Read/write API for HTTP response headers. More...

#include "response_headers.h"

Inheritance diagram for net_instaweb::ResponseHeaders:

Public Types
enum	VaryOption { kRespectVaryOnResources, kIgnoreVaryOnResources }

enum	ValidatorOption { kHasValidator, kNoValidator }

Public Types inherited from net_instaweb::Headers< HttpResponseHeaders >
typedef std::pair< StringPiece, StringPiece >	ValueAndAttributes
	typedef's for manipulating the cookie multimap.

typedef std::multimap < StringPiece, ValueAndAttributes >	CookieMultimap

typedef std::multimap < StringPiece, ValueAndAttributes > ::const_iterator	CookieMultimapConstIter

Public Member Functions
	ResponseHeaders (const HttpOptions &options)
	This constructor with options explicitly set should be used by all callers.

	ResponseHeaders (const ResponseHeaders &other)

ResponseHeaders &	operator= (const ResponseHeaders &other)

	ResponseHeaders ()

void	FixDateHeaders (int64 now_ms)

bool	cache_fields_dirty () const

virtual void	Clear ()

void	CopyFrom (const ResponseHeaders &other)

bool	MergeContentType (const StringPiece &content_type)

virtual void	UpdateFrom (const Headers< HttpResponseHeaders > &other)

void	UpdateFromProto (const HttpResponseHeaders &proto)

virtual bool	WriteAsBinary (Writer writer, MessageHandler message_handler)
	Serialize HTTP response header to a binary stream.

virtual bool	ReadFromBinary (const StringPiece &buf, MessageHandler *handler)

virtual bool	WriteAsHttp (Writer writer, MessageHandler handler) const
	Serialize HTTP response header in HTTP format so it can be re-parsed.

void	ComputeCaching ()

bool	IsProxyCacheable (RequestHeaders::Properties properties, VaryOption respect_vary_on_resources, ValidatorOption has_request_validator) const

bool	IsProxyCacheable () const

bool	IsBrowserCacheable () const

bool	RequiresBrowserRevalidation () const

bool	RequiresProxyRevalidation () const

int64	CacheExpirationTimeMs () const

void	SetDateAndCaching (int64 date_ms, int64 ttl_ms, const StringPiece &cache_control_suffix)

void	SetDateAndCaching (int64 date_ms, int64 ttl_ms)

GoogleString	CacheControlValuesToPreserve ()

void	SetTimeHeader (const StringPiece &header, int64 time_ms)
	Set a time-based header, converting ms since epoch to a string.

void	SetDate (int64 date_ms)

void	SetLastModified (int64 last_modified_ms)

void	SetCacheControlMaxAge (int64 ttl_ms)

void	SetCacheControlPublic ()

void	SetOriginalContentLength (int64 content_length)

void	SetContentLength (int64 content_length)

bool	Sanitize ()

void	GetSanitizedProto (HttpResponseHeaders *proto) const

bool	headers_complete () const

int	status_code () const

bool	has_status_code () const

void	set_status_code (const int code)

const char *	reason_phrase () const

void	set_reason_phrase (const StringPiece &reason_phrase)

const HttpOptions &	http_options () const

int64	implicit_cache_ttl_ms () const

void	set_implicit_cache_ttl_ms (const int64 ttl)

bool	has_last_modified_time_ms () const

int64	last_modified_time_ms () const

int64	date_ms () const
	Timestamp from Date header.

bool	has_date_ms () const

int64	cache_ttl_ms () const

bool	is_implicitly_cacheable () const

GoogleString	ToString () const

void	SetStatusAndReason (HttpStatus::Code code)
	Sets the status code and reason_phrase based on an internal table.

void	DebugPrint () const

bool	IsErrorStatus () const
	Returns true if our status denotes the request failing.

bool	IsServerErrorStatus () const
	Returns true if our status denotes a server side error.

bool	IsRedirectStatus () const
	Returns true if our status denotes a redirect.

bool	IsGzipped () const
	Determines whether a response header is marked as gzipped.

bool	WasGzippedLast () const

const ContentType *	DetermineContentType () const

bool	IsHtmlLike () const
	Does this header have an HTML-like Content-Type (HTML, XHTML, ...).

