Files
SponsorBlockServer/src/routes/getSkipSegments.ts
2021-07-06 01:06:29 -04:00

359 lines
14 KiB
TypeScript

import { Request, Response } from 'express';
import { config } from '../config';
import { db, privateDB } from '../databases/databases';
import { skipSegmentsHashKey, skipSegmentsKey } from '../utils/redisKeys';
import { SBRecord } from '../types/lib.model';
import { ActionType, Category, CategoryActionType, DBSegment, HashedIP, IPAddress, OverlappingSegmentGroup, Segment, SegmentCache, SegmentUUID, Service, VideoData, VideoID, VideoIDHash, Visibility, VotableObject } from "../types/segments.model";
import { getCategoryActionType } from '../utils/categoryInfo';
import { getHash } from '../utils/getHash';
import { getIP } from '../utils/getIP';
import { Logger } from '../utils/logger';
import { QueryCacher } from '../utils/queryCacher';
import { getReputation } from '../utils/reputation';
async function prepareCategorySegments(req: Request, videoID: VideoID, category: Category, segments: DBSegment[],cache: SegmentCache = {shadowHiddenSegmentIPs: {}}): Promise<Segment[]> {
const shouldFilter: boolean[] = await Promise.all(segments.map(async (segment) => {
if (segment.votes < -1 && !segment.required) {
return false; //too untrustworthy, just ignore it
}
//check if shadowHidden
//this means it is hidden to everyone but the original ip that submitted it
if (segment.shadowHidden != Visibility.HIDDEN) {
return true;
}
if (cache.shadowHiddenSegmentIPs[videoID] === undefined) {
cache.shadowHiddenSegmentIPs[videoID] = await privateDB.prepare('all', 'SELECT "hashedIP" FROM "sponsorTimes" WHERE "videoID" = ?', [videoID]) as { hashedIP: HashedIP }[];
}
//if this isn't their ip, don't send it to them
return cache.shadowHiddenSegmentIPs[videoID].some((shadowHiddenSegment) => {
if (cache.userHashedIP === undefined) {
//hash the IP only if it's strictly necessary
cache.userHashedIP = getHash((getIP(req) + config.globalSalt) as IPAddress);
}
return shadowHiddenSegment.hashedIP === cache.userHashedIP;
});
}));
const filteredSegments = segments.filter((_, index) => shouldFilter[index]);
const maxSegments = getCategoryActionType(category) === CategoryActionType.Skippable ? 32 : 1;
return (await chooseSegments(filteredSegments, maxSegments)).map((chosenSegment) => ({
category: chosenSegment.category,
actionType: chosenSegment.actionType,
segment: [chosenSegment.startTime, chosenSegment.endTime],
UUID: chosenSegment.UUID,
videoDuration: chosenSegment.videoDuration
}));
}
async function getSegmentsByVideoID(req: Request, videoID: VideoID, categories: Category[],
actionTypes: ActionType[], requiredSegments: SegmentUUID[], service: Service): Promise<Segment[]> {
const cache: SegmentCache = {shadowHiddenSegmentIPs: {}};
const segments: Segment[] = [];
try {
categories = categories.filter((category) => !/[^a-z|_|-]/.test(category));
if (categories.length === 0) return null;
const segmentsByCategory: SBRecord<Category, DBSegment[]> = (await getSegmentsFromDBByVideoID(videoID, service))
.filter((segment: DBSegment) => categories.includes(segment?.category) && actionTypes.includes(segment?.actionType))
.reduce((acc: SBRecord<Category, DBSegment[]>, segment: DBSegment) => {
if (requiredSegments.includes(segment.UUID)) segment.required = true;
acc[segment.category] ??= [];
acc[segment.category].push(segment);
return acc;
}, {});
for (const [category, categorySegments] of Object.entries(segmentsByCategory)) {
segments.push(...(await prepareCategorySegments(req, videoID, category as Category, categorySegments, cache)));
}
return segments;
} catch (err) {
if (err) {
Logger.error(err);
return null;
}
}
}
async function getSegmentsByHash(req: Request, hashedVideoIDPrefix: VideoIDHash, categories: Category[],
actionTypes: ActionType[], requiredSegments: SegmentUUID[], service: Service): Promise<SBRecord<VideoID, VideoData>> {
const cache: SegmentCache = {shadowHiddenSegmentIPs: {}};
const segments: SBRecord<VideoID, VideoData> = {};
try {
type SegmentWithHashPerVideoID = SBRecord<VideoID, {hash: VideoIDHash, segmentPerCategory: SBRecord<Category, DBSegment[]>}>;
categories = categories.filter((category) => !(/[^a-z|_|-]/.test(category)));
if (categories.length === 0) return null;
const segmentPerVideoID: SegmentWithHashPerVideoID = (await getSegmentsFromDBByHash(hashedVideoIDPrefix, service))
.filter((segment: DBSegment) => categories.includes(segment?.category) && actionTypes.includes(segment?.actionType))
.reduce((acc: SegmentWithHashPerVideoID, segment: DBSegment) => {
acc[segment.videoID] = acc[segment.videoID] || {
hash: segment.hashedVideoID,
segmentPerCategory: {}
};
if (requiredSegments.includes(segment.UUID)) segment.required = true;
acc[segment.videoID].segmentPerCategory[segment.category] ??= [];
acc[segment.videoID].segmentPerCategory[segment.category].push(segment);
return acc;
}, {});
for (const [videoID, videoData] of Object.entries(segmentPerVideoID)) {
segments[videoID] = {
hash: videoData.hash,
segments: [],
};
for (const [category, segmentPerCategory] of Object.entries(videoData.segmentPerCategory)) {
segments[videoID].segments.push(...(await prepareCategorySegments(req, videoID as VideoID, category as Category, segmentPerCategory, cache)));
}
}
return segments;
} catch (err) {
if (err) {
Logger.error(err);
return null;
}
}
}
async function getSegmentsFromDBByHash(hashedVideoIDPrefix: VideoIDHash, service: Service): Promise<DBSegment[]> {
const fetchFromDB = () => db
.prepare(
'all',
`SELECT "videoID", "startTime", "endTime", "votes", "locked", "UUID", "userID", "category", "actionType", "videoDuration", "reputation", "shadowHidden", "hashedVideoID" FROM "sponsorTimes"
WHERE "hashedVideoID" LIKE ? AND "service" = ? AND "hidden" = 0 ORDER BY "startTime"`,
[hashedVideoIDPrefix + '%', service]
) as Promise<DBSegment[]>;
if (hashedVideoIDPrefix.length === 4) {
return await QueryCacher.get(fetchFromDB, skipSegmentsHashKey(hashedVideoIDPrefix, service));
}
return await fetchFromDB();
}
async function getSegmentsFromDBByVideoID(videoID: VideoID, service: Service): Promise<DBSegment[]> {
const fetchFromDB = () => db
.prepare(
'all',
`SELECT "startTime", "endTime", "votes", "locked", "UUID", "userID", "category", "actionType", "videoDuration", "reputation", "shadowHidden" FROM "sponsorTimes"
WHERE "videoID" = ? AND "service" = ? AND "hidden" = 0 ORDER BY "startTime"`,
[videoID, service]
) as Promise<DBSegment[]>;
return await QueryCacher.get(fetchFromDB, skipSegmentsKey(videoID, service));
}
//gets a weighted random choice from the choices array based on their `votes` property.
//amountOfChoices specifies the maximum amount of choices to return, 1 or more.
//choices are unique
function getWeightedRandomChoice<T extends VotableObject>(choices: T[], amountOfChoices: number): T[] {
//trivial case: no need to go through the whole process
if (amountOfChoices >= choices.length) {
return choices;
}
type TWithWeight = T & {
weight: number
}
//assign a weight to each choice
let totalWeight = 0;
const choicesWithWeights: TWithWeight[] = choices.map(choice => {
const boost = Math.min(choice.reputation, 4);
//The 3 makes -2 the minimum votes before being ignored completely
//this can be changed if this system increases in popularity.
const weight = Math.exp(choice.votes * Math.max(1, choice.reputation + 1) + 3 + boost);
totalWeight += Math.max(weight, 0);
return {...choice, weight};
});
//iterate and find amountOfChoices choices
const chosen = [];
while (amountOfChoices-- > 0) {
//weighted random draw of one element of choices
const randomNumber = Math.random() * totalWeight;
let stackWeight = choicesWithWeights[0].weight;
let i = 0;
while (stackWeight < randomNumber) {
stackWeight += choicesWithWeights[++i].weight;
}
//add it to the chosen ones and remove it from the choices before the next iteration
chosen.push(choicesWithWeights[i]);
totalWeight -= choicesWithWeights[i].weight;
choicesWithWeights.splice(i, 1);
}
return chosen;
}
//This function will find segments that are contained inside of eachother, called similar segments
//Only one similar time will be returned, randomly generated based on the sqrt of votes.
