Files
libredesk/internal/image/image.go
T
Abhinav Raut 6b8a0f9521 fix content loss in knowledge base chunking and harden AI agent limits
Final review pass before taking the AI agent branch live.

Knowledge base:
- Text not wrapped in a block tag was never collected, so prose around a
  table or list never reached the index. The assistant answered "no
  relevant information" for questions the snippet covered.
- Blocks over the token limit were truncated and the remainder dropped. They
  are split into several chunks now.
- Trimming an oversized block ran one rune at a time and re-tokenized the
  whole string each step. A large table took minutes. It uses a binary
  search now.
- Overlap text was not escaped, so a sentence containing markup swallowed
  the rest of the chunk.
- SVG and template text no longer reaches the index.

AI agent:
- Verification codes are capped per address and per conversation. The cap
  was per conversation only, so a customer correcting a mistyped email was
  told to check an inbox that never got a code.
- Livechat verification sends synchronously. A queued send returned nil even
  when SMTP failed, so a failure counted as a sent code.
- Queued jobs drain on shutdown and hand off to a human instead of being
  dropped with no reply.
- Deleting an assistant no longer moves resolved and closed conversations
  into the fallback team.
- Image decode is capped at 25 MP. The old bound allowed a 400 MB decode per
  attachment.

Auth and admin:
- A blank OIDC client secret no longer overwrites the stored one. Blank id
  or secret is rejected instead.
- OIDC token exchange uses the SSRF guarded client with a timeout.
- Renaming a tool auth header no longer attaches the secret of whichever row
  now sits at that position.
- Clearing embedding dimensions no longer refills 1536 on the next load,
  which pushed a wrong value to the provider on the next save.
- Copilot conversation lookups filter by access before capping at 10.
2026-07-25 03:52:32 +05:30

103 lines
3.1 KiB
Go

// Package image provides utilities for processing image files, including
// retrieving image dimensions and creating thumbnails.
package image
import (
"bytes"
"encoding/base64"
"fmt"
"image"
"io"
"github.com/disintegration/imaging"
"github.com/gabriel-vasile/mimetype"
)
const (
// llmMaxDim caps an image's longest edge before it is sent to a vision model.
llmMaxDim = 1568
llmJPEGQuality = 85
// maxDecodePixels bounds width*height read from the header, blocking a small file that declares huge dimensions. 25 MP is ~100 MB of RGBA per agent worker.
maxDecodePixels = 25_000_000
)
var (
Exts = []string{"gif", "png", "jpg", "jpeg"}
DefThumbSize = 150
ThumbPrefix = "thumb_"
)
// IsImageByContent returns true when the file's magic bytes identify it as one
// of the raster formats this package can decode. Used as a fallback when the
// filename has no extension or an unreliable one (e.g. attachments arriving
// through email without proper file extensions).
func IsImageByContent(r io.ReadSeeker) bool {
if _, err := r.Seek(0, io.SeekStart); err != nil {
return false
}
defer r.Seek(0, io.SeekStart)
mtype, err := mimetype.DetectReader(r)
if err != nil {
return false
}
switch mtype.String() {
case "image/png", "image/jpeg", "image/gif":
return true
}
return false
}
// GetDimensions returns the width and height of the image in the provided file.
// It returns an error if the image cannot be decoded.
func GetDimensions(r io.Reader) (int, int, error) {
img, err := imaging.Decode(r)
if err != nil {
return 0, 0, err
}
bounds := img.Bounds()
width := bounds.Max.X
height := bounds.Max.Y
return width, height, nil
}
// CreateThumb generates a thumbnail of the given image file with the specified maximum dimension.
// The thumbnail's width will be resized to `thumbPxSize` while maintaining the aspect ratio.
func CreateThumb(thumbPxSize int, r io.Reader) (*bytes.Reader, error) {
img, err := imaging.Decode(r)
if err != nil {
return nil, err
}
thumb := imaging.Resize(img, thumbPxSize, 0, imaging.Lanczos)
var out bytes.Buffer
if err := imaging.Encode(&out, thumb, imaging.PNG); err != nil {
return nil, err
}
return bytes.NewReader(out.Bytes()), nil
}
// EncodeForLLM decodes an image, downscales its longest edge to at most llmMaxDim, re-encodes it as
// JPEG, and returns the base64 payload plus media type for a vision model request.
func EncodeForLLM(content []byte) (data string, mediaType string, err error) {
cfg, _, err := image.DecodeConfig(bytes.NewReader(content))
if err != nil {
return "", "", err
}
if cfg.Width <= 0 || cfg.Height <= 0 || cfg.Width > maxDecodePixels/cfg.Height {
return "", "", fmt.Errorf("invalid or too-large image dimensions %dx%d", cfg.Width, cfg.Height)
}
img, err := imaging.Decode(bytes.NewReader(content))
if err != nil {
return "", "", err
}
img = imaging.Fit(img, llmMaxDim, llmMaxDim, imaging.Lanczos)
var out bytes.Buffer
if err := imaging.Encode(&out, img, imaging.JPEG, imaging.JPEGQuality(llmJPEGQuality)); err != nil {
return "", "", err
}
return base64.StdEncoding.EncodeToString(out.Bytes()), "image/jpeg", nil
}