debian-mirror-gitlab/snowplow-javascript-tracker/core/lib/contexts.ts

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2020-04-13 14:06:41 +05:30
/*
* JavaScript tracker core for Snowplow: contexts.js
*
* Copyright (c) 2014-2018 Snowplow Analytics Ltd. All rights reserved.
*
* This program is licensed to you under the Apache License Version 2.0,
* and you may not use this file except in compliance with the Apache License Version 2.0.
* You may obtain a copy of the Apache License Version 2.0 at http://www.apache.org/licenses/LICENSE-2.0.
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the Apache License Version 2.0 is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the Apache License Version 2.0 for the specific language governing permissions and limitations there under.
*/
import { PayloadData, isNonEmptyJson } from "./payload";
import { SelfDescribingJson } from "./core";
import { base64urldecode } from "./base64";
import isEqual = require('lodash/isEqual');
import has = require('lodash/has');
import get = require('lodash/get');
import isPlainObject = require('lodash/isPlainObject');
import every = require('lodash/every');
import compact = require('lodash/compact');
import map = require('lodash/map');
/**
* Datatypes (some algebraic) for representing context types
*/
/**
* A context generator is a callback that returns a self-describing JSON
* @param {Object} args - Object that contains: event, eventType, eventSchema
* @return {SelfDescribingJson} A self-describing JSON
*/
export type ContextGenerator = (args?: Object) => SelfDescribingJson;
/**
* A context primitive is either a self-describing JSON or a context generator
*/
export type ContextPrimitive = SelfDescribingJson | ContextGenerator;
/**
* A context filter is a user-supplied callback that is evaluated for each event
* to determine if the context associated with the filter should be attached to the event
*/
export type ContextFilter = (args?: Object) => boolean;
/**
* A filter provider is an array that has two parts: a context filter and context primitives
* If the context filter evaluates to true, the tracker will attach the context primitive(s)
*/
export type FilterProvider = [ContextFilter, Array<ContextPrimitive> | ContextPrimitive];
/**
* A ruleset has accept or reject properties that contain rules for matching Iglu schema URIs
*/
export interface RuleSet {
accept?: string[] | string;
reject?: string[] | string;
}
/**
* A ruleset provider is an array that has two parts: a ruleset and context primitives
* If the ruleset allows the current event schema URI, the tracker will attach the context primitive(s)
*/
export type RuleSetProvider = [RuleSet, Array<ContextPrimitive> | ContextPrimitive];
/**
* Conditional context providers are two element arrays used to decide when to attach contexts, where:
* - the first element is some conditional criterion
* - the second element is any number of context primitives
*/
export type ConditionalContextProvider = FilterProvider | RuleSetProvider;
export function getSchemaParts(input: string): Array<string> | undefined {
let re = new RegExp('^iglu:([a-zA-Z0-9-_\.]+)\/([a-zA-Z0-9-_]+)\/jsonschema\/([1-9][0-9]*)\-(0|[1-9][0-9]*)\-(0|[1-9][0-9]*)$');
let matches = re.exec(input);
if (matches !== null)
return matches.slice(1, 6);
return undefined;
}
export function validateVendorParts(parts: Array<string>): boolean {
if (parts[0] === '*' || parts[1] === '*') {
return false; // no wildcard in first or second part
}
if (parts.slice(2).length > 0) {
let asterisk = false;
for (let part of parts.slice(2)) {
if (part === '*') // mark when we've found a wildcard
asterisk = true;
else if (asterisk) // invalid if alpha parts come after wildcard
return false;
}
return true;
} else if (parts.length == 2)
return true;
return false;
}
export function validateVendor(input: string): boolean {
let parts = input.split('.');
if (parts && parts.length > 1)
return validateVendorParts(parts);
return false;
}
export function getRuleParts(input: string): Array<string> | undefined {
const re = new RegExp('^iglu:((?:(?:[a-zA-Z0-9-_]+|\\*)\.)+(?:[a-zA-Z0-9-_]+|\\*))\/([a-zA-Z0-9-_.]+|\\*)\/jsonschema\/([1-9][0-9]*|\\*)-(0|[1-9][0-9]*|\\*)-(0|[1-9][0-9]*|\\*)$');
let matches = re.exec(input);
if (matches !== null && validateVendor(matches[1]))
return matches.slice(1,6);
return undefined;
}
export function isValidRule(input: string): boolean {
let ruleParts = getRuleParts(input);
