Build responses for Hyrax server modules/handlers. More...

#include <ResponseBuilder.h>

Collaboration diagram for libdap::ResponseBuilder:

Public Member Functions
virtual void	dataset_constraint (ostream &out, DDS &dds, ConstraintEvaluator &eval, bool ce_eval=true) const
virtual void	dataset_constraint_ddx (ostream &out, DDS &dds, ConstraintEvaluator &eval, const string &boundary, const string &start, bool ce_eval=true) const
virtual void	establish_timeout (ostream &stream) const
virtual string	get_ce () const
	Get the constraint expression.
virtual string	get_dataset_name () const
	Get the dataset name.
int	get_timeout () const
	ResponseBuilder ()
virtual void	send_das (ostream &out, DAS &das, bool with_mime_headers=true) const
	Transmit a DAS.
virtual void	send_data (ostream &data_stream, DDS &dds, ConstraintEvaluator &eval, bool with_mime_headers=true) const
	Transmit data.
virtual void	send_data_ddx (ostream &data_stream, DDS &dds, ConstraintEvaluator &eval, const string &start, const string &boundary, bool with_mime_headers=true) const
	Transmit data.
virtual void	send_dds (ostream &out, DDS &dds, ConstraintEvaluator &eval, bool constrained=false, bool with_mime_headers=true) const
	Transmit a DDS.
virtual void	send_ddx (ostream &out, DDS &dds, ConstraintEvaluator &eval, bool with_mime_headers=true) const
virtual void	set_ce (string _ce)
virtual void	set_dataset_name (const string _dataset)
void	set_mime_binary (ostream &out, ObjectType type=unknown_type, EncodingType enc=x_plain, const time_t last_modified=0, const string &protocol="") const
void	set_mime_data_boundary (ostream &out, const string &boundary, const string &cid, ObjectType type=unknown_type, EncodingType enc=x_plain) const
void	set_mime_ddx_boundary (ostream &out, const string &boundary, const string &start, ObjectType type=unknown_type, EncodingType enc=x_plain) const
void	set_mime_error (ostream &out, int code=404, const string &reason="Dataset not found", const string &protocol="") const
void	set_mime_html (ostream &out, ObjectType type=unknown_type, EncodingType enc=x_plain, const time_t last_modified=0, const string &protocol="") const
void	set_mime_multipart (ostream &out, const string &boundary, const string &start, ObjectType type=unknown_type, EncodingType enc=x_plain, const time_t last_modified=0, const string &protocol="") const
void	set_mime_text (ostream &out, ObjectType type=unknown_type, EncodingType enc=x_plain, const time_t last_modified=0, const string &protocol="") const
void	set_timeout (int timeout=0)
virtual	~ResponseBuilder ()
Protected Member Functions
void	initialize ()
	Version string for the library's default protocol version.
Protected Attributes
string	d_ce
	Name of the dataset/database.
string	d_dataset
string	d_default_protocol
	Response timeout after N seconds.
int	d_timeout
	Constraint expression.
Friends
class	ResponseBuilderTest

Detailed Description

Author:: jhrg 1/28/2011

Definition at line 60 of file ResponseBuilder.h.

Constructor & Destructor Documentation

libdap::ResponseBuilder::ResponseBuilder ( ) [inline]

Make an empty instance. Use the set_*() methods to load with needed values. You must call at least set_dataset_name() or be requesting version information.

Definition at line 82 of file ResponseBuilder.h.

References initialize().

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

Definition at line 67 of file ResponseBuilder.cc.

Member Function Documentation

void libdap::ResponseBuilder::dataset_constraint	(	ostream &	out,
		DDS &	dds,
		ConstraintEvaluator &	eval,
		bool	ce_eval = `true`
	)		const `[virtual]`

Definition at line 307 of file ResponseBuilder.cc.

References DBG, libdap::DDS::print_constrained(), libdap::DDS::var_begin(), and libdap::DDS::var_end().

