).

Returns Zend\Http\Headers

setPluginClassLoader

setPluginClassLoader(Zend\Loader\PluginClassLocator $pluginClassLoader)

Set an alternate implementation for the plugin class loader

Returns Zend\Http\Headers

getPluginClassLoader

getPluginClassLoader()

Return an instance of a Zend\Loader\PluginClassLocator, lazyload and inject map if necessary.

Returns Zend\Loader\PluginClassLocator

addHeaders

addHeaders(array|Traversable $headers)

Add many headers at once

Expects an array (or Traversable object) of type/value pairs.

Returns Zend\Http\Headers

addHeaderLine

addHeaderLine(string $headerFieldNameOrLine, string $fieldValue)

Add a raw header line, either in name => value, or as a single string ‘name: value’

This method allows for lazy-loading in that the parsing and instantiation of Header object will be delayed until they are retrieved by either get() or current().

Returns Zend\Http\Headers

addHeader

addHeader(Zend\Http\Header\HeaderInterface $header)

Add a Header to this container, for raw values see addHeaderLine() and addHeaders().

Returns Zend\Http\Headers

removeHeader

removeHeader(Zend\Http\Header\HeaderInterface $header)

Remove a Header from the container

Returns bool

clearHeaders

clearHeaders()

Clear all headers

Removes all headers from queue

Returns Zend\Http\Headers

get

get(string $name)

Get all headers of a certain name/type

Returns false| Zend\Http\Header\HeaderInterface| ArrayIterator

has

has(string $name)

Test for existence of a type of header

Returns bool

next

next()

Advance the pointer for this object as an iterator

Returns void

key

key()

Return the current key for this object as an iterator

Returns mixed

valid

valid()

Is this iterator still valid?

Returns bool

rewind

rewind()

Reset the internal pointer for this object as an iterator

Returns void

current

current()

Return the current value for this iterator, lazy loading it if need be

Returns Zend\Http\Header\HeaderInterface

count

count()

Return the number of headers in this container. If all headers have not been parsed, actual count could increase if MultipleHeader objects exist in the Request/Response. If you need an exact count, iterate.

Returns int

toString

toString()

Render all headers at once

This method handles the normal iteration of headers; it is up to the concrete classes to prepend with the appropriate status/request line.

Returns string

toArray

toArray()

Return the headers container as an array

Returns array

forceLoading

forceLoading()

By calling this, it will force parsing and loading of all headers, after this count() will be accurate

Returns bool

Zend\Http\Header\HeaderInterface Methods

fromString

fromString(string $headerLine)

Factory to generate a header object from a string

Returns Zend\Http\Header\GenericHeader

getFieldName

getFieldName()

Retrieve header field name

Returns string

getFieldValue

getFieldValue()

Retrieve header field value

Returns string

toString

toString()

Cast to string as a well formed HTTP header line

Returns in form of “NAME: VALUE”

Returns string

Zend\Http\Header\AbstractAccept Methods

parseHeaderLine

parseHeaderLine(string $headerLine)

Parse the given header line and add the values

Returns void

getFieldValuePartsFromHeaderLine

getFieldValuePartsFromHeaderLine(string $headerLine)

Parse the Field Value Parts represented by a header line

Throws Zend\Http\Header\Exception\InvalidArgumentException if the header is invalid

Returns array

getFieldValue

getFieldValue(array|null $values = null)

Get field value

Returns string

match

match(array|string $matchAgainst)

Match a media string against this header. Returns the matched value or false

Returns Accept\FieldValuePart\AcceptFieldValuePart or bool

getPrioritized

getPrioritized()

Returns all the keys, values and parameters this header represents

Returns array

Zend\Http\Header\AbstractDate Methods

setDateFormat

static setDateFormat(int $format)

Set date output format.

Returns void

getDateFormat

static getDateFormat()

Return current date output format

Returns string

setDate

setDate(string|DateTime $date)

Set the date for this header, this can be a string or an instance of DateTime

Throws Zend\Http\Header\Exception\InvalidArgumentException if the date is neither a valid string nor an instance of \DateTime.

Returns self

getDate

getDate()

Return date for this header

Returns self

date

date()

Return date for this header as an instance of \DateTime

Returns \DateTime

compareTo

compareTo(string|DateTime $date)

Compare provided date to date for this header. Returns < 0 if date in header is less than $date; > 0 if it’s greater, and 0 if they are equal. See strcmp.

Returns int

Zend\Http\Header\AbstractLocation Methods

setUri

setUri(string|Zend\Uri\UriInterface $uri)

Set the URI/URL for this header, this can be a string or an instance of Zend\Uri\Http

Throws Zend\Http\Header\Exception\InvalidArgumentException if $uri is neither a valid URL nor an instance of Zend\Uri\UriInterface.

Returns self

getUri

getUri()

Return the URI for this header

Returns string

uri

uri()

Return the URI for this header as an instance of Zend\Uri\Http

Returns Zend\Uri\UriInterface

List of HTTP Header Types

Some header classes expose methods for manipulating their value. The following list contains all of the classes available in the Zend\Http\Header\* namespace, as well as any specific methods they contain. All these classes implement Zend\Http\Header\HeaderInterface and its methods.