if (ruleParts) {
let vendor = ruleParts[0];
return ruleParts.length === 5 && validateVendor(vendor);
}
return false;
}
export function isStringArray(input: any): boolean {
return Array.isArray(input) && input.every((x) => { return typeof x === 'string' });
}
export function isValidRuleSetArg(input: any): boolean {
if (isStringArray(input))
return input.every((x) => { return isValidRule(x) });
else if (typeof input === 'string')
return isValidRule(input);
return false;
}
export function isSelfDescribingJson(input: any) : boolean {
if (isNonEmptyJson(input))
if ('schema' in input && 'data' in input)
return (typeof(input.schema) === 'string' && typeof(input.data) === 'object');
return false;
}
export function isEventJson(input: any) : boolean {
if (isNonEmptyJson(input) && ('e' in input))
return (typeof(input.e) === 'string');
return false;
}
export function isRuleSet(input: any) : boolean {
let ruleCount = 0;
if (isPlainObject(input)) {
if (has(input, 'accept')) {
if (isValidRuleSetArg(input['accept'])) {
ruleCount += 1;
} else {
return false;
}
}
if (has(input, 'reject')) {
if (isValidRuleSetArg(input['reject'])) {
ruleCount += 1;
} else {
return false;
}
}
// if either 'reject' or 'accept' or both exists,
// we have a valid ruleset
return ruleCount > 0 && ruleCount <= 2;
}
return false;
}
export function isContextGenerator(input: any) : boolean {
return typeof(input) === 'function' && input.length <= 1;
}
export function isContextFilter(input: any) : boolean {
return typeof(input) === 'function' && input.length <= 1;
}
export function isContextPrimitive(input: any) : boolean {
return (isContextGenerator(input) || isSelfDescribingJson(input));
}
export function isFilterProvider(input: any) : boolean {
if (Array.isArray(input)) {
if (input.length === 2) {
if (Array.isArray(input[1])) {
return isContextFilter(input[0]) && every(input[1], isContextPrimitive);
}
return isContextFilter(input[0]) && isContextPrimitive(input[1]);
}
}
return false;
}
export function isRuleSetProvider(input: any) : boolean {
if (Array.isArray(input) && input.length === 2) {
if (!isRuleSet(input[0]))
return false;
if (Array.isArray(input[1]))
return every(input[1], isContextPrimitive);
return isContextPrimitive(input[1]);
}
return false;
}
export function isConditionalContextProvider(input: any) : boolean {
return isFilterProvider(input) || isRuleSetProvider(input);
}
export function matchSchemaAgainstRule(rule: string, schema: string) : boolean {
if (!isValidRule(rule))
return false;
let ruleParts = getRuleParts(rule);
let schemaParts = getSchemaParts(schema);
if (ruleParts && schemaParts) {
if (!matchVendor(ruleParts[0], schemaParts[0]))
return false;
for (let i=1; i<5; i++) {
if (!matchPart(ruleParts[i], schemaParts[i]))
return false;
}
return true; // if it hasn't failed, it passes
}
return false;
}
export function matchVendor(rule: string, vendor: string): boolean {
// rule and vendor must have same number of elements
let vendorParts = vendor.split('.');
let ruleParts = rule.split('.');
if (vendorParts && ruleParts) {
if (vendorParts.length !== ruleParts.length)
return false;
for (let i=0; i<ruleParts.length; i++) {
if (!matchPart(vendorParts[i], ruleParts[i]))
return false;
}
return true;
}
return false;
}
export function matchPart(rule: string, schema: string): boolean {
// parts should be the string nested between slashes in the URI: /example/
return (rule && schema && rule === '*' || rule === schema);
}
export function matchSchemaAgainstRuleSet(ruleSet: RuleSet, schema: string) : boolean {
let rejectCount = 0;
let acceptCount = 0;
let acceptRules = get(ruleSet, 'accept');
if (Array.isArray(acceptRules)) {
if ((ruleSet.accept as Array<string>).some((rule) => (matchSchemaAgainstRule(rule, schema)))) {
acceptCount++;
}
} else if (typeof(acceptRules) === 'string') {
if (matchSchemaAgainstRule(acceptRules, schema)) {
acceptCount++;
}
}
let rejectRules = get(ruleSet, 'reject');
if (Array.isArray(rejectRules)) {
if ((ruleSet.reject as Array<string>).some((rule) => (matchSchemaAgainstRule(rule, schema)))) {
rejectCount++;
}
} else if (typeof(rejectRules) === 'string') {
if (matchSchemaAgainstRule(rejectRules, schema)) {
rejectCount++;
}
}
if (acceptCount > 0 && rejectCount === 0) {
return true;
} else if (acceptCount === 0 && rejectCount > 0) {
return false;
}
return false;
}
// Returns the "useful" schema, i.e. what would someone want to use to identify events.
