Permalink for PDF of article

Question

Permalink for PDF of article

Hal Atkins

2021年10月4日 02:36

I'm trying to learn if this is possible, and how I might go about implementing it. Our site is a scientific journal, and our published articles follow this permalink structure:

http://ehponline.org/article-slug
i.e. http://ehponline.org/1306796

Every article that we publish has a corresponding PDF that is available for viewing/download. Those PDFs are currently stored outside of the WP Media structure.

What I am wondering is if there is a way to have a permalink URL for each article such as this:

http://ehponline.org/article-slug/pdf
i.e. http://ehponline.org/1306796/pdf

and that page either list the available attachment or being redirected to the file itself.

The goals of doing this would be to:

Create an expected URL for the article PDF for our readers
Make an easier means by which we can track PDF views through Google Analytics

Any ideas of how this might be done would be greatly appreciated.

Topic children rewrite-rules permalinks pdf Wordpress

Category Web

jgraup · Accepted Answer · 2016年11月7日 05:38

Using add_rewrite_endpoint

<?php

if ( ! class_exists( 'PDFRewriteEndpoint' ) ):

    class PDFRewriteEndpoint {

        /**
         * Add actions and filters in constructor.
         */
        public function __construct() {
            add_action( 'parse_request', array ( $this, 'sniff_requests' ), 0 );
            add_action( 'init', array ( $this, 'add_endpoint' ), 0 );
        }

        /**
         * Add rewrite rules.
         */
        public function add_endpoint() {

            // article-slug/pdf/
            add_rewrite_endpoint( 'pdf', EP_PERMALINK | EP_PAGES );

            //////////////////////////////////
            flush_rewrite_rules( true );  //// <---------- REMOVE THIS WHEN DONE TESTING
            //////////////////////////////////
        }

        /**
         * Redirect to PDF page or download
         *
         * @param $wp_query
         */
        public function sniff_requests( $wp_query ) {

            if ( isset( $wp_query->query_vars[ 'pdf' ] ) ) {

                // anything after `/pdf/` like `extra/stuff`

                $pdf_extras = $wp_query->query_vars[ 'pdf' ];
                echo $pdf_extras . PHP_EOL;

                // Do PDF Logic Here

                wp_die('PDF of ' . $wp_query->query_vars['name']);
            }
        }
    }

    // Create the class
    $pdfRewriteEndpoint = new PDFRewriteEndpoint();

endif; // PDFRewriteEndpoint

Using add_rewrite_rule

<?php

if ( ! class_exists( 'PDFRewrite' ) ):

    class PDFRewrite {

        const ENDPOINT_QUERY_PARAM = '____pdf_api';

        /**
         * Add actions and filters in constructor.
         */
        public function __construct() {
            add_filter( 'query_vars', array ( $this, 'add_query_vars' ), 0 );
            add_action( 'parse_request', array ( $this, 'sniff_requests' ), 99 );
            add_action( 'init', array ( $this, 'add_endpoint' ), 0 );
        }

        /**
         * Add our custom query arg to later check in `parse_request`.
         *
         * @param $vars
         *
         * @return array
         */
        public function add_query_vars( $vars ) {
            $vars[] = static::ENDPOINT_QUERY_PARAM;
            return $vars;
        }

        /**
         * Add rewrite rules.
         */
        public function add_endpoint() {

            // article-slug/pdf/
            add_rewrite_rule( "^([^/]+)/pdf/?$", 'index.php?' . static::ENDPOINT_QUERY_PARAM . '=1&name=$matches[1]', 'top' );

            //////////////////////////////////
            flush_rewrite_rules( true );  //// <---------- REMOVE THIS WHEN DONE TESTING
            //////////////////////////////////
        }

        /**
         * Redirect to PDF page or download
         *
         * @param $wp_query
         */
        public function sniff_requests( $wp_query ) {

            global $wp;

            if ( isset( $wp->query_vars[ static::ENDPOINT_QUERY_PARAM ] ) ) {

                 // Do PDF Logic Here

                wp_die('PDF of ' . $wp->query_vars['name']);

                exit;
            }
        }
    }

    // Create the class
    $pdfRewrite = new PDFRewrite();

endif; // PDFRewrite

Rarst · Accepted Answer · 2014年11月6日 15:29

This seems like a suitable use case for rewrite endpoint.

If you create one for pdf (targeting your posts, etc) you will be able to check for the respective query var in template or before template is loaded and output or redirect accordingly.

Not sure about GA part of it, but if you have an idea about it for this URL structure then endpoint will get you there relatively easily.

Permalink for PDF of article

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