TypeORM 上传和服务（下载）文件
swi*_*ser 3 file download node.js express typeorm
介绍
\n\n在我的项目中，我尝试将文件存储在 MySQL 中。用户可以上传文件（html WEB-APP）。之后用户就有了上传文件的列表（html WEB-APP），用户可以通过Link下载文件。在后端，我使用一个node.js（TypeORM）项目：
\n\n- \n
- “打字稿”：“3.3.3333” \n
- "body-parser": "^1.19.0", \n
- “调试”：“^4.1.1”， \n
- "express": "^4.17.1", \n
- "express-fileupload": "^1.1.6", \n
- "mysql": "^2.14.1", \n
- "reflect-metadata": "^0.1.10", \n
- “类型”：“0.2.22” \n
问题
\n\n- \n
- \xe2\x9c\x85 在我的代码中，我可以成功上传文件。 \n
- \xe2\x9d\x8c 如果我尝试下载该文件，我得到一个无法读取或已损坏的文件。 \n
下载文件时我的代码有什么问题？
\n\n
我的代码
\n\n实体类
\n\n文件.ts
\n\n\nimport {Entity, Column, PrimaryGeneratedColumn} from "typeorm"\n\n@Entity()\nexport class MYFile{\n\n @PrimaryGeneratedColumn()\n id: number \n\n\n @Column()\n name: string\n\n @Column({\n type: "longblob"\n })\n data: string\n\n @Column()\n mimeType:string\n}\n\n应用程序脚本
\n\n索引.ts
\n\n\nimport "reflect-metadata";\nimport {createConnection, getRepository, getConnection} from "typeorm";\nimport * as express from \'express\';\nimport * as bodyParser from "body-parser";\nimport http = require("http");\nvar debug = require(\'debug\')(\'rkdemo:server\');\nimport * as fileUpload from "express-fileupload";\nconst fs = require(\'fs\');\nimport {User} from "./entity/User";\nimport {MYFile} from "./entity/file"\n\nconst app = express();\nvar port = normalizePort(process.env.PORT || \'3000\');\nvar server = http.createServer(app);\napp.set(\'port\', port);\napp.use(bodyParser.json({limit: \'50mb\'}));\napp.use(bodyParser.urlencoded({limit: \'50mb\', extended: false }));\napp.use(fileUpload({\n limits: { fileSize: 50 * 1024 * 1024 },\n}));\n\n\n\ncreateConnection().then(async connection => {\n\n\n\n app.get(\'/\', (req, res) => {\n res.send(\'Hello world!\');\n });\n\n\n\n app.get("/upload", (req, res)=>{\n res.send(`<form action="http://localhost:3000/upload" method="post" enctype="multipart/form-data">\n <label>W\xc3\xa4hlen Sie die hochzuladenden Dateien von Ihrem Rechner aus:\n <input name="datein" type="file" multiple> \n </label> \n <button>hochladen</button>\n </form>`)\n })\n\n\n\n app.post("/upload", async (req, res)=>{\n let fileData = req.files.datein\n\n console.log(fileData);\n\n\n if (Array.isArray(fileData)){\n console.log("TODO: Array")\n }else{\n\n var newFile = new MYFile()\n newFile.name = fileData.name\n newFile.data = fileData.data.toString(\'base64\')\n newFile.mimeType = fileData.mimetype\n\n try {\n const repo = getConnection().getRepository(MYFile)\n const result_File = await repo.save(newFile)\n res.send("Upload complete")\n } catch (error) {\n console.log(error)\n res.send("ERROR")\n }\n }\n })\n\n\n\n app.get("/file/:id", async (req, res)=>{\n try {\n const repo = getConnection().getRepository(MYFile)\n const result_find = await repo.findOne(req.params.id)\n console.log(result_find);\n var fileData = Buffer.from(result_find.data, \'base64\');\n res.writeHead(200, {\n \'Content-Type\': result_find.mimeType,\n \'Content-Disposition\': \'attachment; filename=\' + result_find.name,\n \'Content-Length\': fileData.length\n });\n res.write(fileData);\n res.end();\n } catch (error) {\n console.log(error)\n res.send("ERROR")\n }\n })\n}).catch(error => console.log(error));\n\n\n\nserver.listen(port, function () {\n console.log(\'Example app listening on port: \' + port);\n });\nserver.on(\'error\', onError);\nserver.on(\'listening\', onListening);\n\n\nfunction normalizePort(val) {\n var port = parseInt(val, 10);\n if (isNaN(port)) {\n return val;\n }\n if (port >= 0) {\n return port;\n }\n return false;\n }\n\n\n\nfunction onError(error) {\n if (error.syscall !== \'listen\') {\n throw error;\n }\n\n var bind = typeof port === \'string\'\n ? \'Pipe \' + port\n : \'Port \' + port;\n\n switch (error.code) {\n case \'EACCES\':\n console.error(bind + \' requires elevated privileges\');\n process.exit(1);\n break;\n case \'EADDRINUSE\':\n console.error(bind + \' is already in use\');\n process.exit(1);\n break;\n default:\n throw error;\n }\n }\n\n\n function onListening() {\n var addr = server.address();\n var bind = typeof addr === \'string\'\n ? \'pipe \' + addr\n : \'port \' + addr.port;\n debug(\'Listening on \' + bind);\n }\n\n我解决了我的问题。
实体类
文件.ts
我data: string改为data: Buffer
应用程序脚本
索引.ts
变成
app.post("/upload", async (req, res) => {
...
newFile.data = fileData.data
...
})
...
app.get("/file/:id", async (req, res) => {
...
let fileData = result_find.data
...
})