/
page_png.go
56 lines (46 loc) · 1.23 KB
/
page_png.go
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package server
import (
"encoding/base64"
"net/http"
"strings"
"go101.org/golds/internal/server/images"
)
func (ds *docServer) pngFile(w http.ResponseWriter, r *http.Request, pngFilename string) {
w.Header().Set("Content-Type", "image/png")
ds.mutex.Lock()
defer ds.mutex.Unlock()
if genDocsMode {
pngFilename = deHashFilename(pngFilename)
}
pageKey := pageCacheKey{
resType: ResTypePNG,
res: pngFilename,
}
data, ok := ds.cachedPage(pageKey)
if !ok {
data = decodeBase64Data(pngFilename)
ds.cachePage(pageKey, data)
// For docs generation.
page := NewHtmlPage(goldsVersion, "", nil, ds.currentTranslation, createPagePathInfo(ResTypePNG, pngFilename))
page.Write(data)
_ = page.Done(w)
}
w.Write(data)
}
var imageFiles = map[string]string{
"go101-wechat": images.Go101WeChat_png,
"go101-twitter": images.Go101Twitter_png,
}
func decodeBase64Data(pngFilename string) []byte {
base64Str, ok := imageFiles[pngFilename]
if !ok {
panic("not found image file: " + pngFilename)
}
encoded := []byte(strings.TrimSpace(strings.ReplaceAll(base64Str, "\n", "")))
decoded := make([]byte, len(encoded)*3/4+3)
n, err := base64.StdEncoding.Decode(decoded, encoded)
if err != nil {
panic(err)
}
return decoded[:n]
}