examples/viewer.html

<!doctype html>
<html>
<head>
  <meta charset="utf-8">
  <title>Viewer</title>
  <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no,minimal-ui">
  <link href='https://fonts.googleapis.com/css?family=Questrial' rel='stylesheet' type='text/css'>
  <style>
    html, body {
      overflow: hidden;
    }

    body {
      font-family: 'Questrial', Arial;
    }

    body, viewer {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      overflow: hidden;
      margin: 0;
      padding: 0;
    }

    viewer {
      background: #eee;
    }

    header {
      position: absolute;
      z-index: 1;
      top: 0;
      left: 0;
      right: 0;
      height: 50px;
      background: #4285F4;
      opacity: 0.7;
      color: #fff;
      display: flex;
      flex-direction: row;
      justify-content: flex-start;
      align-items: center;
      padding: 0 8px;
    }

    @media screen and (min-width: 500px) {
      header {
        height: 64px;
      }
    }

    header h1 {
      font-size: 22px;
      flex-grow: 1;
    }

    header .show-container-anchor {
      flex-grow: 0;
      flex-shrink: 0;
      padding: 8px;
    }

    header #visibilityToggle {
      flex-grow: 0;
      flex-shrink: 0;
      padding: 8px;
    }

    .wait {
      position: absolute;
      z-index: 3;
      top: 100px;
      left: 20px;
      font-size: 12px;
    }

    container {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      overflow-x: hidden;
      visibility: hidden;
    }

    viewer[data-show-container="1"] #container1 {
      visibility: visible;
    }

    viewer[data-show-container="1"] #show-container1-anchor {
      text-decoration: underline;
    }

    viewer[data-show-container="2"] #container2 {
      visibility: visible;
    }

    viewer[data-show-container="2"] #show-container2-anchor {
      text-decoration: underline;
    }

    viewer.natural container {
      overflow-y: hidden;
    }

    viewer.virtual container {
      overflow-y: auto;
      -webkit-overflow-scrolling: touch;
    }

    container iframe {
      border: 0;
      margin: 0;
      padding: 0;
      width: 100%;
    }

    viewer.natural container iframe {
      height: 100%;
    }
  </style>

  <script src="./viewer-integr-messaging.js"></script>

  <script>

    var SENTINEL = '__AMP__';

    var allViewers = [];

    function Viewer(containerId, id, visible) {
      this.id = id;
      this.alreadyLoaded_ = false;
      this.stackIndex_ = 0;
      this.viewportType_ = 'natural';  // "natural" or "virtual"
      this.visibilityState_ = visible ? 'visible' : 'hidden';
      this.prerenderSize_ = 1;

      this.isIos_ = /iPhone|iPad|iPod/i.test(window.navigator.userAgent);

      this.viewer = document.querySelector('viewer');
      this.header = document.querySelector('header');
      this.container = document.getElementById(containerId);
      this.iframe = document.createElement('iframe');
      // TODO(dvoytenko): Set to the final value when crbug/577330 is fixed:
      // this.iframe.setAttribute('sandbox',
      //     'allow-popups allow-scripts allow-forms allow-pointer-lock' +
      //     ' allow-popups-to-escape-sandbox allow-same-origin');

      this.visibilityToggle_ = document.getElementById('visibilityToggle');
      this.visibilityToggle_.onclick = function() {
        this.toggleVisibility(this.visibilityState_ != 'visible');
      }.bind(this);
      if (visible) {
        this.updateVisibilityToggle_();
      }

      this.viewer.classList.add(this.viewportType_);

      if (this.viewportType_ == 'natural' && !this.isIos_) {
        this.iframe.setAttribute('scrolling', 'yes');
      } else {
        this.iframe.setAttribute('scrolling', 'no');
      }

      if (this.viewportType_ == 'virtual') {
        this.container.addEventListener('scroll', this.onScroll_.bind(this));
      }
      window.addEventListener('resize', this.onResize_.bind(this));
      window.addEventListener('popstate', this.onPopState_.bind(this));
    };


