跨域将blob对象保存到本地

应用场景

项目前后端分离，后端环境Django. 需要实现 前端可以下载后端生成的EXCEL文件同时对权限进行控制。

将blob保存到本地

       function saveAs(blob,fileName) {
            if ('download' in document.createElement('a')) { // 不是IE浏览器
                let url = window.URL.createObjectURL(blob)
                let link = document.createElement('a')
                link.style.display = 'none'
                link.href = url
                link.setAttribute('download', fileName)
                document.body.appendChild(link)
                link.click()
                document.body.removeChild(link) // 下载完成移除元素
                window.URL.revokeObjectURL(url) // 释放掉blob对象
            } else { // IE 10+
                window.navigator.msSaveBlob(blob, fileName)
            }
        }

获取blob内容，同样支持GETPOST获取

    var xmlhttp
    xmlhttp = new XMLHttpRequest()
    xmlhttp.onreadystatechange = function () { // Call a function when the state changes.
        if (this.readyState === XMLHttpRequest.DONE && this.status === 200) {
            // Request finished. Do processing here.
            console.log(xmlhttp.response)
            saveAs(xmlhttp.response, 'filename.xlsx')
        }
    }
    // async=false -同步，ture 异步
    xmlhttp.open(method='GET',url='http://ctcnc0378.carsgen.com:8000/budget/file_download?period_id=15', async=true)
    xmlhttp.setRequestHeader('Content-type', 'application/octet-stream')
    // 设置跨域访问的Token头
    xmlhttp.setRequestHeader('Authorization', 'Token 8002f4d3e770ada98ef5360c32e59d24f74b12cb')
    xmlhttp.withCredentials = true
    xmlhttp.responseType = "blob";
    xmlhttp.send(null)

也可以用axios获取

axios({
    method: 'post',
    url: 'api/user/',
    data: {
        period: '2021'
    },
    responseType: 'blob'
}).then(response => {
    saveAs(response)
}).catch((error) => {

})