GoogleString	DetermineCharset () const
	Get the charset. Empty string if none set in a Content-Type header.

void	DetermineContentTypeAndCharset (const ContentType *content_type_out, GoogleString charset_out) const

bool	ParseDateHeader (const StringPiece &attr, int64 *date_ms) const

void	ParseFirstLine (const StringPiece &first_line)
	Parses the first line of an HTTP response, including the "HTTP/".

void	ParseFirstLineHelper (const StringPiece &first_line)
	Parses the first line of an HTTP response, skipping the "HTTP/".

void	set_first_line (int major_version, int minor_version, int status_code, const StringPiece &reason_phrase)
	Set whole first line.

bool	FindContentLength (int64 *content_length) const

void	ForceCaching (int64 ttl_ms)

bool	UpdateCacheHeadersIfForceCached ()
	Update the caching headers if the response has force cached.

int64	SizeEstimate () const

bool	GetCookieString (GoogleString *cookie_str) const

bool	HasCookie (StringPiece name, StringPieceVector values, StringPieceVector attributes) const

bool	HasAnyCookiesWithAttribute (StringPiece attribute_name, StringPiece *attribute_value)

bool	SetQueryParamsAsCookies (const GoogleUrl &gurl, StringPiece query_params, const StringPieceVector &to_exclude, int64 expiration_time)

bool	ClearOptionCookies (const GoogleUrl &gurl, StringPiece option_cookies, const StringPieceVector &to_exclude)

bool	HasLinkRelCanonical () const

void	SetSMaxAge (int s_maxage_sec)

Public Member Functions inherited from net_instaweb::Headers< HttpResponseHeaders >
int	major_version () const

bool	has_major_version () const

int	minor_version () const

void	set_major_version (int major_version)

void	set_minor_version (int major_version)

int	NumAttributes () const
	Raw access for random access to attribute name/value pairs.

const GoogleString &	Name (int i) const

const GoogleString &	Value (int i) const

void	SetValue (int i, StringPiece value)

bool	Lookup (const StringPiece &name, ConstStringStarVector *values) const

GoogleString	LookupJoined (StringPiece name) const

const char *	Lookup1 (const StringPiece &name) const

bool	Has (const StringPiece &name) const
	Does there exist a header with given name.

bool	HasValue (const StringPiece &name, const StringPiece &value) const
	Is value one of the values in Lookup(name)?

int	NumAttributeNames () const
	NumAttributeNames is also const but not thread-safe.

void	RemoveCookie (const StringPiece &cookie_name)

void	Add (const StringPiece &name, const StringPiece &value)

bool	Remove (const StringPiece &name, const StringPiece &value)

bool	RemoveAll (const StringPiece &name)
	Removes all headers by name. Return true if anything was removed.

bool	RemoveAllFromSortedArray (const StringPiece *names, int names_size)

bool	RemoveAllWithPrefix (const StringPiece &prefix)

bool	RemoveIfNotIn (const Headers &keep)

virtual void	Replace (const StringPiece &name, const StringPiece &value)

void	CopyToProto (HttpResponseHeaders *proto) const
	Copy protobuf representation to "proto".

Static Public Member Functions
static bool	IsImminentlyExpiring (int64 start_date_ms, int64 expire_ms, int64 now_ms, const HttpOptions &options)

static VaryOption	GetVaryOption (bool respect_vary)

static bool	ParseTime (const char time_str, int64 time_ms)
	Parses an arbitrary string into milliseconds since 1970.

static GoogleString	RelCanonicalHeaderValue (StringPiece url)
	Constructs a <url>; rel="canonical" value for use with a Link header.

static bool	ApplySMaxAge (int s_maxage_sec, StringPiece existing_cache_control, GoogleString *updated_cache_control)

static bool	IsHopByHopIndication (StringPiece val)

Static Public Member Functions inherited from net_instaweb::Headers< HttpResponseHeaders >
static bool	RemoveFromHeaders (const StringType names, int names_size, protobuf::RepeatedPtrField< NameValue > headers)

static bool	FindValueForName (const StringPieceVector &name_equals_value_vec, StringPiece name_to_find, StringPiece *optional_retval)

static bool	ExtractNameAndValue (StringPiece input, StringPiece name, StringPiece optional_retval)

