cos-js-sdk-v5/lib/request.js

JavaScript SDK for [腾讯云对象存储](https://cloud.tencent.com/product/cos)

var stringifyPrimitive = function (v) {
  switch (typeof v) {
    case 'string':
      return v;
    case 'boolean':
      return v ? 'true' : 'false';
    case 'number':
      return isFinite(v) ? v : '';
    default:
      return '';
  }
};

var queryStringify = function (obj, sep, eq, name) {
  sep = sep || '&';
  eq = eq || '=';
  if (obj === null) {
    obj = undefined;
  }
  if (typeof obj === 'object') {
    return Object.keys(obj)
      .map(function (k) {
        var ks = encodeURIComponent(stringifyPrimitive(k)) + eq;
        if (Array.isArray(obj[k])) {
          return obj[k]
            .map(function (v) {
              return ks + encodeURIComponent(stringifyPrimitive(v));
            })
            .join(sep);
        } else {
          return ks + encodeURIComponent(stringifyPrimitive(obj[k]));
        }
      })
      .filter(Boolean)
      .join(sep);
  }
  if (!name) return '';
  return encodeURIComponent(stringifyPrimitive(name)) + eq + encodeURIComponent(stringifyPrimitive(obj));
};

var xhrRes = function (err, xhr, body) {
  var headers = {};
  var strHeaders = xhr.getAllResponseHeaders();
  if (strHeaders && strHeaders.length > 0) {
    strHeaders
      .trim()
      .split('\n')
      .forEach(function (item) {
        if (item) {
          var index = item.indexOf(':');
          var key = item.substr(0, index).trim().toLowerCase();
          var val = item.substr(index + 1).trim();
          headers[key] = val;
        }
      });
  }
  return {
    error: err,
    statusCode: xhr.status,
    statusMessage: xhr.statusText,
    headers: headers,
    body: body,
  };
};

var xhrBody = function (xhr, dataType) {
  return !dataType && dataType === 'text' ? xhr.responseText : xhr.response;
};

var request = function (opt, callback) {
  // method
  var method = (opt.method || 'GET').toUpperCase();

  // url、qs
  var url = opt.url;
  if (opt.qs) {
    var qsStr = queryStringify(opt.qs);
    if (qsStr) {
      url += (url.indexOf('?') === -1 ? '?' : '&') + qsStr;
    }
  }

  // 创建 ajax 实例
  var xhr = new XMLHttpRequest();
  xhr.open(method, url, true);
  xhr.responseType = opt.dataType || 'text';

  // 处理 xhrFields 属性
  if (opt.xhrFields) {
    for (var xhrField in opt.xhrFields) {
      xhr[xhrField] = opt.xhrFields[xhrField];
    }
  }

  // 处理 headers
  var headers = opt.headers;
  if (headers) {
    for (var key in headers) {
      if (
        headers.hasOwnProperty(key) &&
        key.toLowerCase() !== 'content-length' &&
        key.toLowerCase() !== 'user-agent' &&
        key.toLowerCase() !== 'origin' &&
        key.toLowerCase() !== 'host'
      ) {
        xhr.setRequestHeader(key, headers[key]);
      }
    }
  }

  // onprogress
  if (opt.onProgress && xhr.upload) xhr.upload.onprogress = opt.onProgress;
  if (opt.onDownloadProgress) xhr.onprogress = opt.onDownloadProgress;

  // timeout
  if (opt.timeout) xhr.timeout = opt.timeout;
  xhr.ontimeout = function (event) {
    var error = new Error('timeout');
    callback(xhrRes(error, xhr));
  };

  // success 2xx/3xx/4xx
  xhr.onload = function () {
    callback(xhrRes(null, xhr, xhrBody(xhr, opt.dataType)));
  };

  // error 5xx/0 (网络错误、跨域报错、Https connect-src 限制的报错时 statusCode 为 0)
  xhr.onerror = function (err) {
    var body = xhrBody(xhr, opt.dataType);
    if (body) {
      // 5xx
      callback(xhrRes(null, xhr, body));
    } else {
      // 0
      var error = xhr.statusText;
      if (!error && xhr.status === 0) error = new Error('CORS blocked or network error');
      callback(xhrRes(error, xhr, body));
    }
  };

  // send
  xhr.send(opt.body || '');

  // 返回 ajax 实例，用于外部调用 xhr.abort
  return xhr;
};

module.exports = request;