pikapika/go/main/controller/image.go

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2021-09-29 23:57:09 +00:00
package controller
import (
"bytes"
"errors"
_ "golang.org/x/image/webp"
"image"
_ "image/gif"
_ "image/jpeg"
_ "image/png"
"io/ioutil"
"net/http"
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"pikapika/main/database/comic_center"
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"sync"
)
var mutexCounter = -1
var busMutex *sync.Mutex
var subMutexes []*sync.Mutex
func init() {
busMutex = &sync.Mutex{}
for i := 0; i < 5; i++ {
subMutexes = append(subMutexes, &sync.Mutex{})
}
}
// takeMutex 下载图片获取一个锁, 这样只能同时下载5张图片
func takeMutex() *sync.Mutex {
busMutex.Lock()
defer busMutex.Unlock()
mutexCounter = (mutexCounter + 1) % len(subMutexes)
return subMutexes[mutexCounter]
}
func decodeInfoFromBuff(buff []byte) (image.Image, string, error) {
buffer := bytes.NewBuffer(buff)
return image.Decode(buffer)
}
func decodeFromFile(path string) ([]byte, image.Image, string, error) {
b, e := ioutil.ReadFile(path)
if e != nil {
return nil, nil, "", e
}
i, f, e := decodeInfoFromBuff(b)
if e != nil {
return nil, nil, "", e
}
return b, i, f, e
}
// 下载图片并decode
func decodeFromUrl(fileServer string, path string) ([]byte, image.Image, string, error) {
m := takeMutex()
m.Lock()
defer m.Unlock()
request, err := http.NewRequest("GET", fileServer+"/static/"+path, nil)
if err != nil {
return nil, nil, "", err
}
response, err := client.Do(request)
if err != nil {
return nil, nil, "", err
}
defer response.Body.Close()
if response.StatusCode != 200 {
return nil, nil, "", errors.New("code is not 200")
}
buff, err := ioutil.ReadAll(response.Body)
if err != nil {
return nil, nil, "", err
}
img, format, err := decodeInfoFromBuff(buff)
if err != nil {
return nil, nil, "", err
}
return buff, img, format, err
}
// decodeFromCache 仅下载使用
func decodeFromCache(fileServer string, path string) ([]byte, image.Image, string, error) {
cache := comic_center.FindRemoteImage(fileServer, path)
if cache != nil {
buff, err := ioutil.ReadFile(remotePath(cache.LocalPath))
if err != nil {
return nil, nil, "", err
}
img, format, err := decodeInfoFromBuff(buff)
if err != nil {
return nil, nil, "", err
}
return buff, img, format, err
}
return nil, nil, "", errors.New("not found")
}