libdap::Connect Class Reference

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

#include <Connect.h>

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List of all members.

Public Member Functions

virtual string CE ()
 Get the Connect's constraint expression.
 Connect (const string &name, string uname="", string password="") throw (Error, InternalErr)
 Create an instance of Connect.
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.
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).
virtual void request_das (DAS &das)
 Get the DAS from a server.
virtual void request_das_url (DAS &das)
 Get the DAS from a server.
virtual void request_data (DataDDS &data, string expr="")
 Get the DAS from a server.
virtual void request_data_url (DataDDS &data)
 Get the DAS from a server.
virtual void request_dds (DDS &dds, string expr="")
 Get the DDS from a server.
virtual void request_dds_url (DDS &dds)
 Get the DDS from a server.
virtual void request_ddx (DDS &dds, string expr="")
 Get the DDX from a server.
virtual void request_ddx_url (DDS &dds)
 The 'url' version of request_ddx.
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.
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.
virtual ~Connect ()

Protected Member Functions

Suppress the C++ defaults for these.

 Connect (const Connect &)
 Connect ()
Connectoperator= (const Connect &)

Detailed Description

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, transmission progress reports and error processing. Refer to the GUI and Error classes for more information about these features. See the DODSFilter class for information on servers that compress data.

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
DODSFilter
Error
Author:
jhrg

Definition at line 133 of file Connect.h.


Constructor & Destructor Documentation

libdap::Connect::Connect (  )  [inline, protected]

Definition at line 154 of file Connect.h.

libdap::Connect::Connect ( const Connect  )  [inline, protected]

Definition at line 156 of file Connect.h.

libdap::Connect::Connect ( const string &  n,
string  uname = "",
string  password = "" 
) throw (Error, InternalErr)

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 214 of file Connect.cc.

References DBG, libdap::RCReader::instance(), and libdap::prune_spaces().

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libdap::Connect::~Connect (  )  [virtual]

Definition at line 261 of file Connect.cc.

References DBG2.


Member Function Documentation

string libdap::Connect::CE (  )  [virtual]

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 926 of file Connect.cc.

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 202 of file Connect.h.

Referenced by main().

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 also:
get_protocol()
Deprecated:

Definition at line 194 of file Connect.h.

Referenced by main().

bool libdap::Connect::is_cache_enabled (  ) 

Definition at line 980 of file Connect.cc.

References DBG, DBGN, and libdap::HTTPConnect::is_cache_enabled().

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bool libdap::Connect::is_local (  ) 

Definition at line 883 of file Connect.cc.

Referenced by main().

Connect& libdap::Connect::operator= ( const Connect  )  [inline, protected]

Definition at line 158 of file Connect.h.

void libdap::Connect::read_data ( DataDDS data,
Response rs 
) [virtual]

This is a place holder. A better implementation for reading objects from the local file store is to write FileConnect and have it support the same interface as HTTPConnect.

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 854 of file Connect.cc.

References read_data_no_mime().

Referenced by main().

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void libdap::Connect::read_data_no_mime ( DataDDS data,
Response rs 
) [virtual]
Parameters:
data Result.
rs Read from this Response object.

Definition at line 874 of file Connect.cc.

References libdap::Response::get_protocol(), and libdap::Response::get_version().

Referenced by main(), and read_data().

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void libdap::Connect::request_das ( DAS das  )  [virtual]

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 343 of file Connect.cc.

References libdap::dods_das, libdap::dods_error, libdap::HTTPConnect::fetch_url(), libdap::Response::get_protocol(), libdap::Response::get_stream(), libdap::Response::get_type(), libdap::Response::get_version(), libdap::id2www_ce(), libdap::DAS::parse(), libdap::Error::parse(), and libdap::web_error.

Referenced by main().

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void libdap::Connect::request_das_url ( DAS das  )  [virtual]

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 412 of file Connect.cc.

References libdap::dods_das, libdap::dods_error, libdap::HTTPConnect::fetch_url(), libdap::Response::get_protocol(), libdap::Response::get_stream(), libdap::Response::get_type(), libdap::Response::get_version(), libdap::DAS::parse(), libdap::Error::parse(), and libdap::web_error.

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void libdap::Connect::request_data ( DataDDS data,
string  expr = "" 
) [virtual]

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 767 of file Connect.cc.

References libdap::HTTPConnect::fetch_url(), libdap::Response::get_protocol(), libdap::Response::get_version(), and libdap::id2www_ce().

Referenced by main().

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void libdap::Connect::request_data_url ( DataDDS data  )  [virtual]

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 817 of file Connect.cc.

References libdap::HTTPConnect::fetch_url(), libdap::Response::get_protocol(), and libdap::Response::get_version().

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void libdap::Connect::request_dds ( DDS dds,
string  expr = "" 
) [virtual]

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 475 of file Connect.cc.

References libdap::dods_dds, libdap::dods_error, libdap::HTTPConnect::fetch_url(), libdap::Response::get_protocol(), libdap::Response::get_stream(), libdap::Response::get_type(), libdap::Response::get_version(), libdap::id2www_ce(), libdap::DDS::parse(), libdap::Error::parse(), and libdap::web_error.

Referenced by main().

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void libdap::Connect::request_dds_url ( DDS dds  )  [virtual]

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 559 of file Connect.cc.

References libdap::dods_dds, libdap::dods_error, libdap::HTTPConnect::fetch_url(), libdap::Response::get_protocol(), libdap::Response::get_stream(), libdap::Response::get_type(), libdap::Response::get_version(), libdap::DDS::parse(), libdap::Error::parse(), and libdap::web_error.

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void libdap::Connect::request_ddx ( DDS dds,
string  expr = "" 
) [virtual]

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 619 of file Connect.cc.

References libdap::dap4_ddx, libdap::dods_error, libdap::HTTPConnect::fetch_url(), libdap::DDS::get_factory(), libdap::Response::get_protocol(), libdap::Response::get_stream(), libdap::Response::get_type(), libdap::Response::get_version(), libdap::id2www_ce(), libdap::DDS::parse(), libdap::Error::parse(), and libdap::web_error.

Referenced by main().

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void libdap::Connect::request_ddx_url ( DDS dds  )  [virtual]
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 313 of file Connect.cc.

References libdap::HTTPConnect::fetch_url(), libdap::Response::get_protocol(), libdap::Response::get_version(), and libdap::id2www_ce().

Referenced by main().

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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 279 of file Connect.cc.

References libdap::HTTPConnect::fetch_url(), libdap::Response::get_protocol(), libdap::Response::get_version(), and libdap::id2www_ce().

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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 951 of file Connect.cc.

References libdap::HTTPConnect::set_accept_deflate().

Referenced by main().

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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 973 of file Connect.cc.

References libdap::HTTPConnect::set_cache_enabled().

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void libdap::Connect::set_credentials ( string  u,
string  p 
)
Parameters:
u The username.
p The password.
See also:
extract_auth_info()

Definition at line 941 of file Connect.cc.

References libdap::HTTPConnect::set_credentials().

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void libdap::Connect::set_xdap_accept ( int  major,
int  minor 
)
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 963 of file Connect.cc.

References libdap::HTTPConnect::set_xdap_protocol().

Referenced by main().

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string libdap::Connect::URL ( bool  ce = true  )  [virtual]

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 905 of file Connect.cc.

Referenced by main(), and libdap::AISConnect::request_das().


The documentation for this class was generated from the following files:
Generated on Wed Aug 11 19:41:48 2010 for libdap++ by  doxygen 1.6.3