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void libdap::ResponseBuilder::dataset_constraint_ddx	(	ostream &	out,
		DDS &	dds,
		ConstraintEvaluator &	eval,
		const string &	boundary,
		const string &	start,
		bool	ce_eval = `true`
	)		const `[virtual]`

Definition at line 330 of file ResponseBuilder.cc.

References libdap::binary, libdap::dap4_data, libdap::dap4_ddx, DBG, libdap::DDS::print_xml(), libdap::set_mime_data_boundary(), libdap::set_mime_ddx_boundary(), libdap::DDS::var_begin(), and libdap::DDS::var_end().

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void libdap::ResponseBuilder::establish_timeout ( ostream & stream ) const [virtual]

Use values of this instance to establish a timeout alarm for the server. If the timeout value is zero, do nothing.

Todo:: When the alarm handler is called, two CRLF pairs are dumped to the stream and then an Error object is sent. No attempt is made to write the 'correct' MIME headers for an Error object. Instead, a savvy client will know that when an exception is thrown during a deserialize operation, it should scan ahead in the input stream for an Error object. Add this, or a sensible variant once libdap++ supports reliable error delivery. Dumb clients will never get the Error object...

Definition at line 238 of file ResponseBuilder.cc.

References libdap::SignalHandler::register_handler().

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string libdap::ResponseBuilder::get_ce ( ) const [virtual]

Return the entire constraint expression in a string. This includes both the projection and selection clauses, but not the question mark.

Returns:: A string object that contains the constraint expression.

Definition at line 153 of file ResponseBuilder.cc.

string libdap::ResponseBuilder::get_dataset_name ( ) const [virtual]

The ``dataset name'' is the filename or other string that the filter program will use to access the data. In some cases this will indicate a disk file containing the data. In others, it may represent a database query or some other exotic data access method.

Returns:: A string object that contains the name of the dataset.

Definition at line 203 of file ResponseBuilder.cc.

int libdap::ResponseBuilder::get_timeout ( ) const

Get the server's timeout value.

Definition at line 223 of file ResponseBuilder.cc.

void libdap::ResponseBuilder::initialize ( ) [protected]

Called when initializing a ResponseBuilder that's not going to be passed a command line arguments.

Definition at line 73 of file ResponseBuilder.cc.

References DAP_PROTOCOL_VERSION.

Referenced by ResponseBuilder().

void libdap::ResponseBuilder::send_das	(	ostream &	out,
		DAS &	das,
		bool	with_mime_headers = `true`
	)		const `[virtual]`

This function formats and prints an ASCII representation of a DAS on stdout. This has the effect of sending the DAS object back to the client program.

Parameters:

out	The output stream to which the DAS is to be sent.
das	The DAS object to be sent.
anc_location	The directory in which the external DAS file resides.
with_mime_headers	If true (the default) send MIME headers.

Returns:: void

See also:: DAS

Definition at line 261 of file ResponseBuilder.cc.

References libdap::dods_das, libdap::last_modified_time(), libdap::DAS::print(), libdap::set_mime_text(), and libdap::x_plain.

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void libdap::ResponseBuilder::send_data	(	ostream &	data_stream,
		DDS &	dds,
		ConstraintEvaluator &	eval,
		bool	with_mime_headers = `true`
	)		const `[virtual]`

Send the data in the DDS object back to the client program. The data is encoded using a Marshaller, and enclosed in a MIME document which is all sent to data_stream. If this is being called from a CGI, data_stream is probably stdout and writing to it has the effect of sending the response back to the client.

Parameters:

dds	A DDS object containing the data to be sent.
eval	A reference to the ConstraintEvaluator to use.
data_stream	Write the response to this stream.
anc_location	A directory to search for ancillary files (in addition to the CWD). This is used in a call to get_data_last_modified_time().
with_mime_headers	If true, include the MIME headers in the response. Defaults to true.

Returns:: void

Definition at line 385 of file ResponseBuilder.cc.

References libdap::dods_data, libdap::ConstraintEvaluator::eval_function_clauses(), libdap::ConstraintEvaluator::function_clauses(), libdap::DDS::get_dap_version(), libdap::last_modified_time(), libdap::ConstraintEvaluator::parse_constraint(), libdap::set_mime_binary(), libdap::DDS::set_timeout(), libdap::DDS::tag_nested_sequences(), and libdap::x_plain.

