Holds information about the link from a DAP2 client to a dataset. More...

#include <Connect.h>

Inheritance diagram for libdap::Connect:

Public Member Functions
virtual string	CE ()
	Get the Connect's constraint expression. More...

	Connect (const string &name, string uname="", string password="")
	Create an instance of Connect. More...

string	get_protocol ()

string	get_version ()

bool	is_cache_enabled ()

bool	is_local ()

virtual void	read_data (DataDDS &data, Response *rs)
	Read data which is preceded by MIME headers. This method works for both data dds and data ddx responses. More...

virtual void	read_data (DDS &data, Response *rs)

virtual void	read_data_no_mime (DataDDS &data, Response *rs)
	Read data from a file which does not have response MIME headers. This method is a companion to read_data(). While read_data() assumes that the response has MIME headers, this method does not. If you call this with a Response that does contain headers, it will throw an Error (and the message is likely to be inscrutable). More...

virtual void	read_data_no_mime (DDS &data, Response *rs)

virtual void	request_das (DAS &das)
	Get the DAS from a server. More...

virtual void	request_das_url (DAS &das)
	Get the DAS from a server. More...

virtual void	request_data (DataDDS &data, string expr="")
	Get the DAS from a server. More...

virtual void	request_data_ddx (DataDDS &data, string expr="")

virtual void	request_data_ddx_url (DataDDS &data)

virtual void	request_data_url (DataDDS &data)
	Get the DAS from a server. More...

virtual void	request_dds (DDS &dds, string expr="")
	Get the DDS from a server. More...

virtual void	request_dds_url (DDS &dds)
	Get the DDS from a server. More...

virtual void	request_ddx (DDS &dds, string expr="")
	Get the DDX from a server. More...

virtual void	request_ddx_url (DDS &dds)
	The 'url' version of request_ddx. More...

virtual string	request_protocol ()

virtual string	request_version ()

void	set_accept_deflate (bool deflate)

void	set_cache_enabled (bool enabled)

void	set_credentials (string u, string p)
	Set the credentials for responding to challenges while dereferencing URLs. More...

void	set_xdap_accept (int major, int minor)

void	set_xdap_protocol (int major, int minor)

virtual string	URL (bool CE=true)
	Get the object's URL. More...

Protected Member Functions
Suppress the C++ defaults for these.
	Connect ()

	Connect (const Connect &)

Connect &	operator= (const Connect &)

Detailed Description

Holds information about the link from a DAP2 client to a dataset.

Connect objects are used as containers for information pertaining to the connection a user program makes to a dataset. The dataset may be either local (for example, a file on the user's own computer) or a remote dataset. In the latter case a DAP2 URL will be used to reference the dataset, instead of a filename.

Connect contains methods which can be used to read the DAP2 DAS and DDS objects from the remote dataset as well as reading data. The class understands in a rudimentary way how DAP2 constraint expressions are formed and how to manage them.

Connect also provides additional services such as automatic decompression of compressed data and and error processing.

Note: Update: I removed the DEFAULT_BASETYPE_FACTORY switch because it caused more confusion than it avoided. See Trac #130.; The compile-time symbol DEFAULT_BASETYPE_FACTORY controls whether the old (3.4 and earlier) DDS and DataDDS constructors are supported. These constructors now use a default factory class (BaseTypeFactory, implemented by this library) to instantiate Byte, ..., Grid variables. To use the default ctor in your code you must also define this symbol. If you do choose to define this and fail to provide a specialization of BaseTypeFactory when your software needs one, you code may not link or may fail at run time. In addition to the older ctors for DDS and DataDDS, defining the symbol also makes some of the older methods in Connect available (because those methods require the older DDS and DataDDS ctors.

See also: DDS; DAS; Error

Author: jhrg

Definition at line 129 of file Connect.h.

Constructor & Destructor Documentation

◆ Connect()

libdap::Connect::Connect	(	const string &	n,
		string	uname = `""`,
		string	password = `""`
	)

Create an instance of Connect.

The Connect constructor requires a name, which is the URL to which the connection is to be made.

Parameters

n	The URL for the virtual connection.
uname	Use this username for authentication. Null by default.
password	Password to use for authentication. Null by default.

Definition at line 298 of file Connect.cc.

Member Function Documentation

◆ CE()

string libdap::Connect::CE ( )

virtual

Get the Connect's constraint expression.

Return the constraint expression (CE) part of the Connect URL. Note that this CE is supplied as part of the URL passed to the Connect's constructor. It is not the CE passed to the request_data() function.

Returns: A string containing the constraint expression (if any) submitted to the Connect object's constructor.

Definition at line 1146 of file Connect.cc.

