WebP无法解析原图时直接返回原图数据

internal/nodes/http_request_reverse_proxy.go

@@ -249,10 +249,12 @@ func (this *HTTPRequest) doReverseProxy() {
 	shouldAutoFlush := this.reverseProxy.AutoFlush || this.RawReq.Header.Get("Accept") == "text/event-stream"
 
 	// 准备
-	this.writer.Prepare(resp.ContentLength, resp.StatusCode)
+	delayHeaders := this.writer.Prepare(resp.ContentLength, resp.StatusCode)
 
 	// 设置响应代码
+	if !delayHeaders {
 		this.writer.WriteHeader(resp.StatusCode)
+	}
 
 	// 输出到客户端
 	pool := this.bytePool(resp.ContentLength)

internal/nodes/http_writer.go

@@ -18,7 +18,6 @@ import (
 	_ "image/gif"
 	_ "image/jpeg"
 	_ "image/png"
-	"io"
 	"net"
 	"net/http"
 	"path/filepath"
@@ -43,6 +42,7 @@ type HTTPWriter struct {
 	webpIsEncoding        bool
 	webpBuffer            *bytes.Buffer
 	webpIsWriting         bool
+	webpOriginContentType string
 
 	compressionConfig *serverconfigs.HTTPCompressionConfig
 	compressionWriter compressions.Writer
@@ -93,12 +93,16 @@ func (this *HTTPWriter) SetCompression(config *serverconfigs.HTTPCompressionConf
 
 // Prepare 准备输出
 // 缓存不调用此函数
-func (this *HTTPWriter) Prepare(size int64, status int) {
+func (this *HTTPWriter) Prepare(size int64, status int) (delayHeaders bool) {
 	this.size = size
 	this.statusCode = status
 
 	if status == http.StatusOK {
 		this.prepareWebP(size)
+
+		if this.webpIsEncoding {
+			delayHeaders = true
+		}
 	}
 
 	this.prepareCache(size)
@@ -107,6 +111,8 @@ func (this *HTTPWriter) Prepare(size int64, status int) {
 	if !this.webpIsEncoding {
 		this.PrepareCompression(size)
 	}
+
+	return
 }
 
 // Raw 包装前的原始的Writer
@@ -262,11 +268,15 @@ func (this *HTTPWriter) Close() {
 	// webp writer
 	if this.isOk && this.webpIsEncoding {
 		var bufferLen = int64(this.webpBuffer.Len())
-		atomic.AddInt64(&webpTotalBufferSize, bufferLen*8)
+		atomic.AddInt64(&webpTotalBufferSize, bufferLen*4)
 
+		// 需要把字节读取出来做备份，防止在image.Decode()过程中丢失
+		var imageBytes = this.webpBuffer.Bytes()
 		imageData, _, err := image.Decode(this.webpBuffer)
 		if err != nil {
-			_, _ = io.Copy(this.writer, this.webpBuffer)
+			this.Header().Set("Content-Type", this.webpOriginContentType)
+			this.WriteHeader(http.StatusOK)
+			_, _ = this.writer.Write(imageBytes)
 
 			// 处理缓存
 			if this.cacheWriter != nil {
@@ -290,6 +300,10 @@ func (this *HTTPWriter) Close() {
 					remotelogs.Error("HTTP_WRITER", "encode webp failed: "+err.Error())
 				}
 
+				this.Header().Set("Content-Type", this.webpOriginContentType)
+				this.WriteHeader(http.StatusOK)
+				_, _ = this.writer.Write(imageBytes)
+
 				// 处理缓存
 				if this.cacheWriter != nil {
 					_ = this.cacheWriter.Discard()
@@ -298,7 +312,7 @@ func (this *HTTPWriter) Close() {
 			}
 		}
 
-		atomic.AddInt64(&webpTotalBufferSize, -bufferLen*8)
+		atomic.AddInt64(&webpTotalBufferSize, -bufferLen*4)
 		this.webpBuffer.Reset()
 	}
 
@@ -373,6 +387,7 @@ func (this *HTTPWriter) prepareWebP(size int64) {
 		atomic.LoadInt64(&webpTotalBufferSize) < webpMaxBufferSize {
 		this.webpIsEncoding = true
 		this.webpBuffer = webpBufferPool.Get()
+		this.webpOriginContentType = this.Header().Get("Content-Type")
 
 		this.Header().Del("Content-Length")
 		this.Header().Set("Content-Type", "image/webp")