flutter直接上传文件到阿里云oss
作者：阳春boy
上传视频到oss，之前是走后端上传到oss，会有一个问题就是我要先上传给后端，后端再上传给oss就会导致上传多次，消耗时间过长影响用户体验，所以我参考文档写了直接上传到阿里云oss获取到文件访问路径。
代码实现
以下是我写的一个上传oss的类，只需要替换ossAccessKeyId， ossAccessKeySecret， bucket， url， expiration这几个参数就可以直接实现上传
import 'dart:convert';
import 'dart:io';
import 'dart:math';
import 'package:crypto/crypto.dart';
import 'package:dio/dio.dart';
class UploadOss {
static String ossAccessKeyId = 'ossAccessKeyId';
static String ossAccessKeySecret = 'ossAccessKeySecret';
// oss设置的bucket的名字
static String bucket = 'bucketName';
// 发送请求的url,根据你自己设置的是哪个城市的
static String url = 'https://$bucket.oss-cn-hangzhou.aliyuncs.com';
// 过期时间
static String expiration = '2025-01-01T12:00:00.000Z';
/**
* @params file 要上传的文件对象
* @params rootDir 阿里云oss设置的根目录文件夹名字
* @param fileType 文件类型例如jpg,mp4等
* @param callback 回调函数我这里用于传cancelToken，方便后期关闭请求
* @param onSendProgress 上传的进度事件
*/
static Future<String> upload({ File file , String rootDir = 'moment', String fileType, Function callback, Function onSendProgress}) async {
String policyText = '{"expiration": "$expiration","conditions": [{"bucket": "$bucket" },["content-length-range", 0, 1048576000]]}';
// 获取签名
String signature = getSignature(policyText);
BaseOptions options = new BaseOptions();
options.responseType = ResponseType.plain;
//创建dio对象
Dio dio = new Dio(options);
// 生成oss的路径和文件名我这里目前设置的是moment/20201229/test.mp4
String pathName = '$rootDir/${getDate()}/${getRandom(12)}.${fileType == null ? getFileType(file.path) : fileType}';
// 请求参数的form对象
FormData data = new FormData.fromMap({
'key': pathName,
'policy': getSplicyBase64(policyText),
'OSSAccessKeyId': ossAccessKeyId,
'success_action_status': '200', //让服务端返回200，不然，默认会返回204
'signature': signature,
'contentType': 'multipart/form-data',
'file': MultipartFile.fromFileSync(file.path),
});
Response response;
CancelToken uploadCancelToken = CancelToken();
callback ?? callback(uploadCancelToken);
try {
// 发送请求
response = await dio.post(url, data: data, cancelToken: uploadCancelToken, onSendProgress: (int count, int data) {
onSendProgress(count, data);
});
// 成功后返回文件访问路径
return '$url/$pathName';
} catch(e) {
throw(e.message);
}
}
/*
* 生成固定长度的随机字符串
* */
static String getRandom(int num) {
String alphabet = 'qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM';
String left = '';
for (var i = 0; i < num; i++) {
// right = right + (min + (Random().nextInt(max - min))).toString();
left = left + alphabet[Random().nextInt(alphabet.length)];
}
return left;
}
/*
* 根据图片本地路径获取图片名称
* */
static String getImageNameByPath(String filePath) {
// ignore: null_aware_before_operator
return filePath?.substring(filePath?.lastIndexOf("/")+1,filePath?.length);
}
/**
* 获取文件类型
*/
static String getFileType(String path) {
print(path);
List<String> array = path.split('.');
return array[array.length -1];
}
/// 获取日期
static String getDate() {
DateTime now = DateTime.now();
return '${now.year}${now.month}${now.day}';
}
// 获取plice的base64
static getSplicyBase64(String policyText) {
//进行utf8编码
List<int> policyText_utf8 = utf8.encode(policyText);
//进行base64编码
String policy_base64 = base64.encode(policyText_utf8);
return policy_base64;
}
/// 获取签名
static String getSignature(String policyText) {
//进行utf8编码
List<int> policyText_utf8 = utf8.encode(policyText);
//进行base64编码
String policy_base64 = base64.encode(policyText_utf8);
//再次进行utf8编码
List<int> policy = utf8.encode(policy_base64);
//进行utf8 编码
List<int> key = utf8.encode(ossAccessKeySecret);
//通过hmac,使用sha1进行加密
List<int> signature_pre = Hmac(sha1, key).convert(policy).bytes;
//最后一步，将上述所得进行base64 编码
String signature = base64.encode(signature_pre);
return signature;
}
}
调用上传的例子
其他参事自己根据自己情况上传
Future<String> uploadFile(File file, { Function onSendProgress, Function callback}) async {
final String url = await UploadOss.upload(file: file, onSendProgress: onSendProgress, callback: callback);
return url;
}
另一种方法
目前阿里没有针对Flutter有官方SDK可集成, 但是有人对Flutter的上传有封装库https://pub.dev/packages/aly_oss#-example-tab-, 所以我们只能通过post提交PostObject的形式来上传;
准备工作:
1、获取OSS凭证地址(your oss_sts_server), 通知get直接获取static String ossServerUrl = 'http://.../sts-server/sts.php';
2、上传的存储地址(桶名):static String ossEndPointCdn = '<your endpointcdn>';
// 通过ossServerUrl直接get获取到如下数据
{
"StatusCode": 200,
"AccessKeyId": "STS.NSsrKZes4cqm.....",
"AccessKeySecret": "7eGnLZaEFsRCGYJAnrtdE9n.....",
"Expiration": "2020-04-08T03:44:21Z",
"SecurityToken": "CAISlQJ1q6Ft5B2y....."
