{"id": "plugin_hooks:plugin-hook-filters-from-request", "page": "plugin_hooks", "ref": "plugin-hook-filters-from-request", "title": "filters_from_request(request, database, table, datasette)", "content": "request  -  Request object \n                     \n                         The current HTTP request. \n                     \n                 \n                 \n                     database  - string \n                     \n                         The name of the database. \n                     \n                 \n                 \n                     table  - string \n                     \n                         The name of the table. \n                     \n                 \n                 \n                     datasette  -  Datasette class \n                     \n                         You can use this to access plugin configuration options via  datasette.plugin_config(your_plugin_name) , or to execute SQL queries. \n                     \n                 \n             \n             This hook runs on the  table  page, and can influence the  where  clause of the SQL query used to populate that page, based on query string arguments on the incoming request. \n             The hook should return an instance of  datasette.filters.FilterArguments  which has one required and three optional arguments: \n             return FilterArguments(\n    where_clauses=[\"id > :max_id\"],\n    params={\"max_id\": 5},\n    human_descriptions=[\"max_id is greater than 5\"],\n    extra_context={},\n) \n             The arguments to the  FilterArguments  class constructor are as follows: \n             \n                 \n                     where_clauses  - list of strings, required \n                     \n                         A list of SQL fragments that will be inserted into the SQL query, joined by the  and  operator. These can include  :named  parameters which will be populated using data in  params . \n                     \n                 \n                 \n                     params  - dictionary, optional \n                     \n                         Additional keyword arguments to be used when the query is executed. These should match any  :arguments  in the where clauses. \n                     \n                 \n                 \n                     human_descriptions  - list of strings, optional \n                     \n                         These strings will be included in the human-readable description at the top of the page and the page  <title> . \n                     \n                 \n                 \n                     extra_context  - dictionary, optional \n                     \n                         Additional context variables that should be made available to the  table.html  template when it is rendered. \n                     \n                 \n             \n             This example plugin causes 0 results to be returned if  ?_nothing=1  is added to the URL: \n             from datasette import hookimpl\nfrom datasette.filters import FilterArguments\n\n\n@hookimpl\ndef filters_from_request(self, request):\n    if request.args.get(\"_nothing\"):\n        return FilterArguments(\n            [\"1 = 0\"], human_descriptions=[\"NOTHING\"]\n        ) \n             Example:  datasette-leaflet-freedraw", "breadcrumbs": "[\"Plugin hooks\"]", "references": "[{\"href\": \"https://datasette.io/plugins/datasette-leaflet-freedraw\", \"label\": \"datasette-leaflet-freedraw\"}]"}