基于 Backblaze B2 对象存储的图床与国内外的 CDN 分流

// node_modules/aws4fetch/dist/aws4fetch.esm.mjs
var encoder = new TextEncoder();
var HOST_SERVICES = {
  appstream2: "appstream",
  cloudhsmv2: "cloudhsm",
  email: "ses",
  marketplace: "aws-marketplace",
  mobile: "AWSMobileHubService",
  pinpoint: "mobiletargeting",
  queue: "sqs",
  "git-codecommit": "codecommit",
  "mturk-requester-sandbox": "mturk-requester",
  "personalize-runtime": "personalize"
};
var UNSIGNABLE_HEADERS = /* @__PURE__ */ new Set([
  "authorization",
  "content-type",
  "content-length",
  "user-agent",
  "presigned-expires",
  "expect",
  "x-amzn-trace-id",
  "range",
  "connection"
]);
var AwsClient = class {
  constructor({ accesskeyID, secretAccessKey, sessionToken, service, region, cache, retries, initRetryMs }) {
    if (accesskeyID == null)
      throw new TypeError("accesskeyID is a required option");
    if (secretAccessKey == null)
      throw new TypeError("secretAccessKey is a required option");
    this.accesskeyID = accesskeyID;
    this.secretAccessKey = secretAccessKey;
    this.sessionToken = sessionToken;
    this.service = service;
    this.region = region;
    this.cache = cache || /* @__PURE__ */ new Map();
    this.retries = retries != null ? retries : 10;
    this.initRetryMs = initRetryMs || 50;
  }
  async sign(input, init) {
    if (input instanceof Request) {
      const { method, url, headers, body } = input;
      init = Object.assign({ method, url, headers }, init);
      if (init.body == null && headers.has("Content-Type")) {
        init.body = body != null && headers.has("X-Amz-Content-Sha256") ? body : await input.clone().arrayBuffer();
      }
      input = url;
    }
    const signer = new AwsV4Signer(Object.assign({ url: input }, init, this, init && init.aws));
    const signed = Object.assign({}, init, await signer.sign());
    delete signed.aws;
    try {
      return new Request(signed.url.toString(), signed);
    } catch (e) {
      if (e instanceof TypeError) {
        return new Request(signed.url.toString(), Object.assign({ duplex: "half" }, signed));
      }
      throw e;
    }
  }
  async fetch(input, init) {
    for (let i = 0; i <= this.retries; i++) {
      const fetched = fetch(await this.sign(input, init));
      if (i === this.retries) {
        return fetched;
      }
      const res = await fetched;
      if (res.status < 500 && res.status !== 429) {
        return res;
      }
      await new Promise((resolve) => setTimeout(resolve, Math.random() * this.initRetryMs * Math.pow(2, i)));
    }
    throw new Error("An unknown error occurred, ensure retries is not negative");
  }
};
var AwsV4Signer = class {
  constructor({ method, url, headers, body, accesskeyID, secretAccessKey, sessionToken, service, region, cache, datetime, signQuery, appendSessionToken, allHeaders, singleEncode }) {
    if (url == null)
      throw new TypeError("url is a required option");
    if (accesskeyID == null)
      throw new TypeError("accesskeyID is a required option");
    if (secretAccessKey == null)
      throw new TypeError("secretAccessKey is a required option");
    this.method = method || (body ? "POST" : "GET");
    this.url = new URL(url);
    this.headers = new Headers(headers || {});
    this.body = body;
    this.accesskeyID = accesskeyID;
    this.secretAccessKey = secretAccessKey;
    this.sessionToken = sessionToken;
    let guessedService, guessedRegion;
    if (!service || !region) {
      [guessedService, guessedRegion] = guessServiceRegion(this.url, this.headers);
    }
    this.service = service || guessedService || "";
    this.region = region || guessedRegion || "us-east-1";
    this.cache = cache || /* @__PURE__ */ new Map();
