Defines a set of methods that a servlet uses to communicate with its servlet container. More...

#include <context.h>

Public Types
typedef std::map< std::string, std::string, std::less<> >	init_params_map
	Type definition for initial parameters map.

Public Member Functions
virtual	~servlet_context () noexcept=default
	virtual destructor

const std::string &	get_context_path () const
	Return the main path associated with this context. More...

const std::string &	get_webapp_path () const
	Returns filesystem path of current web application. More...

template<typename T , typename KeyType >
optional_ref< const T >	get_attribute (const KeyType &key) const
	Returns the servlet container attribute with the given name, or empty reference if there is no attribute by that name. More...

template<typename KeyType , typename ValueType >
optional_ref< const ValueType >	get_attribute (const KeyType &key) const
	Finds attribute by key and casts it to specified ValueType. More...

template<typename ValueType >
bool	set_attribute (const std::string &key, ValueType &&value)
	Binds an object to a given attribute name in this servlet context. More...

template<typename ValueType >
bool	set_attribute (std::string &&key, ValueType &&value)
	Move version of set_attribute(const std::string&, ValueType&&) More...

template<typename KeyType >
bool	remove_attribute (const KeyType &key)
	Removes the attribute with the given name from the servlet context. More...

tree_any_map &	get_attributes ()
	Returns an `tree_map` containing all the attributes available within this servlet context. More...

const tree_any_map &	get_attributes () const
	Const version of get_attributes method. More...

template<typename KeyType >
optional_ref< const std::string >	get_init_parameter (const KeyType &key) const
	Returns a reference to a `std::string` containing the value of the named context-wide initialization parameter, or an empty reference if the parameter does not exist. More...

const init_params_map &	get_init_parameters () const
	Returns the context's initialization parameters map of `std::string` objects. More...

virtual optional_ref< const std::string >	get_mime_type (string_view file_name) const =0
	Returns the MIME type of the specified file, or `null` if the MIME type is not known. More...

Protected Member Functions
	servlet_context (const std::string &ctx_path, const std::string &webapp_path, init_params_map &&init_params)
	Protected constructor to be used from derrived classes. More...

Protected Attributes
const std::string &	_ctx_path
	Context path.

tree_any_map	_attr_map
	Attributes map (to be filled by inheriting class).

init_params_map	_init_params_map
	Initial parameters map.

const std::string &	_webapp_path
	Filesystem path of current webapp.

Detailed Description

Defines a set of methods that a servlet uses to communicate with its servlet container.

There is one context per "web application". (A "web application" is a collection of servlets and content installed under a specific subset of the server's URL namespace such as /catalog and possibly installed via a .war file.)

In the case of a web application marked "distributed" in its deployment descriptor. In this situation, the context cannot be used as a location to share global information (because the information won't be truly global). Use an external resource like a database instead.

The servlet_context object is contained within the servlet_config object, which the Web server provides the servlet when the servlet is initialized.

See Also: http_servlet::get_servlet_config; http_filter::get_filter_config; servlet_config::get_servlet_context

Constructor & Destructor Documentation

servlet::servlet_context::servlet_context	(	const std::string &	ctx_path,
		const std::string &	webapp_path,
		init_params_map &&	init_params
	)

inlineprotected

Protected constructor to be used from derrived classes.

Parameters

ctx_path	Context path
webapp_path	Filesystem path to the web application
init_params	Initial parameters map

Member Function Documentation

template<typename T , typename KeyType >

optional_ref<const T> servlet::servlet_context::get_attribute ( const KeyType & key ) const

inline

Returns the servlet container attribute with the given name, or empty reference if there is no attribute by that name.

An attribute allows a servlet container to give the servlet additional information not already provided by this interface. See your server documentation for information about its attributes. Full attributes map can be retrieved using get_attributes.

The attribute is returned as a reference to any.

