gristlabs_grist-core/app/server/lib/ACLFormula.ts

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/**
* Representation and compilation of ACL formulas.
*
* An example of an ACL formula is: "rec.office == 'Seattle' and user.email in ['sally@', 'xie@']".
* These formulas are parsed in Python into a tree with nodes of the form [NODE_TYPE, ...args].
* See sandbox/grist/acl_formula.py for details.
*
* This modules includes typings for the nodes, and compileAclFormula() function that turns such a
* tree into an actual boolean function.
*/
import {CellValue} from 'app/common/DocActions';
import {ErrorWithCode} from 'app/common/ErrorWithCode';
import {AclMatchFunc, AclMatchInput, ParsedAclFormula} from 'app/common/GranularAccessClause';
import constant = require('lodash/constant');
const GRIST_CONSTANTS: Record<string, string> = {
EDITOR: 'editors',
OWNER: 'owners',
VIEWER: 'viewers',
};
/**
* Compile a parsed ACL formula into an actual function that can evaluate a request.
*/
export function compileAclFormula(parsedAclFormula: ParsedAclFormula): AclMatchFunc {
const compiled = _compileNode(parsedAclFormula);
return (input) => Boolean(compiled(input));
}
/**
* Type for intermediate functions, which may return values other than booleans.
*/
type AclEvalFunc = (input: AclMatchInput) => any;
/**
* Compile a single node of the parsed formula tree.
*/
function _compileNode(parsedAclFormula: ParsedAclFormula): AclEvalFunc {
const rawArgs = parsedAclFormula.slice(1);
const args = rawArgs as ParsedAclFormula[];
switch (parsedAclFormula[0]) {
case 'And': { const parts = args.map(_compileNode); return (input) => parts.every(p => p(input)); }
case 'Or': { const parts = args.map(_compileNode); return (input) => parts.some(p => p(input)); }
case 'Add': return _compileAndCombine(args, ([a, b]) => a + b);
case 'Sub': return _compileAndCombine(args, ([a, b]) => a - b);
case 'Mult': return _compileAndCombine(args, ([a, b]) => a * b);
case 'Div': return _compileAndCombine(args, ([a, b]) => a / b);
case 'Mod': return _compileAndCombine(args, ([a, b]) => a % b);
case 'Not': return _compileAndCombine(args, ([a]) => !a);
case 'Eq': return _compileAndCombine(args, ([a, b]) => a === b);
case 'NotEq': return _compileAndCombine(args, ([a, b]) => a !== b);
case 'Lt': return _compileAndCombine(args, ([a, b]) => a < b);
case 'LtE': return _compileAndCombine(args, ([a, b]) => a <= b);
case 'Gt': return _compileAndCombine(args, ([a, b]) => a > b);
case 'GtE': return _compileAndCombine(args, ([a, b]) => a >= b);
case 'Is': return _compileAndCombine(args, ([a, b]) => a === b);
case 'IsNot': return _compileAndCombine(args, ([a, b]) => a !== b);
case 'In': return _compileAndCombine(args, ([a, b]) => b.includes(a));
case 'NotIn': return _compileAndCombine(args, ([a, b]) => !b.includes(a));
case 'List': return _compileAndCombine(args, (values) => values);
case 'Const': return constant(parsedAclFormula[1] as CellValue);
case 'Name': {
const name = rawArgs[0] as keyof AclMatchInput;
if (GRIST_CONSTANTS[name]) { return constant(GRIST_CONSTANTS[name]); }
if (!['user', 'rec', 'newRec'].includes(name)) {
throw new Error(`Unknown variable '${name}'`);
}
return (input) => input[name];
}
case 'Attr': {
const attrName = rawArgs[1] as string;
return _compileAndCombine([args[0]], ([value]) => getAttr(value, attrName, args[0]));
}
case 'Comment': return _compileNode(args[0]);
}
throw new Error(`Unknown node type '${parsedAclFormula[0]}'`);
}
function describeNode(node: ParsedAclFormula): string {
if (node[0] === 'Name') {
return node[1] as string;
} else if (node[0] === 'Attr') {
return describeNode(node[1] as ParsedAclFormula) + '.' + (node[2] as string);
} else {
return 'value';
}
}
function getAttr(value: any, attrName: string, valueNode: ParsedAclFormula): any {
if (value == null) {
if (valueNode[0] === 'Name' && (valueNode[1] === 'rec' || valueNode[1] === 'newRec')) {
// This code is recognized by GranularAccess to know when a rule is row-specific.
throw new ErrorWithCode('NEED_ROW_DATA', `Missing row data '${valueNode[1]}'`);
}
throw new Error(`No value for '${describeNode(valueNode)}'`);
}
return (typeof value.get === 'function' ? value.get(attrName) : // InfoView
value[attrName]);
}
/**
* Helper for operators: compile a list of nodes, then when evaluating, evaluate them all and
* combine the array of results using the given combine() function.
*/
function _compileAndCombine(args: ParsedAclFormula[], combine: (values: any[]) => any): AclEvalFunc {
const compiled = args.map(_compileNode);
return (input: AclMatchInput) => combine(compiled.map(c => c(input)));
}