}
//表单需要的参数: AccessKeyId、AccessKeySecret、SecurityToken;
FormData formdata = new FormData.from({
//文件名，随意
'Filename': OssUtil.instance.getImageName(filePath),
//"可以填写文件夹名（对应于oss服务中的文件夹）/" + fileName
'key': uploadName,//上传后的文件名
'policy': OssUtil.policy,
//Bucket 拥有者的AccessKeyId。
'OSSAccessKeyId': data['AccessKeyId'],
//让服务端返回200，不然，默认会返回204
'success_action_status': '200',
'signature': OssUtil.instance.getSignature(data['AccessKeySecret']),
//临时用户授权时必须，需要携带后台返回的security-token
'x-oss-security-token': data['SecurityToken'],
'file': new UploadFileInfo(
file, OssUtil.instance.getImageNameByPath(filePath))
//必须放在参数最后
});
//然后通过存储地址直接把表单(formdata)上传上去;
Dio dio=Dio();
dio.options.responseType=ResponseType.plain;
Response response=awaitdio.post(<ossEndPointCdn>,data:formData);
......
tips: 上传成功后图片地址 imageUrl = ossEndPointCdn + '/' + uploadName;
给一个工具类
import 'dart:convert';
import 'package:crypto/crypto.dart';
import 'dart:math';
class OssUtil {
获取
//验证文本域
static String _policyText =
'{"expiration": "2069-05-22T03:15:00.000Z","conditions": [["content-length-range", 0, 1048576000]]}';//UTC时间+8=北京时间
//进行utf8编码
// ignore: non_constant_identifier_names
static List<int> _policyText_utf8 = utf8.encode(_policyText);
//进行base64编码
static String policy= base64.encode(_policyText_utf8);
//再次进行utf8编码
// ignore: non_constant_identifier_names
static List<int> _policy_utf8 = utf8.encode(policy);
// 工厂模式
factory OssUtil() => _getInstance();
static OssUtil get instance => _getInstance();
static OssUtil _instance;
OssUtil._internal();
static OssUtil _getInstance() {
if (_instance == null) {
_instance = new OssUtil._internal();
}
return _instance;
}
/*
*获取signature签名参数
*/
String getSignature(String _accessKeySecret){
//进行utf8 编码
// ignore: non_constant_identifier_names
List<int> AccessKeySecretUtf8 = utf8.encode(_accessKeySecret);
//通过hmac,使用sha1进行加密
List<int> signaturePre = new Hmac(sha1, AccessKeySecretUtf8).convert(_policy_utf8).bytes;
//最后一步，将上述所得进行base64 编码
String signature = base64.encode(signaturePre);
return signature;
}
// ignore: slash_for_doc_comments
/**
* 生成上传上传图片的名称 ,获得的格式:photo/20171027175940_oCiobK
* 可以定义上传的路径uploadPath(Oss中保存文件夹的名称)
* @param uploadPath 上传的路径 如：/photo
* @return photo/20171027175940_oCiobK
*/
String getImageUploadName(String uploadPath,String filePath) {
String imageMame = "";
var timestamp = new DateTime.now().millisecondsSinceEpoch;
imageMame =timestamp.toString()+"_"+getRandom(6);
if(uploadPath!=null&&uploadPath.isNotEmpty){
imageMame=uploadPath+"/"+imageMame;
}
String imageType=filePath?.substring(filePath?.lastIndexOf("."),filePath?.length);
return imageMame+imageType;
}
String getImageName(String filePath) {
String imageMame = "";
var timestamp = new DateTime.now().millisecondsSinceEpoch;
imageMame =timestamp.toString()+"_"+getRandom(6);
String imageType=filePath?.substring(filePath?.lastIndexOf("."),filePath?.length);
return imageMame+imageType;
}
/*
* 生成固定长度的随机字符串
* */
String getRandom(int num) {
String alphabet = 'qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM';
String left = '';
for (var i = 0; i < num; i++) {
// right = right + (min + (Random().nextInt(max - min))).toString();
left = left + alphabet[Random().nextInt(alphabet.length)];
}
return left;
}
/*
* 根据图片本地路径获取图片名称
* */
String getImageNameByPath(String filePath) {
// ignore: null_aware_before_operator
return filePath?.substring(filePath?.lastIndexOf("/")+1,filePath?.length);
}
}
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