◆ get_protocol()

string libdap::Connect::get_protocol ( )

inline

Return the DAP protocol version of the most recent response. Before a response is made, this contains the string "2.0."

Definition at line 193 of file Connect.h.

◆ get_version()

string libdap::Connect::get_version ( )

inline

Return the protocol/implementation version of the most recent response. This is a poorly designed method, but it returns information that is useful when used correctly. Before a response is made, this contains the string "unknown." This should ultimately hold the protocol version; it currently holds the implementation version.

@see get_protocol()

Deprecated:

Definition at line 185 of file Connect.h.

◆ read_data()

void libdap::Connect::read_data	(	DataDDS &	data,
		Response *	rs
	)

virtual

Read data which is preceded by MIME headers. This method works for both data dds and data ddx responses.

Note: If you need the DataDDS to hold specializations of the type classes, be sure to include the factory class which will instantiate those specializations in the DataDDS. Either pass a pointer to the factory to DataDDS constructor or use the DDS::set_factory() method after the object is built.

See also: read_data_no_mime()

Parameters

data	Result.
rs	Read from this Response object.

Definition at line 989 of file Connect.cc.

◆ read_data_no_mime()

void libdap::Connect::read_data_no_mime	(	DataDDS &	data,
		Response *	rs
	)

virtual

Read data from a file which does not have response MIME headers. This method is a companion to read_data(). While read_data() assumes that the response has MIME headers, this method does not. If you call this with a Response that does contain headers, it will throw an Error (and the message is likely to be inscrutable).

Note: This method will use the 'type' information in the Response object to choose between processing the response as a data dds or data ddx. If there is no type information, it will attempt to figure it out.

Parameters

data	Result.
rs	Read from this Response object.

Definition at line 1062 of file Connect.cc.

◆ request_das()

void libdap::Connect::request_das ( DAS & das )

virtual

Get the DAS from a server.

Reads the DAS corresponding to the dataset in the Connect object's URL. Although DAP does not support using CEs with DAS requests, if present in the Connect object's instance, they will be escaped and passed as the query string of the request.

Parameters

das Result.

Reimplemented in libdap::AISConnect.

Definition at line 430 of file Connect.cc.

◆ request_das_url()

void libdap::Connect::request_das_url ( DAS & das )

virtual

Get the DAS from a server.

Reads the DAS corresponding to the dataset in the Connect object's URL. Although DAP does not support using CEs with DAS requests, if present in the Connect object's instance, they will be escaped and passed as the query string of the request.

Different from request_das method in that this method uses the URL as given without attaching .das or projections or selections.

Parameters

das Result.

Definition at line 496 of file Connect.cc.

◆ request_data()

void libdap::Connect::request_data	(	DataDDS &	data,
		string	expr = `""`
	)

virtual

Get the DAS from a server.

Reads the DataDDS object corresponding to the dataset in the Connect object's URL. If present in the Connect object's instance, a CE will be escaped, combined with expr and passed as the query string of the request. The result is a DataDDS which contains the data values bound to variables.

Note: If you need the DataDDS to hold specializations of the type classes, be sure to include the factory class which will instantiate those specializations in the DataDDS. Either pass a pointer to the factory to DataDDS constructor or use the DDS::set_factory() method after the object is built.

Parameters

data	Result.
expr	Send this constraint expression to the server.

Definition at line 845 of file Connect.cc.

◆ request_data_url()

void libdap::Connect::request_data_url ( DataDDS & data )

virtual

Get the DAS from a server.

Reads the DataDDS object corresponding to the dataset in the Connect object's URL. If present in the Connect object's instance, a CE will be escaped, combined with expr and passed as the query string of the request. The result is a DataDDS which contains the data values bound to variables.

Different from request_data in that this method uses the syntax of the new OPeNDAP server commands using dispatch

Note: If you need the DataDDS to hold specializations of the type classes, be sure to include the factory class which will instantiate those specializations in the DataDDS. Either pass a pointer to the factory to DataDDS constructor or use the DDS::set_factory() method after the object is built.

Parameters

data Result.

Definition at line 896 of file Connect.cc.

◆ request_dds()

void libdap::Connect::request_dds	(	DDS &	dds,
		string	expr = `""`
	)

virtual

Get the DDS from a server.

Reads the DDS corresponding to the dataset in the Connect object's URL. If present in the Connect object's instance, a CE will be escaped, combined with expr and passed as the query string of the request.

Note: If you need the DDS to hold specializations of the type classes, be sure to include the factory class which will instantiate those specializations in the DDS. Either pass a pointer to the factory to DDS constructor or use the DDS::set_factory() method after the object is built.

Parameters

dds	Result.
expr	Send this constraint expression to the server.

