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merge PR#314 nql5161:docs/document-pdfparser
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@modesty
modesty committed Oct 21, 2023
2 parents c53b3ee + aac18d0 commit b208e7f
Showing 1 changed file with 148 additions and 71 deletions.
219 changes: 148 additions & 71 deletions pdfparser.js
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Original file line number Diff line number Diff line change
Expand Up @@ -7,104 +7,147 @@ import PDFJS from "./lib/pdf.js";
import {ParserStream} from "./lib/parserstream.js";
import {kColors, kFontFaces, kFontStyles} from "./lib/pdfconst.js";

export default class PDFParser extends EventEmitter { // inherit from event emitter
//public static
static get colorDict() {return kColors; }
/**
* Class representing a PDF Parser.
* @extends EventEmitter
*/
export default class PDFParser extends EventEmitter {
/**
* Static method to retrieve color dictionary.
* @returns {object} Color dictionary
*/
static get colorDict() { return kColors; }

/**
* Static method to retrieve font face dictionary.
* @returns {object} Font face dictionary
*/
static get fontFaceDict() { return kFontFaces; }

/**
* Static method to retrieve font style dictionary.
* @returns {object} Font style dictionary
*/
static get fontStyleDict() { return kFontStyles; }

//private static
static #maxBinBufferCount = 10;
static #binBuffer = {};

//private
#password = "";

#context = null; // service context object, only used in Web Service project; null in command line

#pdfFilePath = null; //current PDF file to load and parse, null means loading/parsing not started
#pdfFileMTime = null; // last time the current pdf was modified, used to recognize changes and ignore cache
#data = null; //if file read success, data is PDF content; if failed, data is "err" object
#PDFJS = null; //will be initialized in constructor
#processFieldInfoXML = false;//disable additional _fieldInfo.xml parsing and merging (do NOT set to true)

// constructor
#context = null; // service context object, only used in Web Service project; null in command line #pdfFilePath = null;
#pdfFilePath = null; //current PDF file to load and parse, null means loading/parsing not started #data = null;
#pdfFileMTime = null; // last time the current pdf was modified, used to recognize changes and ignore cache #PDFJS = null;
#data = null; //if file read success, data is PDF content; if failed, data is "err" object #processFieldInfoXML = false;
#PDFJS = null; //will be initialized in constructor
#processFieldInfoXML = false; //disable additional _fieldInfo.xml parsing and merging (do NOT set to true)

/**
* PDFParser constructor.
* @param {object} context - The context object (only used in Web Service project); null in command line
* @param {boolean} needRawText - Whether raw text is needed or not
* @param {string} password - The password for PDF file
* @info Private methods accessible using the [funcName].call(this, ...) syntax
*/
constructor(context, needRawText, password) {
//call constructor for super class
super();

// private
// service context object, only used in Web Service project; null in command line
this.#context = context;

this.#pdfFilePath = null; //current PDF file to load and parse, null means loading/parsing not started
this.#pdfFileMTime = null; // last time the current pdf was modified, used to recognize changes and ignore cache
this.#data = null; //if file read success, data is PDF content; if failed, data is "err" object
this.#pdfFilePath = null; //current PDF file to load and parse, null means loading/parsing not started this.#pdfFileMTime = null;
this.#pdfFileMTime = null; // last time the current pdf was modified, used to recognize changes and ignore cache this.#data = null;
this.#data = null; //if file read success, data is PDF content; if failed, data is "err" object this.#processFieldInfoXML = false;
this.#processFieldInfoXML = false;//disable additional _fieldInfo.xml parsing and merging (do NOT set to true)

this.#PDFJS = new PDFJS(needRawText);
this.#password = password;
}

//private methods, needs to invoked by [funcName].call(this, ...)
#onPDFJSParseDataReady(data) {
if (!data) { //v1.1.2: data===null means end of parsed data
nodeUtil.p2jinfo("PDF parsing completed.");
this.emit("pdfParser_dataReady", this.#data);
}
else {
this.#data = {...this.#data, ...data};
}
}
}

#onPDFJSParserDataError(err) {
this.#data = null;
this.emit("pdfParser_dataError", {"parserError": err});
// this.emit("error", err);
}
/**
* @private
* @param {object} data - The parsed data
*/
#onPDFJSParseDataReady(data) {
if (!data) {
nodeUtil.p2jinfo("PDF parsing completed.");
this.emit("pdfParser_dataReady", this.#data);
}
else {
this.#data = { ...this.#data, ...data };
}
}

#startParsingPDF(buffer) {
this.#data = {};
/**
* @private
* @param {Error} err - The error object
*/
#onPDFJSParserDataError(err) {
this.#data = null;
this.emit("pdfParser_dataError", { "parserError": err });
}

this.#PDFJS.on("pdfjs_parseDataReady", data => this.#onPDFJSParseDataReady(data));
this.#PDFJS.on("pdfjs_parseDataError", err => this.#onPDFJSParserDataError(err));
/**
* @private
* @param {Buffer} buffer - The PDF buffer
*/
#startParsingPDF(buffer) {
this.#data = {};
this.#PDFJS.on("pdfjs_parseDataReady", data => this.#onPDFJSParseDataReady(data));
this.#PDFJS.on("pdfjs_parseDataError", err => this.#onPDFJSParserDataError(err));

