dd99eec4f6
Enforce minimum (25) and maximum (100) bounds on cursor size to prevent negative values or excessively large page sizes. All three API surfaces (GraphQL, MCP, CLI) funnel through NewCursor, so the fix belongs here. Signed-off-by: Bryan Frimin <bryan@getprobo.com>
106 lines
2.8 KiB
Go
106 lines
2.8 KiB
Go
// Copyright (c) 2025 Probo Inc <hello@getprobo.com>.
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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// PERFORMANCE OF THIS SOFTWARE.
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package page
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import (
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"github.com/jackc/pgx/v5"
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)
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type (
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Cursor[T OrderField] struct {
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Size int
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Position Position
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Key *CursorKey
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OrderBy OrderBy[T]
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}
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Position string
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OrderBy[T OrderField] struct {
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Field T
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Direction OrderDirection
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}
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)
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const (
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DefaultCursorSize = 25
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MaxCursorSize = 100
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Tail Position = "TAIL"
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Head Position = "HEAD"
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)
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func NewCursor[T OrderField](size int, from *CursorKey, pos Position, orderBy OrderBy[T]) *Cursor[T] {
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if size <= 0 {
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size = DefaultCursorSize
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} else if size > MaxCursorSize {
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size = MaxCursorSize
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}
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return &Cursor[T]{
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Size: size,
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Key: from,
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Position: pos,
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OrderBy: orderBy,
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}
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}
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func (c *Cursor[T]) SQLFragment() string {
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fieldName := c.OrderBy.Field.Column()
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var orderDirection string
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switch {
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case c.OrderBy.Direction == OrderDirectionAsc && c.Position == Head:
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orderDirection = "ASC"
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case c.OrderBy.Direction == OrderDirectionDesc && c.Position == Head:
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orderDirection = "DESC"
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case c.OrderBy.Direction == OrderDirectionAsc && c.Position == Tail:
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orderDirection = "DESC"
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case c.OrderBy.Direction == OrderDirectionDesc && c.Position == Tail:
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orderDirection = "ASC"
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}
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whereClause := "TRUE"
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if c.Key != nil && orderDirection == "DESC" {
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whereClause = "(" + fieldName + " <= @cursor_field_value) AND NOT (" + fieldName + " = @cursor_field_value AND id > @cursor_id)"
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} else if c.Key != nil && orderDirection == "ASC" {
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whereClause = "(" + fieldName + " >= @cursor_field_value) AND NOT (" + fieldName + " = @cursor_field_value AND id < @cursor_id)"
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}
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orderByClause := fieldName + " " + orderDirection + ", id " + orderDirection
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return whereClause + " ORDER BY " + orderByClause + " LIMIT @cursor_limit"
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}
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func (c *Cursor[T]) SQLArguments() pgx.NamedArgs {
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var size = c.Size
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if c.Key == nil {
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size += 1
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} else {
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size += 2
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}
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arguments := pgx.NamedArgs{
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"cursor_limit": size,
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}
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if c.Key != nil {
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arguments["cursor_id"] = c.Key.ID
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arguments["cursor_field_value"] = c.Key.Value
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}
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return arguments
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}
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