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void libdap::ResponseBuilder::send_data_ddx	(	ostream &	data_stream,
		DDS &	dds,
		ConstraintEvaluator &	eval,
		const string &	start,
		const string &	boundary,
		bool	with_mime_headers = `true`
	)		const `[virtual]`

Send the data in the DDS object back to the client program. The data is encoded using a Marshaller, and enclosed in a MIME document which is all sent to data_stream. If this is being called from a CGI, data_stream is probably stdout and writing to it has the effect of sending the response back to the client.

Parameters:

dds	A DDS object containing the data to be sent.
eval	A reference to the ConstraintEvaluator to use.
data_stream	Write the response to this stream.
anc_location	A directory to search for ancillary files (in addition to the CWD). This is used in a call to get_data_last_modified_time().
with_mime_headers	If true, include the MIME headers in the response. Defaults to true.

Returns:: void

Definition at line 458 of file ResponseBuilder.cc.

References CRLF, libdap::dap4_data_ddx, libdap::ConstraintEvaluator::eval_function_clauses(), libdap::ConstraintEvaluator::function_clauses(), libdap::last_modified_time(), libdap::ConstraintEvaluator::parse_constraint(), libdap::set_mime_multipart(), libdap::DDS::set_timeout(), libdap::DDS::tag_nested_sequences(), and libdap::x_plain.

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void libdap::ResponseBuilder::send_dds	(	ostream &	out,
		DDS &	dds,
		ConstraintEvaluator &	eval,
		bool	constrained = `false`,
		bool	with_mime_headers = `true`
	)		const `[virtual]`

This function formats and prints an ASCII representation of a DDS on stdout. When called by a CGI program, this has the effect of sending a DDS object back to the client program. Either an entire DDS or a constrained DDS may be sent.

Parameters:

out	The output stream to which the DAS is to be sent.
dds	The DDS to send back to a client.
eval	A reference to the ConstraintEvaluator to use.
constrained	If this argument is true, evaluate the current constraint expression and send the `constrained DDS' back to the client.
anc_location	The directory in which the external DAS file resides.
with_mime_headers	If true (the default) send MIME headers.

Returns:: void

See also:: DDS

Definition at line 286 of file ResponseBuilder.cc.

References libdap::dods_dds, libdap::ConstraintEvaluator::functional_expression(), libdap::DDS::get_dap_version(), libdap::last_modified_time(), libdap::ConstraintEvaluator::parse_constraint(), libdap::DDS::print(), libdap::DDS::print_constrained(), libdap::set_mime_text(), and libdap::x_plain.

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void libdap::ResponseBuilder::send_ddx	(	ostream &	out,
		DDS &	dds,
		ConstraintEvaluator &	eval,
		bool	with_mime_headers = `true`
	)		const `[virtual]`

Send the DDX response. The DDX never contains data, instead it holds a reference to a Blob response which is used to get the data values. The DDS and DAS objects are built using code that already exists in the servers.

Parameters:

dds	The dataset's DDS with attributes in the variables.
eval	A reference to the ConstraintEvaluator to use.
out	Destination
with_mime_headers	If true, include the MIME headers in the response. Defaults to true.

Definition at line 427 of file ResponseBuilder.cc.

References libdap::dap4_ddx, libdap::ConstraintEvaluator::functional_expression(), libdap::DDS::get_dap_version(), libdap::last_modified_time(), libdap::ConstraintEvaluator::parse_constraint(), libdap::DDS::print_xml(), libdap::set_mime_text(), and libdap::x_plain.

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void libdap::ResponseBuilder::set_ce ( string _ce ) [virtual]

Definition at line 158 of file ResponseBuilder.cc.

References libdap::www2id().

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void libdap::ResponseBuilder::set_dataset_name ( const string _dataset ) [virtual]

Definition at line 208 of file ResponseBuilder.cc.

References libdap::www2id().