Accept

See Zend\Http\Header\AbstractAccept methods.

addMediaType(string $type, int|float $priority = 1)

Add a media type, with the given priority

Returns self

hasMediaType(string $type)

Does the header have the requested media type?

Returns bool

AcceptCharset

See Zend\Http\Header\AbstractAccept methods.

addCharset(string $type, int|float $priority = 1)

Add a charset, with the given priority

Returns self

hasCharset(string $type)

Does the header have the requested charset?

Returns bool

AcceptEncoding

See Zend\Http\Header\AbstractAccept methods.

addEncoding(string $type, int|float $priority = 1)

Add an encoding, with the given priority

Returns self

hasEncoding(string $type)

Does the header have the requested encoding?

Returns bool

AcceptLanguage

See Zend\Http\Header\AbstractAccept methods.

addLanguage(string $type, int|float $priority = 1)

Add a language, with the given priority

Returns self

hasLanguage(string $type)

Does the header have the requested language?

Returns bool

AcceptRanges

getRangeUnit()

setRangeUnit($rangeUnit)

Age

getDeltaSeconds()

Get number of seconds

Returns int

setDeltaSeconds()

Set number of seconds

Returns self

Allow

getAllMethods()

Get list of all defined methods

Returns array

getAllowedMethods()

Get list of allowed methods

Returns array

allowMethods(array|string $allowedMethods)

Allow methods or list of methods

Returns self

disallowMethods(array|string $allowedMethods)

Disallow methods or list of methods

Returns self

denyMethods(array|string $allowedMethods)

Convenience alias for disallowMethods()

Returns self

isAllowedMethod(string $method)

Check whether method is allowed

Returns bool

AuthenticationInfo

No additional methods

Authorization

No additional methods

CacheControl

isEmpty()

Checks if the internal directives array is empty

Returns bool

addDirective(string $key, string|bool $value)

Add a directive

For directives like ‘max-age=60’, $value = ‘60’

For directives like ‘private’, use the default $value = true

Returns self

hasDirective(string $key)

Check the internal directives array for a directive

Returns bool

getDirective(string $key)

Fetch the value of a directive from the internal directive array

Returns string|null

removeDirective(string $key)

Remove a directive

Returns self

Connection

setValue($value)

Set arbitrary header value

RFC allows any token as value, ‘close’ and ‘keep-alive’ are commonly used

Returns self

isPersistent()

Whether the connection is persistent

Returns bool

setPersistent(bool $flag)

Set Connection header to define persistent connection

Returns self

ContentDisposition

No additional methods

ContentEncoding

No additional methods

ContentLanguage

No additional methods

ContentLength

No additional methods

ContentLocation

See Zend\Http\Header\AbstractLocation methods.

ContentMD5

No additional methods

ContentRange

No additional methods

ContentSecurityPolicy

getDirectives()

Retrieve the defined directives for the policy

Returns an array

setDirective(string $name, array $sources)

Set the directive with the given name to include the sources

As an example: an auction site wishes to load images from any URI, plugin content from a list of trusted media providers (including a content distribution network), and scripts only from a server under its control hosting sanitized ECMAScript:

// http://www.w3.org/TR/2012/CR-CSP-20121115/#sample-policy-definitions
// Example #2
$csp = new ContentSecurityPolicy();
$csp->setDirective('default-src', array()) // No sources
    ->setDirective('img-src', array('*'))
    ->setDirective('object-src' array('media1.example.com', 'media2.example.com', '*.cdn.example.com'))
    ->setDirective('script-src', array('trustedscripts.example.com'));

Returns self

ContentTransferEncoding

No additional methods

ContentType

match(array|string $matchAgainst)

Determine if the mediatype value in this header matches the provided criteria

Returns bool|string

getMediaType()

Get the media type

Returns string

setMediaType(string $mediaType)

Set the media type

Returns self

getParameters()

Get any additional content-type parameters currently set

Returns array

setParameters(array $parameters)

Set additional content-type parameters

Returns self

getCharset()

Get the content-type character set encoding, if any

Returns string|null

setCharset(string $charset)

Set the content-type character set encoding

Returns self

Cookie

Extends ArrayObject

static fromSetCookieArray(array $setCookies)

setEncodeValue()

getEncodeValue()

Date

See Zend\Http\Header\AbstractDate methods.

Etag

No additional methods

Expect

No additional methods

Expires

See Zend\Http\Header\AbstractDate methods.

From

No additional methods

Host

No additional methods

IfMatch

No additional methods

IfModifiedSince

See Zend\Http\Header\AbstractDate methods.

IfNoneMatch

No additional methods

IfRange

No additional methods

IfUnmodifiedSince

See Zend\Http\Header\AbstractDate methods.

KeepAlive

No additional methods

LastModified

See Zend\Http\Header\AbstractDate methods.

Location

See Zend\Http\Header\AbstractLocation methods.

