mirror of
https://github.com/opencloud-eu/opencloud.git
synced 2026-02-22 13:39:24 -06:00
build(deps): bump github.com/google/go-tika from 0.3.0 to 0.3.1
Bumps [github.com/google/go-tika](https://github.com/google/go-tika) from 0.3.0 to 0.3.1. - [Release notes](https://github.com/google/go-tika/releases) - [Commits](https://github.com/google/go-tika/compare/v0.3.0...v0.3.1) --- updated-dependencies: - dependency-name: github.com/google/go-tika dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <support@github.com>
This commit is contained in:
2
go.mod
2
go.mod
@@ -46,7 +46,7 @@ require (
|
||||
github.com/golang-jwt/jwt/v4 v4.5.0
|
||||
github.com/golang/protobuf v1.5.4
|
||||
github.com/google/go-cmp v0.6.0
|
||||
github.com/google/go-tika v0.3.0
|
||||
github.com/google/go-tika v0.3.1
|
||||
github.com/google/uuid v1.6.0
|
||||
github.com/gookit/config/v2 v2.2.5
|
||||
github.com/gorilla/mux v1.8.1
|
||||
|
||||
5
go.sum
5
go.sum
@@ -1367,8 +1367,8 @@ github.com/google/go-pkcs11 v0.2.0/go.mod h1:6eQoGcuNJpa7jnd5pMGdkSaQpNDYvPlXWMc
|
||||
github.com/google/go-querystring v1.0.0/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
|
||||
github.com/google/go-querystring v1.1.0 h1:AnCroh3fv4ZBgVIf1Iwtovgjaw/GiKJo8M8yD/fhyJ8=
|
||||
github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17icRSOU623lUBU=
|
||||
github.com/google/go-tika v0.3.0 h1:JncwikDcIJrSwwoTjWg6NE7g3IW7XTrI6ZeeOGp03Y8=
|
||||
github.com/google/go-tika v0.3.0/go.mod h1:k/Afo/0kDgo9g/9gjIIUBoDXgyGgYO3JAISqowoJdVE=
|
||||
github.com/google/go-tika v0.3.1 h1:l+jr10hDhZjcgxFRfcQChRLo1bPXQeLFluMyvDhXTTA=
|
||||
github.com/google/go-tika v0.3.1/go.mod h1:DJh5N8qxXIl85QkqmXknd+PeeRkUOTbvwyYf7ieDz6c=
|
||||
github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
|
||||
github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
|
||||
github.com/google/martian/v3 v3.0.0/go.mod h1:y5Zk1BBys9G+gd6Jrk0W3cC1+ELVxBWuIGO+w/tUAp0=
|
||||
@@ -2322,6 +2322,7 @@ golang.org/x/net v0.12.0/go.mod h1:zEVYFnQC7m/vmpQFELhcD1EWkZlX69l4oqgmer6hfKA=
|
||||
golang.org/x/net v0.14.0/go.mod h1:PpSgVXXLK0OxS0F31C1/tv6XNguvCrnXIDrFMspZIUI=
|
||||
golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
|
||||
golang.org/x/net v0.22.0/go.mod h1:JKghWKKOSdJwpW2GEx0Ja7fmaKnMsbu+MWVZTokSYmg=
|
||||
golang.org/x/net v0.23.0/go.mod h1:JKghWKKOSdJwpW2GEx0Ja7fmaKnMsbu+MWVZTokSYmg=
|
||||
golang.org/x/net v0.24.0 h1:1PcaxkF854Fu3+lvBIx5SYn9wRlBzzcnHZSiaFFAb0w=
|
||||
golang.org/x/net v0.24.0/go.mod h1:2Q7sJY5mzlzWjKtYUEXSlBWCdyaioyXzRB2RtU8KVE8=
|
||||
golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
|
||||
|
||||
462
vendor/github.com/kovidgoyal/imaging/README.md
generated
vendored
462
vendor/github.com/kovidgoyal/imaging/README.md
generated
vendored
@@ -1,231 +1,231 @@
|
||||
# Imaging
|
||||
|
||||
Package imaging provides basic image processing functions (resize, rotate, crop, brightness/contrast adjustments, etc.).
|
||||
|
||||
All the image processing functions provided by the package accept any image type that implements `image.Image` interface
|
||||
as an input, and return a new image of `*image.NRGBA` type (32bit RGBA colors, non-premultiplied alpha).