Definition at line 562 of file Connect.cc.

◆ request_dds_url()

void libdap::Connect::request_dds_url ( DDS & dds )

virtual

Get the DDS from a server.

Reads the DDS corresponding to the dataset in the Connect object's URL. If present in the Connect object's instance, a CE will be escaped, combined with expr and passed as the query string of the request.

Different from request_dds method above in that this method assumes URL is complete and does not add anything to the command, such as .dds or projections or selections.

Note: If you need the DDS to hold specializations of the type classes, be sure to include the factory class which will instantiate those specializations in the DDS. Either pass a pointer to the factory to DDS constructor or use the DDS::set_factory() method after the object is built.

Parameters

dds Result.

Definition at line 642 of file Connect.cc.

◆ request_ddx()

void libdap::Connect::request_ddx	(	DDS &	dds,
		string	expr = `""`
	)

virtual

Get the DDX from a server.

Reads the DDX corresponding to the dataset in the Connect object's URL. If present in the Connect object's instance, a CE will be escaped, combined with expr and passed as the query string of the request.

Note: A DDX is represented as XML on the wire but in memory libdap uses a DDS object with variables that hold their own attributes (the DDS itself holds the global attributes).

Parameters

dds	Result.
expr	Send this constraint expression to the server.

Definition at line 705 of file Connect.cc.

◆ request_ddx_url()

void libdap::Connect::request_ddx_url ( DDS & dds )

virtual

The 'url' version of request_ddx.

See also: Connect::request_ddx.

Definition at line 773 of file Connect.cc.

◆ request_protocol()

string libdap::Connect::request_protocol ( )

virtual

Get protocol version information from the server. This is a new method which will ease the transition to DAP 4. Note that this method returns the version of the DAP protocol implemented by the server. The request_version() method returns the server's version number, not the DAP protocol version.

Note: This method actually asks the server for the protocol version - use get_protocol() to get the protocol information from the most recent response (e.g., from the last DDX response returned by the server).

Returns: The DAP protocol version string.

Definition at line 398 of file Connect.cc.

◆ request_version()

string libdap::Connect::request_version ( )

virtual

Get version information from the server. This is a new method which will ease the transition to DAP 4.

Note: Use request_protocol() to get the DAP protocol version.

Returns: The DAP version string.

See also: request_protocol()

Definition at line 362 of file Connect.cc.

◆ set_accept_deflate()

void libdap::Connect::set_accept_deflate ( bool deflate )

Set the accept deflate property.

Parameters

deflate True if the client can accept compressed responses, False otherwise.

Definition at line 1168 of file Connect.cc.

◆ set_cache_enabled()

void libdap::Connect::set_cache_enabled ( bool cache )

Disable any further use of the client-side cache. In a future version of this software, this should be handled so that the www library is not initialized with the cache running by default.

Definition at line 1188 of file Connect.cc.

◆ set_credentials()

void libdap::Connect::set_credentials	(	string	u,
		string	p
	)

Set the credentials for responding to challenges while dereferencing URLs.

Parameters

u	The username.
p	The password.

See also: extract_auth_info()

Definition at line 1159 of file Connect.cc.

◆ set_xdap_protocol()

void libdap::Connect::set_xdap_protocol	(	int	major,
		int	minor
	)

Set the XDAP-Accept property/header. This is used to send to a server the (highest) DAP protocol version number that this client understands.

Parameters

major	The client dap protocol major version
minor	The client dap protocol minor version

Definition at line 1179 of file Connect.cc.

◆ URL()

string libdap::Connect::URL ( bool ce = true )

virtual

Get the object's URL.

Return the Connect object's URL in a string. The URL was set by the class constructor, and may not be reset. If you want to open another URL, you must create another Connect object. There is a Connections class created to handle the management of multiple Connect objects.

See also: Connections

Returns: A string containing the URL of the data to which the Connect object refers. If the object refers to local data, the function returns the null string.

Parameters

ce	If TRUE, the returned URL will include any constraint expression enclosed with the Connect object's URL (including the `?`). If FALSE, any constraint expression will be removed from the URL. The default is TRUE.

Definition at line 1127 of file Connect.cc.

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

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ Connect()

Member Function Documentation

◆ CE()

◆ get_protocol()

◆ get_version()

◆ read_data()

◆ read_data_no_mime()

◆ request_das()

◆ request_das_url()

◆ request_data()

◆ request_data_url()

◆ request_dds()

◆ request_dds_url()

◆ request_ddx()

◆ request_ddx_url()

◆ request_protocol()

◆ request_version()

◆ set_accept_deflate()

◆ set_cache_enabled()

◆ set_credentials()

◆ set_xdap_protocol()

◆ URL()