Protected Member Functions
virtual void	UpdateHook ()

Protected Member Functions inherited from net_instaweb::Headers< HttpResponseHeaders >
void	SetProto (HttpResponseHeaders *proto)
	You need to know what you're doing to use these, so for subclasses only. More...

void	CopyProto (const HttpResponseHeaders &proto)

void	PopulateMap () const
	const is a lie, mutates map_.

const CookieMultimap *	PopulateCookieMap (StringPiece header_name) const

const HttpResponseHeaders *	proto () const

HttpResponseHeaders *	mutable_proto ()

Friends
class	ResponseHeadersTest

Detailed Description

Read/write API for HTTP response headers.

Constructor & Destructor Documentation

net_instaweb::ResponseHeaders::ResponseHeaders ( )

inline

This default constructor should only be used in tests.

Todo:: TODO(sligocki): Phase this out so that nobody uses this one by accident.

Member Function Documentation

static bool net_instaweb::ResponseHeaders::ApplySMaxAge	(	int	s_maxage_sec,
		StringPiece	existing_cache_control,
		GoogleString *	updated_cache_control
	)

static

Stand-alone version of SetSMaxAge. If there are changes to make, returns true and sets updated_cache_control.

bool net_instaweb::ResponseHeaders::cache_fields_dirty ( ) const

inline

Returns whether the computed cache fields have been dirtied by a mutation since ComputeCache was called. This is exposed for debug assertions.

GoogleString net_instaweb::ResponseHeaders::CacheControlValuesToPreserve ( )

Returns Cache-Control header values that we might need to preserve. This function is meant to be used with SetDateAndCaching. It currently looks for and returns no-transform and no-store if found.

int64 net_instaweb::ResponseHeaders::CacheExpirationTimeMs ( ) const

Note(sligocki): I think CacheExpirationTimeMs will return 0 if !IsCacheable

Todo:: TODO(sligocki): Look through callsites and make sure this is being interpreted correctly.

void net_instaweb::ResponseHeaders::ComputeCaching ( )

Compute caching information. The current time is used to compute the absolute time when a cache resource will expire. The timestamp is in milliseconds since 1970. It is an error to call any of the accessors before ComputeCaching is called.

const ContentType* net_instaweb::ResponseHeaders::DetermineContentType ( ) const

Get ContentType. NULL if none set or it isn't in our predefined set of known content types.

void net_instaweb::ResponseHeaders::DetermineContentTypeAndCharset	(	const ContentType **	content_type_out,
		GoogleString *	charset_out
	)		const

Determine both the charset and content-type as above. See DetermineContentType() and DetermineCharset() for details. You may also pass in NULL for those of _out parameters you do not need (but in that case the individual functions would be more convenient)

bool net_instaweb::ResponseHeaders::FindContentLength ( int64 * content_length ) const

Finds Content-Length in the response headers, returning true and putting it in *content_length if successful.

void net_instaweb::ResponseHeaders::FixDateHeaders ( int64 now_ms )

This will set Date and (if supplied in the first place, Expires) header to now if the delta of date header wrt now_ms is more than a tolerance. Leaves the ComputeCaching state dirty if it came in dirty, or clean if it came in clean.

void net_instaweb::ResponseHeaders::ForceCaching ( int64 ttl_ms )

Force cache the response with the given TTL even if it is private. Note that this does not change any of the headers. The values of cache_ttl_ms, IsCacheable and IsProxyCacheable are updated once ComputeCaching() is called. Note that for responses which were originally cacheable, the effective cache TTL is the maximum of the original TTL and ttl_ms. For responses which were originally uncacheable, the new cache TTL is ttl_ms.

bool net_instaweb::ResponseHeaders::GetCookieString ( GoogleString * cookie_str ) const

Returns true if the response headers have cookies and false otherwise. If cookies are found then it sets them in cookie_str in javascript array format.

void net_instaweb::ResponseHeaders::GetSanitizedProto ( HttpResponseHeaders * proto ) const

Copies the HttpResponseHeaders proto from the response headers to the given input after removing the Set-Cookie fields.

bool net_instaweb::ResponseHeaders::HasAnyCookiesWithAttribute	(	StringPiece	attribute_name,
		StringPiece *	attribute_value
	)

