About Those Frames Part III

No-frames Xpress Client.

In the previous two posts of this series I talked about why I wanted to examine changing the current Frames based interface for enCore, and the non-frames version of the Xpress Login screen that resulted. In this post I'll describe a non-frames version of the Xpress Client itself.

The Xpress client is a fundamental part of the Xpress interface because it is what the user interacts with the most frequently as Guest, Programmer, or Wizard. Since it is so fundamental to the operation of the whole enCore system any changes made should not interfere with the usability.


The client is a typical web page layout with a menu in a header bar and two columns below. The columns hold the text input and output from the MOO on the left and the WEB display generated by the MOO on the right.  In the existing frames based layout this is really very easy to generate with a frameset document whose contents are the output of the verbs on the xpress_client object.


I figured the same kind of changes I made for the Login screen should work, that is replacing the frameset document with an HTML layout that used iframes and CSS. If possible I wanted to avoid having to change anything other than verbs on the client object itself.

A key thing I wanted was to keep the layout the same at any screen size from fullscreen on a desktop monitor to a screen on a smartphone or tablet. I also wanted the columns to resize cleanly as the client window size changes and without adding extraneous scrollbars.  This is handled by the flexbox system like I used for the login.

Keeping the menu bar in place relative to the columns below was tricky and that is handled by a CSS directive called box-sizing. You can read the gory details of what it does here.

So thanks to Google 😀 and lots of experimenting I applied these tools to the same DIV / iframe setup I used for the login screen.

Surprisingly this worked pretty well, once the inevitable tweaks to make it look the same and behave well at multiple screen sizes were made of course. 

Here is the resulting CSS:

<style>
/*I love me some border-box*/
       * {
        box-sizing: border-box;
       }

       /*Just removing default browser padding/margin*/
        html,
        body {
            padding: 0;
            margin: 0;
            color: #ebebeb;
  }
        /*Flexbox gives us the flexiness we need.
        The top just stays put as there is no scrolling on the body due to the page
        never exceeding viewport height*/
       .menu-frame {
            display: flex;
            align-items: center;
            justify-content: center;
            background-color: darkgreen;
            font-size: 3rem;
            position: relative;
            z-index: 10;
            height: 65px;
        }
        /*This is our main wrapping element, it's made 100vh high to ensure
        it is always the correct size and then moved into place and padded 
        with negative margin and padding*/
        .Container {
            display: flex;
            overflow: hidden;
            height: 100vh;
            margin-top: -65px;
            padding-top: 65px;
            position: relative;
            width: 100%;
            backface-visibility: hidden;
            will-change: overflow;
        }

        .java-frame,
        .web-frame {
            overflow: hidden;
            height: auto;
            padding-bottom: 0.5rem;
        }

        .java-frame {
            width: 50%;
            background-color: white;
        }

        .web-frame {
            flex:1;
            background-color: white;
        }
</style>

I modified the Xpress_Client object to get this code from a .CSS property for easy editing.

The only verb I needed to modify was :vertical_layout horizontal_layout and here is the modified verb that resulted:

