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/*
This file is part of TALER
(C) 2016 GNUnet e.V.
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
"use strict";
/**
* Decorators for validating JSON objects and converting them to a typed
* object.
*
* The decorators are put onto classes, and the validation is done
* via a static method that is filled in by the annotation.
*
* Example:
* ```
* @Checkable.Class
* class Person {
* @Checkable.String
* name: string;
* @Checkable.Number
* age: number;
*
* // Method will be implemented automatically
* static checked(obj: any): Person;
* }
* ```
*/
export namespace Checkable {
type Path = Array<number | string>;
interface SchemaErrorConstructor {
new (err: string): SchemaError;
}
interface SchemaError {
name: string;
message: string;
}
interface Prop {
propertyKey: any;
checker: any;
type?: any;
elementChecker?: any;
elementProp?: any;
keyProp?: any;
valueProp?: any;
optional?: boolean;
extraAllowed?: boolean;
}
interface CheckableInfo {
props: Prop[];
}
export const SchemaError = (function SchemaError(this: any, message: string) {
const that: any = this as any;
that.name = "SchemaError";
that.message = message;
that.stack = (new Error() as any).stack;
}) as any as SchemaErrorConstructor;
SchemaError.prototype = new Error();
/**
* Classes that are checkable are annotated with this
* checkable info symbol, which contains the information necessary
* to check if they're valid.
*/
const checkableInfoSym = Symbol("checkableInfo");
/**
* Get the current property list for a checkable type.
*/
function getCheckableInfo(target: any): CheckableInfo {
let chk = target[checkableInfoSym] as CheckableInfo|undefined;
if (!chk) {
chk = { props: [] };
target[checkableInfoSym] = chk;
}
return chk;
}
function checkNumber(target: any, prop: Prop, path: Path): any {
if ((typeof target) !== "number") {
throw new SchemaError(`expected number for ${path}`);
}
return target;
}
function checkString(target: any, prop: Prop, path: Path): any {
if (typeof target !== "string") {
throw new SchemaError(`expected string for ${path}, got ${typeof target} instead`);
}
return target;
}
function checkBoolean(target: any, prop: Prop, path: Path): any {
if (typeof target !== "boolean") {
throw new SchemaError(`expected boolean for ${path}, got ${typeof target} instead`);
}
return target;
}
function checkAnyObject(target: any, prop: Prop, path: Path): any {
if (typeof target !== "object") {
throw new SchemaError(`expected (any) object for ${path}, got ${typeof target} instead`);
}
return target;
}
function checkAny(target: any, prop: Prop, path: Path): any {
return target;
}
function checkList(target: any, prop: Prop, path: Path): any {
if (!Array.isArray(target)) {
throw new SchemaError(`array expected for ${path}, got ${typeof target} instead`);
}
for (let i = 0; i < target.length; i++) {
const v = target[i];
prop.elementChecker(v, prop.elementProp, path.concat([i]));
}
return target;
}
function checkMap(target: any, prop: Prop, path: Path): any {
if (typeof target !== "object") {
throw new SchemaError(`expected object for ${path}, got ${typeof target} instead`);
}
for (const key in target) {
prop.keyProp.checker(key, prop.keyProp, path.concat([key]));
const value = target[key];
prop.valueProp.checker(value, prop.valueProp, path.concat([key]));
}
}
function checkOptional(target: any, prop: Prop, path: Path): any {
console.assert(prop.propertyKey);
prop.elementChecker(target,
prop.elementProp,
path.concat([prop.propertyKey]));
return target;
}
function checkValue(target: any, prop: Prop, path: Path): any {
const type = prop.type;
if (!type) {
throw Error(`assertion failed (prop is ${JSON.stringify(prop)})`);
}
const v = target;
if (!v || typeof v !== "object") {
throw new SchemaError(
`expected object for ${path.join(".")}, got ${typeof v} instead`);
}
const props = type.prototype[checkableInfoSym].props;
const remainingPropNames = new Set(Object.getOwnPropertyNames(v));
const obj = new type();
for (const innerProp of props) {
if (!remainingPropNames.has(innerProp.propertyKey)) {
if (innerProp.optional) {
continue;
}
throw new SchemaError(`Property ${innerProp.propertyKey} missing on ${path} of ${type.name||"??"}`);
}
if (!remainingPropNames.delete(innerProp.propertyKey)) {
throw new SchemaError("assertion failed");
}
const propVal = v[innerProp.propertyKey];
obj[innerProp.propertyKey] = innerProp.checker(propVal,
innerProp,
path.concat([innerProp.propertyKey]));
}
if (!prop.extraAllowed && remainingPropNames.size !== 0) {
throw new SchemaError(`superfluous properties ${JSON.stringify(Array.from(remainingPropNames.values()))} of ${type.name||"??"}`);
}
return obj;
}
/**
* Class with checkable annotations on fields.