Returns true if any cookies in the response headers have an attribute with the given name, returning the value for the first one found in '*attribute_value' iff it isn't NULL.

bool net_instaweb::ResponseHeaders::HasCookie	(	StringPiece	name,
		StringPieceVector *	values,
		StringPieceVector *	attributes
	)		const

Returns true if the response headers have a cookie with the given name. 'values' gives the associated values. 'attributes' gives the attributes. name results in "" in values and nothing in attributes. name=; HttpOnly results in "" in values and "HttpOnly" in attributes. name=value results in "value" in values and nothing in attributes. name=value; Expires=yaddayadda; HttpOnly results in "value" in values and " Expires=yaddayadda" and " HttpOnly" in attributes. Note that the attributes are not trimmed of whitespace. The return value is true in all the above cases. It is a limitation of this API that a cookie with no value set is indistinguishable from a cookie with an empty value. Furthermore, if the cookie is set in multiple headers, values and attributes will be the union of those headers' contents.

Todo:: TODO(matterbury): Fix this to implement the correct behavior, which should take into account the domain and path of the cookie as part of uniqueness.

bool net_instaweb::ResponseHeaders::HasLinkRelCanonical ( ) const

Returns true if the headers may contain a Link: rel = canonical entry. (Slightly approximate, will never say 'no' if it's there).

bool net_instaweb::ResponseHeaders::headers_complete ( ) const

inline

Todo:: TODO(jmarantz): consider an alternative representation

int64 net_instaweb::ResponseHeaders::implicit_cache_ttl_ms ( ) const

inline

Todo:: TODO(sligocki): Remove these setters (and getters) once we make sure that all values are set at construction time.

bool net_instaweb::ResponseHeaders::IsBrowserCacheable ( ) const

Returns true if the response is privately cacheable.

Generally you want to use IsProxyCacheable*() instead.

static bool net_instaweb::ResponseHeaders::IsHopByHopIndication ( StringPiece val )

static

Returns true if the given value should be interpreted as a header being marked as hop by hop when listed as a value in a Connection: header.

static bool net_instaweb::ResponseHeaders::IsImminentlyExpiring	(	int64	start_date_ms,
		int64	expire_ms,
		int64	now_ms,
		const HttpOptions &	options
	)

static

Returns true if the resource with given date and TTL is going to expire shortly and should hence be proactively re-fetched. All the parameters are absolute times.

bool net_instaweb::ResponseHeaders::IsProxyCacheable	(	RequestHeaders::Properties	properties,
		VaryOption	respect_vary_on_resources,
		ValidatorOption	has_request_validator
	)		const

Returns true if these response headers indicate the response is publicly cacheable if it was fetched w/o special authorization headers.

See also RequiresProxyRevalidation(), which must be used to determine whether stale content can be re-used by a proxy.

The difference between HTML and non-HTML is tolerance for Vary:Cookie. In HTML we are willing to cache cookieless responses and serve them to other cookieless requests, but this requires the requests to be validated. Callers can indicate their ability to validate requests by passing kHasRequestValidator for has_request_validator.

Parameters

respect_vary_on_resources

Todo:: TODO(sligocki): Use http_options_.respect_vary. Some inconsistencies need to be worked out first.

bool net_instaweb::ResponseHeaders::IsProxyCacheable ( ) const

inline

The zero-arg version of IsProxyCacheable gives a pessimistic answer, assuming the request has cookies, there is no validator, and we respect Vary.

bool net_instaweb::ResponseHeaders::MergeContentType ( const StringPiece & content_type )

Merge the new content_type with what is already in the headers. Returns true if the existing content-type header was changed. If the new content_type contains non-printable characters, the change will be rejected silently (and false will be returned).

bool net_instaweb::ResponseHeaders::ParseDateHeader	(	const StringPiece &	attr,
		int64 *	date_ms
	)		const

Parses a date header such as HttpAttributes::kDate or HttpAttributes::kExpires, returning the timestamp as number of milliseconds since 1970.

virtual bool net_instaweb::ResponseHeaders::ReadFromBinary	(	const StringPiece &	buf,
		MessageHandler *	handler
	)

virtual

Read HTTP response header from a binary string. Note that this is distinct from HTTP response-header parsing, which is in ResponseHeadersParser.

