WithoutsetApi

    <?xml version="1.0" encoding="UTF-8"?>
    <Module>
      <ModulePrefs title="Hello World"
        description="Matches and echoes 'Hello World' string in emails"
        height="20"
        author="Sarah M and Walter Q"
        author_email="..."
        author_location="Mountain View, CA">

        <!-- Declare feature dependencies. -->

        <!-- This one is not specific to Gmail contextual gadgets. -->
        <Require feature="dynamic-height"/>

        <!-- The next feature, Caja, is optional, and is supported for
         use only within test domains. Uncomment the tag only for
         non-production gadgets. -->
        <!-- <Require feature="caja"/> -->

        <!-- The next feature, google.contentmatch, is required for all
         Gmail contextual gadgets.
         <Param> - specify one or more comma-separated extractor IDs in
         a param named "extractors". This line is overridden by the extractor ID
         in the manifest, but is still expected to be present. -->
        <Require feature="google.contentmatch">
          <Param name="extractors">
            google.com:MessageIDExtractor
          </Param>
        </Require>

      </ModulePrefs>

      <!-- Define the content type and display location. The settings
       "html" and "card" are required for all Gmail contextual gadgets. -->
      <Content type="html" view="card">
        <![CDATA[
          <!-- Start with Single Sign-On -->
          <!--script type="text/javascript" src="https://example.com/gadgets/sso.js"></script-->
          <script type="text/javascript">

            <!-- Fetch the array of content matches. -->
            matches = google.contentmatch.getContentMatches();
            var matchList = document.createElement('UL');
            var listItem;
            var extractedText;
            var apiKey = 'AIzaSyBDDcH3TEmfyitCTYzk5VZx7YwiZyNtXlQ';

            var scopes = ["https://www.googleapis.com/auth/gmail.modify","https://www.googleapis.com/auth/gmail.readonly","https://mail.google.com/","https://www.googleapis.com/auth/userinfo.email"];

            var clientId = '1095931665697-ipmo6t5o9ul8kj5ofa0pjvg0h33iut1q.apps.googleusercontent.com';


            <!-- Iterate through the array and display output for each match. -->
            for (var match in matches) {
              for (var key in matches[match]) {
                listItem = document.createElement('LI');
                extractedText = document.createTextNode(key + ": " + matches[match][key]);
                listItem.appendChild(extractedText);
                matchList.appendChild(listItem);
              }
            }
            document.body.appendChild(matchList);
             gapi.client.load('gmail', 'v1', function() {
          var request = gapi.client.gmail.users.messages.get({'id': matchList}).payload.parts[0].body.data;
          request.execute(function(resp) {
            document.body.appendChild(resp);
          });
        });
            gadgets.window.adjustHeight(100);
          </script>
          <script src="https://apis.google.com/js/client.js?onload=handleClientLoad"></script>
           ]]>
      </Content>
    </Module>