src/module/pdf/subservices/PDFGenerator.core.ts
Properties |
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Methods |
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| Private Readonly logger |
Default value : new Logger(PDFGenerator.name)
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| Protected Async generatePDFFromBodyContent | ||||||||
generatePDFFromBodyContent(body: string)
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Generates a PDF from the given body. The body gets put in an HTML wrapper first.
Parameters :
Returns :
Promise<Buffer>
Buffer containing the generated PDF. |
| Private Static getCustomCSS |
getCustomCSS()
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Returns :
string
Some small customizations to the GitHub markdown CSS. |
| Private Async getGithubMarkdownCSS |
getGithubMarkdownCSS()
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Returns :
Promise<string>
The GitHub markdown CSS. |
| Private Async getHighlightCSS |
getHighlightCSS()
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Returns :
Promise<string>
The HighlightJS CSS. |
| Private Async loadCSSFile | ||||||
loadCSSFile(moduleName: string)
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Parameters :
Returns :
Promise<string>
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| Private Async putBodyInHTML | ||||||||
putBodyInHTML(body: string)
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Puts the given body in corresponding a
Parameters :
Returns :
Promise<string>
Complete HTML "file" which contains the given |
import { Logger } from '@nestjs/common';
import axios from 'axios';
import FormData from 'form-data';
import fs from 'fs';
import { StaticSettings } from 'module/settings/settings.static';
/**
* @param T Type of the options passed to `generatePDF`.
*/
export abstract class PDFGenerator<T = Record<string, unknown>> {
private readonly logger = new Logger(PDFGenerator.name);
/**
* Generates a PDF from the given options.
*
* @param options Options from which the PDF gets generated.
*
* @returns Generated PDF as Buffer.
*/
public abstract generatePDF(options: T): Promise<Buffer>;
/**
* Generates a PDF from the given body. The body gets put in an HTML wrapper first.
*
* @param body Body content to be put in the PDF as HTML body.
*
* @returns Buffer containing the generated PDF.
*/
protected async generatePDFFromBodyContent(body: string): Promise<Buffer> {
const html = await this.putBodyInHTML(body);
const gotenbergConfig = StaticSettings.getService().getGotenbergConfiguration();
try {
const form = new FormData();
form.append('files', html, { filename: 'index.html', contentType: 'text/html' });
this.logger.debug('Sending request to Gotenberg for PDF generation...');
const response = await axios.post(
`http://${gotenbergConfig?.host}:${gotenbergConfig?.port}/forms/chromium/convert/html`,
form,
{
headers: {
...form.getHeaders(),
},
timeout: gotenbergConfig?.timeout,
responseType: 'arraybuffer',
}
);
this.logger.debug('PDF generated successfully from Gotenberg.');
return Buffer.from(response.data);
} catch (err) {
this.logger.error('Failed to generate PDF:', err);
throw err;
}
}
/**
* Puts the given body in corresponding a `<body>` element. The returned string is a complete HTML "file" with slightly customized GitHub Markdown CSS.
*
* @param body Body to embed in HTML.
*
* @returns Complete HTML "file" which contains the given `body` as body.
*/
private async putBodyInHTML(body: string): Promise<string> {
const githubCSS = await this.getGithubMarkdownCSS();
const highlightCSS = await this.getHighlightCSS();
return `
<html>
<head>
<style>${githubCSS}</style>
<style>${highlightCSS}</style>
<style>${PDFGenerator.getCustomCSS()}</style>
</head>
<body class='markdown-body'>${body}</body>
</html>
`;
}
/**
* @returns The GitHub markdown CSS.
*/
private async getGithubMarkdownCSS(): Promise<string> {
return this.loadCSSFile('github-markdown-css/github-markdown.css');
}
/**
* @returns The HighlightJS CSS.
*/
private async getHighlightCSS(): Promise<string> {
return this.loadCSSFile('highlight.js/styles/googlecode.css');
}
private async loadCSSFile(moduleName: string): Promise<string> {
try {
const pathToFile = require.resolve(moduleName);
const css = fs.readFileSync(pathToFile);
return css.toString();
} catch (err) {
this.logger.error(`Could not load CSS file '${moduleName}'`);
return '';
}
}
/**
* @returns Some small customizations to the GitHub markdown CSS.
*/
private static getCustomCSS(): string {
return '.markdown-body table { display: table; width: 100%; }';
}
}