base64字符串使用Node.JS被写为无效图像

base64 string gets written as an invalid image using Node.JS

本文关键字：无效 图像 JS 字符串 Node base64      更新时间：2024-02-16

我有以下代码：

var __dirname = '/home/ubuntu/Site/public/uploads/';
var base64Data = '/9j/2wBDABAICAgICBAICAgQEBAQECAYEBAQECggIBggMCgwMDAoMDAwOEhAMDhIODAwQFhASFBQUFBQMEBYYFhQYEhQUFD/2wBDARAQEBAQECgYGChQODA4UFBQUFBQUFBQUA==UFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUP/AABEIADwAUAMBIgACEQEDEQH/xAAfAAABBQEBAQEBAQAAAAAAAAAAAQIDBAUGBwgJCgv/xAC1EAACAQ==AwMCBAMFBQQEAAABfQECAwAEEQUSITFBBhNRYQcicRQygZGhCCNCscEVUtHwJDNicoIJChYXGBkaJSYnKCkqNDU2Nzg5OkNERUZHSElKU1RVVldYWVpjZGVmZ2hpanN0dXZ3eA==eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/8QAHwEAAwEBAQEBAQEBAQAAAAAAAAECAw==BAUGBwgJCgv/xAC1EQACAQIEBAMEBwUEBAABAncAAQIDEQQFITEGEkFRB2FxEyIygQgUQpGhscEJIzNS8BVictEKFiQ04SXxFxgZGiYnKCkqNTY3ODk6Q0RFRkdISUpTVFVWVw==WFlaY2RlZmdoaWpzdHV2d3h5eoKDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uLj5OXm5+jp6vLz9PX29/j5+v/aAAwDAQACEQ==AxEAPwDmraLzIyTzkYINUby+njmEKtxH1HqeamkvXs7cxoPnPHPas4lyxZsknrUpGjZNJGsn7+2/4EvcUscjKMMKhViDkZqZJJnXaQSPcUwTAznOAKka2cJukxuPY06C3ELedA==oII+6PepA0074EW0E5x/n8qENu5Hb2zn5RkcGmeQ7zbCCMHmtKKMxuFHPBAPv6/zpJIgX4x+P+f85HpTTFYksFEafLxgdv8AP+fwp5k/doxYfLxz7f5J/P1pbYbUbn8cf59/1g==oYpMxMgP3T1/l/LNMogmt4rsHHUn+p/+tVY6W45DZHfj/PvU43xNkHIB/wA/y/WrEFwrDa/p/TH9Ki5NrlEWnlnLLx/F7f55/Kp7dEbnAwf8/wBTWi1vFOPl55/r/wDX/Wqktg==zQsWA6/eGev+fmoHYfbLHLHiQAsDwD74/wDZiPwBpXRcAx5x/D/T8hg/U1HauXmZF6nt/tf/AK2/SppkJTbGPvfd+nX+QX86ABVV2Mijj7q+4/8Arnim4+bcT+J/n/n1PpU6wA==dm0L7Y/p+v8A49TTCVO4n8f1z/X8TQMVflU9vr/n2x+HvWdJI8E5ZD9Rj/Pt+dX3YKMAdPX/AD+FULv7xYVQE5iOOR/niozCycjt/n+lS22oW8y4Zh0/oP8ACrIiikPB7/1NQA==FWG4kh4z/n/IFXkmiuVKsoOT3Hvj+oqBrX5dw9M/oDUW2WE/Ken/ANf/AAoAnayAkE9vJg+/Uf49f19qvaZZG/Mrx4jaJARHI3Xnt+QH4VRS5BHJ9v5/4ile7bAuIcEo3KH+JQ==PUfy/M0ATyh4hg8jGAPUf/q4+v0qB5SwLMR/j/n/ANmqeS8jZN5YYI6/1/kfxNZ9zdITiPgUDCabPGaqyupB5FJLN71VmmJ71SAhjWVT8oNXrO8uoiMgkA1TYlD8pNPjkc8ZpA==QjTXU224x2x+hFObUVY/Mnf+v/16zS7DvTSzY60Fl57xRjDAdP6f4U2K8BDKH49/pWc8jZojkbJ5osFy1Nc+SxMTkgnlaYb3PIFMVRK3zGnyWsUZUjPLYOTTsK5G1wzUxydhNQ==NNDHGDtFRFR5LH0xTE2f/9k=';
var buffer = new Buffer(base64Data, 'base64');
fs.writeFileSync(__dirname + 'zorro.jpg', buffer, 0, buffer.length);

