uniapp img header 请求图片

由于 uni-app 没有 Blob 对象。只能用内置的 uni.download 下载图片了。

wx.downloadFile({
    url: `http://192.168.1.1:8999/view/1MsDmdpGRI27FaRDKNmgQ/wx`,
    header: { 'Device-Info': getDeviceInfo(), 'content-type': 'application/json', Authorization: uni.getStorageSync('token') || '', token: uni.getStorageSync('token') || '' },
    responseType: 'arraybuffer',
    success: (res) => {
        console.log('downloadfile', res)
        this.src = res.tempFilePath
    },
    fail(err) {
        console.log('downloadfile err', err)
        uni.showToast({ title: '图片下载失败', icon: 'error' })
    }
})

如果是普通网页的话，我猜测下面的代码片段能带来一些灵感。但具体没实验

// 切记请求头加入 { responseType: 'blob', responseData: 'response',}
export function downloadFile(res, name) {
  const blob = new Blob([res], { type: res.type + ';charset=utf-8', endings: 'transparent' })
  console.log(20221116123327, URL.createObjectURL(blob))
}

// 虽然是下载 excel 的，但应该能用到
getExport() {
    let that = this
    that.listLoading = true

    let apiUrl = /api/ResourceCatalog/DataExcel?dbname=${this.params.dbname}&table=${this.params.table}
    var xhr = new XMLHttpRequest()
    xhr.open('GET', apiUrl, true)
    xhr.setRequestHeader('Authorization', 'Bearer ' + this.$store.getters.token)
    xhr.responseType = 'blob'

    xhr.onload = function (e) {
        that.listLoading = false
        if (this.status === 200) {
            var blob = new Blob([this.response], { type: 'application/octet-stream', })
            var filename = '导出.xls'
            var url = URL.createObjectURL(blob)
            var a = document.createElement('a')
            a.href = url
            a.download = filename
            a.click()
            window.URL.revokeObjectURL(url)
        } else {
            //  处理 blob 类型的错误信息
            // https://www.cnblogs.com/laoli-boke/p/14049549.html
            if (this.response.type === 'application/json') {
                const reader = new FileReader()
                reader.readAsText(this.response, 'utf-8')
                reader.onload = () => {
                    const { code, msg } = JSON.parse(reader.result)
                    if (msg.includes('65536')) {
                        that.$message('导出超过65535行数据，无法导出')
                    } else {
                        that.$message(msg)
                    }
                }
            }
        }
    }
    xhr.onerror = function (e) {
        that.$message('导出失败' + e.message)
    }
    //发送请求
    xhr.send()
},

// request.js 
// axios request 响应拦截器也可以拦截，直接打开的一种，前提是后端返回的是 blob

if (request.responseType === 'blob') {
    // 处理blob类型的错误响应
    const reader = new FileReader()
    reader.onload = e => {
        const responseText = JSON.parse((e.target || {}).result || '{}')
        const blobMsg = getPropLoop(['msg'], responseText) || '无相关数据'
        Message.closeAll()
        Message({ message: blobMsg, type: 'error', duration: 5 * 1000, })
    }
    reader.readAsText(data, 'utf-8')
}