将pdf转换为base 64字符串到字节数组时，输入不是有效的Base-64字符串

Question

在使用Cordova Plugin FileReader转换pdf文件并将其发送到.Net服务器后，服务器在将base64字符串转换为字节数组时抛出错误“输入不是有效的Base-64字符串，因为它包含非base64字符、两个以上的填充字符或填充字符中的非法字符。”。

Java脚本代码:

window.resolveLocalFileSystemURL(data, 
function (fileEntry) {
    fileEntry.file(function (fileObj) {
        var reader = new FileReader();
        reader.onloadend = function (evt) {             
            base64StringDocument = evt.target.result;
        };
        reader.readAsDataURL(fileObj);    
    },
    function (error) {
        console.log('get fileEntry error: ' + error.message);
    });
},
function (error) {
  console.log('resolve error: ' + error.message);
});

C#代码：

int startIndexOfBase64 = base64String.IndexOf("base64,") + "base64,".Length;
base64String = base64String.Substring(startIndexOfBase64);

byte[] blob = Convert.FromBase64String(base64String);

Base64字符串开头:

data：application/pdf;base64，JVBERi0xLjQKMSAwIG9iago8PCAvVHlwZSAvQ2F0YWxvZwovUGFnZXMgMiAwIFIKPj4KZW5kb2JqCjMgMCBvYmoKPDwgL1R5cGUgL1BhZ2UKL1BhcmVudCAyIDAgUgovUmVzb3VyY2VzIDQgMCBSCi9NZWRpYUJveCBbMCAwIDU5NSA4NDJdCi9Db250ZW50cyA1IDAgUgo PgplbmRvYmoKNCAwIG9iago8PCAvUHJvY1NldCBbL1BERiAvSW

Base64字符串结尾:

wmdiyoti 1 niawmdawmbudwqowmdawmji 5 mzyxidawmdaw4g ncjawmdaymjk 0 zmgmdawmdabg 0 mdawmdiyotu 5 miawmdawmcbudwqowmdawndu 1 mdkwidawmdawig 4 ncnryywlszxikpdwgl 1 npemugmtmkl 1j VB 3 qgmsawifikpj 4 C3 rhcnr 4 cmvmcjq 1 nte3 nwoljuvprg = =

Answer 1

非常感谢您的评论，但是在base64上应用以下正则表达式解决了这个问题。

window.resolveLocalFileSystemURL(data, 
function (fileEntry) {
    fileEntry.file(function (fileObj) {
        var reader = new FileReader();
        reader.onloadend = function (evt) {            
            base64StringDocument = evt.target.result.match(/,(.*)$/)[1];
        };
        reader.readAsDataURL(fileObj);    
    },
    function (error) {
        console.log('get fileEntry error: ' + error.message);
    });
},
function (error) {
  console.log('resolve error: ' + error.message);
});