switched from executeScript() to message-based communication between scripts so the content script can be executed repeatedly

background.js

@@ -18,6 +18,7 @@ function onFailure(error) {
   console.log(`background.js: onFailure(): Promise rejected with error '${error}'`);
 }
 
+// actually download an attached  file
 async function downloadFile(url, filename, saveAs=false) {
   console.log(`background.js: downloadFile(): url is '${url}' and filename is '${filename}'`);
   return browser.downloads.download({
@@ -27,57 +28,43 @@ async function downloadFile(url, filename, saveAs=false) {
   });
 }
 
+// sequentially initiate download for each attached file
 async function downloadAllFiles(urlsAndFilenames) {
-  console.log(`background.js: downloadAllFiles(): started with ${JSON.stringify(urlsAndFilenames)}`);
   const currentDate = getCurrentDate();
   
-  
   for (let i = 0; i < urlsAndFilenames.length; i++) {
     // prefix filename
     let prefixedFilename = currentDate + " " + urlsAndFilenames[i].filename;
     console.log(`background.js: downloadAllFiles(): i is ${i}`);
-    if ( i == 0 ) {
     await downloadFile(urlsAndFilenames[i].url, prefixedFilename, true).then(onSuccess, onFailure);
-    } else {
-      downloadFile(urlsAndFilenames[i].url, prefixedFilename, true).then(onSuccess, onFailure);
-    }
   }
 }
 
-function handlePageactionClick(tab, onClickData) {
+// page action handler
-  console.log("background.js: handlePageactionClick(): executing content script");
+function handlePageactionClick(tab) {
+  console.log("background.js: handlePageactionClick(): sending message");
   
   // get base url
-  browser.tabs.query(
+  browser.tabs.query({
-    {
     currentWindow: true, 
      active: true
-    }
+  })
-  )
+  .then(tabs => {
-  .then(
-    tabs => {
     console.log(`background.js: handlePageactionClick(): tab query returned ${JSON.stringify(tabs)}`);
     baseUrl = tabs[0].url;
-    }
+  })
-  )
   
-  // execute content script
+  // send message to content script which will trigger said content script 
-  browser.scripting.executeScript(
+  browser.tabs.sendMessage(
-    {
+    tab.id,
-      files: [ "/contentscript.js" ],
+    "pageAction was clicked"
-      target: 
-      {
-        tabId: tab.id,
-        allFrames: false
-      }
-    }
   )
-  .then(results => {
+  .then(message => {
-    console.log(`background.js: handlePageactionClick(): content script execution successful with results '${JSON.stringify(results)}'`);
+    console.log(`background.js: received a response from contentscript.js with content ${JSON.stringify(message.urlsAndFilenames)}`);
-    results.forEach(r => downloadAllFiles(r.result));
+    downloadAllFiles(message.urlsAndFilenames);
   })
   .catch(error =>
-    console.error(`background.js: handlePageactionClick(): The following error occured while executing a content script: ${error}`)
+    console.error(`background.js: handlePageactionClick(): The following error occured while handling a page action: ${error}`)
   )
 }
 

contentscript.js

@@ -1,14 +1,27 @@
 console.log("contentscript.js started!");
 
+// 
+function handleReceivedMessage(message) {
+  // log received message
+  console.log(`contentscript.js received a message with content ${message}`);
+
+  // execute script regardless of message content
+  const urlsAndFilenames = extractUrlsAndFilenames();
+  clickPrintButton();
+  console.log(`contentscript.js: URLs and filenames extracted ->  ${JSON.stringify(urlsAndFilenames)}`);
+
+  // return data as the resolved Promise's payload
+  return Promise.resolve({ urlsAndFilenames: urlsAndFilenames });
+};
+
+// extract URL and filename for each mail attachment
 function extractUrlsAndFilenames() {
   console.log("contentscript.js: this is extractFileUrlsAndNames()");
   // get the correct frame
   let frame = document.querySelector("iframe.js-mail-content");
 
   // get all divs containing attachments
-  let divs = frame.contentWindow.document.body.querySelectorAll(
+  let divs = frame.contentWindow.document.body.querySelectorAll("div.samoware-mail-message__attach__item[attachment-ref]");
-    "div.samoware-mail-message__attach__item[attachment-ref]"
-  );
 
   // loop over divs and extract attachment information
   let urlsAndFilenames = [];
@@ -26,22 +39,10 @@ function extractUrlsAndFilenames() {
   return urlsAndFilenames;
 }
 
+// trigger a click event on samoware's print button 
 function clickPrintButton() {
-  let printElement = document.querySelector(
+  let printElement = document.querySelector('li[ng-click="printMessage(selectedMessage)"]');
-    'li[ng-click="printMessage(selectedMessage)"]'
-  );
   printElement.click();
 }
 
-const urlsAndFilenames = extractUrlsAndFilenames();
+browser.runtime.onMessage.addListener(handleReceivedMessage);
-console.log(
-  `contentscript.js: URLs and filenames extracted ->  ${JSON.stringify(
-    urlsAndFilenames
-  )}`
-);
-
-clickPrintButton();
-console.log(`contentscript.js: clicked the print button`);
-
-// this last statement is important – it's evaluation value is the return value for the background script
-urlsAndFilenames;

manifest.json

@@ -3,7 +3,7 @@
   "name": "samoware-multisave",
   "version": "1.0",
 
-  "description": "When using the groupware CommuniGate with the web application Samoware, this browser extension saves all attachments from the currently opened email to a directory of the user's choosing, prefixing each entry's filename with the current date. Yep, it's quite specific.",
+  "description": "When using the groupware CommuniGate in combination with the web application Samoware, this browser extension saves all attachments from the currently opened email to a directory of the user's choosing, prefixing each entry's filename with the current date, while also raising a print dialog for the mail body. Yep, it's quite specific.",
   
   "icons": {
     "48": "icons/samovar-48.png",
@@ -34,5 +34,12 @@
     "scripts": [
       "background.js"
     ]
+  },
+
+  "content_scripts": [
+  {
+    "matches": ["https://communigate.aip.de/*"],
+    "js": ["contentscript.js"]
   }
+]
 }