    this.datetime = datetime || (/* @__PURE__ */ new Date()).toISOString().replace(/[:-]|\.\d{3}/g, "");
    this.signQuery = signQuery;
    this.appendSessionToken = appendSessionToken || this.service === "iotdevicegateway";
    this.headers.delete("Host");
    if (this.service === "s3" && !this.signQuery && !this.headers.has("X-Amz-Content-Sha256")) {
      this.headers.set("X-Amz-Content-Sha256", "UNSIGNED-PAYLOAD");
    }
    const params = this.signQuery ? this.url.searchParams : this.headers;
    params.set("X-Amz-Date", this.datetime);
    if (this.sessionToken && !this.appendSessionToken) {
      params.set("X-Amz-Security-Token", this.sessionToken);
    }
    this.signableHeaders = ["host", ...this.headers.keys()].filter((header) => allHeaders || !UNSIGNABLE_HEADERS.has(header)).sort();
    this.signedHeaders = this.signableHeaders.join(";");
    this.canonicalHeaders = this.signableHeaders.map((header) => header + ":" + (header === "host" ? this.url.host : (this.headers.get(header) || "").replace(/\s+/g, " "))).join("\n");
    this.credentialString = [this.datetime.slice(0, 8), this.region, this.service, "aws4_request"].join("/");
    if (this.signQuery) {
      if (this.service === "s3" && !params.has("X-Amz-Expires")) {
        params.set("X-Amz-Expires", "86400");
      }
      params.set("X-Amz-Algorithm", "AWS4-HMAC-SHA256");
      params.set("X-Amz-Credential", this.accesskeyID + "/" + this.credentialString);
      params.set("X-Amz-SignedHeaders", this.signedHeaders);
    }
    if (this.service === "s3") {
      try {
        this.encodedPath = decodeURIComponent(this.url.pathname.replace(/\+/g, " "));
      } catch (e) {
        this.encodedPath = this.url.pathname;
      }
    } else {
      this.encodedPath = this.url.pathname.replace(/\/+/g, "/");
    }
    if (!singleEncode) {
      this.encodedPath = encodeURIComponent(this.encodedPath).replace(/%2F/g, "/");
    }
    this.encodedPath = encodeRfc3986(this.encodedPath);
    const seenKeys = /* @__PURE__ */ new Set();
    this.encodedSearch = [...this.url.searchParams].filter(([k]) => {
      if (!k)
        return false;
      if (this.service === "s3") {
        if (seenKeys.has(k))
          return false;
        seenKeys.add(k);
      }
      return true;
    }).map((pair) => pair.map((p) => encodeRfc3986(encodeURIComponent(p)))).sort(([k1, v1], [k2, v2]) => k1 < k2 ? -1 : k1 > k2 ? 1 : v1 < v2 ? -1 : v1 > v2 ? 1 : 0).map((pair) => pair.join("=")).join("&");
  }
  async sign() {
    if (this.signQuery) {
      this.url.searchParams.set("X-Amz-Signature", await this.signature());
      if (this.sessionToken && this.appendSessionToken) {
        this.url.searchParams.set("X-Amz-Security-Token", this.sessionToken);
      }
    } else {
      this.headers.set("Authorization", await this.authHeader());
    }
    return {
      method: this.method,
      url: this.url,
      headers: this.headers,
      body: this.body
    };
  }
  async authHeader() {
    return [
      "AWS4-HMAC-SHA256 Credential=" + this.accesskeyID + "/" + this.credentialString,
      "SignedHeaders=" + this.signedHeaders,
      "Signature=" + await this.signature()
    ].join(", ");
  }
  async signature() {
    const date = this.datetime.slice(0, 8);
    const cacheKey = [this.secretAccessKey, date, this.region, this.service].join();
    let kCredentials = this.cache.get(cacheKey);
    if (!kCredentials) {
      const kDate = await hmac("AWS4" + this.secretAccessKey, date);
      const kRegion = await hmac(kDate, this.region);
      const kService = await hmac(kRegion, this.service);
      kCredentials = await hmac(kService, "aws4_request");
      this.cache.set(cacheKey, kCredentials);
    }
    return buf2hex(await hmac(kCredentials, await this.stringToSign()));
