First commit

.gitignore

+*.zip
+*.user.js

LICENSE

+MIT License
+
+Copyright (c) 2019 Iain Murray
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

make_icons.sh

+#!/bin/sh
+
+# Needs:
+# https://www.imagemagick.org/
+# https://www.gnu.org/software/parallel/  (or just delete the "| parallel")
+
+set -e
+
+for sz in 16 19 38 48 96 128 512 ; do
+    for img in src/icons/*.svg ; do
+        echo convert -density 600 -background none -geometry "$sz"x"$sz" "$img" "${img%.svg}"_"$sz".png
+    done
+done | parallel
+

package.sh

+#!/bin/sh
+
+set -e
+
+EXTENSION=drps_arrows
+SRC=src
+
+# Set working directory to location of this script
+cd $(dirname $(readlink -m "$0"))
+
+VERSION=$(grep '"version":' "$SRC"/manifest.json | sed 's/.*"\([0-9.]*\)".*/\1/')
+OUT="$EXTENSION"-"$VERSION".zip
+
+
+# Stuff specific to this extension:
+USERJS="$EXTENSION"-"$VERSION".user.js
+[ -e "$SRC"/icons/green_arrows_16.png ] || ./make_icons.sh
+
+(cat <<EOF
+// ==UserScript==
+// @name         DRPS Arrows
+// @namespace    https://homepages.inf.ed.ac.uk/imurray2/pt/drps_arrows/
+EOF
+echo '// @version      '"$VERSION" ; \
+cat <<EOF
+// @description  Navigate DRPS sessions with ctrl-left, ctrl-right, ctrl-up. Also add links to course codes in DRPS plain text.
+// @author       Iain Murray
+// @match        *://www.drps.ed.ac.uk/*
+// @grant        none
+// ==/UserScript==
+
+(function() {
+EOF
+    cat "$SRC"/session.js ; \
+    sed -n '/session\.js/{ :a; n; p; ba; }' "$SRC"/content.js ; \
+    echo '})();' ) > "$USERJS"
+echo Created "$USERJS"
+
+
+# Generic zipping:
+rm -f "$OUT"
+cd "$SRC"
+zip -r -FS ../"$OUT" *
+echo Created zip for upload to mozilla addons and Chrome store: "$OUT"
+

src/background.js

+"use strict";
+
+// Assumes shared code in session.js included here through the manifest.
+
+let sessionsRegex = /(\/)([0-9][0-9])(-)([0-9][0-9])(\/)/;
+
+function handleContentHide(request, sender, sendResponse) {
+  chrome.pageAction.setIcon({tabId: sender.tab.id, path: "icons/gray_arrows.svg"});
+  chrome.pageAction.hide(sender.tab.id);
+}
+
+
+function handleContentShow(request, sender, sendResponse) {
+  if (sender.url.search(thisSession) >= 0) {
+    chrome.pageAction.setIcon({tabId: sender.tab.id, path: "icons/gray_arrows.svg"});
+    chrome.pageAction.show(sender.tab.id);
+  } else if (sender.url.match(sessionsRegex)) {
+    if (Number(sender.url.match(sessionsRegex)[0].slice(1, 3)) < Number(thisSession.slice(0, 2))) {
+      chrome.pageAction.setIcon({tabId: sender.tab.id, path: "icons/red_arrows.svg"});
+    } else {
+      chrome.pageAction.setIcon({tabId: sender.tab.id, path: "icons/green_arrows.svg"});
+    }
+    chrome.pageAction.show(sender.tab.id);
+  } else {
+    handleContentHide(request, sender, sendResponse);
+  }
+}
+
+
+let SESSIONS;
+let BASE_URL;
+let TAB;
+function handleMenuInit(request, sender, sendResponse) {
+  let cur;
+  let prev;
+  let next;
+  chrome.tabs.query({active: true, currentWindow: true}, tabs => {
+    TAB = tabs[0];
+    BASE_URL = TAB && TAB.url;
+    if (BASE_URL) {
+      if (BASE_URL.search(thisSession) >= 0) {
+        cur = undefined;
+        prev = sessionString(curStartYear - 1);
+        next = sessionString(curStartYear + 1);
+      } else {
+        let match = BASE_URL.match(sessionsRegex);
+        cur = thisSession;
+        let startYear = Number(match[2]);
+        prev = sessionString(startYear - 1);
+        next = sessionString(startYear + 1);
+      }
+      SESSIONS = {cur: cur, prev: prev, next: next};
+      sendResponse(SESSIONS);
+    }
+  });
+}
+
+
+function handleMenu(request, sender, sendResponse) {
+  let newURL = BASE_URL.replace(sessionsRegex, '$1' + SESSIONS[request.menu] + '$5');
+  chrome.tabs.update(TAB.id, {url: newURL});
+  sendResponse(true);
+}
+
+
+function handleMessage(request, sender, sendResponse) {
+  const dispatch = {
+    'src_content_hide': handleContentHide,
+    'src_content_show': handleContentShow,
+    'src_menu_init': handleMenuInit,
+    'src_menu': handleMenu
+  };
+  let key = "src_" + request.source;
+  if (key in dispatch) {
+    dispatch[key](request, sender, sendResponse);
+  } else {
+    console.log("background.js didn't recognize request", request);
+  }
+  return true;
+};
+chrome.runtime.onMessage.addListener(handleMessage);

