我有一个 csv 文件，想使用 Angular 和 NodeJS 将其中的数据转储到 mongodb 中。
需要帮助使用 Angular 读取 csv 文件的数据并解析它并存储在 mongodb 中
import { Injectable } from '@angular/core';
import { Http } from '@angular/http';
import 'rxjs/add/operator/map';
@Injectable()
export class TemplateService {
domain = 'http://localhost:3000';
constructor(private http: Http) { }
postCsvToMongo(csvJson: any) {
console.log('CSV!!!' + csvJson);
return this.http.post(this.domain + '/fu/fileupload', csvJson).map(res => res.json());
}
}这是我用来通过 post 路由发送 json 对象的代码。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Error</title>
</head>
<body>
<pre>TypeError: Converting circular structure to JSON
<br> at JSON.stringify (<anonymous>)
<br> at router.post (/home/agam/projects/AMEX/routes/fileUpload.js:10:23)
<br> at Layer.handle [as handle_request] (/home/agam/projects/AMEX/node_modules/express/lib/router/layer.js:95:5)
<br> at next (/home/agam/projects/AMEX/node_modules/express/lib/router/route.js:137:13)
<br> at Route.dispatch (/home/agam/projects/AMEX/node_modules/express/lib/router/route.js:112:3)
<br> at Layer.handle [as handle_request] (/home/agam/projects/AMEX/node_modules/express/lib/router/layer.js:95:5)
<br> at /home/agam/projects/AMEX/node_modules/express/lib/router/index.js:281:22
<br> at Function.process_params (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:335:12)
<br> at next (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:275:10)
<br> at Function.handle (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:174:3)
<br> at router (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:47:12)
<br> at Layer.handle [as handle_request] (/home/agam/projects/AMEX/node_modules/express/lib/router/layer.js:95:5)
<br> at trim_prefix (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:317:13)
<br> at /home/agam/projects/AMEX/node_modules/express/lib/router/index.js:284:7
<br> at Function.process_params (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:335:12)
<br> at next (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:275:10)
</pre>
</body>
</html>这是我在尝试调试通过 Node 端的 post 请求收到的请求时遇到的错误。 以及如何通过后端接收文件？
var csv = require('fast-csv');
var mongoose = require('mongoose');
var Bulletin = require('../models/bulletin');
var multer = require("multer");
module.exports = (router) => {
router.post('/fileupload', (req, res) => {
console.log('@@@ ' + req);
res.send(req.files);
});
/*router.post('/fileupload', multer({dest: "./uploads/"}).array("uploads", 12), function(req, res) {
res.send(req.files);
});*/
return router;
};这是nodejs代码
1","Fed official says weak data caused by weather, should not slow taper","http://www.latimes.com/business/money/la-fi-mo-federal-reserve-plosser-stimulus-economy-20140310,0,1312750.story\?track=rss","Los Angeles Times","b","www.latimes.com","1394470370698
2","Fed's Charles Plosser sees high bar for change in pace of tapering","http://www.livemint.com/Politics/H2EvwJSK2VE6OF7iK1g3PP/Feds-Charles-Plosser-sees-high-bar-for-change-in-pace-of-ta.html","Livemint","b","www.livemint.com","1394470371207
3","US open: Stocks fall after Fed official hints at accelerated tapering","http://www.ifamagazine.com/news/us-open-stocks-fall-after-fed-official-hints-at-accelerated-tapering-294436","IFA Magazine","b","www.ifamagazine.com","1394470371550
4","Fed risks falling 'behind the curve', Charles Plosser says","http://www.ifamagazine.com/news/fed-risks-falling-behind-the-curve-charles-plosser-says-294430","IFA Magazine","b","www.ifamagazine.com","1394470371793
5","Fed's Plosser: Nasty Weather Has Curbed Job Growth","http://www.moneynews.com/Economy/federal-reserve-charles-plosser-weather-job-growth/2014/03/10/id/557011","Moneynews","b","www.moneynews.com","1394470372027
6","Plosser: Fed May Have to Accelerate Tapering Pace","http://www.nasdaq.com/article/plosser-fed-may-have-to-accelerate-tapering-pace-20140310-00371","NASDAQ","b","www.nasdaq.com","1394470372212这是我的示例 csv 文件
> amex@1.0.0 start /home/agam/projects/AMEX
> node index.js
(node:6478) DeprecationWarning: current URL string parser is deprecated, and will be removed in a future version. To use the new parser, pass option { useNewUrlParser: true } to MongoClient.connect.
listening on port 3000
Conected to database: amex
@@@ [object Object]这就是它正在打印的内容
// 1) Express for nodejs
const express = require('express');
const app = express();
const template = require('./routes/template');
const upload = require('./routes/upload');
const path = require('path');
// const fileUpload = require('express-fileupload');
const router = express.Router();
const fu = require('./routes/fileUpload')(router);
//const carts = require('./routes/carts')(router);
// 5) body parser
const bodyParser = require('body-parser');
const cors = require('cors'); // CORS is a node.js package for providing a Connect/Express middleware that can be used to enable CORS with various options.
