微信小程序上传图片到阿里云OSS，读取上传后oss后的图片

一、config.js

var fileHost="xxxx.aliyuncs.com(你的阿里云oss地址)"
var config = {
  //aliyun OSS config
  uploadImageUrl: `${fileHost}`, //默认存在根目录，可根据需求改
  AccessKeySecret: '填你自己的AccessKeySecret',
  OSSAccessKeyId: '填你自己的 OSSAccessKeyId',
  timeout: 87600 //这个是上传文件时Policy的失效时间
};
module.exports = config

二、Base64,hmac,sha1,crypto相关算法

https://github.com/peterhuang007/weixinFileToaliyun

三、UploadAliyun.js

const env = require('../config.js');

const Base64 = require('./Base64.js');

require('./hmac.js');
require('./sha1.js');
const Crypto = require('./crypto.js');


const uploadFile = function (params) {
  if (!params.filePath || params.filePath.length < 9) {
    wx.showModal({
      title: '图片错误',
      content: '请重试',
      showCancel: false,
    })
    return;
  }
  const aliyunFileKey = params.dir + params.filePath.replace('wxfile://', '');

  const aliyunServerURL = env.uploadImageUrl;
  const accessid = env.OSSAccessKeyId;
  const policyBase64 = getPolicyBase64();
  const signature = getSignature(policyBase64);

  console.log('aliyunFileKey=', aliyunFileKey);
  console.log('aliyunServerURL', aliyunServerURL);
  wx.uploadFile({
    url: aliyunServerURL, 
    filePath: params.filePath,
    name: 'file',
    formData: {
      'key': aliyunFileKey,
      'policy': policyBase64,
      'OSSAccessKeyId': accessid,
      'signature': signature,
      'success_action_status': '200',
    },
    success: function (res) {
      if (res.statusCode != 200) {
        if(params.fail){
          params.fail(res)
        }
        return;
      }
      if(params.success){
        params.success(aliyunFileKey);
      }
    },
    fail: function (err) {
      err.wxaddinfo = aliyunServerURL;
      if (params.fail) {
        params.fail(err)
      }
    },
  })
}

const getPolicyBase64 = function () {
  let date = new Date();
  date.setHours(date.getHours() + env.timeout);
  let srcT = date.toISOString();
  const policyText = {
    "expiration": srcT, //设置该Policy的失效时间
    "conditions": [
      ["content-length-range", 0, 5 * 1024 * 1024] // 设置上传文件的大小限制,5mb
    ]
  };

  const policyBase64 = Base64.encode(JSON.stringify(policyText));
  return policyBase64;
}

const getSignature = function (policyBase64) {
  const accesskey = env.AccessKeySecret;

  const bytes = Crypto.HMAC(Crypto.SHA1, policyBase64, accesskey, {
    asBytes: true
  });
  const signature = Crypto.util.bytesToBase64(bytes);

  return signature;
}

module.exports = uploadFile;

四、使用

const uploadImage = require('../../utils/uploadAliyun.js');

五、在需要使用的地方

uploadImage(
{
  filePath: filePath,
  dir: "images/",
  success: function (res) {
    console.log("上传成功")
  },
  fail: function (res) {
    console.log("上传失败")
    console.log(res)
  }
})

六 ，注意在开发者工具上传图片oss只有文件夹没有图片，但是真机上传没问题

七，读取在线的oss，

        1、首先桶Bucket要设置域名

        2、桶Bucket要设置公共读取

        3、线上的域名拼接路径

uploadImage({
      filePath: this.data.avatarUrl,
      dir: "images1/",
      success: function (res) {
        console.log('路径',`线上的域名/${res}`);
        console.log("上传成功",res)
      },
      fail: function (res) {
        console.log("上传失败")
        console.log(res)
      }
    })