Question

我有一个csv文件，想使用angular和nodejs将其中的数据转储到mongodb中。

需要帮助来使用angular读取csv文件的数据并将其解析并存储在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());
  }

}

这是我用于通过发布路线发送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> &nbsp; &nbsp;at JSON.stringify (&lt;anonymous&gt;)
            <br> &nbsp; &nbsp;at router.post (/home/agam/projects/AMEX/routes/fileUpload.js:10:23)
            <br> &nbsp; &nbsp;at Layer.handle [as handle_request] (/home/agam/projects/AMEX/node_modules/express/lib/router/layer.js:95:5)
            <br> &nbsp; &nbsp;at next (/home/agam/projects/AMEX/node_modules/express/lib/router/route.js:137:13)
            <br> &nbsp; &nbsp;at Route.dispatch (/home/agam/projects/AMEX/node_modules/express/lib/router/route.js:112:3)
            <br> &nbsp; &nbsp;at Layer.handle [as handle_request] (/home/agam/projects/AMEX/node_modules/express/lib/router/layer.js:95:5)
            <br> &nbsp; &nbsp;at /home/agam/projects/AMEX/node_modules/express/lib/router/index.js:281:22
            <br> &nbsp; &nbsp;at Function.process_params (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:335:12)
            <br> &nbsp; &nbsp;at next (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:275:10)
            <br> &nbsp; &nbsp;at Function.handle (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:174:3)
            <br> &nbsp; &nbsp;at router (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:47:12)
            <br> &nbsp; &nbsp;at Layer.handle [as handle_request] (/home/agam/projects/AMEX/node_modules/express/lib/router/layer.js:95:5)
            <br> &nbsp; &nbsp;at trim_prefix (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:317:13)
            <br> &nbsp; &nbsp;at /home/agam/projects/AMEX/node_modules/express/lib/router/index.js:284:7
            <br> &nbsp; &nbsp;at Function.process_params (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:335:12)
            <br> &nbsp; &nbsp;at next (/home/agam/projects/AMEX/node_modules/express/lib/router/index.js:275:10)
        </pre>
    </body>
</html>

这是我尝试调试在节点侧通过发布请求接收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]

这就是它要打印的东西

// 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');
});

这是您期望的index.js文件

Answer 1

您好，我在您的StackBiltz示例中做了一些更改，因此我能够实现通过JSON数组形式的post调用来发布有效负载，并创建了一个接受该有效负载的服务并在订阅时将有效负载传递给您的节点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)));
  }
}

如何使用angular和nodejs将csv数据转储到mongoDB中

1 个答案: