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index.js
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index.js
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import "gm-base64"
import gm from "gm"
import path from "path"
import fs from "fs-extra"
export default class PDF2Pic {
static defaultOptions = {
quality: 0,
format: "png",
size: "768x512",
density: 72,
savedir: "./",
savename: "untitled",
compression: "jpeg"
}
constructor(options = {}) {
this.options = { ...PDF2Pic.defaultOptions, ...options }
}
/**
* GM command - identify
* @param {String} filepath path to valid file
* @param {Mixed} argument gm identify argument
* @returns {Promise} Promise
*/
identify(filepath, argument) {
let image = gm(filepath)
return new Promise((resolve, reject) => {
if (argument) {
image.identify(argument, (error, data) => {
if (error) {
return reject(error)
}
return resolve(data.replace(/^[\w\W]*?1/, "1"))
})
} else {
image.identify((error, data) => {
if (error) {
return reject(error)
}
return resolve(data)
})
}
})
}
/**
* Initialize base graphicmagick setup.
* @param {Stream} stream fs stream
* @param {String} filename save file name
* @returns {gm} graphicsmagick object
*/
graphicMagickBaseCommand(stream, filename) {
let { density, size, quality, compression } = this.options
const width = size.split(/x/i)[0]
const height = size.split(/x/i)[1]
if (!height) {
return gm(stream, filename)
.density(density, density)
.resize(size)
.quality(quality)
.compress(compression)
}
return gm(stream, filename)
.density(density, density)
.resize(width, height)
.quality(quality)
.compress(compression)
}
/**
* GM command - write
* @param {Stream} stream fs stream
* @param {String} output output
* @param {String} filename filename
* @param {Integer} page page count
* @returns {Promise} Promise
*/
writeImage(stream, output, filename, page) {
return new Promise((resolve, reject) => {
this.graphicMagickBaseCommand(stream, filename)
.write(output, (error) => {
if (error) {
return reject(error)
}
return resolve({
name: path.basename(output),
size: fs.statSync(output).size / 1000.0,
path: output,
page
})
})
})
}
/**
* GM command - toBase64
* @param {Stream} stream fs stream
* @param {String} filename filename
* @param {Integer} page page count
* @returns {Promise} Promise
*/
toBase64(stream, filename, page) {
let { format } = this.options
return new Promise((resolve, reject) => {
this.graphicMagickBaseCommand(stream, filename)
.toBase64(format, (error, base64) => {
if (error) {
return reject(error)
}
return resolve({
base64,
page
})
})
})
}
/**
* Intialize converter
* @param {String} pdf_path path to file
* @param {Page} page page number to be converted
* @returns {Object} image status
*/
async convert(pdf_path, page = 1) {
this.isValidPDF(pdf_path)
this.fileExists(pdf_path)
let output = path.basename(pdf_path, path.extname(path.basename(pdf_path)))
// Set output dir
if (this.getOption("savedir")) {
this.setOption("savedir", this.getOption("savedir") + path.sep)
} else {
this.setOption("savedir", output + path.sep)
}
fs.mkdirsSync(this.getOption("savedir"))
if (!this.getOption("savename")) {
this.setOption("savename", output)
}
let pages = await this.getPageCount(pdf_path)
if (page > pages) {
throw new Error("Cannot convert non-existent page")
}
return await this.toImage(pdf_path, page)
}
/**
* Intialize pdftobase64 converter,
* @param {String} pdf_path path to file
* @param {Page} page page number to be converted
* @returns {Object} image status
*/
async convertToBase64(pdf_path, page = 1) {
this.isValidPDF(pdf_path)
this.fileExists(pdf_path)
let output = path.basename(pdf_path, path.extname(path.basename(pdf_path)))
// Set output dir
if (this.getOption("savedir")) {
this.setOption("savedir", this.getOption("savedir") + path.sep)
} else {