* This annotation adds the implementation of the `checked`
* static method.
*/
export function Class(opts: {extra?: boolean, validate?: boolean} = {}) {
return (target: any) => {
target.checked = (v: any) => {
const cv = checkValue(v, {
checker: checkValue,
extraAllowed: !!opts.extra,
propertyKey: "(root)",
type: target,
}, ["(root)"]);
if (opts.validate) {
if (typeof target.validate !== "function") {
console.error("target", target);
throw Error("invalid Checkable annotion: validate method required");
}
// May throw exception
target.validate(cv);
}
return cv;
};
return target;
};
}
/**
* Target property must be a Checkable object of the given type.
*/
export function Value(type: any) {
if (!type) {
throw Error("Type does not exist yet (wrong order of definitions?)");
}
function deco(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({
checker: checkValue,
propertyKey,
type,
});
}
return deco;
}
/**
* List of values that match the given annotation. For example, `@Checkable.List(Checkable.String)` is
* an annotation for a list of strings.
*/
export function List(type: any) {
const stub = {};
type(stub, "(list-element)");
const elementProp = getCheckableInfo(stub).props[0];
const elementChecker = elementProp.checker;
if (!elementChecker) {
throw Error("assertion failed");
}
function deco(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({
checker: checkList,
elementChecker,
elementProp,
propertyKey,
});
}
return deco;
}
/**
* Map from the key type to value type. Takes two annotations,
* one for the key type and one for the value type.
*/
export function Map(keyType: any, valueType: any) {
const keyStub = {};
keyType(keyStub, "(map-key)");
const keyProp = getCheckableInfo(keyStub).props[0];
if (!keyProp) {
throw Error("assertion failed");
}
const valueStub = {};
valueType(valueStub, "(map-value)");
const valueProp = getCheckableInfo(valueStub).props[0];
if (!valueProp) {
throw Error("assertion failed");
}
function deco(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({
checker: checkMap,
keyProp,
propertyKey,
valueProp,
});
}
return deco;
}
/**
* Makes another annotation optional, for example `@Checkable.Optional(Checkable.Number)`.
*/
export function Optional(type: any) {
const stub = {};
type(stub, "(optional-element)");
const elementProp = getCheckableInfo(stub).props[0];
const elementChecker = elementProp.checker;
if (!elementChecker) {
throw Error("assertion failed");
}
function deco(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({
checker: checkOptional,
elementChecker,
elementProp,
optional: true,
propertyKey,
});
}
return deco;
}
/**
* Target property must be a number.
*/
export function Number(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({checker: checkNumber, propertyKey});
}
/**
* Target property must be an arbitary object.
*/
export function AnyObject(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({
checker: checkAnyObject,
propertyKey,
});
}
/**
* Target property can be anything.
*
* Not useful by itself, but in combination with higher-order annotations
* such as List or Map.
*/
export function Any(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({
checker: checkAny,
optional: true,
propertyKey,
});
}
/**
* Target property must be a string.
*/
export function String(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({ checker: checkString, propertyKey });
}
/**
* Target property must be a boolean value.
*/
export function Boolean(target: object, propertyKey: string | symbol): void {
const chk = getCheckableInfo(target);
chk.props.push({ checker: checkBoolean, propertyKey });
}
}
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