SearchHeadline

This class represents a database function that generates highlighted text fragments from a search query match. It allows for extensive customization of the output, including the ability to define custom highlight tags, fragment lengths, and delimiters. The class automatically handles the integration of search configurations and query expressions to produce formatted text results.

Attributes

Attribute	Type	Description
function	string = ts_headline	The name of the database function used to generate the search headline.
template	string = %(function)s(%(expressions)s%(options)s)	The SQL template string used to construct the function call with expressions and options.
output_field	[TextField](../../../db/models/fields/textfield.md?sid=django_db_models_fields_textfield) = TextField()	The database field type used to represent the resulting highlighted text.

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Constructor

Signature

def SearchHeadline(
    expression: Any,
    query: Any,
    config: Any = None,
    start_sel: str = None,
    stop_sel: str = None,
    max_words: int = None,
    min_words: int = None,
    short_word: int = None,
    highlight_all: bool = None,
    max_fragments: int = None,
    fragment_delimiter: str = None
) - > null

Parameters

Name	Type	Description
expression	Any	The field or expression containing the text to be highlighted.
query	Any	The search query to match against the text.
config	Any = None	Optional search configuration for language-specific processing.
start_sel	str = None	The starting HTML tag or string for highlighting matches.
stop_sel	str = None	The closing HTML tag or string for highlighting matches.
max_words	int = None	The maximum number of words to include in the headline.
min_words	int = None	The minimum number of words to include in the headline.
short_word	int = None	Words shorter than this length will be discarded.
highlight_all	bool = None	Whether to highlight the entire document instead of a fragment.
max_fragments	int = None	The maximum number of fragments to display.
fragment_delimiter	str = None	The delimiter used to separate text fragments.

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Signature

def SearchHeadline(
    expression: [Expression](../../../db/models/expressions/expression.md?sid=django_db_models_expressions_expression),
    query: SearchQuery | str,
    config: str | Expression,
    start_sel: str,
    stop_sel: str,
    max_words: int,
    min_words: int,
    short_word: int,
    highlight_all: bool,
    max_fragments: int,
    fragment_delimiter: str
) - > null

Parameters

Name	Type	Description
expression	[Expression](../../../db/models/expressions/expression.md?sid=django_db_models_expressions_expression)	The field or expression containing the text to be highlighted.
query	`SearchQuery	str`
config	`str	Expression`
start_sel	str	The HTML tag or string used to open the highlighted portion of a match.
stop_sel	str	The HTML tag or string used to close the highlighted portion of a match.
max_words	int	The maximum number of words to include in the resulting headline snippet.
min_words	int	The minimum number of words to include in the resulting headline snippet.
short_word	int	Words of this length or shorter will be discarded from the headline unless they are search terms.
highlight_all	bool	If true, the entire document will be used as the headline instead of a fragment.
max_fragments	int	The maximum number of fragments to display when multiple matches are found.
fragment_delimiter	str	The string used to separate multiple fragments in the output headline.

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Methods

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as_sql()

@classmethod
def as_sql(
    compiler: [SQLCompiler](../../../db/models/sql/compiler/sqlcompiler.md?sid=django_db_models_sql_compiler_sqlcompiler),
    connection: BaseDatabaseConnection,
    function: str,
    template: str
) - > tuple

Generates the SQL fragment for the PostgreSQL ts_headline function, including the formatting options string.

Parameters

Name	Type	Description
compiler	[SQLCompiler](../../../db/models/sql/compiler/sqlcompiler.md?sid=django_db_models_sql_compiler_sqlcompiler)	The query compiler instance responsible for generating the SQL string.
connection	BaseDatabaseConnection	The current database connection used to handle vendor-specific SQL formatting.
function	str	An optional override for the SQL function name, defaulting to ts_headline.
template	str	An optional override for the SQL template string used to format the function call.

Returns

Type	Description
tuple	A tuple containing the SQL string with placeholders and the list of parameters to be merged by the database driver.

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