this.setOption("savedir", output + path.sep)
}
fs.mkdirsSync(this.getOption("savedir"))
if (!this.getOption("savename")) {
this.setOption("savename", output)
}
let pages = await this.getPageCount(pdf_path)
if (page > pages) {
throw new Error("Cannot convert non-existent page")
}
return await this.streamToBase64(pdf_path, page, true)
}
/**
* Intialize pdftobase64 converter, well the bulk version
* @param {String} pdf_path path to file
* @param {Page} pages page number to be converted (-1 for all pages)
* @returns {Object} image status
*/
async convertToBase64Bulk(pdf_path, pages = -1) {
let result = []
let pageCount = Array.isArray(pages) ? pages : [1]
pages = pages === -1
? await this.getPages(pdf_path)
: pageCount
pages = pages.map(page => {
return this.convertToBase64(pdf_path, page)
})
result = await Promise.all(pages)
return result
}
/**
* Intialize converter, well the bulk version
* @param {String} pdf_path path to file
* @param {Page} pagesToConvert page number to be converted (-1 for all pages)
* @returns {Object} image status
*/
async convertBulk(pdf_path, pagesToConvert = -1) {
let result = []
if (pagesToConvert === -1) {
pagesToConvert = await this.getPages(pdf_path)
} else if (!Array.isArray(pagesToConvert)) {
pagesToConvert = [pagesToConvert]
}
/** not sure yet if this would work */
const pages = pagesToConvert.map(page => {
return this.convert(pdf_path, page)
})
result = await Promise.all(pages)
return result
}
/**
* Get how many pages are there in the pdf file
* @param {String} pdf_path path to file
* @returns {Integer} number of pages
*/
async getPageCount(pdf_path) {
return await this.getPages(pdf_path).length
}
/**
* Get pages numbers
* @param {String} pdf_path path to file
* @returns {Array} pages
*/
async getPages(pdf_path) {
let page = await this.identify(pdf_path, "%p ")
return page.split(" ").map(Number)
}
/**
* Converts pdf to image
* @param {String} pdf_path pdf path
* @param {Integer} page page count
* @returns {Promise} Promise
*/
async toImage(pdf_path, page = 1) {
let { savedir, savename, format } = this.getOption()
let iStream = fs.createReadStream(pdf_path)
let file = `${savedir.replace(/\/*$/, "/")}${savename}_${page}.${format}`
let filename = `${this.getFilePath(iStream)}[${page - 1}]`
return await this.writeImage(iStream, file, filename, page)
}
/**
* Converts pdf to image
* @param {String} pdf_path pdf path
* @param {Integer} page page count
* @returns {Promise} Promise
*/
async streamToBase64(pdf_path, page = 1) {
let iStream = fs.createReadStream(pdf_path)
let filename = `${this.getFilePath(iStream)}[${page - 1}]`
return await this.toBase64(iStream, filename, page)
}
/**
* Get file path
* @param {Stream} stream fs stream
* @returns {String} path
*/
getFilePath(stream) {
if (!stream) {
throw new Error("Invalid Stream")
}
return stream.path
}
/**
* Checks if the supplied file has the exact file format
* @param {String} pdf_path path to file
* @returns {Mixed} file status
*/
isValidPDF(pdf_path) {
if (path.extname(path.basename(pdf_path)).toLowerCase() !== ".pdf") {
throw new Error("File supplied is not a valid PDF")
}
return true
}
/**
* Checks if the supplied file has exists
* @param {String} pdf_path path to file
* @returns {Mixed} file status
*/
fileExists(pdf_path) {
if (!fs.existsSync(pdf_path)) {
throw new Error("File supplied cannot be found")
}
return true
}
/**
* Returns a value from this.options
* @param {string} key key from this.options
* @returns {mixed} value from this.options
*/
getOption(key) {
return key ? this.options[key] : this.options
}
/**
* Set a key-value to this options
* @param {*} key key from this.options
* @param {*} value value to be assigned on this.options[key]
* @returns {object} this
*/
setOption(key, value) {
this.options[key] = value
return this
}
}