diff --git a/resources/assets/src/components/skinlib/Upload.vue b/resources/assets/src/components/skinlib/Upload.vue
index 505b5bd4..5b1d309a 100644
--- a/resources/assets/src/components/skinlib/Upload.vue
+++ b/resources/assets/src/components/skinlib/Upload.vue
@@ -112,7 +112,6 @@
 <script>
 import FileUpload from 'vue-upload-component';
 import toastr from 'toastr';
-import { walkFetch } from '../../js/net';
 import { swal } from '../../js/notify';
 
 export default {
@@ -168,16 +167,7 @@ export default {
             data.append('public', !this.isPrivate);
 
             this.uploading = true;
-            const request = new Request(`${blessing.base_url}/skinlib/upload`, {
-                body: data,
-                credentials: 'same-origin',
-                headers: {
-                    Accept: 'application/json',
-                    'X-CSRF-TOKEN': document.querySelector('meta[name="csrf-token"]').content
-                },
-                method: 'POST'
-            });
-            const { errno, msg, tid } = await walkFetch(request);
+            const { errno, msg, tid } = await this.$http.post('/skinlib/upload', data);
             if (errno === 0) {
                 await swal({ type: 'success', text: msg });
                 toastr.info(this.$t('skinlib.redirecting'));
diff --git a/resources/assets/src/js/net.js b/resources/assets/src/js/net.js
index 010426b4..8af5c37d 100644
--- a/resources/assets/src/js/net.js
+++ b/resources/assets/src/js/net.js
@@ -9,7 +9,6 @@ export const init = {
     credentials: 'same-origin',
     headers: {
         'Accept': 'application/json',
-        'Content-Type': 'application/json',
     }
 };
 
@@ -27,11 +26,16 @@ export async function walkFetch(request) {
     try {
         const response = await fetch(request);
         if (response.ok) {
-            return response.json();
+            return response.headers.get('Content-Type') === 'application/json'
+                ? response.json()
+                : response.text();
         } else {
-            showAjaxError(await response.text());
+            const text = await response.text();
+            emit('fetchError', text);
+            showAjaxError(text);
         }
     } catch (error) {
+        emit('fetchError', error);
         showAjaxError(error);
     }
 }
@@ -55,11 +59,16 @@ export async function post(url, data = empty) {
         data
     });
 
-    return walkFetch(new Request(`${blessing.base_url}${url}`, {
-        body: JSON.stringify(data),
+    const isFormData = data instanceof FormData;
+
+    const request = new Request(`${blessing.base_url}${url}`, {
+        body: isFormData ? data : JSON.stringify(data),
         method: 'POST',
         ...init
-    }));
+    });
+    !isFormData && request.headers.set('Content-Type', 'application/json');
+
+    return walkFetch(request);
 }
 
 Vue.use(_Vue => {
@@ -69,4 +78,4 @@ Vue.use(_Vue => {
     };
 });
 
-blessing.fetch = { get, post, walkFetch };
+blessing.fetch = { get, post };
diff --git a/resources/assets/tests/components/skinlib/Upload.test.js b/resources/assets/tests/components/skinlib/Upload.test.js
index b954ae0d..6b5f2c42 100644
--- a/resources/assets/tests/components/skinlib/Upload.test.js
+++ b/resources/assets/tests/components/skinlib/Upload.test.js
@@ -4,11 +4,9 @@ import Upload from '@/components/skinlib/Upload';
 import { flushPromises } from '../../utils';
 import toastr from 'toastr';
 import { swal } from '@/js/notify';
-import { walkFetch } from '@/js/net';
 
 jest.mock('toastr');
 jest.mock('@/js/notify');
-jest.mock('@/js/net');
 
 window.blessing.extra = {
     textureNameRule: 'rule',
@@ -96,7 +94,7 @@ test('process input file', () => {
 
 test('upload file', async () => {
     window.Request = jest.fn();
-    walkFetch
+    Vue.prototype.$http.post
         .mockResolvedValueOnce({ errno: 1, msg: '1' })
         .mockResolvedValueOnce({ errno: 0, msg: '0', tid: 1 });
     jest.spyOn(toastr, 'info');
@@ -108,32 +106,23 @@ test('upload file', async () => {
     const button = wrapper.find('.box-footer > button');
 
     button.trigger('click');
-    expect(walkFetch).not.toBeCalled();
+    expect(Vue.prototype.$http.post).not.toBeCalled();
     expect(toastr.info).toBeCalledWith('skinlib.emptyUploadFile');
 
