http_parameters.pl

http_parameters(+Request, ?Parms) is det

http_parameters(+Request, ?Parms, :Options) is det

Get HTTP GET or POST form-data, applying type validation, default values, etc. Provided options are:

attribute_declarations(:Goal): Causes the declarations for an attributed named A to be fetched using call(Goal, A, Declarations).
form_data(-Data): Return the data read from the GET or POST request as a list Name = Value. All data, including name/value pairs used for Parms, is unified with Data.

The attribute_declarations hook allows sharing the declaration of attribute-properties between many http_parameters/3 calls. In this form, the requested attribute takes only one argument and the options are acquired by calling the hook. For example:

    ...,
    http_parameters(Request,
                    [ sex(Sex)
                    ],
                    [ attribute_declarations(http_param)
                    ]),
    ...

http_param(sex, [ oneof(male, female),
                  description('Sex of the person')
                ]).

bug: - If both request parameters (?name=value&...) and a POST are present the parameters are extracted from the request parameters. Still, as it is valid to have request parameters in a POST request this predicate should not process POST requests. We will keep the current behaviour as the it is not common for a request to have both request parameters and a POST data of the type application/x-www-form-urlencoded.
In the unlikely event this poses a problem the request may be specified as [method(get)|Request].

posted_form(+Request, -Data) is det[private]

True when Data is list of Name=Value pairs representing the posted data.

fill_parameters(+ParamDecls, +FormData, +DeclGoal)[private]

Fill values from the parameter list

http_convert_parameters(+Data, ?Params) is det

http_convert_parameters(+Data, ?Params, :AttrDecl) is det

Implements the parameter translation of http_parameters/2 or http_parameters/3. I.e., http_parameters/2 for a POST request can be implemented as:

http_parameters(Request, Params) :-
    http_read_data(Request, Data, []),
    http_convert_parameters(Data, Params).

http_convert_parameter(+Options, +FieldName, +ValueIn, -ValueOut) is det

Conversion of an HTTP form value. First tries the multifile hook http:convert_parameter/3 and next the built-in checks.

Arguments:

`Option`	- List as provided with the parameter
`FieldName`	- Name of the HTTP field (for better message)
`ValueIn`	- Atom value as received from HTTP layer
`ValueOut`	- Possibly converted final value

Errors

- type_error(Type, Value)

check_type3(+Type, +ValueIn, -ValueOut) is semidet[private]

HTTP parameter type-check for types that need converting.

check_type2(+Type, +ValueIn) is semidet[private]

HTTP parameter type-check for types that need no conversion.

truth(+In, -Boolean) is semidet[private]

Translate some commonly used textual representations for true and false into their canonical representation.

Re-exported predicates

The following predicates are exported from this file while their implementation is defined in imported modules or non-module files loaded by this module.