    Viewer.prototype.start = function() {
      allViewers.push(this);

      var params = {
        history: 1,
        viewportType: this.viewportType_,
        width: this.container./*OK*/offsetWidth,
        height: this.container./*OK*/offsetHeight,
        paddingTop: this.header./*OK*/offsetHeight,
        visibilityState: this.visibilityState_,
        prerenderSize: this.prerenderSize_
      };
      log('Params:' + JSON.stringify(params));

      var url = './article-access.amp.max.html#' + paramsStr(params);
      if (window.location.hash && window.location.hash.length > 1) {
        url += '&' + window.location.hash.substring(1);
      }
      log('AMP URL = ', url);
      this.iframe.style.display = 'none';
      this.container.appendChild(this.iframe);

      // Notice that name can only be set once the IFrame is in the DOM.
      this.iframe.contentWindow.name = SENTINEL + paramsStr(params);

      this.messaging_ = new ViewerMessaging(this.iframe.contentWindow,
          this.processRequest_.bind(this));

      this.iframe.onload = this.loaded_.bind(this);
      setTimeout(function() {
        this.iframe.style.visibility = 'hidden';
        if (this.viewportType_ == 'virtual') {
          this.iframe.style.height = this.container./*OK*/offsetHeight + 'px';
        }
        this.iframe.style.display = '';
        this.iframe.setAttribute('src', url);
      }.bind(this));
    };


    Viewer.prototype.toggleVisibility = function(visible) {
      log('Viewer ' + this.id + ' visibility -> ', visible);
      this.visibilityState_ = visible ? 'visible' : 'hidden';
      this.messaging_.sendRequest('visibilitychange', {
        state: this.visibilityState_,
        prerenderSize: this.prerenderSize
      }, true);
      if (visible) {
        this.updateVisibilityToggle_();
      }
    };


    Viewer.prototype.loaded_ = function() {
      if (this.alreadyLoaded_) {
        return;
      }
      log('AMP Loaded');
      this.alreadyLoaded_ = true;

      var waiter = this.container.querySelector('.wait');
      if (waiter) {
        waiter.parentElement.removeChild(waiter);
      }

      this.iframe.style.display = '';
      this.iframe.style.visibility = '';
    };


    Viewer.prototype.documentReady_ = function() {
      log('AMP document ready');
      this.loaded_();
      return Promise.resolve();
    };


    Viewer.prototype.documentHeight_ = function(documentHeight) {
      log('AMP document height:', documentHeight);
      if (this.viewportType_ == 'virtual') {
        this.iframe.style.height = Math.max(documentHeight,
            this.container./*OK*/offsetHeight) + 'px';
      }
      return Promise.resolve();
    };


    Viewer.prototype.onScroll_ = function() {
      this.messaging_.sendRequest('viewport', {
        scrollTop: this.container./*OK*/scrollTop
      }, false);
    };


    Viewer.prototype.onResize_ = function() {
      log('Resized to ', this.container./*OK*/offsetWidth,
          this.container./*OK*/offsetHeight,
          this.header./*OK*/offsetHeight,
          this.container./*OK*/scrollTop);
      this.messaging_.sendRequest('viewport', {
        scrollTop: this.container./*OK*/scrollTop,
        width: this.container./*OK*/offsetWidth,
        height: this.container./*OK*/offsetHeight,
        paddingTop: this.header./*OK*/offsetHeight
      }, false);
    };


    Viewer.prototype.requestFullOverlay_ = function() {
      log('requestFullOverlay');
      this.header.style.opacity = 0;
      return Promise.resolve();
    };


    Viewer.prototype.cancelFullOverlay_ = function() {
      log('cancelFullOverlay');
      this.header.style.opacity = 1;
      return Promise.resolve();
    };