MaxForwards

No additional methods

Origin

No additional methods

Pragma

No additional methods

ProxyAuthenticate

toStringMultipleHeaders(array $headers)

ProxyAuthorization

No additional methods

Range

No additional methods

Referer

See Zend\Http\Header\AbstractLocation methods.

Refresh

No additional methods

RetryAfter

See Zend\Http\Header\AbstractDate methods.

setDeltaSeconds(int $delta)

Set number of seconds

Returns self

getDeltaSeconds()

Get number of seconds

Returns int

Server

No additional methods

SetCookie

getName() / setName(string $name)

The cookie name

getValue() / setValue(string $value)

The cookie value

getExpires() / setExpires(int|string $expires)

The time frame the cookie is valid for, null is a session cookie

getPath() / setPath(string $path)

The URI path the cookie is bound to

getDomain() / setDomain(string $domain)

The domain the cookie applies to

getMaxAge() / setMaxAge(int $maxAge)

The maximum age of the cookie

getVersion() / setVersion(int $version)

The cookie version

isSecure()

Whether the cookies contains the Secure flag

Returns bool

setSecure(bool $secure)

Set whether the cookies contains the Secure flag

Returns self

isHttponly()

Whether the cookies can be accessed via HTTP only

Returns bool

setHttponly(bool $httponly)

Set whether the cookies can be accessed via HTTP only

Returns self

isExpired()

Whether the cookie is expired

Returns bool

isSessionCookie()

Whether the cookie is a session cookie

Returns bool

setQuoteFieldValue(bool $quotedValue)

Set whether the value for this cookie should be quoted

Returns self

hasQuoteFieldValue()

Check whether the value for this cookie should be quoted

Returns bool

isValidForRequest()

Whether the cookie is valid for a given request domain, path and isSecure

Returns bool

match(string $uri, bool $matchSessionCookies, int $now)

Checks whether the cookie should be sent or not in a specific scenario

Returns bool

static matchCookieDomain(string $cookieDomain, string $host)

Check if a cookie’s domain matches a host name.

Returns bool

static matchCookiePath(string $cookiePath, string $path)

Check if a cookie’s path matches a URL path

Returns bool

toStringMultipleHeaders(array $headers)

Returns string

TE

No additional methods

Trailer

No additional methods

TransferEncoding

No additional methods

Upgrade

No additional methods

UserAgent

No additional methods

Vary

No additional methods

Via

No additional methods

Warning

No additional methods

WWWAuthenticate

toStringMultipleHeaders(array $headers)

Examples

Retrieving headers from a Zend\Http\Headers object

// $client is an instance of Zend\Http\Client
$response = $client->send();
$headers = $response->getHeaders();

// We can check if the Request contains a specific header by
// using the ``has`` method. Returns boolean ``TRUE`` if at least
// one matching header found, and ``FALSE`` otherwise
$headers->has('Content-Type');

// We can retrieve all instances of a specific header by using
// the ``get`` method:
$contentTypeHeaders = $headers->get('Content-Type');

There are three possibilities for the return value of the above call to the get method:

• If no Content-Type header was set in the Request, get will return false.
• If only one Content-Type header was set in the Request, get will return an instance of Zend\Http\Header\ContentType.
• If more than one Content-Type header was set in the Request, get will return an ArrayIterator containing one Zend\Http\Header\ContentType instance per header.

Adding headers to a Zend\Http\Headers object

$headers = new Zend\Http\Headers();

// We can directly add any object that implements Zend\Http\Header\HeaderInterface
$typeHeader = Zend\Http\Header\ContentType::fromString('Content-Type: text/html');
$headers->addHeader($typeHeader);

// We can add headers using the raw string representation, either
// passing the header name and value as separate arguments...
$headers->addHeaderLine('Content-Type', 'text/html');

// .. or we can pass the entire header as the only argument
$headers->addHeaderLine('Content-Type: text/html');

// We can also add headers in bulk using addHeaders, which accepts
// an array of individual header definitions that can be in any of
// the accepted formats outlined below:
$headers->addHeaders(array(

    // An object implementing Zend\Http\Header\HeaderInterface
    Zend\Http\Header\ContentType::fromString('Content-Type: text/html'),

    // A raw header string
    'Content-Type: text/html',

    // We can also pass the header name as the array key and the
    // header content as that array key's value
    'Content-Type' => 'text/html');

));

Removing headers from a Zend\Http\Headers object

We can remove all headers of a specific type using the removeHeader method, which accepts a single object implementing Zend\Http\Header\HeaderInterface

// $headers is a pre-configured instance of Zend\Http\Headers

// We can also delete individual headers or groups of headers
$matches = $headers->get('Content-Type');

// If more than one header was found, iterate over the collection
// and remove each one individually
if ($matches instanceof ArrayIterator) {
    foreach ($headers as $header) {
        $headers->removeHeader($header);
    }
// If only a single header was found, remove it directly
} elseif ($matches instanceof Zend\Http\Header\HeaderInterface) {
    $headers->removeHeader($header);
}

// In addition to this, we can clear all the headers currently stored in
// the container by calling the clearHeaders() method
$matches->clearHeaders();