|
||||
|
||||
## Installation
|
||||
|
||||
go get -u github.com/kovidgoyal/imaging
|
||||
|
||||
## Documentation
|
||||
|
||||
https://pkg.go.dev/github.com/kovidgoyal/imaging
|
||||
|
||||
## Usage examples
|
||||
|
||||
A few usage examples can be found below. See the documentation for the full list of supported functions.
|
||||
|
||||
### Image resizing
|
||||
|
||||
```go
|
||||
// Resize srcImage to size = 128x128px using the Lanczos filter.
|
||||
dstImage128 := imaging.Resize(srcImage, 128, 128, imaging.Lanczos)
|
||||
|
||||
// Resize srcImage to width = 800px preserving the aspect ratio.
|
||||
dstImage800 := imaging.Resize(srcImage, 800, 0, imaging.Lanczos)
|
||||
|
||||
// Scale down srcImage to fit the 800x600px bounding box.
|
||||
dstImageFit := imaging.Fit(srcImage, 800, 600, imaging.Lanczos)
|
||||
|
||||
// Resize and crop the srcImage to fill the 100x100px area.
|
||||
dstImageFill := imaging.Fill(srcImage, 100, 100, imaging.Center, imaging.Lanczos)
|
||||
```
|
||||
|
||||
Imaging supports image resizing using various resampling filters. The most notable ones:
|
||||
- `Lanczos` - A high-quality resampling filter for photographic images yielding sharp results.
|
||||
- `CatmullRom` - A sharp cubic filter that is faster than Lanczos filter while providing similar results.
|
||||
- `MitchellNetravali` - A cubic filter that produces smoother results with less ringing artifacts than CatmullRom.
|
||||
- `Linear` - Bilinear resampling filter, produces smooth output. Faster than cubic filters.
|
||||
- `Box` - Simple and fast averaging filter appropriate for downscaling. When upscaling it's similar to NearestNeighbor.
|
||||
- `NearestNeighbor` - Fastest resampling filter, no antialiasing.
|
||||
|
||||
The full list of supported filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali, CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine. Custom filters can be created using ResampleFilter struct.
|
||||
|
||||
**Resampling filters comparison**
|
||||
|
||||
Original image:
|
||||
|
||||

|
||||
|
||||
The same image resized from 600x400px to 150x100px using different resampling filters.
|
||||
From faster (lower quality) to slower (higher quality):
|
||||
|
||||
Filter | Resize result
|
||||
--------------------------|---------------------------------------------
|
||||
`imaging.NearestNeighbor` | 
|
||||
`imaging.Linear` | 
|
||||
`imaging.CatmullRom` | 
|
||||
`imaging.Lanczos` | 
|
||||
|
||||
|
||||
### Gaussian Blur
|
||||
|
||||
```go
|
||||
dstImage := imaging.Blur(srcImage, 0.5)
|
||||
```
|
||||
|
||||
Sigma parameter allows to control the strength of the blurring effect.
|
||||
|
||||
Original image | Sigma = 0.5 | Sigma = 1.5
|
||||
-----------------------------------|----------------------------------------|---------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Sharpening
|
||||
|
||||
```go
|
||||
dstImage := imaging.Sharpen(srcImage, 0.5)
|
||||
```
|
||||
|
||||
`Sharpen` uses gaussian function internally. Sigma parameter allows to control the strength of the sharpening effect.
|
||||
|
||||
Original image | Sigma = 0.5 | Sigma = 1.5
|
||||
-----------------------------------|-------------------------------------------|------------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Gamma correction
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustGamma(srcImage, 0.75)
|
||||
```
|
||||
|
||||
Original image | Gamma = 0.75 | Gamma = 1.25
|
||||
-----------------------------------|------------------------------------------|-----------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Contrast adjustment
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustContrast(srcImage, 20)
|
||||
```
|
||||
|
||||
Original image | Contrast = 15 | Contrast = -15
|
||||
-----------------------------------|--------------------------------------------|-------------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Brightness adjustment
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustBrightness(srcImage, 20)
|
||||
```
|
||||
|
||||
Original image | Brightness = 10 | Brightness = -10
|
||||
-----------------------------------|----------------------------------------------|---------------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Saturation adjustment
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustSaturation(srcImage, 20)
|
||||
```
|
||||
|
||||
Original image | Saturation = 30 | Saturation = -30
|
||||
-----------------------------------|----------------------------------------------|---------------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Hue adjustment
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustHue(srcImage, 20)
|
||||
```
|
||||
|
||||
Original image | Hue = 60 | Hue = -60
|
||||
-----------------------------------|----------------------------------------------|---------------------------------------------
|
||||
 |  | 
|
||||
|
||||
## FAQ
|
||||
|
||||
### Incorrect image orientation after processing (e.g. an image appears rotated after resizing)
|
||||
|
||||
Most probably, the given image contains the EXIF orientation tag.
