[英]How to download picture and convert to base64 correctly in Dart?
I'm in struggle with downloading a picture and then showing it on a page. 我正在努力下载图片然后在页面上显示它。 Printed base64-encoded string looks wrong; 打印base64编码的字符串看起来不对; it's not identical with eg http://www.freeformatter.com/base64-encoder.html result. 它与例如http://www.freeformatter.com/base64-encoder.html结果不同。
This is my code: 这是我的代码:
HttpRequest.request(_url).then((HttpRequest response) {
String contentType = response.getResponseHeader('Content-Type');
if (_supportedContentType(contentType)) {
List bytes = new Utf8Encoder().convert(response.responseText);
String header = 'data:$contentType;base64,';
String base64 = CryptoUtils.bytesToBase64(bytes);
String image = "${header}${base64}";
me.avatar = image;
print(image);
}
}
When you set the responseType you get binary data 设置responseType时,您将获得二进制数据
import 'dart:html' show HttpRequest;
import 'dart:convert' show base64;
import 'dart:typed_data' show Uint8List, ByteBuffer;
main() {
HttpRequest
.request("Zacharie_Noterman_-_Monkey_business.jpg",
responseType: "arraybuffer")
.then((HttpRequest response) {
String contentType = response.getResponseHeader('Content-Type');
var list = new Uint8List.view((response.response as ByteBuffer));
String header = 'data:$contentType;base64,';
String base64 = base64.encode(list);
String image = "${header}${base64}";
// me.avatar = image;
print(image);
//}
});
}
result: 结果:
data:image/png;base64,/9j/4AAQSkZJRgABAQEAYABgAAD.... 数据:图像/ PNG; BASE64,/ 9J / 4AAQSkZJRgABAQEAYABgAAD ....
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