    Viewer.prototype.pushHistory_ = function(stackIndex) {
      log('push history to ', stackIndex);
      // Super trivial. Only one step allowed.
      if (stackIndex != this.stackIndex_ + 1) {
        throw new Error('Only one step push allowed');
      }
      this.stackIndex_ = stackIndex;
      window.history.pushState({}, '');
    };


    Viewer.prototype.popHistory_ = function(stackIndex) {
      log('pop history at ', stackIndex);
      // Super trivial. Only one step allowed.
      if (stackIndex != this.stackIndex_) {
        throw new Error('Only one step pop allowed');
      }
      this.stackIndex_ = stackIndex;
      window.history.go(-1);
    };


    Viewer.prototype.onPopState_ = function() {
      // Even more trivial. Always assumes that only one step was popped in
      // history.
      this.stackIndex_--;
      this.messaging_.sendRequest('historyPopped', {
        newStackIndex: this.stackIndex_
      }, false);
      log('history popped to ', this.stackIndex_);
    };


    Viewer.prototype.updateVisibilityToggle_ = function() {
      this.visibilityToggle_.textContent = this.visibilityState_ == 'visible' ?
          'Visible' : 'Prerendering';
    };

    Viewer.prototype.broadcast_ = function(message) {
      log('broadcast: ', message);
      var self = this;
      allViewers.forEach(function(viewer) {
        if (viewer != self) {
          viewer.messaging_.sendRequest('broadcast', message, false);
        }
      });
    };


    Viewer.prototype.processRequest_ = function(type, data, awaitResponse) {
      if (type == 'documentLoaded') {
        return this.documentReady_();
      }
      if (type == 'documentResized') {
        return this.documentHeight_(data.height);
      }
      if (type == 'requestFullOverlay') {
        return this.requestFullOverlay_();
      }
      if (type == 'cancelFullOverlay') {
        return this.cancelFullOverlay_();
      }
      if (type == 'pushHistory') {
        return this.pushHistory_(data.stackIndex);
      }
      if (type == 'popHistory') {
        return this.popHistory_(data.stackIndex);
      }
      if (type == 'broadcast') {
        return this.broadcast_(data);
      }
      return Promise.reject('request not supported: ' + type);
    };


    function log() {
      var var_args = Array.prototype.slice.call(arguments, 0);
      var_args.unshift('[VIEWER]');
      console/*OK*/.log.apply(console, var_args);
    }


    function paramsStr(params) {
      var s = '';
      for (var k in params) {
        var v = params[k];
        if (v === null || v === undefined) {
          continue;
        }
        if (s.length > 0) {
          s += '&';
        }
        s += encodeURIComponent(k) + '=' + encodeURIComponent(v);
      }
      return s;
    }


    function loadAmpDoc() {
      new Viewer('container1', '1', true).start();
      addShowContainer('1');

      new Viewer('container2', '2', false).start();
      addShowContainer('2');

      showContainer('1');
    }

    function addShowContainer(id) {
      var anchor = document.getElementById('show-container' + id + '-anchor');
      anchor.onclick = function() {
        showContainer(id);
      };
    }

    function showContainer(id) {
      log('Show container: ', id);
      var viewerEl = document.querySelector('viewer');
      viewerEl.setAttribute('data-show-container', id);
      allViewers.forEach(function(viewer) {
        viewer.toggleVisibility(viewer.id == id);
      });
    }

    window.onload = loadAmpDoc;
  </script>
</head>
<body>
  <viewer>
    <header>
      <h1>Viewer</h1>
      <a class="show-container-anchor" id="show-container1-anchor">One</a>
      <a class="show-container-anchor" id="show-container2-anchor">Two</a>
      <a>|</a>
      <a id="visibilityToggle">Visible</a>
    </header>
    <container id="container1">
      <div class="wait">
        Please wait, the AMP doc will appear here...
      </div>
    </container>
    <container id="container2">
      <div class="wait">
        Please wait, the AMP doc will appear here...
      </div>
    </container>
  </viewer>
</body>
</html>