diff --git a/source/_posts/浏览器端crc32文件计算以及分片上传思路.md b/source/_posts/浏览器端crc32文件计算以及分片上传思路.md
new file mode 100644
index 0000000..c903ae2
--- /dev/null
+++ b/source/_posts/浏览器端crc32文件计算以及分片上传思路.md
@@ -0,0 +1,133 @@
+---
+title: 浏览器端crc32文件计算以及分片上传思路
+id: '362'
+cover: '/images/AAAABSGsf8u86EvIjRhj.jpg'
+categories:
+ - 分享
+tags:
+ - JavaScript
+ - html
+ - crc32
+ - 浏览器
+ - 分片上传
+date: 2020-12-27 15:21:00
+---
+
+大文件上传我们知道需要做MD5计算以及文件分片，由于最近业务业务上的调整，需要把MD5换成crc32，，crc32可以校验文件的完整性，对于业务处理比较方便。这里记录一下解决思路吧。
+
+# 1. 文件分片
+
+考虑到文件可能很大，出于性能的考虑，优先把文件分片，这里我设置默认5M大小一个分片：
+
+``` js
+const createFileChunk = (file, size = 5 * 1024 * 1024) => {
+    let chunks = [];
+    let cur = 0;
+    while (cur < file.size) {
+        chunks.push(file.slice(cur, cur + size));
+        cur += size;
+    }
+    return chunks;
+};
+```
+
+# 2. 文件crc32计算
+
+首先找一个crc32的库，这里我选了sheetjs的[crc32](https://github.com/SheetJS/js-crc32)库。
+为了提高性能，这种纯计算的功能使用web workers另起一个线程处理。
+
+``` js
+// crc32_worker.js  
+
+// 引入crc32.js库，importScripts只支持url引入
+self.importScripts("https://cdn.bootcdn.net/ajax/libs/crc-32/1.2.0/crc32.js");
+
+// 生成文件 hash
+self.onmessage = e => {
+    const {
+        fileChunks
+    } = e.data;
+    let crc32 = null;
+    let percentage = 0;
+    let count = 0;
+    const loadNext = index => {
+        const reader = new FileReader();
+        reader.readAsArrayBuffer(fileChunks[index]);
+        reader.onload = e => {
+            count++;
+            const blob = new Uint8Array(e.target.result);
+            if (index === 0) {
+                crc32 = self.CRC32.buf(blob);
+            } else {
+                crc32 = self.CRC32.buf(blob, crc32);
+            }
+
+            if (count === fileChunks.length) {
+                self.postMessage({
+                    percentage: 100,
+                    hash: crc32
+                });
+                self.close();
+            } else {
+                percentage += 100 / fileChunks.length;
+                self.postMessage({
+                    percentage
+                });
+                loadNext(count);
+            }
+        };
+    };
+    loadNext(0);
+};
+```
+
+web workers调用以及封装：
+
+``` js
+// 计算文件 crc32（web-worker）参数为上面分片后返回的chunks
+const createFileCRC32InWorker = fileChunks => {
+    return new Promise(resolve => {
+        // 引入上面的worker文件
+        const worker = new Worker("./crc32_worker.js");
+        worker.postMessage({
+            fileChunks
+        });
+        worker.onmessage = e => {
+            // 这边加了进度条 这里的进度条，看需要显示
+            const {
+                percentage,
+                hash
+            } = e.data;
+            hash && resolve(hash);
+        };
+    });
+};
+```
+
+# 3. 上传进度本地缓存
+
+计算出的crc32值用来作为判断文件的key，可在localStorage缓存分片上传的进度。
+
+``` js
+const uploadCache = {
+    1259060791: {
+        position: [0, 0, 0]
+    }
+}
+```
+
+如上代码， ` 1259060791 ` 为文件的crc32值，把它作为key， ` position ` 为上传的进度，比如一个15M的文件，会分成3片（默认设置了每片5M），然后根据自己的上传业务，上传完成的分片标记为 ` 1 ` 。
+
+``` js
+const uploadCache = {
+    1259060791: {
+        position: [1, 0, 0] // 第一片上传完成后标记为1
+    }
+}
+```
+
+值得注意的是，通常分片上传都会多个分片并行上传，标记为 ` 1 ` 需要留意 ` position ` 的下标跟分片的下标是否一致。
+
+# 4. 浏览器刷新后获取文件的问题
+
+由于浏览器的安全机制，刷新后无法自动获取到原来的文件，所以需要通过提示去引导用户重现选择该文件，然后才可以断点续传。
diff --git a/source/images/AAAABSGsf8u86EvIjRhj.jpg b/source/images/AAAABSGsf8u86EvIjRhj.jpg
new file mode 100644
index 0000000..2efd57e
Binary files /dev/null and b/source/images/AAAABSGsf8u86EvIjRhj.jpg differ
diff --git a/source/images/v2-0dff7a84fe57e0d911f6efd2ba445db5_720w.jpg b/source/images/config/v2-0dff7a84fe57e0d911f6efd2ba445db5_720w.jpg
similarity index 100%
rename from source/images/v2-0dff7a84fe57e0d911f6efd2ba445db5_720w.jpg
rename to source/images/config/v2-0dff7a84fe57e0d911f6efd2ba445db5_720w.jpg
