node.js 中的本地 PDF 文件抓取

Question

我已经使用 fs 通过 MEAN 堆栈 Web 应用程序上传了一个 pdf。我想从 pdf 中提取某些字段并将它们显示在网络应用程序上。我看过几个 npm 包，比如 pdf.js、pdf2json。我无法弄清楚可用示例中使用的文档和 javascript 回调。请帮忙！

Answer 1

我希望我能帮助回答你的问题。使用 pdf2json 可用于解析 pdf 并提取文本。需要采取几个步骤才能使其正常工作。我改编了来自https://github.com/modesty/pdf2json 的示例。

设置是在node app中安装pdf2json，也下划线。示例页面没有解释定义您自己的回调函数的必要性。它还使用self 而不是this 来注册它们。因此，通过适当的更改，从 pdf 中提取所有文本的代码将如下所示：

// Get the dependencies that have already been installed
// to ./node_modules with `npm install <dep>`in the root director
// of your app 

var _ = require('underscore'),
    PDFParser = require('pdf2json');

var pdfParser = new PDFParser();

// Create a function to handle the pdf once it has been parsed.
// In this case we cycle through all the pages and extraxt
// All the text blocks and print them to console.
// If you do `console.log(JSON.stringify(pdf))` you will 
// see how the parsed pdf is composed. Drill down into it
// to find the data you are looking for.
var _onPDFBinDataReady = function (pdf) {
  console.log('Loaded pdf:\n');
  for (var i in pdf.data.Pages) {
    var page = pdf.data.Pages[i];
    for (var j in page.Texts) { 
      var text = page.Texts[j];
      console.log(text.R[0].T);
    }
  }
};

// Create an error handling function
var _onPDFBinDataError = function (error) {
  console.log(error);
};

// Use underscore to bind the data ready function to the pdfParser
// so that when the data ready event is emitted your function will
// be called. As opposed to the example, I have used `this` instead
// of `self` since self had no meaning in this context
pdfParser.on('pdfParser_dataReady', _.bind(_onPDFBinDataReady, this));

// Register error handling function
pdfParser.on('pdfParser_dataError', _.bind(_onPDFBinDataError, this));

// Construct the file path of the pdf
var pdfFilePath = 'test3.pdf';

// Load the pdf. When it is loaded your data ready function will be called.
pdfParser.loadPDF(pdfFilePath);

Answer 2

我正在从我的服务器端控制器运行代码。

module.exports = (function() {
return {
    add: function(req, res) {
        var tmp_path = req.files.pdf.path;
        var target_path = './uploads/' + req.files.pdf.name;
        fs.rename(tmp_path, target_path, function(err) {
            if (err) throw err;
            // delete the temporary file, so that the explicitly set temporary upload dir does not get filled with unwanted files
            fs.unlink(tmp_path, function() {
                if (err) throw err;
            //edit here pdf parser

            res.redirect('#/');

            });
        })
    },
    show: function(req, res) {

    var pdfParser = new PDFParser();

    var _onPDFBinDataReady = function (pdf) {
      console.log('Loaded pdf:\n');

      for (var i in pdf.data.Pages) {

        var page = pdf.data.Pages[i];
        // console.log(page.Texts);
        for (var j in page.Texts) { 
          var text = page.Texts[j];
          // console.log(text.R[0].T);

        }
      }
      console.log(JSON.stringify(pdf));
    };
    // Create an error handling function
    var _onPDFBinDataError = function (error) {
      console.log(error);
    };
    pdfParser.on('pdfParser_dataReady', _.bind(_onPDFBinDataReady, this));
    // Register error handling function
    pdfParser.on('pdfParser_dataError', _.bind(_onPDFBinDataError, this));
    // Construct the file path of the pdf
    var pdfFilePath = './uploads/Invoice_template.pdf';
    // Load the pdf. When it is loaded your data ready function will be called.
    pdfParser.loadPDF(pdfFilePath);

},

//end controller

}