http::headers::HeaderMap Class Reference

#include <userver/http/header_map.hpp>

Detailed Description

Container that maps case-insensitive header name into header value.

Allows storing up to 24576 name->value pairs, after that an attempt to insert a new pair will throw.

Has an anti-hashdos collisions resolution built-in, and the capacity limit might be lowered in case of an attack being detected.

Iterators/pointers invalidation loosely matches that of std::vector:

• if an insertion took place, iterators/pointers are invalidated;
• successful erase invalidates the iterator being erased and begin (it's implemented via swap and pop_back idiom, and begin is actually an rbegin of underlying vector).

Definition at line 38 of file header_map.hpp.

Classes
class	ConstIterator
class	Iterator
class	TooManyHeadersException
	The exception being thrown in case of capacity overflow. More...

Public Types
using	iterator = Iterator
using	const_iterator = ConstIterator
using	key_type = std::string
using	mapped_type = std::string

Public Member Functions
	HeaderMap ()
	Default constructor.
	HeaderMap (std::initializer_list< std::pair< std::string, std::string > > headers)
	HeaderMap (std::initializer_list< std::pair< PredefinedHeader, std::string > > headers)
	HeaderMap (std::size_t capacity)
template<typename InputIt >
	HeaderMap (InputIt first, InputIt last)
	~HeaderMap ()
	Destructor.
	HeaderMap (const HeaderMap &other)
	Copy constructor.
	HeaderMap (HeaderMap &&other) noexcept
	Move constructor.
HeaderMap &	operator= (const HeaderMap &other)
	Copy assignment operator.
HeaderMap &	operator= (HeaderMap &&other) noexcept
	Move assignment operator.
void	reserve (std::size_t capacity)
	Non-binding call to reserve capacity elements for internal storage.
std::size_t	size () const noexcept
	Returns the amount of name-value-pairs being stored.
bool	empty () const noexcept
	Return true if no name-value-pairs are being stored, false otherwise.
void	clear ()
std::size_t	count (std::string_view key) const noexcept
	Returns 1 if the key exists, 0 otherwise.
std::size_t	count (const PredefinedHeader &key) const noexcept
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<std::size_t Size>
std::size_t	count (const char(&)[Size]) const noexcept
bool	contains (std::string_view key) const noexcept
	Returns true if the key exists, false otherwise.
bool	contains (const PredefinedHeader &key) const noexcept
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<std::size_t Size>
bool	contains (const char(&)[Size]) const noexcept
std::string &	operator[] (std::string &&key)
std::string &	operator[] (std::string_view key)
std::string &	operator[] (const PredefinedHeader &key)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<std::size_t Size>
std::string &	operator[] (const char(&)[Size])
Iterator	find (std::string_view key) noexcept
ConstIterator	find (std::string_view key) const noexcept
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Iterator	find (const PredefinedHeader &key) noexcept
ConstIterator	find (const PredefinedHeader &key) const noexcept
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<std::size_t Size>
Iterator	find (const char(&)[Size]) noexcept
template<std::size_t Size>
ConstIterator	find (const char(&)[Size]) const noexcept
template<typename... Args>
void	emplace (std::string_view key, Args &&... args)
template<typename... Args>
void	emplace (std::string key, Args &&... args)
template<typename... Args>
void	try_emplace (std::string key, Args &&... args)
template<typename InputIt >
void	insert (InputIt first, InputIt last)
void	insert (const std::pair< std::string, std::string > &kvp)
void	insert (std::pair< std::string, std::string > &&kvp)
void	insert_or_assign (std::string key, std::string value)
void	insert_or_assign (const PredefinedHeader &key, std::string value)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
void	InsertOrAppend (std::string key, std::string value)
void	InsertOrAppend (const PredefinedHeader &key, std::string value)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
Iterator	erase (Iterator it)
Iterator	erase (ConstIterator it)
Iterator	erase (std::string_view key)
Iterator	erase (const PredefinedHeader &key)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<std::size_t Size>
Iterator	erase (const char(&)[Size])
std::string &	at (std::string_view key)
std::string &	at (const PredefinedHeader &key)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
const std::string &	at (std::string_view key) const
const std::string &	at (const PredefinedHeader &key) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<std::size_t Size>
std::string &	at (const char(&)[Size])
template<std::size_t Size>
const std::string &	at (const char(&)[Size]) const
Iterator	begin () noexcept
	Returns an iterator to the first name-value-pair being stored.
ConstIterator	begin () const noexcept
	Returns an iterator to the first name-value-pair being stored.
ConstIterator	cbegin () const noexcept
	Returns an iterator to the first name-value-pair being stored.
Iterator	end () noexcept
	Returns an iterator to the end (valid but not dereferenceable).
ConstIterator	end () const noexcept
	Returns an iterator to the end (valid but not dereferenceable).
ConstIterator	cend () const noexcept
	Returns an iterator to the end (valid but not dereferenceable).
bool	operator== (const HeaderMap &other) const noexcept
void	OutputInHttpFormat (HeadersString &buffer) const

Member Typedef Documentation

const_iterator

using http::headers::HeaderMap::const_iterator = ConstIterator

Definition at line 46 of file header_map.hpp.

iterator

using http::headers::HeaderMap::iterator = Iterator

Definition at line 45 of file header_map.hpp.

key_type

using http::headers::HeaderMap::key_type = std::string

Definition at line 48 of file header_map.hpp.

mapped_type

using http::headers::HeaderMap::mapped_type = std::string

Definition at line 49 of file header_map.hpp.

Constructor & Destructor Documentation

HeaderMap() [1/4]

http::headers::HeaderMap::HeaderMap

(

std::initializer_list< std::pair< std::string, std::string > >

headers

)

Constructor from initializer list: HeaderMap({{"a", "b"}, {"c", "d"}}). Its unspecified which pair is inserted in case of names not being unique.

HeaderMap() [2/4]

http::headers::HeaderMap::HeaderMap

(

std::initializer_list< std::pair< PredefinedHeader, std::string > >

headers

)

Constructor from initializer list: HeaderMap({{"a", "b"}, {"c", "d"}}). Its unspecified which pair is inserted in case of names not being unique.

HeaderMap() [3/4]

http::headers::HeaderMap::HeaderMap

(

std::size_t

capacity

)

Constructor with capacity: preallocates capacity elements for internal storage.

HeaderMap() [4/4]

template<typename InputIt >

http::headers::HeaderMap::HeaderMap	(	InputIt	first,
		InputIt	last )

Constructor from iterator pair: HeaderMap{key_value_pairs.begin(), key_value_pairs.end()}. Its unspecified which pair is inserted in case of names not being unique.

Definition at line 276 of file header_map.hpp.

Member Function Documentation

at() [1/4]

template<std::size_t Size>

std::string & http::headers::HeaderMap::at ( const char(&)[Size] )

inline

Definition at line 227 of file header_map.hpp.

at() [2/4]

template<std::size_t Size>

const std::string & http::headers::HeaderMap::at ( const char(&)[Size] ) const

inline

Definition at line 231 of file header_map.hpp.

at() [3/4]

std::string & http::headers::HeaderMap::at

(

std::string_view

key

)

If the key is present in container, returns reference to its header value, otherwise throws std::out_of_range.

at() [4/4]

const std::string & http::headers::HeaderMap::at

(

std::string_view

key

)

const

If the key is present in container, returns reference to its header value, otherwise throws std::out_of_range.

clear()

void http::headers::HeaderMap::clear

(

)

Removes all the key-value-pairs being stored, doesn't shrink underlying storage.

contains()

template<std::size_t Size>

bool http::headers::HeaderMap::contains ( const char(&)[Size] ) const

inlinenoexcept

Definition at line 112 of file header_map.hpp.

count()

template<std::size_t Size>

std::size_t http::headers::HeaderMap::count ( const char(&)[Size] ) const

inlinenoexcept

Definition at line 102 of file header_map.hpp.

emplace() [1/2]

template<typename... Args>

void http::headers::HeaderMap::emplace ( std::string key, Args &&... args )

inline

If the key is already present in the map, does nothing. Otherwise inserts a pair of key and inplace constructed value.

Definition at line 162 of file header_map.hpp.

emplace() [2/2]

template<typename... Args>

void http::headers::HeaderMap::emplace ( std::string_view key, Args &&... args )

inline

If the key is already present in the map, does nothing. Otherwise inserts a pair of key and in-place constructed value.