//v1.3.0 the following Readable Stream-like events are replacement for the top two custom events
this.#PDFJS.on("readable", meta => this.emit("readable", meta));
this.#PDFJS.on("data", data => this.emit("data", data));
this.#PDFJS.on("error", err => this.#onPDFJSParserDataError(err));

this.#PDFJS.parsePDFData(buffer || PDFParser.#binBuffer[this.binBufferKey], this.#password);
}

this.#PDFJS.parsePDFData(buffer || PDFParser.#binBuffer[this.binBufferKey], this.#password);
}

#processBinaryCache() {
/**
* @private
* @returns {boolean}
*/
#processBinaryCache() {
if (this.binBufferKey in PDFParser.#binBuffer) {
this.#startParsingPDF();
return true;
}

const allKeys = Object.keys(PDFParser.#binBuffer);
if (allKeys.length > PDFParser.#maxBinBufferCount) {
const idx = this.id % PDFParser.#maxBinBufferCount;
const key = allKeys[idx];
PDFParser.#binBuffer[key] = null;
delete PDFParser.#binBuffer[key];

const allKeys = Object.keys(PDFParser.#binBuffer);
if (allKeys.length > PDFParser.#maxBinBufferCount) {
const idx = this.id % PDFParser.#maxBinBufferCount;
const key = allKeys[idx];
PDFParser.#binBuffer[key] = null;
delete PDFParser.#binBuffer[key];

nodeUtil.p2jinfo("re-cycled cache for " + key);
}
nodeUtil.p2jinfo("re-cycled cache for " + key);
}

return false;
}

//public getter
/**
* Getter for #data
* @returns {object|null} Data
*/
get data() { return this.#data; }

/**
* Getter for binBufferKey
* @returns {string} The binBufferKey
*/
get binBufferKey() { return this.#pdfFilePath + this.#pdfFileMTime; }

//public APIs

/**
* Creates a parser stream
* @returns {ParserStream} A new parser stream
*/
createParserStream() {
return new ParserStream(this, {objectMode: true, bufferSize: 64 * 1024});
return new ParserStream(this, { objectMode: true, bufferSize: 64 * 1024 });
}

/**
* Asynchronously load a PDF from a file path.
* @param {string} pdfFilePath - Path of the PDF file
* @param {number} verbosity - Verbosity level
*/
async loadPDF(pdfFilePath, verbosity) {
nodeUtil.verbosity(verbosity || 0);
nodeUtil.p2jinfo("about to load PDF file " + pdfFilePath);
Expand All @@ -130,21 +173,55 @@ export default class PDFParser extends EventEmitter { // inherit from event emit
}
}

// Introduce a way to directly process buffers without the need to write it to a temporary file
/**
* Parse PDF buffer. Introduce a way to directly process buffers without the need to write it to a temporary file
* @param {Buffer} pdfBuffer - PDF buffer
* @param {number} verbosity - Verbosity level
*/
parseBuffer(pdfBuffer, verbosity) {
nodeUtil.verbosity(verbosity || 0);
this.#startParsingPDF(pdfBuffer);
}

getRawTextContent() { return this.#PDFJS.getRawTextContent(); }
getRawTextContentStream() { return ParserStream.createContentStream(this.getRawTextContent()); }

getAllFieldsTypes() { return this.#PDFJS.getAllFieldsTypes(); };
getAllFieldsTypesStream() { return ParserStream.createContentStream(this.getAllFieldsTypes()); }

getMergedTextBlocksIfNeeded() { return this.#PDFJS.getMergedTextBlocksIfNeeded(); }
getMergedTextBlocksStream() { return ParserStream.createContentStream(this.getMergedTextBlocksIfNeeded()) }

/**
* Retrieve raw text content from PDF.
* @returns {string} Raw text content
*/
getRawTextContent() { return this.#PDFJS.getRawTextContent(); }

/**
* Retrieve raw text content stream.
* @returns {Stream} Raw text content stream
*/
getRawTextContentStream() { return ParserStream.createContentStream(this.getRawTextContent()); }

/**
* Retrieve all field types.
* @returns {object[]} All field types
*/
getAllFieldsTypes() { return this.#PDFJS.getAllFieldsTypes(); }

/**
* Retrieve all field types stream.
* @returns {Stream} All field types stream
*/
getAllFieldsTypesStream() { return ParserStream.createContentStream(this.getAllFieldsTypes()); }

/**
* Retrieve merged text blocks if needed.
* @returns {object} Merged text blocks
*/
getMergedTextBlocksIfNeeded() { return this.#PDFJS.getMergedTextBlocksIfNeeded(); }

/**
* Retrieve merged text blocks stream.
* @returns {Stream} Merged text blocks stream
*/
getMergedTextBlocksStream() { return ParserStream.createContentStream(this.getMergedTextBlocksIfNeeded()) }

/**
* Destroy the PDFParser instance.
*/
destroy() { // invoked with stream transform process
super.removeAllListeners();

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