但是，保存的图像已损坏，无法在Finder中打开。我做错了什么？我是不是遗漏了一些标题？base64字符串以带有img标记的内联数据的形式完美打开。

编辑：这对我来说是HTML格式的：

<img src="data:image/jpg;base64,/9j/2wBDABAICAgICBAICAgQEBAQECAYEBAQECggIBggMCgwMDAoMDAwOEhAMDhIODAwQFhASFBQUFBQMEBYYFhQYEhQUFD/2wBDARAQEBAQECgYGChQODA4UFBQUFBQUFBQUA==UFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUP/AABEIADwAUAMBIgACEQEDEQH/xAAfAAABBQEBAQEBAQAAAAAAAAAAAQIDBAUGBwgJCgv/xAC1EAACAQ==AwMCBAMFBQQEAAABfQECAwAEEQUSITFBBhNRYQcicRQygZGhCCNCscEVUtHwJDNicoIJChYXGBkaJSYnKCkqNDU2Nzg5OkNERUZHSElKU1RVVldYWVpjZGVmZ2hpanN0dXZ3eA==eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/8QAHwEAAwEBAQEBAQEBAQAAAAAAAAECAw==BAUGBwgJCgv/xAC1EQACAQIEBAMEBwUEBAABAncAAQIDEQQFITEGEkFRB2FxEyIygQgUQpGhscEJIzNS8BVictEKFiQ04SXxFxgZGiYnKCkqNTY3ODk6Q0RFRkdISUpTVFVWVw==WFlaY2RlZmdoaWpzdHV2d3h5eoKDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uLj5OXm5+jp6vLz9PX29/j5+v/aAAwDAQACEQ==AxEAPwDmraLzIyTzkYINUby+njmEKtxH1HqeamkvXs7cxoPnPHPas4lyxZsknrUpGjZNJGsn7+2/4EvcUscjKMMKhViDkZqZJJnXaQSPcUwTAznOAKka2cJukxuPY06C3ELedA==oII+6PepA0074EW0E5x/n8qENu5Hb2zn5RkcGmeQ7zbCCMHmtKKMxuFHPBAPv6/zpJIgX4x+P+f85HpTTFYksFEafLxgdv8AP+fwp5k/doxYfLxz7f5J/P1pbYbUbn8cf59/1g==oYpMxMgP3T1/l/LNMogmt4rsHHUn+p/+tVY6W45DZHfj/PvU43xNkHIB/wA/y/WrEFwrDa/p/TH9Ki5NrlEWnlnLLx/F7f55/Kp7dEbnAwf8/wBTWi1vFOPl55/r/wDX/Wqktg==zQsWA6/eGev+fmoHYfbLHLHiQAsDwD74/wDZiPwBpXRcAx5x/D/T8hg/U1HauXmZF6nt/tf/AK2/SppkJTbGPvfd+nX+QX86ABVV2Mijj7q+4/8Arnim4+bcT+J/n/n1PpU6wA==dm0L7Y/p+v8A49TTCVO4n8f1z/X8TQMVflU9vr/n2x+HvWdJI8E5ZD9Rj/Pt+dX3YKMAdPX/AD+FULv7xYVQE5iOOR/niozCycjt/n+lS22oW8y4Zh0/oP8ACrIiikPB7/1NQA==FWG4kh4z/n/IFXkmiuVKsoOT3Hvj+oqBrX5dw9M/oDUW2WE/Ken/ANf/AAoAnayAkE9vJg+/Uf49f19qvaZZG/Mrx4jaJARHI3Xnt+QH4VRS5BHJ9v5/4ile7bAuIcEo3KH+JQ==PUfy/M0ATyh4hg8jGAPUf/q4+v0qB5SwLMR/j/n/ANmqeS8jZN5YYI6/1/kfxNZ9zdITiPgUDCabPGaqyupB5FJLN71VmmJ71SAhjWVT8oNXrO8uoiMgkA1TYlD8pNPjkc8ZpA==QjTXU224x2x+hFObUVY/Mnf+v/16zS7DvTSzY60Fl57xRjDAdP6f4U2K8BDKH49/pWc8jZojkbJ5osFy1Nc+SxMTkgnlaYb3PIFMVRK3zGnyWsUZUjPLYOTTsK5G1wzUxydhNQ==NNDHGDtFRFR5LH0xTE2f/9k="/>

我将您的字符串重新编码为正确的base64
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==

至于为什么base64编码的数据在我端工作，base64的RFC4648声明如下：

此外，这样的规范可以忽略填充字符"0"=&"；，如果它出现在末尾之前，则将其视为非字母数据编码数据的。如果超过允许的焊盘数量字符位于字符串的末尾（例如，基64
字符串以"===&"），多余的填充字符也可能是
已忽略。