|
||||
The standard `image/*` packages do not support loading and saving
|
||||
this kind of information. To fix the issue, try opening images with
|
||||
the `AutoOrientation` decode option. If this option is set to `true`,
|
||||
the image orientation is changed after decoding, according to the
|
||||
orientation tag (if present). Here's the example:
|
||||
|
||||
```go
|
||||
img, err := imaging.Open("test.jpg", imaging.AutoOrientation(true))
|
||||
```
|
||||
|
||||
### What's the difference between `imaging` and `gift` packages?
|
||||
|
||||
[imaging](https://github.com/kovidgoyal/imaging)
|
||||
is designed to be a lightweight and simple image manipulation package.
|
||||
It provides basic image processing functions and a few helper functions
|
||||
such as `Open` and `Save`. It consistently returns *image.NRGBA image
|
||||
type (8 bits per channel, RGBA).
|
||||
|
||||
[gift](https://github.com/disintegration/gift)
|
||||
supports more advanced image processing, for example, sRGB/Linear color
|
||||
space conversions. It also supports different output image types
|
||||
(e.g. 16 bits per channel) and provides easy-to-use API for chaining
|
||||
multiple processing steps together.
|
||||
|
||||
## Example code
|
||||
|
||||
```go
|
||||
package main
|
||||
|
||||
import (
|
||||
"image"
|
||||
"image/color"
|
||||
"log"
|
||||
|
||||
"github.com/kovidgoyal/imaging"
|
||||
)
|
||||
|
||||
func main() {
|
||||
// Open a test image.
|
||||
src, err := imaging.Open("testdata/flowers.png")
|
||||
if err != nil {
|
||||
log.Fatalf("failed to open image: %v", err)
|
||||
}
|
||||
|
||||
// Crop the original image to 300x300px size using the center anchor.
|
||||
src = imaging.CropAnchor(src, 300, 300, imaging.Center)
|
||||
|
||||
// Resize the cropped image to width = 200px preserving the aspect ratio.
|
||||
src = imaging.Resize(src, 200, 0, imaging.Lanczos)
|
||||
|
||||
// Create a blurred version of the image.
|
||||
img1 := imaging.Blur(src, 5)
|
||||
|
||||
// Create a grayscale version of the image with higher contrast and sharpness.
|
||||
img2 := imaging.Grayscale(src)
|
||||
img2 = imaging.AdjustContrast(img2, 20)
|
||||
img2 = imaging.Sharpen(img2, 2)
|
||||
|
||||
// Create an inverted version of the image.
|
||||
img3 := imaging.Invert(src)
|
||||
|
||||
// Create an embossed version of the image using a convolution filter.
|
||||
img4 := imaging.Convolve3x3(
|
||||
src,
|
||||
[9]float64{
|
||||
-1, -1, 0,
|
||||
-1, 1, 1,
|
||||
0, 1, 1,
|
||||
},
|
||||
nil,
|
||||
)
|
||||
|
||||
// Create a new image and paste the four produced images into it.
|
||||
dst := imaging.New(400, 400, color.NRGBA{0, 0, 0, 0})
|
||||
dst = imaging.Paste(dst, img1, image.Pt(0, 0))
|
||||
dst = imaging.Paste(dst, img2, image.Pt(0, 200))
|
||||
dst = imaging.Paste(dst, img3, image.Pt(200, 0))
|
||||
dst = imaging.Paste(dst, img4, image.Pt(200, 200))
|
||||
|
||||
// Save the resulting image as JPEG.
|
||||
err = imaging.Save(dst, "testdata/out_example.jpg")
|
||||
if err != nil {
|
||||
log.Fatalf("failed to save image: %v", err)
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||

|
||||
# Imaging
|
||||
|
||||
Package imaging provides basic image processing functions (resize, rotate, crop, brightness/contrast adjustments, etc.).
|
||||
|
||||
All the image processing functions provided by the package accept any image type that implements `image.Image` interface
|
||||
as an input, and return a new image of `*image.NRGBA` type (32bit RGBA colors, non-premultiplied alpha).
|
||||
|
||||
## Installation
|
||||
|
||||
go get -u github.com/kovidgoyal/imaging
|
||||
|
||||
## Documentation
|
||||
|
||||
https://pkg.go.dev/github.com/kovidgoyal/imaging
|
||||
|
||||
## Usage examples
|
||||
|
||||
A few usage examples can be found below. See the documentation for the full list of supported functions.