src/content.js

+"use strict";
+
+// Everything beneath here could be in a Userscript (for Greasemonkey, TamperMonkey, etc.)
+// ...if concatenate to end of session.js
+
+const URL = location.href;
+const match = URL.match(/[0-9]{2}-[0-9]{2}(?=\/)/);
+const SESSION = match && match[0];
+
+// Navigate sessions with ctrl-left and ctrl-right
+
+if (SESSION) {
+  const y1 = Number(SESSION.slice(0, 2));
+  const prev = sessionString(y1 - 1);
+  const next = sessionString(y1 + 1);
+
+  for (const [key, newSession] of [['Right', next], ['Left', prev], ['Up', thisSession]]) {
+    document.addEventListener('keyup', e => {
+      if ((e.code == ('Arrow' + key)) && (e.ctrlKey || e.metaKey)) {
+        location.href = URL.replace(SESSION, newSession);
+      }
+    });
+  }
+}
+
+
+// Add hyperlinks to course codes and unformatted URLs.
+
+function addLinks(node, regex, urlFn) {
+  for (let curNode of [... node.childNodes]) {
+    if (curNode.nodeType == Node.ELEMENT_NODE) {
+      const skip = ['a', 'style', 'script', 'h1'];
+      const tag = curNode.tagName.toLowerCase();
+      if (skip.indexOf(tag) == -1) {
+        addLinks(curNode, regex, urlFn);
+      }
+    } else if (curNode.nodeType == Node.TEXT_NODE) {
+      let match;
+      while (match = curNode.textContent.match(regex)) { // not ==
+        if (match.index == undefined) {
+          console.log('Problem with matching. Maybe used g in regex?');
+          return;
+        }
+        const nextNode = curNode.splitText(match.index + match[0].length);
+        curNode.textContent = curNode.textContent.slice(0, match.index);
+        let linkNode = document.createElement('a');
+        linkNode.href = urlFn(match[0]);
+        linkNode.innerHTML = match[0];
+        node.insertBefore(linkNode, nextNode);
+        curNode = nextNode;
+      }
+    }
+  }
+}
+
+// There's a trade-off with last character in this regex. Will miss some URLs,
+// but will spuriously pull in punctuation and formatting less often.
+if (SESSION) {
+  const urlRegex = /(https?:\/\/|www\.)[^ \n]+[a-zA-Z0-9/]/;
+  addLinks(document.body, urlRegex, x => (x.slice(0, 4) == 'http') ? x : 'http://' + x);
+  function courseLink(code) {
+    return 'http://www.drps.ed.ac.uk/' + SESSION + '/dpt/cx' + code.toLowerCase() + '.htm';
+  }
+  const courseRegex = /([a-zA-Z]{4}[01][0-9]{4})(?=([^0-9]|$))/;
+  addLinks(document.body, courseRegex, courseLink);
+}