Reimplemented from net_instaweb::Headers< HttpResponseHeaders >.

bool net_instaweb::ResponseHeaders::RequiresBrowserRevalidation ( ) const

Determines whether must-revalidate is in any Cache-Control setting.

Proxies such as PSOL likely want to use RequiresProxyRevalidation() instead.

bool net_instaweb::ResponseHeaders::RequiresProxyRevalidation ( ) const

Determines whether either must-revalidate or proxy-revalidate is in any Cache-Control setting. These must be checked to see whether it's OK to serve stale content while freshening in the background.

bool net_instaweb::ResponseHeaders::Sanitize ( )

Removes hop-by-hop plus cookie headers, and returns true if any changes were made.

void net_instaweb::ResponseHeaders::SetCacheControlMaxAge ( int64 ttl_ms )

Sets the cache-control max-age to the specified value leaving the remaining Cache-Control attributes the same. This also updates the Expires header appropriately. Note that all existing max-age values are removed.

void net_instaweb::ResponseHeaders::SetCacheControlPublic ( )

Sets the cache-control to explicitly have 'public', as long as that's not in conflict with other CC headers.

void net_instaweb::ResponseHeaders::SetContentLength ( int64 content_length )

Sets the content-length attribute, removing any matching x-orginal-content-length header.

void net_instaweb::ResponseHeaders::SetDateAndCaching	(	int64	date_ms,
		int64	ttl_ms,
		const StringPiece &	cache_control_suffix
	)

Set Date, Cache-Control and Expires headers appropriately. If cache_control_suffix is provided it is appended onto the Cache-Control: "max-age=%d" string. For example, cache_control_suffix = ", private" or ", no-cache, no-store".

void net_instaweb::ResponseHeaders::SetOriginalContentLength ( int64 content_length )

Sets the x-original-content-length header, used to relay information on the original size of optimized resources.

bool net_instaweb::ResponseHeaders::SetQueryParamsAsCookies	(	const GoogleUrl &	gurl,
		StringPiece	query_params,
		const StringPieceVector &	to_exclude,
		int64	expiration_time
	)

Set or clears the given query parameters as response header cookies, skipping any in to_exclude. query_params and option_cookies are both query parameters (name=value separated by '&'s) and are treated as untrusted data. Sets the cookies' Expires attributes to the given value. Returns true if any cookies were set, false if not.

void net_instaweb::ResponseHeaders::SetSMaxAge ( int s_maxage_sec )

Gives a new value for the cache control header, making it more restrictive by adding s-maxage=<s_maxage_sec>. Takes into account existing s-maxage and maxage segments:

If there is no s-maxage:
- If there's a maxage <= s_maxage_sec:
  - Make no changes.
- Otherwise append an s_maxage
Otherwise, bring s-maxage down to s_maxage_sec if it's larger.

int64 net_instaweb::ResponseHeaders::SizeEstimate ( ) const

Returns estimated size in bytes of these headers (if transferred over HTTP, not SPDY or other protocols). This is an estimate because it may not properly account for things like spacing around : or whether multiple headers were on a single or multiple lines.

virtual void net_instaweb::ResponseHeaders::UpdateFrom ( const Headers< HttpResponseHeaders > & other )

virtual

Merge headers. Replaces all headers specified both here and in other with the version in other. Useful for updating headers when recieving 304 Not Modified responses. Note: We must use Headers<HttpResponseHeaders> instead of ResponseHeaders so that we don't expose the base UpdateFrom (and to avoid "hiding" errors).

Reimplemented from net_instaweb::Headers< HttpResponseHeaders >.

void net_instaweb::ResponseHeaders::UpdateFromProto ( const HttpResponseHeaders & proto )

Initializes the response headers with the one in proto, clearing the existing fields.

virtual void net_instaweb::ResponseHeaders::UpdateHook ( )

protectedvirtual

Called whenever a mutation occurrs. Subclasses may override to update any local copies of data.

Reimplemented from net_instaweb::Headers< HttpResponseHeaders >.

The documentation for this class was generated from the following file:

pagespeed/kernel/http/response_headers.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation