{"id": "plugin_hooks:plugin-hook-register-magic-parameters", "page": "plugin_hooks", "ref": "plugin-hook-register-magic-parameters", "title": "register_magic_parameters(datasette)", "content": "datasette  -  Datasette class \n                     \n                         You can use this to access plugin configuration options via  datasette.plugin_config(your_plugin_name) . \n                     \n                 \n             \n             Magic parameters  can be used to add automatic parameters to  canned queries . This plugin hook allows additional magic parameters to be defined by plugins. \n             Magic parameters all take this format:  _prefix_rest_of_parameter . The prefix indicates which magic parameter function should be called - the rest of the parameter is passed as an argument to that function. \n             To register a new function, return it as a tuple of  (string prefix, function)  from this hook. The function you register should take two arguments:  key  and  request , where  key  is the  rest_of_parameter  portion of the parameter and  request  is the current  Request object . \n             This example registers two new magic parameters:  :_request_http_version  returning the HTTP version of the current request, and  :_uuid_new  which returns a new UUID: \n             from datasette import hookimpl\nfrom uuid import uuid4\n\n\ndef uuid(key, request):\n    if key == \"new\":\n        return str(uuid4())\n    else:\n        raise KeyError\n\n\ndef request(key, request):\n    if key == \"http_version\":\n        return request.scope[\"http_version\"]\n    else:\n        raise KeyError\n\n\n@hookimpl\ndef register_magic_parameters(datasette):\n    return [\n        (\"request\", request),\n        (\"uuid\", uuid),\n    ]", "breadcrumbs": "[\"Plugin hooks\"]", "references": "[]"}