src/icons/.gitignore

+*.png

src/icons/gray_arrows.svg

+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg width="2cm" height="2cm" viewBox="10 9.4 2 1.2"
+ xmlns="http://www.w3.org/2000/svg"
+ xmlns:xlink="http://www.w3.org/1999/xlink">
+<polygon fill="#797979" points="11.2,9.7 11.6,9.7 11.6,9.4 12.0,10.0 11.6,10.6 11.6,10.3 11.2,10.3"/>
+<polygon fill="#797979" points="10.8,9.7 10.4,9.7 10.4,9.4 10.0,10.0 10.4,10.6 10.4,10.3 10.8,10.3"/>
+</svg>

src/icons/green_arrows.svg

+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg width="2cm" height="2cm" viewBox="10 9.4 2 1.2"
+ xmlns="http://www.w3.org/2000/svg"
+ xmlns:xlink="http://www.w3.org/1999/xlink">
+<polygon fill="#77c131" points="11.2,9.7 11.6,9.7 11.6,9.4 12.0,10.0 11.6,10.6 11.6,10.3 11.2,10.3"/>
+<polygon fill="#77c131" points="10.8,9.7 10.4,9.7 10.4,9.4 10.0,10.0 10.4,10.6 10.4,10.3 10.8,10.3"/>
+</svg>

src/icons/red_arrows.svg

+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg width="2cm" height="2cm" viewBox="10 9.4 2 1.2"
+ xmlns="http://www.w3.org/2000/svg"
+ xmlns:xlink="http://www.w3.org/1999/xlink">
+<polygon fill="#F80404" points="11.2,9.7 11.6,9.7 11.6,9.4 12.0,10.0 11.6,10.6 11.6,10.3 11.2,10.3"/>
+<polygon fill="#F80404" points="10.8,9.7 10.4,9.7 10.4,9.4 10.0,10.0 10.4,10.6 10.4,10.3 10.8,10.3"/>
+</svg>

src/manifest.json

+{
+
+  "manifest_version": 2,
+  "name": "DRPS navigation",
+  "version": "0.0.1",
+
+  "description": "Adds a navigate button and keyboard short-cuts when browsing the DRPS. Also creates links in course descriptions that contain plain-text URLs or course codes.",
+
+  "homepage_url": "http://homepages.inf.ed.ac.uk/imurray2/pt/drps_arrows/",
+
+  "permissions": [
+    "activeTab"
+  ],
+
+  "content_scripts": [
+    {
+      "matches": ["*://www.drps.ed.ac.uk/*"],
+      "js": ["session.js", "content.js", "page_messages.js"],
+      "all_frames": false
+    }
+  ],
+
+  "background": {
+    "scripts": ["session.js", "background.js"]
+  },
+
+  "icons": {
+    "16": "icons/red_arrows_16.png",
+    "48": "icons/red_arrows_48.png",
+    "96": "icons/red_arrows_96.png",
+    "128": "icons/red_arrows_128.png",
+    "512": "icons/red_arrows_512.png"
+  },
+
+  "page_action": {
+    "browser_style": false,
+    "default_icon": {
+      "16": "icons/gray_arrows_16.png",
+      "19": "icons/gray_arrows_19.png",
+      "38": "icons/gray_arrows_38.png"
+    },
+    "default_title": "DRPS navigation extension",
+    "default_popup": "menu.html"
+  }
+
+}

src/menu.html

+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<style type="text/css">
+  body {
+    margin-left: 0;
+    margin-right: 0;
+    margin-top: 0.8ex;
+    margin-bottom: 0.8ex;
+    padding: 0;
+    background-color: #fbfbfb;
+    font: caption;
+  }
+  div.item:hover { background-color: #ebebeb; }
+  div.row {
+    user-select: none;
+    -moz-user-select: none;
+    -webkit-user-select: none;
+    margin: 0;
+    padding-left: 1ex;
+    padding-right: 2ex;
+    padding-top: 0.5ex;
+    padding-bottom: 0.5ex;
+    white-space: nowrap;
+  }
+  hr {
+    color : #858585;
+    background-color : #858585;
+    height : 1px;
+    border: 0 solid #858585;
+    padding: 0;
+    margin-left: 0;
+    margin-right: 0;
+    margin-top: 0.5ex;
+    margin-bottom: 0.5ex;
+  }
+</style>
+</head>
+<body>
+    <div id="cur_block">
+    <div class="item row" id="cur"><div style="float: left;">Current Session</div>
+        <div style="float: right;">Ctrl+↑</div><div style="clear: both;"></div></div>
+    <hr>
+    </div>
+    <div class="item row" id="prev"><div style="float: left;">← Previous</div>
+        <div style="float: right;">Ctrl+←</div><div style="clear: both;"></div></div>
+    <div class="item row" id="next"><div style="float: left;">→ Next</div>
+        <div style="float: right;">Ctrl+→</div><div style="clear: both;"></div></div>
+    <hr>
+    <div class="row"><a target="_blank" rel="noopener noreferrer" href="http://homepages.inf.ed.ac.uk/imurray2/pt/drps_arrows/">DRPS arrows extension <span style="font-size: 75%;">(unofficial)</span></a></div>
+    <script src="menu.js"></script>
+</body>
+</html>

src/menu.js

+"use strict";
+
+function formatItem(left, right) {
+  return `<div style="float: left;">${left}</div><div style="float: right;">${right}</div><div style="clear: both;"></div>`
+}
+
+chrome.runtime.sendMessage({source: 'menu_init'}, sessions => {
+  if (sessions.cur) {
+    document.getElementById('cur').innerHTML = formatItem('Current session, ' + sessions.cur, '&nbsp;&nbsp;Ctrl+↑');
+  } else {
+    document.getElementById('cur_block').hidden = true;
+  }
+  document.getElementById('prev').innerHTML = formatItem('← ' + sessions.prev, 'Ctrl+←');
+  document.getElementById('next').innerHTML = formatItem('→ ' + sessions.next, 'Ctrl+→');
+});
+
+document.addEventListener('click', event => {
+  let id = event.target.id || event.target.parentNode.id;
+  if (id != "") {
+    chrome.runtime.sendMessage({source: 'menu', menu: id}, () => window.close());
+  }
+});
+

src/page_messages.js

+"use strict";
+
+// Unless I catch errors, chrome gives error messages when restarting the
+// extension, as it doesn't remove old versions of the content script.
+let listeners = [];
+function killListeners() {
+  for (const [e, action] of listeners) {
+    window.removeEventListener(e, action);
+  }
+  listeners = [];
+}
+
+const hideMessage = () => { try { chrome.runtime.sendMessage({source: 'content_hide'}); } catch { killListeners(); } };
+const showMessage = () => { try { chrome.runtime.sendMessage({source: 'content_show'}); } catch { killListeners(); } };
+
+// The timeout pushes the messages to the end of the queue, so that on extension
+// creation the background script has a chance to start up. In Firefox, the
+// right page actions then appear. In Chrome the content scripts aren't loaded
+// unless the user manually refreshes.
+setTimeout(() => {
+  listeners.push(['pagehide', hideMessage]);
+  listeners.push(['pageshow', showMessage]);
+  for (const [e, action] of listeners) {
+    window.addEventListener(e, action);
+  }
+  chrome.runtime.sendMessage({source: 'content_show'});
+}, 0);

src/session.js

+"use strict";
+
+let curDate = new Date();
+let curYear = Number(String(curDate.getFullYear()).slice(-2));
+let curStartYear;
+// From June, start showing session that starts this year
+if (curDate.getMonth() < 6) {
+  curStartYear = curYear - 1;
+} else {
+  curStartYear = curYear;
+}
+function sessionString(y1) {
+  function f(year) {
+    return ("0" + year).slice(-2);
+  }
+  return f(y1) + '-' + f(y1 + 1);
+}
+let thisSession = sessionString(curStartYear);
+