Query Results Formatter

Query Results Formatter — Query results formatted into a syntax.

Synopsis

typedef             rasqal_query_results_formatter;
enum                rasqal_query_results_format_flags;
int                 rasqal_query_results_formats_check  (rasqal_world *world,
                                                         const char *name,
                                                         raptor_uri *uri,
                                                         const char *mime_type,
                                                         int flags);
int                 rasqal_query_results_formats_check2 (rasqal_world *world,
                                                         const char *name,
                                                         raptor_uri *uri,
                                                         const char *mime_type,
                                                         int flags);
rasqal_query_results_formatter * rasqal_new_query_results_formatter
                                                        (rasqal_world *world,
                                                         const char *name,
                                                         const char *mime_type,
                                                         raptor_uri *format_uri);
rasqal_query_results_formatter * rasqal_new_query_results_formatter_for_content
                                                        (rasqal_world *world,
                                                         raptor_uri *uri,
                                                         const char *mime_type,
                                                         const char *buffer,
                                                         size_t len,
                                                         const unsigned char *identifier);
void                rasqal_free_query_results_formatter (rasqal_query_results_formatter *formatter);
int                 rasqal_query_results_formatter_read (rasqal_world *world,
                                                         raptor_iostream *iostr,
                                                         rasqal_query_results_formatter *formatter,
                                                         rasqal_query_results *results,
                                                         raptor_uri *base_uri);
int                 rasqal_query_results_formatter_write
                                                        (raptor_iostream *iostr,
                                                         rasqal_query_results_formatter *formatter,
                                                         rasqal_query_results *results,
                                                         raptor_uri *base_uri);

Description

Variable bindings and boolean query results can be formatted into different syntaxes such as SPARQL Query Results Format or JSON. The rasqal_query_results_formatter class allows choosing a formatter for a particular syntax and writing the syntax to a raptor_iostream which allows turning the syntax into a string, writing to a file handle or other custom destination.

Details

rasqal_query_results_formatter

rasqal_graph_query_results_formatter* query_results_formatter;

Rasqal query results formatter class.

enum rasqal_query_results_format_flags

typedef enum {
  RASQAL_QUERY_RESULTS_FORMAT_FLAG_READER = 1,
  RASQAL_QUERY_RESULTS_FORMAT_FLAG_WRITER = 2
} rasqal_query_results_format_flags;

Bitflags for rasqal_query_results_formats_check() to find formats with features.

RASQAL_QUERY_RESULTS_FORMAT_FLAG_READER

 format can be read.

RASQAL_QUERY_RESULTS_FORMAT_FLAG_WRITER

 format can be written.

rasqal_query_results_formats_check ()

int                 rasqal_query_results_formats_check  (rasqal_world *world,
                                                         const char *name,
                                                         raptor_uri *uri,
                                                         const char *mime_type,
                                                         int flags);

Check if a query results formatter exists for the requested format.

Deprecated: use rasqal_query_results_formats_check2() since the implementation of this function returned an inverted boolean result.

world :

 rasqal_world object

name :

 the query results format name (or NULL)

uri :

 raptor_uri query results format uri (or NULL)

mime_type :

 mime type name

flags :

 bitmask of flags to signify that format is needed for reading (RASQAL_QUERY_RESULTS_FORMAT_FLAG_READER ) or writing ( RASQAL_QUERY_RESULTS_FORMAT_FLAG_WRITER )

Returns :

 0 if a formatter exists.

rasqal_query_results_formats_check2 ()

int                 rasqal_query_results_formats_check2 (rasqal_world *world,
                                                         const char *name,
                                                         raptor_uri *uri,
                                                         const char *mime_type,
                                                         int flags);

Check if a query results formatter exists for the requested format.

world :

 rasqal_world object

name :

 the query results format name (or NULL)

uri :

 raptor_uri query results format uri (or NULL)

mime_type :

 mime type name

flags :

 bitmask of flags to signify that format is needed for reading (RASQAL_QUERY_RESULTS_FORMAT_FLAG_READER ) or writing ( RASQAL_QUERY_RESULTS_FORMAT_FLAG_WRITER )

Returns :

 non-0 if a formatter exists.

rasqal_new_query_results_formatter ()

rasqal_query_results_formatter * rasqal_new_query_results_formatter
                                                        (rasqal_world *world,
                                                         const char *name,
                                                         const char *mime_type,
                                                         raptor_uri *format_uri);

Constructor - create a new rasqal_query_results_formatter for an identified format.

A query results format can be found by name, mime type or URI, all of which are optional. If multiple fields are given, the first match is given that matches the name, URI, mime_type in that order. The default query results format will be used if all are format identifying fields are NULL.

See rasqal_world_get_query_results_format_description() for obtaining the supported format URIs at run time.

world :

 rasqal_world object

name :

 the query results format name (or NULL)

mime_type :

 the query results format mime type (or NULL)

format_uri :

 raptor_uri query results format uri (or NULL)

Returns :

 a new rasqal_query_results_formatter object or NULL on failure

rasqal_new_query_results_formatter_for_content ()

rasqal_query_results_formatter * rasqal_new_query_results_formatter_for_content
                                                        (rasqal_world *world,
                                                         raptor_uri *uri,
                                                         const char *mime_type,
                                                         const char *buffer,
                                                         size_t len,
                                                         const unsigned char *identifier);

Constructor - create a new queryresults formatter for an identified format.

Uses rasqal_world_guess_query_results_format_name() to find a query results formatter by scoring recognition of the syntax by a block of characters, the content identifier or a mime type. The content identifier is typically a filename or URI or some other identifier.

world :

 world object

uri :

 URI identifying the syntax (or NULL)

mime_type :

 mime type identifying the content (or NULL)

buffer :

 buffer of content to guess (or NULL)

len :

 length of buffer

identifier :

 identifier of content (or NULL)

Returns :

 a new rasqal_query_results_formatter object or NULL on failure

rasqal_free_query_results_formatter ()

void                rasqal_free_query_results_formatter (rasqal_query_results_formatter *formatter);

Destructor - destroy a rasqal_query_results_formatter object.

formatter :

 rasqal_query_results_formatter object

rasqal_query_results_formatter_read ()

int                 rasqal_query_results_formatter_read (rasqal_world *world,
                                                         raptor_iostream *iostr,
                                                         rasqal_query_results_formatter *formatter,
                                                         rasqal_query_results *results,
                                                         raptor_uri *base_uri);

Read the query results using the given formatter from an iostream

See rasqal_world_get_query_results_format_description() for obtaining the supported format URIs at run time.

world :

 rasqal world object

iostr :

 raptor_iostream to read the query from

formatter :

 rasqal_query_results_formatter object

results :

 rasqal_query_results query results format

base_uri :

 raptor_uri base URI of the input format

Returns :

 non-0 on failure

rasqal_query_results_formatter_write ()

int                 rasqal_query_results_formatter_write
                                                        (raptor_iostream *iostr,
                                                         rasqal_query_results_formatter *formatter,
                                                         rasqal_query_results *results,
                                                         raptor_uri *base_uri);

Write the query results using the given formatter to an iostream

Note that after calling this method, the query results will be empty and rasqal_query_results_finished() will return true (non-0)

See rasqal_world_get_query_results_format_description() for obtaining the supported format URIs at run time.

iostr :

 raptor_iostream to write the query to

formatter :

 rasqal_query_results_formatter object

results :

 rasqal_query_results query results format

base_uri :

 raptor_uri base URI of the output format (or NULL)

Returns :

 non-0 on failure
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