     wrapper.setData({ files: [{ file: {}, name: 't', type: 'image/jpeg' }] });
     button.trigger('click');
-    expect(walkFetch).not.toBeCalled();
+    expect(Vue.prototype.$http.post).not.toBeCalled();
     expect(toastr.info).toBeCalledWith('skinlib.emptyTextureName');
 
     wrapper.find('[type=text]').setValue('t');
     button.trigger('click');
-    expect(walkFetch).not.toBeCalled();
+    expect(Vue.prototype.$http.post).not.toBeCalled();
     expect(toastr.info).toBeCalledWith('skinlib.fileExtError');
 
     wrapper.setData({ files: [{ file: new Blob, name: 't.png', type: 'image/png' }] });
     button.trigger('click');
     await flushPromises();
-    expect(window.Request).toBeCalledWith('/skinlib/upload', {
-        body: expect.any(FormData),
-        credentials: 'same-origin',
-        headers: {
-            Accept: 'application/json',
-            'X-CSRF-TOKEN': 'token'
-        },
-        method: 'POST'
-    });
-    expect(walkFetch).toBeCalledWith(expect.any(window.Request));
+    expect(Vue.prototype.$http.post).toBeCalledWith('/skinlib/upload', expect.any(FormData));
     expect(swal).toBeCalledWith({ type: 'warning', text: '1' });
 
     button.trigger('click');
diff --git a/resources/assets/tests/js/net.test.js b/resources/assets/tests/js/net.test.js
index 32ecab2e..63f9ad6c 100644
--- a/resources/assets/tests/js/net.test.js
+++ b/resources/assets/tests/js/net.test.js
@@ -14,7 +14,8 @@ test('the GET method', async () => {
     const json = jest.fn().mockResolvedValue({});
     window.fetch = jest.fn().mockResolvedValue({
         ok: true,
-        json
+        json,
+        headers: new Map([['Content-Type', 'application/json']])
     });
 
     const stub = jest.fn();
@@ -34,10 +35,12 @@ test('the GET method', async () => {
 });
 
 test('the POST method', async () => {
-    window.fetch = jest.fn().mockResolvedValue({
-        ok: true,
-        json: () => Promise.resolve({})
-    });
+    window.fetch = jest.fn()
+        .mockResolvedValue({
+            ok: true,
+            json: () => Promise.resolve({}),
+            headers: new Map([['Content-Type', 'application/json']])
+        });
 
     const meta = document.createElement('meta');
     meta.name = 'csrf-token';
@@ -47,20 +50,29 @@ test('the POST method', async () => {
     const stub = jest.fn();
     on('beforeFetch', stub);
 
+    const formData = new FormData();
+    await net.post('/abc', formData);
+    expect(stub).toBeCalledWith({
+        method: 'POST',
+        url: '/abc',
+        data: formData
+    });
+
     await net.post('/abc', { a: 'b' });
     expect(stub).toBeCalledWith({
         method: 'POST',
         url: '/abc',
         data: { a: 'b' }
     });
-    const request = window.fetch.mock.calls[0][0];
+    const request = window.fetch.mock.calls[1][0];
     expect(request.url).toBe('/abc');
     expect(request.method).toBe('POST');
     expect(request.body).toBe(JSON.stringify({ a: 'b' }));
     expect(request.headers.get('X-CSRF-TOKEN')).toBe('token');
+    expect(request.headers.get('Content-Type')).toBe('application/json');
 
     await net.post('/abc');
-    expect(window.fetch.mock.calls[1][0].body).toBe('{}');
+    expect(window.fetch.mock.calls[2][0].body).toBe('{}');
 });
 
 test('low level fetch', async () => {
@@ -73,17 +85,30 @@ test('low level fetch', async () => {
         })
         .mockResolvedValueOnce({
             ok: true,
-            json
+            json,
+            headers: new Map([['Content-Type', 'application/json']])
+        })
+        .mockResolvedValueOnce({
+            ok: true,
+            headers: new Map(),
+            text: () => Promise.resolve('text')
         });
 
     const request = { headers: new Map() };
 
+    const stub = jest.fn();
+    on('fetchError', stub);
+
     await net.walkFetch(request);
     expect(showAjaxError.mock.calls[0][0]).toBeInstanceOf(Error);
+    expect(stub).toBeCalledWith(expect.any(Error));
 
     await net.walkFetch(request);
     expect(showAjaxError).toBeCalledWith('404');
+    expect(stub).toBeCalledWith('404');
 
     await net.walkFetch(request);
     expect(json).toBeCalled();
+
+    expect(await net.walkFetch(request)).toBe('text');
 });