diff --git a/source/images/v2-1497fa6a5de2596909dc2af7a6233e37_1440w.jpg b/source/images/config/v2-1497fa6a5de2596909dc2af7a6233e37_1440w.jpg
similarity index 100%
rename from source/images/v2-1497fa6a5de2596909dc2af7a6233e37_1440w.jpg
rename to source/images/config/v2-1497fa6a5de2596909dc2af7a6233e37_1440w.jpg
diff --git a/source/images/v2-1ff0597480e2ef8999a2bc86a69f6a3e_r.jpg b/source/images/config/v2-1ff0597480e2ef8999a2bc86a69f6a3e_r.jpg
similarity index 100%
rename from source/images/v2-1ff0597480e2ef8999a2bc86a69f6a3e_r.jpg
rename to source/images/config/v2-1ff0597480e2ef8999a2bc86a69f6a3e_r.jpg
diff --git a/source/images/v2-498e45cff82e401ae43378031b8fc740_1440w.jpg b/source/images/config/v2-498e45cff82e401ae43378031b8fc740_1440w.jpg
similarity index 100%
rename from source/images/v2-498e45cff82e401ae43378031b8fc740_1440w.jpg
rename to source/images/config/v2-498e45cff82e401ae43378031b8fc740_1440w.jpg
diff --git a/source/images/v2-498e45cff82e401ae43378031b8fc740_256w.jpg b/source/images/config/v2-498e45cff82e401ae43378031b8fc740_256w.jpg
similarity index 100%
rename from source/images/v2-498e45cff82e401ae43378031b8fc740_256w.jpg
rename to source/images/config/v2-498e45cff82e401ae43378031b8fc740_256w.jpg
diff --git a/source/images/v2-5d580945ed25ce42f2fa5bea4cb0d278_r.jpg b/source/images/config/v2-5d580945ed25ce42f2fa5bea4cb0d278_r.jpg
similarity index 100%
rename from source/images/v2-5d580945ed25ce42f2fa5bea4cb0d278_r.jpg
rename to source/images/config/v2-5d580945ed25ce42f2fa5bea4cb0d278_r.jpg
diff --git a/source/images/v2-71c2d3e28a607d4732580d5fa8fcbac7_r.jpg b/source/images/config/v2-71c2d3e28a607d4732580d5fa8fcbac7_r.jpg
similarity index 100%
rename from source/images/v2-71c2d3e28a607d4732580d5fa8fcbac7_r.jpg
rename to source/images/config/v2-71c2d3e28a607d4732580d5fa8fcbac7_r.jpg
diff --git a/source/images/v2-8336cecd23d2a4134033791a8e5211fa_720w.jpg b/source/images/config/v2-8336cecd23d2a4134033791a8e5211fa_720w.jpg
similarity index 100%
rename from source/images/v2-8336cecd23d2a4134033791a8e5211fa_720w.jpg
rename to source/images/config/v2-8336cecd23d2a4134033791a8e5211fa_720w.jpg
diff --git a/source/images/v2-94c8508fb5f0acc59dd3616512a6cf47_720w.jpg b/source/images/config/v2-94c8508fb5f0acc59dd3616512a6cf47_720w.jpg
similarity index 100%
rename from source/images/v2-94c8508fb5f0acc59dd3616512a6cf47_720w.jpg
rename to source/images/config/v2-94c8508fb5f0acc59dd3616512a6cf47_720w.jpg
diff --git a/source/images/v2-be9ee0a7eef1372e6ff9891436c61389_hd.gif b/source/images/config/v2-be9ee0a7eef1372e6ff9891436c61389_hd.gif
similarity index 100%
rename from source/images/v2-be9ee0a7eef1372e6ff9891436c61389_hd.gif
rename to source/images/config/v2-be9ee0a7eef1372e6ff9891436c61389_hd.gif
diff --git a/source/images/v2-d1ccc3ef1cec99e3ae06d300c5ca0f7c_720w.jpg b/source/images/config/v2-d1ccc3ef1cec99e3ae06d300c5ca0f7c_720w.jpg
similarity index 100%
rename from source/images/v2-d1ccc3ef1cec99e3ae06d300c5ca0f7c_720w.jpg
rename to source/images/config/v2-d1ccc3ef1cec99e3ae06d300c5ca0f7c_720w.jpg
diff --git a/source/images/v2-e6df90886acf0bfc934f2902cec54143_720w.jpg b/source/images/config/v2-e6df90886acf0bfc934f2902cec54143_720w.jpg
similarity index 100%
rename from source/images/v2-e6df90886acf0bfc934f2902cec54143_720w.jpg
rename to source/images/config/v2-e6df90886acf0bfc934f2902cec54143_720w.jpg
diff --git a/source/images/v2-f119c1dab2d95d62b0808f3b334dd8a1_720w.jpg b/source/images/config/v2-f119c1dab2d95d62b0808f3b334dd8a1_720w.jpg
similarity index 100%
rename from source/images/v2-f119c1dab2d95d62b0808f3b334dd8a1_720w.jpg
rename to source/images/config/v2-f119c1dab2d95d62b0808f3b334dd8a1_720w.jpg
diff --git a/themes/butterfly/_config.yml b/themes/butterfly/_config.yml
index 5895a7a..097be30 100644
--- a/themes/butterfly/_config.yml
+++ b/themes/butterfly/_config.yml
@@ -83,14 +83,14 @@ favicon: /img/favicon.png
 