  }
  async stringToSign() {
    return [
      "AWS4-HMAC-SHA256",
      this.datetime,
      this.credentialString,
      buf2hex(await hash(await this.canonicalString()))
    ].join("\n");
  }
  async canonicalString() {
    return [
      this.method.toUpperCase(),
      this.encodedPath,
      this.encodedSearch,
      this.canonicalHeaders + "\n",
      this.signedHeaders,
      await this.hexBodyHash()
    ].join("\n");
  }
  async hexBodyHash() {
    let hashHeader = this.headers.get("X-Amz-Content-Sha256") || (this.service === "s3" && this.signQuery ? "UNSIGNED-PAYLOAD" : null);
    if (hashHeader == null) {
      if (this.body && typeof this.body !== "string" && !("byteLength" in this.body)) {
        throw new Error("body must be a string, ArrayBuffer or ArrayBufferView, unless you include the X-Amz-Content-Sha256 header");
      }
      hashHeader = buf2hex(await hash(this.body || ""));
    }
    return hashHeader;
  }
};
async function hmac(key, string) {
  const cryptoKey = await crypto.subtle.importKey(
    "raw",
    typeof key === "string" ? encoder.encode(key) : key,
    { name: "HMAC", hash: { name: "SHA-256" } },
    false,
    ["sign"]
  );
  return crypto.subtle.sign("HMAC", cryptoKey, encoder.encode(string));
}
async function hash(content) {
  return crypto.subtle.digest("SHA-256", typeof content === "string" ? encoder.encode(content) : content);
}
function buf2hex(buffer) {
  return Array.prototype.map.call(new Uint8Array(buffer), (x) => ("0" + x.toString(16)).slice(-2)).join("");
}
function encodeRfc3986(urlEncodedStr) {
  return urlEncodedStr.replace(/[!'()*]/g, (c) => "%" + c.charCodeAt(0).toString(16).toUpperCase());
}
function guessServiceRegion(url, headers) {
  const { hostname, pathname } = url;
  if (hostname.endsWith(".r2.cloudflarestorage.com")) {
    return ["s3", "auto"];
  }
  if (hostname.endsWith(".backblazeb2.com")) {
    const match2 = hostname.match(/^(?:[^.]+\.)?s3\.([^.]+)\.backblazeb2\.com$/);
    return match2 != null ? ["s3", match2[1]] : ["", ""];
  }
  const match = hostname.replace("dualstack.", "").match(/([^.]+)\.(?:([^.]*)\.)?amazonaws\.com(?:\.cn)?$/);
  let [service, region] = (match || ["", ""]).slice(1, 3);
  if (region === "us-gov") {
    region = "us-gov-west-1";
  } else if (region === "s3" || region === "s3-accelerate") {
    region = "us-east-1";
    service = "s3";
  } else if (service === "iot") {
    if (hostname.startsWith("iot.")) {
      service = "execute-api";
    } else if (hostname.startsWith("data.jobs.iot.")) {
      service = "iot-jobs-data";
    } else {
      service = pathname === "/mqtt" ? "iotdevicegateway" : "iotdata";
    }
  } else if (service === "autoscaling") {
    const targetPrefix = (headers.get("X-Amz-Target") || "").split(".")[0];
    if (targetPrefix === "AnyScaleFrontendService") {
      service = "application-autoscaling";
    } else if (targetPrefix === "AnyScaleScalingPlannerFrontendService") {
      service = "autoscaling-plans";
    }
  } else if (region == null && service.startsWith("s3-")) {
    region = service.slice(3).replace(/^fips-|^external-1/, "");
    service = "s3";
  } else if (service.endsWith("-fips")) {
    service = service.slice(0, -5);
  } else if (region && /-\d$/.test(service) && !/-\d$/.test(region)) {
    [service, region] = [region, service];
  }
  return [HOST_SERVICES[service] || service, region];
}

// index.js
var UNSIGNABLE_HEADERS2 = [
  // These headers appear in the request, but are not passed upstream
  "x-forwarded-proto",
  "x-real-ip",
  // We can't include accept-encoding in the signature because Cloudflare
  // sets the incoming accept-encoding header to "gzip, br", then modifies
  // the outgoing request to set accept-encoding to "gzip".