Template Parameters

T	type of the value to return
KeyType	a type comparable to `std::string`

Parameters

key	a `std::string` specifying the name of the attribute

Returns: a reference to any containing the value of the attribute, or empty reference if no attribute exists matching the given name

Exceptions

any_bad_cast if the stored type cannot be casted to the requested type.

See Also: get_attributes

template<typename KeyType , typename ValueType >

optional_ref<const ValueType> servlet::servlet_context::get_attribute ( const KeyType & key ) const

inline

Finds attribute by key and casts it to specified ValueType.

Template Parameters

T	type of the value to return
KeyType	a type comparable to `std::string`

Parameters

key	Key to find attribute value by.

Returns: optional reference to attribute corresponding to key

Exceptions

any_bad_cast if the stored type cannot be casted to the requested type.

tree_any_map& servlet::servlet_context::get_attributes ( )

inline

Returns an tree_map containing all the attributes available within this servlet context.

Returns: a tree_map of attributes

See Also: get_attribute

const tree_any_map& servlet::servlet_context::get_attributes ( ) const

inline

Const version of get_attributes method.

Returns: a const tree_map of attributes

const std::string& servlet::servlet_context::get_context_path ( ) const

inline

Return the main path associated with this context.

Returns: The main context path

template<typename KeyType >

optional_ref<const std::string> servlet::servlet_context::get_init_parameter ( const KeyType & key ) const

inline

Returns a reference to a std::string containing the value of the named context-wide initialization parameter, or an empty reference if the parameter does not exist.

This method can make available configuration information useful to an entire "web application". For example, it can provide a webmaster's email address or the name of a system that holds critical data.

Template Parameters

KeyType a type comparable to std::string

Parameters

key	a `std::string` containing the name of the parameter whose value is requested

Returns: a reference to a std::string containing the value of the initialization parameter

See Also: servlet_config::get_init_parameter

const init_params_map& servlet::servlet_context::get_init_parameters ( ) const

inline

Returns the context's initialization parameters map of std::string objects.

The returned map can be empty if the context has no initialization parameters.

Returns: an tree_map of the context's initialization parameters

See Also: servlet_config::get_init_parameters; servlet_config::get_init_parameter

virtual optional_ref<const std::string> servlet::servlet_context::get_mime_type ( string_view file_name ) const

pure virtual

Returns the MIME type of the specified file, or null if the MIME type is not known.

The MIME type is determined by the configuration of the servlet container, and may be specified in a web application deployment descriptor. Common MIME types are "text/html" and "image/gif".

Parameters

file_name a std::string specifying the name of a file

Returns: a std::string specifying the file's MIME type

const std::string& servlet::servlet_context::get_webapp_path ( ) const

inline

Returns filesystem path of current web application.

Returns: The webapp filesystem path.

template<typename KeyType >

bool servlet::servlet_context::remove_attribute ( const KeyType & key )

inline

Removes the attribute with the given name from the servlet context.

After removal, subsequent calls to get_attribute to retrieve the attribute's value will return an empty reference.

Template Parameters

KeyType a type comparable to std::string

Parameters

key	a `string` specifying the name of the attribute to be removed

template<typename ValueType >

bool servlet::servlet_context::set_attribute	(	const std::string &	key,
		ValueType &&	value
	)

inline

Binds an object to a given attribute name in this servlet context.

If the name specified is already used for an attribute, this method will replace the attribute with the new to the new attribute.

Template Parameters

ValueType type of the value to set.

Parameters

key	a `std::string` specifying the name of the attribute
value	a value of the arbitrary type which will be stored in `any` object representing the attribute

Returns: true if value in the map was replaced.

template<typename ValueType >

bool servlet::servlet_context::set_attribute	(	std::string &&	key,
		ValueType &&	value
	)

inline

Move version of set_attribute(const std::string&, ValueType&&)

Template Parameters

ValueType type of the value to set.

Parameters

key	a map key by which to store element
value	value of the element to store

Returns: true if value in the map was replaced.

See Also: set_attribute(const std::string&, ValueType&&)

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

include/servlet/context.h

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation