gotosocial/internal/db/bundb/search.go

422 lines
13 KiB
Go

// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package bundb
import (
"context"
"strings"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
"github.com/superseriousbusiness/gotosocial/internal/id"
"github.com/superseriousbusiness/gotosocial/internal/log"
"github.com/superseriousbusiness/gotosocial/internal/state"
"github.com/uptrace/bun"
"github.com/uptrace/bun/dialect"
)
// todo: currently we pass an 'offset' parameter into functions owned by this struct,
// which is ignored.
//
// The idea of 'offset' is to allow callers to page through results without supplying
// maxID or minID params; they simply use the offset as more or less a 'page number'.
// This works fine when you're dealing with something like Elasticsearch, but for
// SQLite or Postgres 'LIKE' queries it doesn't really, because for each higher offset
// you have to calculate the value of all the previous offsets as well *within the
// execution time of the query*. It's MUCH more efficient to page using maxID and
// minID for queries like this. For now, then, we just ignore the offset and hope that
// the caller will page using maxID and minID instead.
//
// In future, however, it would be good to support offset in a way that doesn't totally
// destroy database queries. One option would be to cache previous offsets when paging
// down (which is the most common use case).
//
// For example, say a caller makes a call with offset 0: we run the query as normal,
// and in a 10 minute cache or something, store the next maxID value as it would be for
// offset 1, for the supplied query, limit, following, etc. Then when they call for
// offset 1, instead of supplying 'offset' in the query and causing slowdown, we check
// the cache to see if we have the next maxID value stored for that query, and use that
// instead. If a caller out of the blue requests offset 4 or something, on an empty cache,
// we could run the previous 4 queries and store the offsets for those before making the
// 5th call for page 4.
//
// This isn't ideal, of course, but at least we could cover the most common use case of
// a caller paging down through results.
type searchDB struct {
conn *DBConn
state *state.State
}
// replacer is a thread-safe string replacer which escapes
// common SQLite + Postgres `LIKE` wildcard chars using the
// escape character `\`. Initialized as a var in this package
// so it can be reused.
var replacer = strings.NewReplacer(
`\`, `\\`, // Escape char.
`%`, `\%`, // Zero or more char.
`_`, `\_`, // Exactly one char.
)
// whereSubqueryLike appends a WHERE clause to the
// given SelectQuery q, which searches for matches
// of searchQuery in the given subQuery using LIKE.
func whereSubqueryLike(
q *bun.SelectQuery,
subQuery *bun.SelectQuery,
searchQuery string,
) *bun.SelectQuery {
// Escape existing wildcard + escape
// chars in the search query string.
searchQuery = replacer.Replace(searchQuery)
// Add our own wildcards back in; search
// zero or more chars around the query.
searchQuery = `%` + searchQuery + `%`
// Append resulting WHERE
// clause to the main query.
return q.Where(
"(?) LIKE ? ESCAPE ?",
subQuery, searchQuery, `\`,
)
}
// Query example (SQLite):
//
// SELECT "account"."id" FROM "accounts" AS "account"
// WHERE (("account"."domain" IS NULL) OR ("account"."domain" != "account"."username"))
// AND ("account"."id" < 'ZZZZZZZZZZZZZZZZZZZZZZZZZZ')
// AND ("account"."id" IN (SELECT "target_account_id" FROM "follows" WHERE ("account_id" = '016T5Q3SQKBT337DAKVSKNXXW1')))
// AND ((SELECT LOWER("account"."username" || COALESCE("account"."display_name", '') || COALESCE("account"."note", '')) AS "account_text") LIKE '%turtle%' ESCAPE '\')
// ORDER BY "account"."id" DESC LIMIT 10
func (s *searchDB) SearchForAccounts(
ctx context.Context,
accountID string,
query string,
maxID string,
minID string,
limit int,
following bool,
offset int,
) ([]*gtsmodel.Account, error) {
// Ensure reasonable
if limit < 0 {
limit = 0
}
// Make educated guess for slice size
var (
accountIDs = make([]string, 0, limit)
frontToBack = true
)
q := s.conn.
NewSelect().
TableExpr("? AS ?", bun.Ident("accounts"), bun.Ident("account")).
// Select only IDs from table.
Column("account.id").
// Try to ignore instance accounts. Account domain must
// be either nil or, if set, not equal to the account's
// username (which is commonly used to indicate it's an
// instance service account).
WhereGroup(" AND ", func(q *bun.SelectQuery) *bun.SelectQuery {
return q.
Where("? IS NULL", bun.Ident("account.domain")).
WhereOr("? != ?", bun.Ident("account.domain"), bun.Ident("account.username"))
})
// Return only items with a LOWER id than maxID.
if maxID == "" {
maxID = id.Highest
}
q = q.Where("? < ?", bun.Ident("account.id"), maxID)
if minID != "" {
// Return only items with a HIGHER id than minID.
q = q.Where("? > ?", bun.Ident("account.id"), minID)
// page up
frontToBack = false
}
if following {
// Select only from accounts followed by accountID.
q = q.Where(
"? IN (?)",
bun.Ident("account.id"),
s.followedAccounts(accountID),
)
}
// Select account text as subquery.
accountTextSubq := s.accountText(following)
// Search using LIKE for matches of query
// string within accountText subquery.
q = whereSubqueryLike(q, accountTextSubq, query)
if limit > 0 {
// Limit amount of accounts returned.
q = q.Limit(limit)
}
if frontToBack {
// Page down.
q = q.Order("account.id DESC")
} else {
// Page up.
q = q.Order("account.id ASC")
}
if err := q.Scan(ctx, &accountIDs); err != nil {
return nil, s.conn.ProcessError(err)
}
if len(accountIDs) == 0 {
return nil, nil
}
// If we're paging up, we still want accounts
// to be sorted by ID desc, so reverse ids slice.
// https://zchee.github.io/golang-wiki/SliceTricks/#reversing
if !frontToBack {
for l, r := 0, len(accountIDs)-1; l < r; l, r = l+1, r-1 {
accountIDs[l], accountIDs[r] = accountIDs[r], accountIDs[l]
}
}
accounts := make([]*gtsmodel.Account, 0, len(accountIDs))
for _, id := range accountIDs {
// Fetch account from db for ID
account, err := s.state.DB.GetAccountByID(ctx, id)
if err != nil {
log.Errorf(ctx, "error fetching account %q: %v", id, err)
continue
}
// Append account to slice
accounts = append(accounts, account)
}
return accounts, nil
}
// followedAccounts returns a subquery that selects only IDs
// of accounts that are followed by the given accountID.
func (s *searchDB) followedAccounts(accountID string) *bun.SelectQuery {
return s.conn.
NewSelect().
TableExpr("? AS ?", bun.Ident("follows"), bun.Ident("follow")).
Column("follow.target_account_id").
Where("? = ?", bun.Ident("follow.account_id"), accountID)
}
// statusText returns a subquery that selects a concatenation
// of account username and display name as "account_text". If
// `following` is true, then account note will also be included
// in the concatenation.
func (s *searchDB) accountText(following bool) *bun.SelectQuery {
var (
accountText = s.conn.NewSelect()
query string
args []interface{}
)
if following {
// If querying for accounts we follow,
// include note in text search params.
args = []interface{}{
bun.Ident("account.username"),
bun.Ident("account.display_name"), "",
bun.Ident("account.note"), "",
bun.Ident("account_text"),
}
} else {
// If querying for accounts we're not following,
// don't include note in text search params.
args = []interface{}{
bun.Ident("account.username"),
bun.Ident("account.display_name"), "",
bun.Ident("account_text"),
}
}
// SQLite and Postgres use different syntaxes for
// concatenation, and we also need to use a
// different number of placeholders depending on
// following/not following. COALESCE calls ensure
// that we're not trying to concatenate null values.
d := s.conn.Dialect().Name()
switch {
case d == dialect.SQLite && following:
query = "LOWER(? || COALESCE(?, ?) || COALESCE(?, ?)) AS ?"
case d == dialect.SQLite && !following:
query = "LOWER(? || COALESCE(?, ?)) AS ?"
case d == dialect.PG && following:
query = "LOWER(CONCAT(?, COALESCE(?, ?), COALESCE(?, ?))) AS ?"
case d == dialect.PG && !following:
query = "LOWER(CONCAT(?, COALESCE(?, ?))) AS ?"
default:
panic("db conn was neither pg not sqlite")
}
return accountText.ColumnExpr(query, args...)
}
// Query example (SQLite):
//
// SELECT "status"."id"
// FROM "statuses" AS "status"
// WHERE ("status"."boost_of_id" IS NULL)
// AND (("status"."account_id" = '01F8MH1H7YV1Z7D2C8K2730QBF') OR ("status"."in_reply_to_account_id" = '01F8MH1H7YV1Z7D2C8K2730QBF'))
// AND ("status"."id" < 'ZZZZZZZZZZZZZZZZZZZZZZZZZZ')
// AND ((SELECT LOWER("status"."content" || COALESCE("status"."content_warning", '')) AS "status_text") LIKE '%hello%' ESCAPE '\')
// ORDER BY "status"."id" DESC LIMIT 10
func (s *searchDB) SearchForStatuses(
ctx context.Context,
accountID string,
query string,
maxID string,
minID string,
limit int,
offset int,
) ([]*gtsmodel.Status, error) {
// Ensure reasonable
if limit < 0 {
limit = 0
}
// Make educated guess for slice size
var (
statusIDs = make([]string, 0, limit)
frontToBack = true
)
q := s.conn.
NewSelect().
TableExpr("? AS ?", bun.Ident("statuses"), bun.Ident("status")).
// Select only IDs from table
Column("status.id").
// Ignore boosts.
Where("? IS NULL", bun.Ident("status.boost_of_id")).
// Select only statuses created by
// accountID or replying to accountID.
WhereGroup(" AND ", func(q *bun.SelectQuery) *bun.SelectQuery {
return q.
Where("? = ?", bun.Ident("status.account_id"), accountID).
WhereOr("? = ?", bun.Ident("status.in_reply_to_account_id"), accountID)
})
// Return only items with a LOWER id than maxID.
if maxID == "" {
maxID = id.Highest
}
q = q.Where("? < ?", bun.Ident("status.id"), maxID)
if minID != "" {
// return only statuses HIGHER (ie., newer) than minID
q = q.Where("? > ?", bun.Ident("status.id"), minID)
// page up
frontToBack = false
}
// Select status text as subquery.
statusTextSubq := s.statusText()
// Search using LIKE for matches of query
// string within statusText subquery.
q = whereSubqueryLike(q, statusTextSubq, query)
if limit > 0 {
// Limit amount of statuses returned.
q = q.Limit(limit)
}
if frontToBack {
// Page down.
q = q.Order("status.id DESC")
} else {
// Page up.
q = q.Order("status.id ASC")
}
if err := q.Scan(ctx, &statusIDs); err != nil {
return nil, s.conn.ProcessError(err)
}
if len(statusIDs) == 0 {
return nil, nil
}
// If we're paging up, we still want statuses
// to be sorted by ID desc, so reverse ids slice.
// https://zchee.github.io/golang-wiki/SliceTricks/#reversing
if !frontToBack {
for l, r := 0, len(statusIDs)-1; l < r; l, r = l+1, r-1 {
statusIDs[l], statusIDs[r] = statusIDs[r], statusIDs[l]
}
}
statuses := make([]*gtsmodel.Status, 0, len(statusIDs))
for _, id := range statusIDs {
// Fetch status from db for ID
status, err := s.state.DB.GetStatusByID(ctx, id)
if err != nil {
log.Errorf(ctx, "error fetching status %q: %v", id, err)
continue
}
// Append status to slice
statuses = append(statuses, status)
}
return statuses, nil
}
// statusText returns a subquery that selects a concatenation
// of status content and content warning as "status_text".
func (s *searchDB) statusText() *bun.SelectQuery {
statusText := s.conn.NewSelect()
// SQLite and Postgres use different
// syntaxes for concatenation.
switch s.conn.Dialect().Name() {
case dialect.SQLite:
statusText = statusText.ColumnExpr(
"LOWER(? || COALESCE(?, ?)) AS ?",
bun.Ident("status.content"), bun.Ident("status.content_warning"), "",
bun.Ident("status_text"))
case dialect.PG:
statusText = statusText.ColumnExpr(
"LOWER(CONCAT(?, COALESCE(?, ?))) AS ?",
bun.Ident("status.content"), bun.Ident("status.content_warning"), "",
bun.Ident("status_text"))
default:
panic("db conn was neither pg not sqlite")
}
return statusText
}