// The idea being that you can determine the event type from 'e', so getting the schema from
// 'ue_px.schema'/'ue_pr.schema' would be redundant - it'll return the unstructured event schema.
// Instead the schema nested inside the unstructured event is more useful!
// This doesn't decode ue_px, it works because it's called by code that has already decoded it
export function getUsefulSchema(sb: SelfDescribingJson): string {
if (typeof get(sb, 'ue_px.data.schema') === 'string')
return get(sb, 'ue_px.data.schema');
else if (typeof get(sb, 'ue_pr.data.schema') === 'string')
return get(sb, 'ue_pr.data.schema');
else if (typeof get(sb, 'schema') === 'string')
return get(sb, 'schema');
return '';
}
export function getDecodedEvent(sb: SelfDescribingJson): SelfDescribingJson {
let decodedEvent = {...sb}; // spread operator, instantiates new object
try {
if (has(decodedEvent, 'ue_px')) {
decodedEvent['ue_px'] = JSON.parse(base64urldecode(get(decodedEvent, ['ue_px'])));
}
} catch(e) {}
return decodedEvent;
}
export function getEventType(sb: {}): string {
return get(sb, 'e', '');
}
export function buildGenerator(generator: ContextGenerator,
event: SelfDescribingJson,
eventType: string,
eventSchema: string) : SelfDescribingJson | Array<SelfDescribingJson> | undefined {
let contextGeneratorResult : SelfDescribingJson | Array<SelfDescribingJson> | undefined = undefined;
try {
// try to evaluate context generator
let args = {
event: event,
eventType: eventType,
eventSchema: eventSchema
};
contextGeneratorResult = generator(args);
// determine if the produced result is a valid SDJ
if (isSelfDescribingJson(contextGeneratorResult)) {
return contextGeneratorResult;
} else if (Array.isArray(contextGeneratorResult) && every(contextGeneratorResult, isSelfDescribingJson)) {
return contextGeneratorResult;
} else {
return undefined;
}
} catch (error) {
contextGeneratorResult = undefined;
}
return contextGeneratorResult;
}
export function normalizeToArray(input: any) : Array<any> {
if (Array.isArray(input)) {
return input;
}
return Array.of(input);
}
export function generatePrimitives(contextPrimitives: Array<ContextPrimitive> | ContextPrimitive,
event: SelfDescribingJson,
eventType: string,
eventSchema: string) : Array<SelfDescribingJson> {
let normalizedInputs : Array<ContextPrimitive> = normalizeToArray(contextPrimitives);
let partialEvaluate = (primitive) => {
let result = evaluatePrimitive(primitive, event, eventType, eventSchema);
if (result && result.length !== 0) {
return result;
}
};
let generatedContexts = map(normalizedInputs, partialEvaluate);
return [].concat(...compact(generatedContexts));
}
export function evaluatePrimitive(contextPrimitive: ContextPrimitive,
event: SelfDescribingJson,
eventType: string,
eventSchema: string) : Array<SelfDescribingJson> | undefined {
if (isSelfDescribingJson(contextPrimitive)) {
return [contextPrimitive as SelfDescribingJson];
} else if (isContextGenerator(contextPrimitive)) {
let generatorOutput = buildGenerator(contextPrimitive as ContextGenerator, event, eventType, eventSchema);
if (isSelfDescribingJson(generatorOutput)) {
return [generatorOutput as SelfDescribingJson];
} else if (Array.isArray(generatorOutput)) {
return generatorOutput;
}
}
return undefined;
}
export function evaluateProvider(provider: ConditionalContextProvider,
event: SelfDescribingJson,
eventType: string,
