Moved validator to shared code directory.

server/shared/validation/validator.ts

@@ -0,0 +1,145 @@
+import {parseInteger} from "../utils/strings";
+import {isBoolean, isNumber, isObject, isOptional, isRegExp, isString, toIsArray} from "../types";
+
+export interface Constraint {
+    type: string,
+
+    default?: any,
+
+    optional?: boolean,
+
+    allowed?: string[],
+
+    min?: number,
+    max?: number,
+
+    regex?: RegExp,
+}
+
+export type Constraints = { [key: string]: Constraint };
+export type Values = { [key: string]: any };
+
+export function isConstraint(arg: unknown): arg is Constraint {
+    if (!isObject(arg)) {
+        return false;
+    }
+
+    const constraint = arg as Constraint;
+    return (
+        isString(constraint.type) &&
+        // default?: any
+        isOptional(constraint.optional, isBoolean) &&
+        isOptional(constraint.allowed, toIsArray(isString)) &&
+        isOptional(constraint.min, isNumber) &&
+        isOptional(constraint.max, isNumber) &&
+        isOptional(constraint.regex, isRegExp)
+    );
+}
+
+export function isConstraints(constraints: unknown): constraints is Constraints {
+    if (!isObject(constraints)) {
+        return false;
+    }
+
+    return Object.entries(constraints).every(([key, constraint]) => isString(key) && isConstraint(constraint));
+}
+
+// TODO: sanitize input for further processing as specified by constraints (correct types, trimming, etc.)
+
+function isValidBoolean(value: unknown): boolean {
+    return isBoolean(value) || value === 'true' || value === 'false';
+}
+
+function isValidNumber(constraint: Constraint, value: unknown): boolean {
+    if (isString(value)) {
+        value = parseInteger(value);
+    }
+
+    if (!isNumber(value)) {
+        return false;
+    }
+
+    if (isNaN(value) || !isFinite(value)) {
+        return false;
+    }
+
+    if (isNumber(constraint.min) && value < constraint.min) {
+        return false;
+    }
+
+    // noinspection RedundantIfStatementJS
+    if (isNumber(constraint.max) && value > constraint.max) {
+        return false;
+    }
+
+    return true;
+}
+
+function isValidEnum(constraint: Constraint, value: unknown): boolean {
+    if (!isString(value)) {
+        return false;
+    }
+
+    const allowed = constraint.allowed || [];
+    return allowed.indexOf(value) >= 0;
+}
+
+function isValidString(constraint: Constraint, value: unknown): boolean {
+    if (!constraint.regex) {
+        throw new Error("String constraints must have regex set: " + constraint);
+    }
+
+    if (!isString(value)) {
+        return false;
+    }
+
+    const trimmed = value.trim();
+    return (trimmed === '' && constraint.optional) || constraint.regex.test(trimmed);
+}
+
+function isValid(constraint: Constraint, acceptUndefined: boolean, value: unknown): boolean {
+    if (value === undefined) {
+        return acceptUndefined || constraint.optional === true;
+    }
+
+    switch (constraint.type) {
+        case 'boolean':
+            return isValidBoolean(value);
+
+        case 'number':
+            return isValidNumber(constraint, value);
+
+        case 'enum':
+            return isValidEnum(constraint, value);
+
+        case 'string':
+            return isValidString(constraint, value);
+    }
+
+    return false;
+}
+
+function areValid(constraints: Constraints, acceptUndefined: boolean, values: Values): boolean {
+    const fields = new Set(Object.keys(constraints));
+    for (const field of fields) {
+        if (!isValid(constraints[field], acceptUndefined, values[field])) {
+            return false;
+        }
+    }
+
+    for (const field of Object.keys(values)) {
+        if (!fields.has(field)) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+export function forConstraint(constraint: Constraint, acceptUndefined: boolean): (value: unknown) => boolean {
+    return ((value: unknown): boolean => isValid(constraint, acceptUndefined, value));
+}
+
+export function forConstraints(constraints: Constraints, acceptUndefined: boolean): (values: Values) => boolean {
+    return ((values: Values): boolean => areValid(constraints, acceptUndefined, values));
+}