// 2) Mongodb connection
var mongoose = require('mongoose');
const config = require('./config/database');
mongoose.connect(config.uri, (err) => {
if (err) {
console.log('error ' + err);
} else {
console.log('Conected to database: ' + config.db);
}
});
app.use(cors({ origin: 'http://localhost:4200' }));
// 5) put bodyparser code before the routes (converts request to req.body)
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
app.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header('Access-Control-Allow-Methods', 'PUT, GET, POST, DELETE, OPTIONS');
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
next();
});
// 3) connect node.js to angular
app.use(express.static(__dirname + '/client/dist/'));
// app.use(fileUpload());
app.use('/fu', fu); // Use Product routes in application
//app.use('/carts', carts);
//
app.get('*', (req, res) => {
res.sendFile(path.join(__dirname + '/client/dist/index.html'));
});
app.listen(3000, () => {
console.log('listening on port 3000');
});这是我所期待的 index.js 文件
最佳答案
您好，我对您的 StackBiltz 做了一些更改例如，所以我能够实现通过 post 调用以 JSON 数组的形式发布的有效负载，并创建一个接受此有效负载的服务，并在订阅时将有效负载传递到您的 Node post api
创建了一个名为 pass 的函数
test.component.ts
import { Component, OnInit } from '@angular/core';
import { Router } from "@angular/router";
import { FileUtil } from './file.util';
import { Constants } from './test.constants';
import {TestService} from './test.service';
@Component({
selector: 'app-test',
templateUrl: './test.component.html',
styleUrls: ['./test.component.css']
})
export class TestComponent implements OnInit {
fileImportInput: any;
data;
csvRecords:any = [];
constructor(private _router: Router,
private _fileUtil: FileUtil,private testService:TestService
) { }
ngOnInit() {
}
// METHOD CALLED WHEN CSV FILE IS IMPORTED
fileChangeListener($event): void {
var text = [];
var target = $event.target || $event.srcElement;
var files = target.files;
if (Constants.validateHeaderAndRecordLengthFlag) {
if (!this._fileUtil.isCSVFile(files[0])) {
alert("Please import valid .csv file.");
this.fileReset();
}
}
var input = $event.target;
var reader = new FileReader();
reader.readAsText(input.files[0]);
reader.onload = (data) => {
let csvData = reader.result;
let csvRecordsArray = csvData.split(/\r\n|\n/);
var headerLength = -1;
if (Constants.isHeaderPresentFlag) {
let headersRow = this._fileUtil.getHeaderArray(csvRecordsArray, Constants.tokenDelimeter);
headerLength = headersRow.length;
}
this.csvRecords = this._fileUtil.getDataRecordsArrayFromCSVFile(csvRecordsArray,
headerLength, Constants.validateHeaderAndRecordLengthFlag, Constants.tokenDelimeter);
this.passThisFunction(this.csvRecords);
console.log('this.csvRecords',this.csvRecords);
if (this.csvRecords == null) {
//If control reached here it means csv file contains error, reset file.
this.fileReset();
}
}
reader.onerror = function () {
alert('Unable to read ' + input.files[0]);
};
};
fileReset() {
this.fileImportInput.nativeElement.value = "";
this.csvRecords = [];
}
passThisFunction(records:any){
console.log('inside function call');
console.log('records',records);
let json=JSON.stringify(records);
console.log('jsonified',json);
var str = json.replace(/},/g, "},\r\n");
console.log('das' + str);
this.testService.postCsvToMongo(str).subscribe((data) => {
console.log(data);
});
}
}
test.component.html
<h4>Read .CSV File using Angular2, JQuery and Bootstrap</h4>
<table>
<tr>
<td>
<input type="file"
#fileImportInput
name="File Upload"
id="txtFileUpload"
class="btn btn-primary"
(change)="fileChangeListener($event)"
accept=".csv"
/>
</td>
</tr>
</table>
<div>
<table class="table table-responsive table-hover" border="1"
style="width : 50%;">
<tbody>
<ng-container >
<tr >
<td *ngFor="let csvRec of csvRecords;let i=index">{{csvRec}}</td>
</tr>
</ng-container>
</tbody>
</table>
</div>
file.util.ts
import { Injectable } from '@angular/core';
@Injectable()
export class FileUtil {
constructor() {}
isCSVFile(file) {
return file.name.endsWith(".csv");
}
getHeaderArray(csvRecordsArr, tokenDelimeter) {
let headers = csvRecordsArr[0].split(tokenDelimeter);
let headerArray = [];
for (let j = 0; j < headers.length; j++) {
headerArray.push(headers[j]);
}
return headerArray;
}
validateHeaders(origHeaders, fileHeaaders) {
if (origHeaders.length != fileHeaaders.length) {
return false;
}
var fileHeaderMatchFlag = true;
for (let j = 0; j < origHeaders.length; j++) {
if (origHeaders[j] != fileHeaaders[j]) {
fileHeaderMatchFlag = false;
break;
}
}
return fileHeaderMatchFlag;
}
getDataRecordsArrayFromCSVFile(csvRecordsArray, headerLength,
validateHeaderAndRecordLengthFlag, tokenDelimeter) {
console.log(csvRecordsArray);
console.log(headerLength);
console.log(validateHeaderAndRecordLengthFlag);
console.log(tokenDelimeter);
var dataArr:any = [];
for (let i = 0; i < csvRecordsArray.length; i++) {
let data = csvRecordsArray[i].split(tokenDelimeter);
if(validateHeaderAndRecordLengthFlag && data.length != headerLength){
if(data==""){
alert("Extra blank line is present at line number "+i+", please remove it.");
return null;
}else{
alert("Record at line number "+i+" contain "+data.length+" tokens, and is not matching with header length of :"+headerLength);
return null;
}
}
dataArr=data;
console.log('dataArr',dataArr);
}
return dataArr;
}
}
test.service.ts
import{Injectable} from '@angular/core';
import{Http} from '@angular/http';
import {map} from 'rxjs/operators';
@Injectable()
export class TestService{
API_URL:string='your api url';
constructor(private http:Http){}
postCsvToMongo(csvJson:any){
return this.http.post(this.API_URL,csvJson)
.pipe(map((res)=>console.log(res)));
}
}
关于javascript - 如何使用 Angular 和 NodeJS 将 csv 数据转储到 mongoDB，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51869761/