eventSchema: string): Array<SelfDescribingJson> {
if (isFilterProvider(provider)) {
let filter : ContextFilter = (provider as FilterProvider)[0];
let filterResult = false;
try {
let args = {
event: event,
eventType: eventType,
eventSchema: eventSchema
};
filterResult = filter(args);
} catch(error) {
filterResult = false;
}
if (filterResult === true) {
return generatePrimitives((provider as FilterProvider)[1], event, eventType, eventSchema);
}
} else if (isRuleSetProvider(provider)) {
if (matchSchemaAgainstRuleSet((provider as RuleSetProvider)[0], eventSchema)) {
return generatePrimitives((provider as RuleSetProvider)[1], event, eventType, eventSchema);
}
}
return [];
}
export function generateConditionals(providers: Array<ConditionalContextProvider> | ConditionalContextProvider,
event: SelfDescribingJson,
eventType: string,
eventSchema: string) : Array<SelfDescribingJson> {
let normalizedInput : Array<ConditionalContextProvider> = normalizeToArray(providers);
let partialEvaluate = (provider) => {
let result = evaluateProvider(provider, event, eventType, eventSchema);
if (result && result.length !== 0) {
return result;
}
};
let generatedContexts = map(normalizedInput, partialEvaluate);
return [].concat(...compact(generatedContexts));
}
export function contextModule() {
let globalPrimitives : Array<ContextPrimitive> = [];
let conditionalProviders : Array<ConditionalContextProvider> = [];
function assembleAllContexts(event: SelfDescribingJson) : Array<SelfDescribingJson> {
let eventSchema = getUsefulSchema(event);
let eventType = getEventType(event);
let contexts : Array<SelfDescribingJson> = [];
let generatedPrimitives = generatePrimitives(globalPrimitives, event, eventType, eventSchema);
contexts.push(...generatedPrimitives);
let generatedConditionals = generateConditionals(conditionalProviders, event, eventType, eventSchema);
contexts.push(...generatedConditionals);
return contexts;
}
return {
getGlobalPrimitives: function () {
return globalPrimitives;
},
getConditionalProviders: function () {
return conditionalProviders;
},
addGlobalContexts: function (contexts: Array<any>) {
let acceptedConditionalContexts : ConditionalContextProvider[] = [];
let acceptedContextPrimitives : ContextPrimitive[] = [];
for (let context of contexts) {
if (isConditionalContextProvider(context)) {
acceptedConditionalContexts.push(context);
} else if (isContextPrimitive(context)) {
acceptedContextPrimitives.push(context);
}
}
globalPrimitives = globalPrimitives.concat(acceptedContextPrimitives);
conditionalProviders = conditionalProviders.concat(acceptedConditionalContexts);
},
clearGlobalContexts: function () {
conditionalProviders = [];
globalPrimitives = [];
},
removeGlobalContexts: function (contexts: Array<any>) {
for (let context of contexts) {
if (isConditionalContextProvider(context)) {
conditionalProviders = conditionalProviders.filter(item => !isEqual(item, context));
} else if (isContextPrimitive(context)) {
globalPrimitives = globalPrimitives.filter(item => !isEqual(item, context));
} else {
// error message here?
}
}
},
getApplicableContexts: function (event: PayloadData) : Array<SelfDescribingJson> {
const builtEvent = event.build();
if (isEventJson(builtEvent)) {
const decodedEvent = getDecodedEvent(builtEvent as SelfDescribingJson);
return assembleAllContexts(decodedEvent);
} else {
return [];
}
}
};
}