  // Not cool, Cloudflare!
  "accept-encoding"
];
var HTTPS_PROTOCOL = "https:";
var HTTPS_PORT = "443";
var RANGE_RETRY_ATTEMPTS = 3;
function filterHeaders(headers, env) {
  return new Headers(Array.from(headers.entries()).filter(
    (pair) => !UNSIGNABLE_HEADERS2.includes(pair[0]) && !pair[0].startsWith("cf-") && !("ALLOWED_HEADERS" in env && !env.ALLOWED_HEADERS.includes(pair[0]))
  ));
}
var my_proxy_default = {
  async fetch(request, env) {
    if (!["GET", "HEAD"].includes(request.method)) {
      return new Response(null, {
        status: 405,
        statusText: "Method Not Allowed"
      });
    }
    const url = new URL(request.url);
    url.protocol = HTTPS_PROTOCOL;
    url.port = HTTPS_PORT;
    let path = url.pathname.replace(/^\//, "");
    path = path.replace(/\/$/, "");
    const pathSegments = path.split("/");
    if (env.ALLOW_LIST_BUCKET !== "true") {
      if (env.BUCKET_NAME === "$path" && pathSegments.length < 2 || env.BUCKET_NAME !== "$path" && path.length === 0) {
        return new Response(null, {
          status: 404,
          statusText: "Not Found"
        });
      }
    }
    switch (env.BUCKET_NAME) {
      case "$path":
        url.hostname = env.B2_ENDPOINT;
        break;
      case "$host":
        url.hostname = url.hostname.split(".")[0] + "." + env.B2_ENDPOINT;
        break;
      default:
        url.hostname = env.BUCKET_NAME + "." + env.B2_ENDPOINT;
        break;
    }
    const headers = filterHeaders(request.headers, env);
    const endpointRegex = /^s3\.([a-zA-Z0-9-]+)\.backblazeb2\.com$/;
    const [, aws_region] = env.B2_ENDPOINT.match(endpointRegex);
    const client = new AwsClient({
      "accesskeyID": env.B2_APPLICATION_KEY_ID,
      "secretAccessKey": env.B2_APPLICATION_KEY,
      "service": "s3",
      "region": aws_region
    });
    const signedRequest = await client.sign(url.toString(), {
      method: request.method,
      headers
    });
    if (signedRequest.headers.has("range")) {
      let attempts = RANGE_RETRY_ATTEMPTS;
      let response;
      do {
        let controller = new AbortController();
        response = await fetch(signedRequest.url, {
          method: signedRequest.method,
          headers: signedRequest.headers,
          signal: controller.signal
        });
        if (response.headers.has("content-range")) {
          if (attempts < RANGE_RETRY_ATTEMPTS) {
            console.log(`Retry for ${signedRequest.url} succeeded - response has content-range header`);
          }
          break;
        } else if (response.ok) {
          attempts -= 1;
          console.error(`Range header in request for ${signedRequest.url} but no content-range header in response. Will retry ${attempts} more times`);
          if (attempts > 0) {
            controller.abort();
          }
        } else {
          break;
        }
      } while (attempts > 0);
      if (attempts <= 0) {
        console.error(`Tried range request for ${signedRequest.url} ${RANGE_RETRY_ATTEMPTS} times, but no content-range in response.`);
      }
      return response;
    }
    return fetch(signedRequest);
  }
};
export {
  my_proxy_default as default
};
/*! Bundled license information:

aws4fetch/dist/aws4fetch.esm.mjs:
  (**
   * @license MIT <https://opensource.org/licenses/MIT>
   * @copyright Michael Hart 2022
   *)
*/
//# sourceMappingURL=index.js.map