Google Apps Script quick hack to extract inline images from Gmail

apps_script_extract_inline_images_from_gmail.js

function fetchInlineImage() {
  var results = GmailApp.search("Subject: Inline Image Test");
  for(var i in results) {
    var thread = results[i];
    messages = thread.getMessages();
    for(var j in messages) {
      var msg = messages[j];
      var pattern = /<img.*src="([^"]*)"[^>]*>/;
      var matches = pattern.exec(msg.getBody());
      
      if(matches) {
        var url = matches[1];
        
        var urlPattern = /^https*\:\/\/.*$/;
        // If this matches, that means this was copied and pasted from a browser and it's a
        // standard URL that we can urlFetch
        if(urlPattern.exec(url)) {
          // NO OP!
        } else {
          // Else this means the user copied and pasted from an OS clipboard and the image 
          // exists on Google's servers. The image can only be retrieved when logged in. Fortunately,
          // if we use URLFetchApp, this will act as a logged in user and be able to URLFetch the image.
          // We'll need to prepend a Gmail URL (subject to change)
          url = "https://mail.google.com/mail/u/0/" + url;         
        }
        
        // TODO - there is one more case that we're not covering - embedded images that newsletters use
        Logger.log("Fetching image from URL: " + url);
        
        var response = UrlFetchApp.fetch(url);
        Logger.log("Response status: " + Utilities.jsonStringify(response.getHeaders()));
          
        var blob = response.getBlob();
        Logger.log("Response blob: " + blob.getBytes().length);
      }
    }
  }    
};