|
||||
|
||||
### Image resizing
|
||||
|
||||
```go
|
||||
// Resize srcImage to size = 128x128px using the Lanczos filter.
|
||||
dstImage128 := imaging.Resize(srcImage, 128, 128, imaging.Lanczos)
|
||||
|
||||
// Resize srcImage to width = 800px preserving the aspect ratio.
|
||||
dstImage800 := imaging.Resize(srcImage, 800, 0, imaging.Lanczos)
|
||||
|
||||
// Scale down srcImage to fit the 800x600px bounding box.
|
||||
dstImageFit := imaging.Fit(srcImage, 800, 600, imaging.Lanczos)
|
||||
|
||||
// Resize and crop the srcImage to fill the 100x100px area.
|
||||
dstImageFill := imaging.Fill(srcImage, 100, 100, imaging.Center, imaging.Lanczos)
|
||||
```
|
||||
|
||||
Imaging supports image resizing using various resampling filters. The most notable ones:
|
||||
- `Lanczos` - A high-quality resampling filter for photographic images yielding sharp results.
|
||||
- `CatmullRom` - A sharp cubic filter that is faster than Lanczos filter while providing similar results.
|
||||
- `MitchellNetravali` - A cubic filter that produces smoother results with less ringing artifacts than CatmullRom.
|
||||
- `Linear` - Bilinear resampling filter, produces smooth output. Faster than cubic filters.
|
||||
- `Box` - Simple and fast averaging filter appropriate for downscaling. When upscaling it's similar to NearestNeighbor.
|
||||
- `NearestNeighbor` - Fastest resampling filter, no antialiasing.
|
||||
|
||||
The full list of supported filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali, CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine. Custom filters can be created using ResampleFilter struct.
|
||||
|
||||
**Resampling filters comparison**
|
||||
|
||||
Original image:
|
||||
|
||||

|
||||
|
||||
The same image resized from 600x400px to 150x100px using different resampling filters.
|
||||
From faster (lower quality) to slower (higher quality):
|
||||
|
||||
Filter | Resize result
|
||||
--------------------------|---------------------------------------------
|
||||
`imaging.NearestNeighbor` | 
|
||||
`imaging.Linear` | 
|
||||
`imaging.CatmullRom` | 
|
||||
`imaging.Lanczos` | 
|
||||
|
||||
|
||||
### Gaussian Blur
|
||||
|
||||
```go
|
||||
dstImage := imaging.Blur(srcImage, 0.5)
|
||||
```
|
||||
|
||||
Sigma parameter allows to control the strength of the blurring effect.
|
||||
|
||||
Original image | Sigma = 0.5 | Sigma = 1.5
|
||||
-----------------------------------|----------------------------------------|---------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Sharpening
|
||||
|
||||
```go
|
||||
dstImage := imaging.Sharpen(srcImage, 0.5)
|
||||
```
|
||||
|
||||
`Sharpen` uses gaussian function internally. Sigma parameter allows to control the strength of the sharpening effect.
|
||||
|
||||
Original image | Sigma = 0.5 | Sigma = 1.5
|
||||
-----------------------------------|-------------------------------------------|------------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Gamma correction
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustGamma(srcImage, 0.75)
|
||||
```
|
||||
|
||||
Original image | Gamma = 0.75 | Gamma = 1.25
|
||||
-----------------------------------|------------------------------------------|-----------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Contrast adjustment
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustContrast(srcImage, 20)
|
||||
```
|
||||
|
||||
Original image | Contrast = 15 | Contrast = -15
|
||||
-----------------------------------|--------------------------------------------|-------------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Brightness adjustment
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustBrightness(srcImage, 20)
|
||||
```
|
||||
|
||||
Original image | Brightness = 10 | Brightness = -10
|
||||
-----------------------------------|----------------------------------------------|---------------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Saturation adjustment
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustSaturation(srcImage, 20)
|
||||
```
|
||||
|
||||
Original image | Saturation = 30 | Saturation = -30
|
||||
-----------------------------------|----------------------------------------------|---------------------------------------------
|
||||
 |  | 
|
||||
|
||||
### Hue adjustment
|
||||
|
||||
```go
|
||||
dstImage := imaging.AdjustHue(srcImage, 20)
|
||||
```
|
||||
|
||||
Original image | Hue = 60 | Hue = -60
|
||||
-----------------------------------|----------------------------------------------|---------------------------------------------
|
||||
 |  | 
|
||||
|
||||
## FAQ
|
||||
|
||||
### Incorrect image orientation after processing (e.g. an image appears rotated after resizing)
|
||||
|
||||
Most probably, the given image contains the EXIF orientation tag.
|
||||
The standard `image/*` packages do not support loading and saving
|
||||
this kind of information. To fix the issue, try opening images with
|
||||
the `AutoOrientation` decode option. If this option is set to `true`,
|
||||
the image orientation is changed after decoding, according to the
|
||||
orientation tag (if present). Here's the example:
|
||||
|
||||
```go
|
||||
img, err := imaging.Open("test.jpg", imaging.AutoOrientation(true))
|
||||
```
|
||||
|
||||
### What's the difference between `imaging` and `gift` packages?
|
||||
|
||||
[imaging](https://github.com/kovidgoyal/imaging)
|
||||
is designed to be a lightweight and simple image manipulation package.
|
||||
It provides basic image processing functions and a few helper functions
|
||||
such as `Open` and `Save`. It consistently returns *image.NRGBA image
|
||||
type (8 bits per channel, RGBA).
|
||||
|
||||
[gift](https://github.com/disintegration/gift)
|
||||
supports more advanced image processing, for example, sRGB/Linear color
|
||||
space conversions. It also supports different output image types
|
||||
(e.g. 16 bits per channel) and provides easy-to-use API for chaining
|
||||
multiple processing steps together.
|
||||
|
||||
## Example code
|
||||
|
||||
```go
|
||||
package main
|
||||
|
||||
import (
|
||||
"image"
|
||||
"image/color"
|
||||
"log"
|
||||
|
||||
"github.com/kovidgoyal/imaging"
|
||||
)
|
||||
|
||||
func main() {
|
||||
// Open a test image.
|
||||
src, err := imaging.Open("testdata/flowers.png")
|
||||
if err != nil {
|
||||
log.Fatalf("failed to open image: %v", err)
|
||||
}
|
||||
|
||||
// Crop the original image to 300x300px size using the center anchor.
|
||||
src = imaging.CropAnchor(src, 300, 300, imaging.Center)
|
||||
|
||||
// Resize the cropped image to width = 200px preserving the aspect ratio.
|
||||
src = imaging.Resize(src, 200, 0, imaging.Lanczos)
|
||||
|
||||
// Create a blurred version of the image.
|
||||
img1 := imaging.Blur(src, 5)
|
||||
|
||||
// Create a grayscale version of the image with higher contrast and sharpness.
|
||||
img2 := imaging.Grayscale(src)
|
||||
img2 = imaging.AdjustContrast(img2, 20)
|
||||
img2 = imaging.Sharpen(img2, 2)
|
||||
|
||||
// Create an inverted version of the image.
|
||||
img3 := imaging.Invert(src)
|
||||
|
||||
// Create an embossed version of the image using a convolution filter.
|
||||
img4 := imaging.Convolve3x3(
|
||||
src,
|
||||
[9]float64{
|
||||
-1, -1, 0,
|
||||
-1, 1, 1,
|
||||
0, 1, 1,
|
||||
},
|
||||
nil,
|
||||
)
|
||||
|
||||
// Create a new image and paste the four produced images into it.
|
||||
dst := imaging.New(400, 400, color.NRGBA{0, 0, 0, 0})
|
||||
dst = imaging.Paste(dst, img1, image.Pt(0, 0))
|
||||
dst = imaging.Paste(dst, img2, image.Pt(0, 200))
|
||||
dst = imaging.Paste(dst, img3, image.Pt(200, 0))
|
||||
dst = imaging.Paste(dst, img4, image.Pt(200, 200))
|
||||
|
||||
// Save the resulting image as JPEG.
|
||||
err = imaging.Save(dst, "testdata/out_example.jpg")
|
||||
if err != nil {
|
||||
log.Fatalf("failed to save image: %v", err)
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||

|
||||
|
||||
2
vendor/modules.txt
vendored
2
vendor/modules.txt
vendored
@@ -1104,7 +1104,7 @@ github.com/google/go-cmp/cmp/internal/value
|
||||
# github.com/google/go-querystring v1.1.0
|
||||
## explicit; go 1.10
|
||||
github.com/google/go-querystring/query
|
||||
# github.com/google/go-tika v0.3.0
|
||||
# github.com/google/go-tika v0.3.1
|
||||
## explicit; go 1.11
|
||||
github.com/google/go-tika/tika
|
||||
# github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1
|
||||
|
||||
Reference in New Issue
Block a user