Operations Reference
Reference | Automatic Validation
This page describes the operations available as part of a validation rule.
Common operations
These operations are available for more than one field type
REQ (Required)
REQ[:ERROR_CODE]
Available for
All types
Parameters
No parameters
Usage
The REQ operation indicates that the field being checked must have been ‘set’. The definition
of set changes according to the underlying Go data type:
- For basic Go types (string, intX, floatX etc)
REQwill always pass - For nilable types, ‘object’ and ‘slice’ types,
REQwill fail if the caller did not explicitly provide a value for the field.
MEX (Mutally Exclusive)
MEX:field1,field2...fieldN[:ERROR_CODE]
Available for
All types
Parameters
MEX requires a comma separated list of one or more field names.
Usage
The MEX operation allows you to declare that a field is not allowed to be set if any of the other
fields specified have been set.
For example MEX:WeightLbs,WeightStones would fail if either WeightLbs or WeightStones is set. The logic
for whether a field is considered to be ‘set’ is the same as the logic described above in the REQ operation.
BREAK
BREAK
Available for
- INT
- FLOAT
- STR
Parameters
None
Usage
BREAK stops execution of the current rule if any check operations have already failed for that rule. BREAK is used
to prevent expensive or irrelevant checks being made on a field that is already known to be invalid in some way.
STOPALL
STOPALL
Available for
All types
Parameters
None
Usage
The presence of STOPALL in a rule indicates that no other rules should be run if that rule fails.
IN
IN:value1,value2...valueN[:ERROR_CODE]
Available for
- INT
- FLOAT
- STR
Parameters
IN requires a comma separated list of one or more values.
Usage
IN fails if the value of the field being checked is not one of the values specified in the list of allowed values.
For FLOAT rules, the values in the allowed list are parsed as float64 and int64 for INT rules.
Please note that there is currently no support for escaping the value list separator (comma) for STR rules.
LEN (Length)
IN:[min]-[max][:ERROR_CODE]
Available for
- STR
- SLICE
Parameters
LEN requires a minimum length, a maximum length or both
Usage
LEN checks either the number of characters (not bytes) in a string or the elements in a slice/array. You can specify a
minimum and maximum length (LEN:2-10), just a maximum (LEN:-10) or just a minimum (LEN:2-)
EXT (External component)
EXT:componentName[:ERROR_CODE]
Available for
- STR
- INT
- FLOAT
Parameters
EXT requires the component name of a component registered in the Granitic IoC container
that can determine whether or not the field under validation is allowed.
Usage
EXT allows complex checks that cannot be modelled using Granitic’s rules/operations or that require access to an external
data source. For example, you might want to check if an email address is already being used by another user before
allowing someone to claim it.
The component that is used to perform the check must implement one of validate.ExternalStringValidator, validate.ExternalFloat64Validator or validate.ExternalInt64Validator according to the type of the field under consideration.
RANGE
RANGE:[min]|[max][:ERROR_CODE]
Available for
- INT
- FLOAT
Parameters
RANGE requires a minimum allowed value or a maximum allowed value or both.
Usage
RANGE allows to check whether a numeric value is within a pre-defined range. As the minimum and maximum parameters are
both optional, this operation can also be used to implement minimum (with no maximum) or maximum (with no minimum) value checks.
Examples:
RANGE:1|10 value must be between 1 and 10 inclusive
RANGE:-2| value must be a minimum of -2, with no upper limit
RANGE:|0.98 value must be a maximum of 0.98 with no lower limit
BOOL operations
The following operations are only available for checks on BOOL fields.
IS
IS:boolValue[:ERROR_CODE]
Parameters
IS takes either true or false as a parameter
Usage
IS is used to require a boolean value to be set to the same value (true or false) as specified in the check.
STRING operations
The following operations are only available for checks on STRING fields.
TRIM
TRIM
Usage
TRIM temporarily removes leading and trailing whitespace (using strings.TrimSpace())
for the purposes of all validation checks. If the value passes all checks, it is the original untrimmed version of the value which
is passed to your application logic.
HARDTRIM
HARDTRIM
Usage
HARDTRIM behaves in a similar way to TRIM, except that the value is permanently changed to its trimmed value
(e.g your application logic will receive the trimmed version of the value.
REG (regular expression)
REG:expression[:ERROR_CODE]
Parameters
REG requires a mandatory regular expression pattern. The validity of the expression
is checked during Granitic startup with regexp.MustCompile(). If this
fails your application will shutdown with an error.
Usage
The string value being checked will be matched against the compiled pattern using regexp.MatchString() and the check will fail if there is no match.
SLICE operations
The following operations are only available for checks on SLICE fields.
ELEM (validate elements)
ELEM:sharedRuleName[:ERROR_CODE]
Parameters
ELEM requires the name of a shared rule to apply to each element of the array/slice to be checked.
The shared rule must be of type INT, FLOAT, STRING or BOOL (multi-dimensional and object arrays cannot
currently be validated used ELEM)
Usage
Each element of the slice/array to be checked will be validated against the supplied rule. Validation of the remaining elements will continue even if an element fails validation.
If you are using the default formatter for service errors, the index of the element with a problem will be included in the field name. For example:
{
"ByField":{
"SliceCheck[0]":[
{
"Code": "C-TOOSHORT",
"Message": "Length of element must be four or greater"
}
]
}
}
Next: Shared rules