react-native-cos-sdk/lib/module/credentials/scope_credentials.js

Tencent COS XML SDK for React Native

function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
export class ScopeLimitCredentialsProvider {
  constructor() {
    _defineProperty(this, "credentialPairs", new Map());
  }
  forceInvalidationScopeCredentials() {
    this.credentialPairs.clear();
  }
  async fetchScopeLimitCredentials(stsScopesArrayJson, callback) {
    // 先从缓存中获取，当scope一样的时候并且没有过期则使用缓存，否则调研业务回调方法获取最新的临时秘钥
    // 用于解决类似分块上传这种频繁但是秘钥大概率一样的情况
    const scopeId = this.hashCode(stsScopesArrayJson);
    let credentials = this.lookupValidCredentials(scopeId);
    if (credentials == null) {
      const stsScopesArray = JSON.parse(stsScopesArrayJson);
      credentials = await callback(stsScopesArray.map(e => {
        const scop = {
          action: e == null ? '' : e.action ?? '',
          region: e == null ? '' : e.region ?? '',
          bucket: e == null ? '' : e.bucket ?? '',
          prefix: e == null ? '' : e.prefix ?? ''
        };
        return scop;
      }));
      if (credentials) {
        this.cacheCredentialsAndCleanUp(scopeId, credentials);
      }
    }
    return credentials;
  }

  // 以下为实现范围限制临时秘钥缓存的代码
  lookupValidCredentials(scopeId) {
    const credentials = this.credentialPairs.get(scopeId);
    if (credentials != null && this.isValid(credentials)) {
      return credentials;
    }
    return null;
  }
  cacheCredentialsAndCleanUp(scopeId, newCredentials) {
    this.credentialPairs.forEach((value, key) => {
      if (!this.isValid(value)) {
        this.credentialPairs.delete(key);
      }
    });
    if (this.credentialPairs.size > ScopeLimitCredentialsProvider.MAX_CACHE_CREDENTIAL_SIZE) {
      const overSize = this.credentialPairs.size - ScopeLimitCredentialsProvider.MAX_CACHE_CREDENTIAL_SIZE;
      let count = 0;
      this.credentialPairs.forEach((_value, key) => {
        if (count < overSize) {
          this.credentialPairs.delete(key);
          count++;
        }
      });
    }
    this.credentialPairs.set(scopeId, newCredentials);
  }
  hashCode(str) {
    return str.split('').reduce((prevHash, currVal) => (prevHash << 5) - prevHash + currVal.charCodeAt(0), 0);
  }
  isValid(credentials) {
    const now = new Date();
    const timestamp = Math.floor(now.getTime() / 1000);
    return timestamp <= credentials.expiredTime - 60;
  }
}
_defineProperty(ScopeLimitCredentialsProvider, "MAX_CACHE_CREDENTIAL_SIZE", 100);
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