Webviewer Html Proxy Server

This is a proxy server to use with HTML sample by PDFTron

Disclaimer

This project is experimental. A proxy server is used to serve webpage assets. This is done to get around various security issues, when loading a webpage in an iframe. This works for a good amount of pages but there are many exceptions. If you have a subset of web pages that you would like to support then we recommend forking this repository and making the necessary fixes. We won't be making those changes because it would likely result in other pages failing.

Install

npm install @pdftron/webviewer-html-proxy-server

How to use

Call the createServer function in your server component and pass in an object that includes SERVER_ROOT and PORT. You can, optionally, pass in

• CORS_OPTIONS: an object to configure CORS, see: https://expressjs.com/en/resources/middleware/cors.html
• COOKIE_SETTING: an object to configure COOKIE, see https://expressjs.com/en/api.html#res.cookie
• ALLOW_POTENTIALLY_UNSAFE_URL, a boolean value to disable URL validation. Setting this to true will override ALLOW_HTTP_PROXY
• ALLOW_HTTP_PROXY, a boolean value to allow loading localhost files and for unsecured HTTP websites to be proxied

Example

const HTMLProxyServer = require('@pdftron/webviewer-html-proxy-server');
HTMLProxyServer.createServer({
    SERVER_ROOT: `http://localhost`,
    PORT: 3100
});

Setting CORS_OPTIONS example:

HTMLProxyServer.createServer({
    SERVER_ROOT: `http://localhost`,
    PORT: 3100,
    CORS_OPTIONS: {
        "origin": "*",
        "methods": "GET,HEAD,PUT,PATCH,POST,DELETE",
        "preflightContinue": false,
        "optionsSuccessStatus": 204
    }
});

Setting COOKIE_SETTING example:

HTMLProxyServer.createServer({
    SERVER_ROOT: `http://localhost`,
    PORT: 3100,
    COOKIE_SETTING: {
        sameSite: 'none',
        secure: true
    }
});

Setting ALLOW_POTENTIALLY_UNSAFE_URL example:

HTMLProxyServer.createServer({
    SERVER_ROOT: `http://localhost`,
    PORT: 3100,
    ALLOW_POTENTIALLY_UNSAFE_URL: true
});

Setting ALLOW_HTTP_PROXY example:

HTMLProxyServer.createServer({
    SERVER_ROOT: `http://localhost`,
    PORT: 3100,
    ALLOW_POTENTIALLY_UNSAFE_URL: false,
    ALLOW_HTTP_PROXY: true
});

API Endpoints

Proxy a URL

URL : /pdftron-proxy?url=

Query Parameters : url=[string] where url is a publicly accessible link.

Method : GET

Success Response

Condition : If the URL can be successfuly proxied

Code : 200 OK

Content example

{
    "validUrl": "https://www.pdftron.com/"
}

Error Responses

Condition : If URL can not be proxied.

Code : 400

Content : { errorMessage: 'Please enter a valid URL and try again.' }

Download a PDF

URL : /pdftron-download?url=

Query Parameters : url=[string] where url is a publicly accessible link.

Method : GET

Success Response

Condition : If URL can be loaded in puppeteer.

Code : 200 OK

Content example

{
    "buffer": "<some image buffer>",
    "pageDimensions": { "width": 1440, "height": 770 }
}

Error Responses

Condition : If URL can not be loaded in puppeteer.

Code : 400

Content : { errorMessage: 'Error taking screenshot from puppeteer' }