Backblaze B2 + CloudFlare 搭建图床

Backblaze B2 在大厂的对象存储里算是非常便宜的了，如果不考虑国内访问速度，应该是非常不错的选择。由于 B2 与 CloudFlare 合作，所以套上 CloudFlare 后并不会消耗流量，所以拿来做图床是个不错的选择，下面介绍下步骤。

配置 CDN

以下步骤参考官方教程

Using Backblaze B2 with the Cloudflare CDN

创建一个公开的存储桶并上传文件
通过查看文件详细信息获得地址，比如我这里就是
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https://f002.backblazeb2.com/file/<存储桶名称>/......
在 CloudFlare 里新建一条 CNAME 解析，地址就填刚才获得的这个 f002.backblazeb2.com
在页面规则里创建页面规则
URL 匹配填写如下内容
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https://<刚才解析的域名>/file/<存储桶>/*
添加设置中选择缓存级别 - 缓存所有内容
再添加一条

URL 匹配填写如下内容
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https://<解析的域名>/file/*/*
设置填写转发 URL - 302重定向 - https://secure.backblaze.com/404notfound
设定缓存控制时间，内容如下
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{"cache-control":"max-age=720000"}

隐藏 Bucket 名称

这样设置完后，虽然能免流了，但是 Bucket 名称还是暴露了，为了避免被人搞事情，所以要隐藏 Bucket 名称。这里用到了 cf 的 workers，参考下面站点的内容。

Using Backblaze B2 and Cloudflare Workers for free image hosting

Workers - 管理 Workers

添加一个 Worker 并部署，内容如下。你需要做的就是修改开头的 b2Domain 和 b2Bucket 两个变量即可。

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'use strict';
const b2Domain = 'files.jross.me'; // configure this as per instructions above
const b2Bucket = 'jross-files'; // configure this as per instructions above

const b2UrlPath = `/file/${b2Bucket}/`;
addEventListener('fetch', event => {
	return event.respondWith(fileReq(event));
});

// define the file extensions we wish to add basic access control headers to
const corsFileTypes = ['png', 'jpg', 'gif', 'jpeg', 'webp'];

// backblaze returns some additional headers that are useful for debugging, but unnecessary in production. We can remove these to save some size
const removeHeaders = [
	'x-bz-content-sha1',
	'x-bz-file-id',
	'x-bz-file-name',
	'x-bz-info-src_last_modified_millis',
	'X-Bz-Upload-Timestamp',
	'Expires'
];
const expiration = 31536000; // override browser cache for images - 1 year

// define a function we can re-use to fix headers
const fixHeaders = function(url, status, headers){
	let newHdrs = new Headers(headers);
	// add basic cors headers for images
	if(corsFileTypes.includes(url.pathname.split('.').pop())){
		newHdrs.set('Access-Control-Allow-Origin', '*');
	}
	// override browser cache for files when 200
	if(status === 200){
		newHdrs.set('Cache-Control', "public, max-age=" + expiration);
	}else{
		// only cache other things for 5 minutes
		newHdrs.set('Cache-Control', 'public, max-age=300');
	}
	// set ETag for efficient caching where possible
	const ETag = newHdrs.get('x-bz-content-sha1') || newHdrs.get('x-bz-info-src_last_modified_millis') || newHdrs.get('x-bz-file-id');
	if(ETag){
		newHdrs.set('ETag', ETag);
	}
	// remove unnecessary headers
	removeHeaders.forEach(header => {
		newHdrs.delete(header);
	});
	return newHdrs;
};
async function fileReq(event){
	const cache = caches.default; // Cloudflare edge caching
	const url = new URL(event.request.url);
	if(url.host === b2Domain && !url.pathname.startsWith(b2UrlPath)){
		url.pathname = b2UrlPath + url.pathname;
	}
	let response = await cache.match(url); // try to find match for this request in the edge cache
	if(response){
		// use cache found on Cloudflare edge. Set X-Worker-Cache header for helpful debug
		let newHdrs = fixHeaders(url, response.status, response.headers);
		newHdrs.set('X-Worker-Cache', "true");
		return new Response(response.body, {
			status: response.status,
			statusText: response.statusText,
			headers: newHdrs
		});
	}
	// no cache, fetch image, apply Cloudflare lossless compression
	response = await fetch(url, {cf: {polish: "lossless"}});
	let newHdrs = fixHeaders(url, response.status, response.headers);
	response = new Response(response.body, {
		status: response.status,
		statusText: response.statusText,
		headers: newHdrs
	});

	event.waitUntil(cache.put(url, response.clone()));
	return response;
}

添加完后设置路由
地址为
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<解析的域名>/*
Worker 就选择刚才添加的 Worker

然后就可以直接通过 https://<域名>/<Bucket内路径> 引用文件了

Photo by C M on Unsplash