Creation of "Make Messages Downloadable"

v1

osm-org-messages-greasemonkey.user.js

@@ -0,0 +1,77 @@
+// ==UserScript==
+// @name        Make openstreetmap.org messages downloadable
+// @description This script allows to download OSM DMs as .eml-files
+// @version     1
+// @grant       none
+// @copyright   2023, https://github.com/kmpoppe
+// @license     MIT
+// @namespace   https://github.com/OSM-de/osm-org-greasemonkey
+// @updateURL   https://cdn.jsdelivr.net/gh/OSM-de/osm-org-greasemonkey@master/osm-org-messages-greasemonkey.user.js
+// @installURL  https://cdn.jsdelivr.net/gh/OSM-de/osm-org-greasemonkey@master/osm-org-messages-greasemonkey.user.js
+// @downloadURL https://cdn.jsdelivr.net/gh/OSM-de/osm-org-greasemonkey@master/osm-org-messages-greasemonkey.user.js
+// @icon        https://www.openstreetmap.org/assets/favicon-16x16-474476c1b2381628a81361a9e2bf04b936d21f77c59e84b48c6c69ea376fb6cf.png
+// @match       https://www.openstreetmap.org/messages/*
+// ==/UserScript==
+
+var oldHref = document.location.href;
+
+window.onload = function() {
+  modifyContent();
+};
+
+function modifyContent() {
+  // parse the current URI into RegEx matches
+  loc = window.location.toString();
+
+  messageMatch = loc.match(/messages\/(\d+)/);
+  if (messageMatch) {
+    msgId = messageMatch[1];
+    contentHeadObject = document.getElementsByClassName("content-heading");
+    subjectObject = contentHeadObject[0].getElementsByTagName("h1");
+    subjectString = subjectObject[0].innerText;
+    headerInfo = document.getElementsByClassName("mb-3 border-bottom border-grey py-1 d-flex gap-1 flex-wrap");
+    otherUserObject = headerInfo[0].getElementsByTagName("a");
+    otherUserString = otherUserObject[0].innerText;
+    dateTimeObject = headerInfo[0].getElementsByTagName("span");
+    dateTimeString = dateTimeObject[0].innerText;
+    msgContentObject = document.getElementsByClassName("richtext text-break");
+    msgContentString = msgContentObject[0].innerHTML.replaceAll("#", "%23");
+    meObject = document.getElementsByClassName("username");
+    meString = meObject[0].innerHTML.trim();
+
+    innerContentBtns = document.getElementsByClassName("btn btn-primary");
+    direction = "s";
+    if (innerContentBtns.length > 0 && /messages\/(\d+)\/reply/.test(innerContentBtns[0].outerHTML)) {
+      direction = "r";
+    }
+
+    senderString = (direction == "s" ? meString : otherUserString);
+    receiverString = (direction == "r" ? meString : otherUserString);
+
+    dateTimeReg = dateTimeString.match(/(\d+) (January|February|March|April|May|June|July|August|September|October|November|December) (\d{4}) at (\d\d\:\d\d)/);
+    dtObj = new Date(Date.parse(dateTimeReg[1] + " " + dateTimeReg[2].substring(0,3) + " " + dateTimeReg[3] + " " + dateTimeReg[4] + " UTC"));
+
+    // Email creation sourced from https://stackoverflow.com/q/27951843
+    var emlContent = "data:message/rfc822 eml;charset=utf-8,";
+    emlContent += 'To: '+receiverString+'@users.openstreetmap.org\n';
+    emlContent += 'From: '+senderString+'@users.openstreetmap.org\n';
+    emlContent += 'Date: '+dtObj.toString()+'\n';
+    emlContent += 'Subject: '+subjectString+'\n';
+    emlContent += 'X-Unsent: 0'+'\n';
+    emlContent += 'Content-Type: text/html'+'\n';
+    emlContent += ''+'\n';
+    emlContent += msgContentString;
+
+    var encodedUri = encodeURI(emlContent); //encode spaces etc like a url
+    var a = document.createElement('a'); //make a link in document
+    var linkText = document.createTextNode("Download as .eml-file");
+    a.appendChild(linkText);
+    a.href = encodedUri;
+    a.id = 'fileLink';
+    a.download = msgId+'.eml';
+    a.className = "btn btn-primary";
+    a.style = "background-color:#00cf00;border-color:#00cf00";
+    buttonsObject = document.getElementsByClassName("content-body")[0].getElementsByClassName("content-inner")[0].getElementsByTagName("div")[2];
+    buttonsObject.appendChild(a);
+  }
+}