diff --git a/src/route/manga.ts b/src/route/manga.ts
index 610baf2..a109c2a 100644
--- a/src/route/manga.ts
+++ b/src/route/manga.ts
@@ -1,45 +1,10 @@
 
 import {Context, DefaultContext, DefaultState, Next} from 'koa';
-import StreamZip, { ZipEntry } from 'node-stream-zip';
-import {orderBy} from 'natural-orderby';
+import {readZip,entriesByNaturalOrder,createReadStreamFromZip} from '../util/zipwrap';
 import {since_last_modified} from './util';
 import {ContentContext} from './context';
 import Router from 'koa-router';
 
-export async function readZip(path : string):Promise<StreamZip>{
-    return new Promise((resolve,reject)=>{
-            let zip = new StreamZip({
-                file:path,
-                storeEntries: true
-            });
-            zip.on('error',(err)=>{
-                console.error(`read zip file ${path}`);
-                reject(err);
-            });
-            zip.on('ready',()=>{
-                resolve(zip);
-            });
-        }
-    );
-}
-export function entriesByNaturalOrder(zip: StreamZip){
-    const entries = zip.entries();
-    const ret = orderBy(Object.values(entries),v=>v.name);
-    return ret;
-}
-export async function createReadStreamFromZip(zip:StreamZip,entry: ZipEntry):Promise<NodeJS.ReadableStream>{
-    return new Promise((resolve,reject)=>{
-        zip.stream(entry,(err, stream)=>{
-            if(stream !== undefined){
-                resolve(stream);
-            }
-            else{
-                reject(err);
-            }
-        });}
-    );
-}
-
 async function renderZipImage(ctx: Context,path : string, page:number){
     const image_ext = ['gif', 'png', 'jpeg', 'bmp', 'webp', 'jpg'];
     let zip = await readZip(path);
diff --git a/src/util/zipwrap.ts b/src/util/zipwrap.ts
new file mode 100644
index 0000000..505ff81
--- /dev/null
+++ b/src/util/zipwrap.ts
@@ -0,0 +1,36 @@
+import StreamZip, { ZipEntry } from 'node-stream-zip';
+import {orderBy} from 'natural-orderby';
+
+export async function readZip(path : string):Promise<StreamZip>{
+    return new Promise((resolve,reject)=>{
+            let zip = new StreamZip({
+                file:path,
+                storeEntries: true
+            });
+            zip.on('error',(err)=>{
+                console.error(`read zip file ${path}`);
+                reject(err);
+            });
+            zip.on('ready',()=>{
+                resolve(zip);
+            });
+        }
+    );
+}
+export function entriesByNaturalOrder(zip: StreamZip){
+    const entries = zip.entries();
+    const ret = orderBy(Object.values(entries),v=>v.name);
+    return ret;
+}
+export async function createReadStreamFromZip(zip:StreamZip,entry: ZipEntry):Promise<NodeJS.ReadableStream>{
+    return new Promise((resolve,reject)=>{
+        zip.stream(entry,(err, stream)=>{
+            if(stream !== undefined){
+                resolve(stream);
+            }
+            else{
+                reject(err);
+            }
+        });}
+    );
+}
\ No newline at end of file