//This allows new less voted items to still sometimes appear to give them a chance at getting votes.
//Segments with less than -1 votes are already ignored before this function is called
async function chooseSegments(segments: DBSegment[], max: number): Promise<DBSegment[]> {
//Create groups of segments that are similar to eachother
//Segments must be sorted by their startTime so that we can build groups chronologically:
//1. As long as the segments' startTime fall inside the currentGroup, we keep adding them to that group
//2. If a segment starts after the end of the currentGroup (> cursor), no other segment will ever fall
// inside that group (because they're sorted) so we can create a new one
const overlappingSegmentsGroups: OverlappingSegmentGroup[] = [];
let currentGroup: OverlappingSegmentGroup;
let cursor = -1; //-1 to make sure that, even if the 1st segment starts at 0, a new group is created
for (const segment of segments) {
if (segment.startTime > cursor) {
currentGroup = {segments: [], votes: 0, reputation: 0, locked: false, required: false};
overlappingSegmentsGroups.push(currentGroup);
}
currentGroup.segments.push(segment);
//only if it is a positive vote, otherwise it is probably just a sponsor time with slightly wrong time
if (segment.votes > 0) {
currentGroup.votes += segment.votes;
}
if (segment.userID) segment.reputation = Math.min(segment.reputation, await getReputation(segment.userID));
if (segment.reputation > 0) {
currentGroup.reputation += segment.reputation;
}
if (segment.locked) {
currentGroup.locked = true;
}
if (segment.required) {
currentGroup.required = true;
}
cursor = Math.max(cursor, segment.endTime);
}
overlappingSegmentsGroups.forEach((group) => {
if (group.required) {
// Required beats locked
group.segments = group.segments.filter((segment) => segment.required);
} else if (group.locked) {
group.segments = group.segments.filter((segment) => segment.locked);
}
group.reputation = group.reputation / group.segments.length;
});
//if there are too many groups, find the best ones
return getWeightedRandomChoice(overlappingSegmentsGroups, max).map(
//randomly choose 1 good segment per group and return them
group => getWeightedRandomChoice(group.segments, 1)[0],
);
}
/**
*
* Returns what would be sent to the client.
* Will respond with errors if required. Returns false if it errors.
*
* @param req
* @param res
*
* @returns
*/
async function handleGetSegments(req: Request, res: Response): Promise<Segment[] | false> {
const videoID = req.query.videoID as VideoID;
// Default to sponsor
// If using params instead of JSON, only one category can be pulled
const categories: Category[] = req.query.categories
? JSON.parse(req.query.categories as string)
: req.query.category
? Array.isArray(req.query.category)
? req.query.category
: [req.query.category]
: ['sponsor'];
if (!Array.isArray(categories)) {
res.status(400).send("Categories parameter does not match format requirements.");
return false;
}
const actionTypes: ActionType[] = req.query.actionTypes
? JSON.parse(req.query.actionTypes as string)
: req.query.actionType
? Array.isArray(req.query.actionType)
? req.query.actionType
: [req.query.actionType]
: [ActionType.Skip];
if (!Array.isArray(actionTypes)) {
res.status(400).send("actionTypes parameter does not match format requirements.");
return false;
}
const requiredSegments: SegmentUUID[] = req.query.requiredSegments
? JSON.parse(req.query.requiredSegments as string)
: req.query.requiredSegment
? Array.isArray(req.query.requiredSegment)
? req.query.requiredSegment
: [req.query.requiredSegment]
: [];
if (!Array.isArray(requiredSegments)) {
res.status(400).send("requiredSegments parameter does not match format requirements.");
return false;
}
let service: Service = req.query.service ?? req.body.service ?? Service.YouTube;
if (!Object.values(Service).some((val) => val == service)) {
service = Service.YouTube;
}
const segments = await getSegmentsByVideoID(req, videoID, categories, actionTypes, requiredSegments, service);
if (segments === null || segments === undefined) {
res.sendStatus(500);
return false;
}
if (segments.length === 0) {
res.sendStatus(404);
return false;
}
return segments;
}
async function endpoint(req: Request, res: Response): Promise<Response> {
try {
const segments = await handleGetSegments(req, res);
// If false, res.send has already been called
if (segments) {
//send result
return res.send(segments);
}
} catch (err) {
if (err instanceof SyntaxError) {
return res.status(400).send("Categories parameter does not match format requirements.");
} else return res.sendStatus(500);
}
}
export {
getSegmentsByVideoID,
getSegmentsByHash,
endpoint,
handleGetSegments
};