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void libdap::ResponseBuilder::set_mime_binary	(	ostream &	strm,
		ObjectType	type = `unknown_type`,
		EncodingType	enc = `x_plain`,
		const time_t	last_modified = `0`,
		const string &	protocol = `""`
	)		const

Write an HTTP 1.0 response header for our binary response document (i.e., the DataDDS object).

Parameters:

strm	Write the MIME header to this stream.
type	The type of this this response. Defaults to application/octet-stream.
ver	The version string; denotes the libdap implementation version.
enc	How is this response encoded? Can be plain or deflate or the x_... versions of those. Default is x_plain.
last_modified	The time to use for the Last-Modified header value. Default is zero which means use the current time.

Definition at line 609 of file ResponseBuilder.cc.

References CRLF, DVR, libdap::rfc822_date(), and libdap::x_plain.

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void libdap::ResponseBuilder::set_mime_data_boundary	(	ostream &	out,
		const string &	boundary,
		const string &	cid,
		ObjectType	type = `unknown_type`,
		EncodingType	enc = `x_plain`
	)		const

Definition at line 685 of file ResponseBuilder.cc.

References CRLF, and libdap::x_plain.

void libdap::ResponseBuilder::set_mime_ddx_boundary	(	ostream &	out,
		const string &	boundary,
		const string &	start,
		ObjectType	type = `unknown_type`,
		EncodingType	enc = `x_plain`
	)		const

Definition at line 672 of file ResponseBuilder.cc.

References CRLF, and libdap::x_plain.

void libdap::ResponseBuilder::set_mime_error	(	ostream &	strm,
		int	code = `404`,
		const string &	reason = `"Dataset not found"`,
		const string &	protocol = `""`
	)		const

Generate an HTTP 1.0 response header for an Error object.

Parameters:

strm	Write the MIME header to this stream.
code	HTTP 1.0 response code. Should be 400, ... 500, ...
reason	Reason string of the HTTP 1.0 response header.
version	The version string; denotes the DAP spec and implementation version.

Definition at line 704 of file ResponseBuilder.cc.

References CRLF, DVR, and libdap::rfc822_date().

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void libdap::ResponseBuilder::set_mime_html	(	ostream &	strm,
		ObjectType	type = `unknown_type`,
		EncodingType	enc = `x_plain`,
		const time_t	last_modified = `0`,
		const string &	protocol = `""`
	)		const

Generate an HTTP 1.0 response header for a html document.

Parameters:

strm	Write the MIME header to this stream.
type	The type of this this response.
ver	The version string; denotes the libdap implementation version.
enc	How is this response encoded? Can be plain or deflate or the x_... versions of those. Default is x_plain.
last_modified	The time to use for the Last-Modified header value. Default is zero which means use the current time.

Definition at line 561 of file ResponseBuilder.cc.

References CRLF, libdap::dods_error, DVR, libdap::rfc822_date(), and libdap::x_plain.

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void libdap::ResponseBuilder::set_mime_multipart	(	ostream &	out,
		const string &	boundary,
		const string &	start,
		ObjectType	type = `unknown_type`,
		EncodingType	enc = `x_plain`,
		const time_t	last_modified = `0`,
		const string &	protocol = `""`
	)		const

Definition at line 640 of file ResponseBuilder.cc.

References CRLF, DVR, libdap::rfc822_date(), and libdap::x_plain.

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void libdap::ResponseBuilder::set_mime_text	(	ostream &	strm,
		ObjectType	type = `unknown_type`,
		EncodingType	enc = `x_plain`,
		const time_t	last_modified = `0`,
		const string &	protocol = `""`
	)		const

Generate an HTTP 1.0 response header for a text document. This is used when returning a serialized DAS or DDS object.

Parameters:

strm	Write the MIME header to this stream.
type	The type of this this response. Defaults to application/octet-stream.
ver	The version string; denotes the libdap implementation version.
enc	How is this response encoded? Can be plain or deflate or the x_... versions of those. Default is x_plain.
last_modified	The time to use for the Last-Modified header value. Default is zero which means use the current time.