前端跨域请求资源

前言: 作为一个前端,在开发项目期间不可避免的就会遇到,跨域请求这类问题....

正文:

1. 前几天在开发项目期间:遇到跨域请求这类问题,由于一开始找不到问题所在之处,采坑不少.所遇问题如下图

      

     找了好久才发现,产生这种情况的原因: 在请求头部需要添加一些代码

beforeSend: function(xhr) { xhr.setRequestHeader('Authorization', "Basic " + new Base64().encode('trusted' + ":" + 'secret')); },

 

  再添加这些之后又报了 :   Access-Control-Allow-Origin在同一个项目出现多个headers,Google浏览器默认会对其进行拦截...

于是又搞了半天修改Chrome的属性,具体的方式参考这个链接...

具体方式是在目标中添加这个:         C:\Users\jack\AppData\Local\Google\Chrome\Application\chrome.exe --disable-web-security --user-data-dir=C:\Users\jack\Desktop\mychromdev

意味在可以桌面上新建一个文件夹(用来临时存储资源):

:

2.上面顺序走完之后,项目就能进行跨域访问了,  具体代码如下:

 $.ajax({
            type: 'POST',
            dataType: 'json',
            url: 'http://api/uaa/oauth/token',//api:请求的url
            //data: {username:userName, password:password,grant_type:'password'},
            //测试
            data: {username:'sales', password:'000000',grant_type:'password'},
            success: function(data) {
              console.log(data);     
            },
            beforeSend: function(xhr) {
              xhr.setRequestHeader('Authorization', "Basic " + new Base64().encode('trusted' + ":" + 'secret'));
            },
          });
          function Base64() {
            var _keyStr;
            // private property
            _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

            // public method for encoding
            this.encode = function (input) {
              var output = "";
              var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
              var i = 0;
              input = _utf8_encode(input);
              while (i < input.length) {
                chr1 = input.charCodeAt(i++);
                chr2 = input.charCodeAt(i++);
                chr3 = input.charCodeAt(i++);
                enc1 = chr1 >> 2;
                enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
                enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
                enc4 = chr3 & 63;
                if (isNaN(chr2)) {
                  enc3 = enc4 = 64;
                } else if (isNaN(chr3)) {
                  enc4 = 64;
                }
                output = output +
                  _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
                  _keyStr.charAt(enc3) + _keyStr.charAt(enc4);
              }
              return output;
            }

            // public method for decoding
            this.decode = function (input) {
              var output = "";
              var chr1, chr2, chr3;
              var enc1, enc2, enc3, enc4;
              var i = 0;
              input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
              while (i < input.length) {
                enc1 = _keyStr.indexOf(input.charAt(i++));
                enc2 = _keyStr.indexOf(input.charAt(i++));
                enc3 = _keyStr.indexOf(input.charAt(i++));
                enc4 = _keyStr.indexOf(input.charAt(i++));
                chr1 = (enc1 << 2) | (enc2 >> 4);
                chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
                chr3 = ((enc3 & 3) << 6) | enc4;
                output = output + String.fromCharCode(chr1);
                if (enc3 != 64) {
                  output = output + String.fromCharCode(chr2);
                }
                if (enc4 != 64) {
                  output = output + String.fromCharCode(chr3);
                }
              }
              output = _utf8_decode(output);
              return output;
            }
            var _utf8_encode;
            // private method for UTF-8 encoding
            _utf8_encode = function (string) {
              string = string.replace(/\r\n/g, "\n");
              var utftext = "";
              for (var n = 0; n < string.length; n++) {
                var c = string.charCodeAt(n);
                if (c < 128) {
                  utftext += String.fromCharCode(c);
                } else if ((c > 127) && (c < 2048)) {
                  utftext += String.fromCharCode((c >> 6) | 192);
                  utftext += String.fromCharCode((c & 63) | 128);
                } else {
                  utftext += String.fromCharCode((c >> 12) | 224);
                  utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                  utftext += String.fromCharCode((c & 63) | 128);
                }

              }
              return utftext;
            }
            var _utf8_decode;
            // private method for UTF-8 decoding
            _utf8_decode = function (utftext) {
              var string = "";
              var i = 0;
              var c = c1 = c2 = 0;
              while (i < utftext.length) {
                c = utftext.charCodeAt(i);
                if (c < 128) {
                  string += String.fromCharCode(c);
                  i++;
                } else if ((c > 191) && (c < 224)) {
                  c2 = utftext.charCodeAt(i + 1);
                  string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
                  i += 2;
                } else {
                  c2 = utftext.charCodeAt(i + 1);
                  c3 = utftext.charCodeAt(i + 2);
                  string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
                  i += 3;
                }
              }
              return string;
            }
          }