Definition at line 155 of file header_map.hpp.

erase() [1/4]

template<std::size_t Size>

HeaderMap::Iterator http::headers::HeaderMap::erase

(

const

char(&)[Size]

)

Definition at line 446 of file header_map.hpp.

erase() [2/4]

Iterator http::headers::HeaderMap::erase

(

ConstIterator

it

)

Erases the pair to which the iterator points, returns iterator following the last removed element. Iterators/pointers to erased value and begin are invalidated.

erase() [3/4]

Iterator http::headers::HeaderMap::erase

(

Iterator

it

)

Erases the pair to which the iterator points, returns iterator following the last removed element. Iterators/pointers to erased value and begin are invalidated.

erase() [4/4]

Iterator http::headers::HeaderMap::erase

(

std::string_view

key

)

If the key is present in container, behaves exactly like erase(Iterator). Otherwise does nothing and returns end().

find() [1/4]

template<std::size_t Size>

HeaderMap::ConstIterator http::headers::HeaderMap::find ( const char(&)[Size] ) const

noexcept

Definition at line 441 of file header_map.hpp.

find() [2/4]

template<std::size_t Size>

HeaderMap::Iterator http::headers::HeaderMap::find ( const char(&)[Size] )

noexcept

Definition at line 436 of file header_map.hpp.

find() [3/4]

Iterator http::headers::HeaderMap::find ( const PredefinedHeader & key )

noexcept

If the key is present, returns iterator to its name-value pair, otherwise return end().

find() [4/4]

Iterator http::headers::HeaderMap::find ( std::string_view key )

noexcept

If the key is present, returns iterator to its name-value pair, otherwise return end().

insert() [1/3]

void http::headers::HeaderMap::insert

(

const std::pair< std::string, std::string > &

kvp

)

If kvp.first is already present in the map, does nothing, otherwise inserts the pair into container.

insert() [2/3]

template<typename InputIt >

void http::headers::HeaderMap::insert	(	InputIt	first,
		InputIt	last )

For every iterator it in [first, last) inserts *it. Its unspecified which pair is inserted in case of names not being unique.

Definition at line 281 of file header_map.hpp.

insert() [3/3]

void http::headers::HeaderMap::insert

(

std::pair< std::string, std::string > &&

kvp

)

If kvp.first is already present in the map, does nothing, otherwise inserts the pair into container.

insert_or_assign()

void http::headers::HeaderMap::insert_or_assign	(	std::string	key,
		std::string	value )

If key is already present in the map, changes corresponding header value to provided value, otherwise inserts the pair into container.

InsertOrAppend()

void http::headers::HeaderMap::InsertOrAppend	(	std::string	key,
		std::string	value )

If key is already present in the map, appends ",{value}" to the corresponding header value, otherwise inserts the pair into container.

operator==()

bool http::headers::HeaderMap::operator== ( const HeaderMap & other ) const

noexcept

Returns true if other contains exactly the same set of name-value-pairs, false otherwise.

operator[]() [1/3]

template<std::size_t Size>

std::string & http::headers::HeaderMap::operator[] ( const char(&)[Size] )

inline

Definition at line 130 of file header_map.hpp.

operator[]() [2/3]

std::string & http::headers::HeaderMap::operator[]

(

std::string &&

key

)

If the key is present, returns reference to it's header value, otherwise inserts a pair (key, "") and returns reference to newly inserted empty string. In an insertion took place, key is moved-out, otherwise key is left unchanged.

operator[]() [3/3]

std::string & http::headers::HeaderMap::operator[]

(

std::string_view

key

)

If the key is present, returns reference to it's header value, otherwise inserts a pair (key, "") and returns reference to newly inserted empty string.

OutputInHttpFormat()

void http::headers::HeaderMap::OutputInHttpFormat

(

HeadersString &

buffer

)

const

Appends container content in http headers format to provided buffer, that is appends

header1: value1\r\n
header2: value2\r\n
...

resizing buffer as needed.

try_emplace()

template<typename... Args>

void http::headers::HeaderMap::try_emplace ( std::string key, Args &&... args )

inline

If the key is already present in the map, does nothing. Otherwise inserts a pair of key and inplace constructed value.

Definition at line 169 of file header_map.hpp.

Friends And Related Symbol Documentation

TestsHelper

friend class TestsHelper

friend

Definition at line 264 of file header_map.hpp.

---

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

• userver/http/header_map.hpp