如何自定义文件上传

在使用微搭官方文件上传组件时，有时候我们需要自定义上传动作，此时可以用自定义云函数实现文件上传。

1. 自定义云函数

在微搭环境下，新建一个云函数新增package.json文件

{
    "name": "app",
    "version": "1.0.0",
    "description": "",
    "main": "index.js",
    "scripts": {},
    "author": "",
    "license": "ISC",
    "dependencies": {
        "@cloudbase/node-sdk": "latest",
        "@cloudbase/manager-node": "^4.2.8",
        "axios": "^1.6.3",
        "form-data": "^4.0.0"
    }
}

新增index.js文件

'use strict';
const CloudBase = require("@cloudbase/manager-node");
const FormData = require("form-data");
const axios = require("axios");
const fs = require("fs");
const path = require("path");

exports.main = async (event, context) => {
    const file = event.file // base64编码后的文件
    const fileName = event.fileName // 文件名
    const cloudPath = "./" + fileName; // 云端路径
    const baseStr = file.split("base64,")[1]
    const binaryData = Buffer.from(baseStr, 'base64');
    // 初始化
    const app = CloudBase.init({});

    // 获取功能模块
    const { storage } = app;

    // 获取文件扩展名
    const ext = path.extname(fileName).toLowerCase();
    if (ext !== ".docx") {
        return { result: "文件类型不支持" }
    } else {
        let msg = ''
        // 获取到元数据后，使用元数据内的信息，上传文件到云存储
        await storage.getUploadMetadata(cloudPath).then(async (res) => {
            const { authorization, token, cosFileId, url } = res;

            // 构造提交表单
            const form = new FormData();
            form.append("Signature", authorization);
            form.append("x-cos-security-token", token);
            form.append("x-cos-meta-fileid", cosFileId);
            form.append("key", cloudPath);
            form.append("file", binaryData);
            try {
                await axios.post(url, form, { headers: form.getHeaders() })
                msg = "上传成功"
            } catch{
                msg = "上传失败"
            }

        }).catch(() => {
            msg = "上传失败"
        });
        return { result: msg }
    }
};