一些实现将忽略添加的"="有些人不会。

编辑：正如其他人所指出的，您的base64字符串似乎是许多base64字符串连接在一起。这是你的字符串：

/9j/2wBDABAICAgICBAICAgQEBAQECAYEBAQECggIBggMCgwMDAoMDAwOEhAMDhIODAwQFhASFBQUFBQMEBYYFhQYEhQUFD/2wBDARAQEBAQECgYGChQODA4UFBQUFBQUFBQUA==
UFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUP/AABEIADwAUAMBIgACEQEDEQH/xAAfAAABBQEBAQEBAQAAAAAAAAAAAQIDBAUGBwgJCgv/xAC1EAACAQ==
AwMCBAMFBQQEAAABfQECAwAEEQUSITFBBhNRYQcicRQygZGhCCNCscEVUtHwJDNicoIJChYXGBkaJSYnKCkqNDU2Nzg5OkNERUZHSElKU1RVVldYWVpjZGVmZ2hpanN0dXZ3eA==
eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/8QAHwEAAwEBAQEBAQEBAQAAAAAAAAECAw==
BAUGBwgJCgv/xAC1EQACAQIEBAMEBwUEBAABAncAAQIDEQQFITEGEkFRB2FxEyIygQgUQpGhscEJIzNS8BVictEKFiQ04SXxFxgZGiYnKCkqNTY3ODk6Q0RFRkdISUpTVFVWVw==
WFlaY2RlZmdoaWpzdHV2d3h5eoKDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uLj5OXm5+jp6vLz9PX29/j5+v/aAAwDAQACEQ==
AxEAPwDmraLzIyTzkYINUby+njmEKtxH1HqeamkvXs7cxoPnPHPas4lyxZsknrUpGjZNJGsn7+2/4EvcUscjKMMKhViDkZqZJJnXaQSPcUwTAznOAKka2cJukxuPY06C3ELedA==
oII+6PepA0074EW0E5x/n8qENu5Hb2zn5RkcGmeQ7zbCCMHmtKKMxuFHPBAPv6/zpJIgX4x+P+f85HpTTFYksFEafLxgdv8AP+fwp5k/doxYfLxz7f5J/P1pbYbUbn8cf59/1g==
oYpMxMgP3T1/l/LNMogmt4rsHHUn+p/+tVY6W45DZHfj/PvU43xNkHIB/wA/y/WrEFwrDa/p/TH9Ki5NrlEWnlnLLx/F7f55/Kp7dEbnAwf8/wBTWi1vFOPl55/r/wDX/Wqktg==
zQsWA6/eGev+fmoHYfbLHLHiQAsDwD74/wDZiPwBpXRcAx5x/D/T8hg/U1HauXmZF6nt/tf/AK2/SppkJTbGPvfd+nX+QX86ABVV2Mijj7q+4/8Arnim4+bcT+J/n/n1PpU6wA==
dm0L7Y/p+v8A49TTCVO4n8f1z/X8TQMVflU9vr/n2x+HvWdJI8E5ZD9Rj/Pt+dX3YKMAdPX/AD+FULv7xYVQE5iOOR/niozCycjt/n+lS22oW8y4Zh0/oP8ACrIiikPB7/1NQA==
FWG4kh4z/n/IFXkmiuVKsoOT3Hvj+oqBrX5dw9M/oDUW2WE/Ken/ANf/AAoAnayAkE9vJg+/Uf49f19qvaZZG/Mrx4jaJARHI3Xnt+QH4VRS5BHJ9v5/4ile7bAuIcEo3KH+JQ==
PUfy/M0ATyh4hg8jGAPUf/q4+v0qB5SwLMR/j/n/ANmqeS8jZN5YYI6/1/kfxNZ9zdITiPgUDCabPGaqyupB5FJLN71VmmJ71SAhjWVT8oNXrO8uoiMgkA1TYlD8pNPjkc8ZpA==
QjTXU224x2x+hFObUVY/Mnf+v/16zS7DvTSzY60Fl57xRjDAdP6f4U2K8BDKH49/pWc8jZojkbJ5osFy1Nc+SxMTkgnlaYb3PIFMVRK3zGnyWsUZUjPLYOTTsK5G1wzUxydhNQ==
NNDHGDtFRFR5LH0xTE2f/9k=

注意每个base64字符串的长度是136个chracter。如果你解码了这些base64中的每一个，并将每个解码base64的结果附加到一个文件中，你就会得到你的图像。

相关文章：