Exbuvasa

EXpression BUilder VAlidator and SAnitizer for javascript

Expressions can be built using a set of predefined or user defined functions, operators and variables. This keeps yours expressions safe from containing dangerous or injected code.

Exbuvasa can be used with or without jquery.

If used with jquery inside an input of type text, it shows available terms as jquery-ui autocomplete (if available) and colors the background of the input according to the result of validating the expression. It also restricts the special characters (other but numbers and letters) that the user can type inside the input field.

Whitout jquery, exbuvasa can be given and expression that would be validated and converted to a javascript expression. It can return the converted expressionand the result of evaluating it, or the error messages from the validation

Demo

Demo

Basics

Given an expression, exbuasa parses it and returns an obect containing:

"ok": true if the expression has succesfully parsed and evaluated
"msg": error messages,
"terms": array of terms that conform the resulting expression,
"expression": resulting javascript expression,
"result": result of evaluating the resulting expression

Basic Usage with jQuery:

var props={
  jqinputselector: "#expression"
};
var ebvs=new exbuvasa(props);

jqinputselector has to be an input of type text or textarea

As the user types an expression, exbuvasa sets the following attributes on the element (ie #expression)

exbuvasa-ok
exbuvasa-result
exbuvasa-msg
exbuvasa-expression

Basic usage without jQuery

console.log(new exbuvasa(props).parse("2 in (1,2,3,4)").result);

Functions and operators

You can use the built in functions and operators or define your own.

Built in operators:

and

or

not

gt (>)

ge (>=)

lt (<)

le (<=)

eq (==)

neq (!=)

in ie: ‘a’ in (‘c’,’b’,’a’) returns true

contains ie: ‘javascript’ contains(‘java’) returns true

Built in functions:

left ie: left(‘javascript’,4) returns ‘java’

right ie: right(‘javascript’,6) returns ‘script’

substring ie: substring(‘javascript’,2,4) returns ‘va’

date converts a string to a Date object

Properties

An object which can contain the following:

okcolor: default to ‘#dfd’

notokcolor: default to ‘#fdd’

showtitle: default to true. If true, the title attribute of the input field will show a status message, ie. an error. If false, then original title attribute for input field is kept.

allowedchars: String containing all special chars accepted as user input. Defaults to

" |!#%&/()=?',;.:-_+*@  "

jqinputselector: css selector used to find the input element/s to use with

jqexpressionselector: element in which the resulting javascript expression will be showed

jqresultselector: element in which the result of evaluating te javascript expression will be showed

text: object containing strings for messages. You can supply your own messages in your language. Example

text:{
	"doubleQuotesNotAllowed": "Double quotes are not allowed. Always use single quotes",
	"unclosedQuote": "Unclosed quote",
	"invalidExpression":"Invalid expression",
	"emptyExpression": "Empty expression",
	"openParWasExpected": "( was expected",
	"closeParWasExpected": ") was expected",
	"charIsNotAllowed": "is not allowed",
	"pastedText": "Pasted text",
	"hasNotAllowedChars": "has not allowed characters",
	"allowedCharsAre": "Allowed chars are letters, numbers and"
	}

variables: object containing names of variables mapped with its values. String values must be enclosed in single quotes. Example

variables:{
	"name":"'peter'",
	"age": "44",
	"checkin": "'2020-05-25'"
}

functions: object containing names of the functions as string. The elements are the names of the functions that the user types and the values are the names of the real functions as a string. The real functions has to be javascript native funcionts or exist elsewhere. Example:

functions:{
	"part_of_a_string": "substring",
	"date": "date",
	"make_upper_case": "ucase"
    }

operators: object containing names of the operators as string. The elements are the names of the operators that the user types and the values are the names of the real functions as a string. The real functions has to be javascript native funcionts or exist elsewhere. The difference between operators and functions is the operators takes the preceeding term as the first parameter. Example

operators:{
	"and": "&&",
	"or": "||",
	"not": "!",
	"gt": ">",
	"ge": ">=",
	"lt": "<",
	"le": "<=",
	"eq": "==",
	"neq": "!=",
	"in": "isin",
	"contains": "contains"
}

In the expression ‘java’ in (‘java’,’phyton’,’c++’) the operator “in” is processed in the function “isin” which will take ‘java’ as the fisrt parameter and the array [‘java’,’phyton’,’c++’] as the second

function isin(val, arr) {
        if (arr.indexOf(val) >= 0) {
            return true;
        } else {
            return false;
        }
    }

Full properties example

props={
	operators: {
			"and": "&&",
			"or": "||",
			"not": "!",
			"gt": ">",
			"ge": ">=",
			"lt": "<",
			"le": "<=",
			"eq": "==",
			"neq": "!=",
			"in": "isin",
			"contains": "contains"
		},
	variables : {
		"name":"'peter'",
		"age": "42"
	},
	functions : {
			"left": "left",
			"right": "right",
			"substring": "substr",
			"date": "date"
		},
	okcolor :"#dfd",
	notokcolor: "#fdd",
	text:{
			"doubleQuotesNotAllowed": "Double quotes are not allowed. Always use single quotes",
			"unclosedQuote": "Unclosed quote",
			"invalidExpression":"Invalid expression",
			"emptyExpression": "Empty expression",
			"openParWasExpected": "( was expected",
			"closeParWasExpected": ") was expected",
			"charIsNotAllowed": "is not allowed",
			"pastedText": "Pasted text",
			"hasNotAllowedChars": "has not allowed characters",
			"allowedCharsAre": "Allowed chars are letters, numbers and"
		},
	showtitle:true,
	allowedchars: "|!#%&/()=?',;.:-_+*@ ",
	jqinputselector: "",
	jqexpressionselector :"",
	jqresultselector:""
}

Exbuvasa was inspired by filtrex (https://github.com/joewalnes/filtrex). But I needed to run it not only as a jquery plugin, but also inside a java scriptengine