 # Avatar (頭像)
 avatar:
-  img: /images/v2-498e45cff82e401ae43378031b8fc740_256w.jpg
+  img: /images/config/v2-498e45cff82e401ae43378031b8fc740_256w.jpg
   effect: false
 
 # The banner image of home page
 index_img:
 
 # If the banner of page not setting, it will show the top_img
-default_top_img: /images/v2-1ff0597480e2ef8999a2bc86a69f6a3e_r.jpg
+default_top_img: /images/config/v2-1ff0597480e2ef8999a2bc86a69f6a3e_r.jpg
 
 # The banner image of archive page
 archive_img:
@@ -124,15 +124,15 @@ cover:
   # When cover is not set, the default cover is displayed (當沒有設置cover時，默認的封面顯示)
   default_cover:
     # - https://cdn.jsdelivr.net/gh/jerryc127/CDN@latest/cover/default_bg.png
-    - /images/v2-0dff7a84fe57e0d911f6efd2ba445db5_720w.jpg
-    - /images/v2-5d580945ed25ce42f2fa5bea4cb0d278_r.jpg
-    - /images/v2-71c2d3e28a607d4732580d5fa8fcbac7_r.jpg
-    - /images/v2-94c8508fb5f0acc59dd3616512a6cf47_720w.jpg
-    - /images/v2-8336cecd23d2a4134033791a8e5211fa_720w.jpg
-    - /images/v2-be9ee0a7eef1372e6ff9891436c61389_hd.gif
-    - /images/v2-d1ccc3ef1cec99e3ae06d300c5ca0f7c_720w.jpg
-    - /images/v2-e6df90886acf0bfc934f2902cec54143_720w.jpg
-    - /images/v2-f119c1dab2d95d62b0808f3b334dd8a1_720w.jpg
+    - /images/config/v2-0dff7a84fe57e0d911f6efd2ba445db5_720w.jpg
+    - /images/config/v2-5d580945ed25ce42f2fa5bea4cb0d278_r.jpg
+    - /images/config/v2-71c2d3e28a607d4732580d5fa8fcbac7_r.jpg
+    - /images/config/v2-94c8508fb5f0acc59dd3616512a6cf47_720w.jpg
+    - /images/config/v2-8336cecd23d2a4134033791a8e5211fa_720w.jpg
+    - /images/config/v2-be9ee0a7eef1372e6ff9891436c61389_hd.gif
+    - /images/config/v2-d1ccc3ef1cec99e3ae06d300c5ca0f7c_720w.jpg
+    - /images/config/v2-e6df90886acf0bfc934f2902cec54143_720w.jpg
+    - /images/config/v2-f119c1dab2d95d62b0808f3b334dd8a1_720w.jpg
 
 # Replace Broken Images (替換無法顯示的圖片)
 error_img: