1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
package goproxy_image
import (
"bytes"
. "github.com/elazarl/goproxy"
"github.com/elazarl/goproxy/regretable"
"image"
_ "image/gif"
"image/jpeg"
"image/png"
"io/ioutil"
"net/http"
)
var RespIsImage = ContentTypeIs("image/gif",
"image/jpeg",
"image/pjpeg",
"application/octet-stream",
"image/png")
// "image/tiff" tiff support is in external package, and rarely used, so we omitted it
func HandleImage(f func(img image.Image, ctx *ProxyCtx) image.Image) RespHandler {
return FuncRespHandler(func(resp *http.Response, ctx *ProxyCtx) *http.Response {
if !RespIsImage.HandleResp(resp, ctx) {
return resp
}
if resp.StatusCode != 200 {
// we might get 304 - not modified response without data
return resp
}
contentType := resp.Header.Get("Content-Type")
const kb = 1024
regret := regretable.NewRegretableReaderCloserSize(resp.Body, 16*kb)
resp.Body = regret
img, imgType, err := image.Decode(resp.Body)
if err != nil {
regret.Regret()
ctx.Warnf("%s: %s", ctx.Req.Method+" "+ctx.Req.URL.String()+" Image from "+ctx.Req.RequestURI+"content type"+
contentType+"cannot be decoded returning original image", err)
return resp
}
result := f(img, ctx)
buf := bytes.NewBuffer([]byte{})
switch contentType {
// No gif image encoder in go - convert to png
case "image/gif", "image/png":
if err := png.Encode(buf, result); err != nil {
ctx.Warnf("Cannot encode image, returning orig %v %v", ctx.Req.URL.String(), err)
return resp
}
resp.Header.Set("Content-Type", "image/png")
case "image/jpeg", "image/pjpeg":
if err := jpeg.Encode(buf, result, nil); err != nil {
ctx.Warnf("Cannot encode image, returning orig %v %v", ctx.Req.URL.String(), err)
return resp
}
case "application/octet-stream":
switch imgType {
case "jpeg":
if err := jpeg.Encode(buf, result, nil); err != nil {
ctx.Warnf("Cannot encode image as jpeg, returning orig %v %v", ctx.Req.URL.String(), err)
return resp
}
case "png", "gif":
if err := png.Encode(buf, result); err != nil {
ctx.Warnf("Cannot encode image as png, returning orig %v %v", ctx.Req.URL.String(), err)
return resp
}
}
default:
panic("unhandlable type" + contentType)
}
resp.Body = ioutil.NopCloser(buf)
return resp
})
}
|