"===========================================================";
"Copyright (C) 1999-2004, Jan Rune Holmevik";
"Generates the main enCore Xpress client user screen using three frames";
"Modified to use iframes and DIVs instead of frames";
"KRJ June 2017";
"Vertical layout only!";
"===========================================================";
if (caller != $httpd)
  return E_PERM;
endif
user = args[1];
html = {};
base_url = tostr("http://", $network.site, ":", $network.webport, "/Xpress_client/");
menu = tostr(base_url, "menu.html");
java = tostr(base_url, "java.html");
web = tostr(base_url, "web.html");
html = $list_utils:append(html, this.CSS);
html = {@html, "  <div class=\"menu-frame\">"};
html = {@html, tostr("               <iframe src=\"", menu, "\" name=\"", this.menu_frame, "\" width=\"100%\"  height=\"100%\" noresize=\"noresize\" scrolling=\"no\" marginwidth=\"0\" marginheight=\"0\" frameborder=\"", this.frameborder, "\"></iframe>")};
html = {@html, "  </div>"};
html = {@html, "  <div class=\"Container\">"};
html = {@html, "      <div class=\"java-frame\">"};
html = {@html, tostr("                    <iframe src=\"", java, "\" name=\"", this.java_frame, "\"height=\"100%\" width=\"100%\" scrolling=\"no\" marginwidth=\"0\" marginheight=\"0\" frameborder=\"", this.frameborder, "\"> </iframe>")};
html = {@html, "      </div>"};
html = {@html, "      <div class=\"web-frame\">"};
html = {@html, tostr("                    <iframe src=\"", web, "\" name=\"", this.web_frame, "\" height=\"100%\" width=\"100%\" scrolling=\"auto\" marginwidth=\"", this.frame_marginwidth, "\" marginheight=\"", this.frame_marginheight, "\" frameborder=\"", this.frameborder, "\"> </iframe>")};
html = {@html, "      </div> "};
html = {@html, "  </div>"};
result = this:build(user, html, tostr($httpd.server_name, $core_version), "", "", "", "", this.doctype_frameset);
return result;
"Last modified Sat Jun 17 10:54:40 2017 MDT by Wizard (#2).";


Now the existing Xpress_Client has lots of options for changing the display. Things like whether the client is aligned vertically or horizontally and how big the text display is relative to the web display.  To keep things simple the no-frames client only handles the vertical display, which I think most people use anyways.  Allowing those settings to be changed I will leave as an exercise for the reader 😀

Again to test this safely I did an "@dump with create $Xpress_Client", created a new enCore_CGI_Application object called Xpress_Client_Noframes, pasted the @dump into it making an exact copy of the original which I could modify, and then replaced the object number in #0 for the Xpress_Client with the new object. If it didn't work, more times than not frankly, I would just change the object number in #0 back to the original using the text client and still be able to login with the old client. 

This same system should be able to be used for any of the utilities in enCore too. Some of them like the Program Editor, Help Browser, and Mail Client would be tricky given the number of frames they use but I don't see any reason they couldn't be converted in a similar way.

I hope this client will be useful.

Let me know if you try it and how it works, and as always suggestions and critiques are welcome.

Thanks for reading.
KJ 

About those frames... Part II

Happy Canada Day!

Previously I wrote about why I wanted to examine changing the current Frames based interface for enCore.

After much experimentation, reading up on "current" web development tools, plus a dash of hair pulling, some heavy coffee consumption, and staring at the ceiling going "Why me..." for longer than my wife thought healthy 😆, I have a no-frames version of both the login page and the Xpress Client.


I'll start with the Login page first. Mainly because it is just a two column layout with one fixed page, the welcome page, and the login page. The welcome page is a static html file and the login screen is built by a verb on the Xpress_login object and is also basically an html file.

I experimented with a pure html/CSS/javascript design but I couldn't make it robust. That is it was difficult to make it work without changing more of the MOO code associated with the login object itself. So following my "If it isn't broke don't fix it "plan, I looked for ways to use the existing functionality as much as possible.

The best option turned out to be the last remaining "frame" allowed in current web development, the lowly iframe!

I replaced the frameset with a page using divs that held two iframes whose source is the output of the two verbs on the Xpress_login object.  The problem was then to arrange the display of the page in such a way that extraneous scrollbars from the iframes were removed  and the page would resize without getting too badly messed up.  This took a while to do and much of what I tried looked OK at full screen but scrambled badly when the browser screen was shrunk to what a mobile or tablet user would see..

However, since we need to be using HTML5 capable browsers anyways I figured I might as well use some of the newer CSS tools. Flexbox and viewport relative sizes were the key.

The resulting page is mobile friendly, and does not need any javascript at all.  I put the required CSS in a property on the object called login_css, and added it to the html being generated by the verb.
It still uses two vertical columns and the login column is a fixed size but that could be changed using flexbox settings in the CSS if desired.

Here is the revised verb on Xpress_Login:

"===========================================================";
"Copyright (C) 2001-2004, Jan Rune Holmevik";
"Generates the main enCore Xpress Login Screen";
"Revised to us a defined welcome page named on this.welcome_page";
"KRJ Sep 3, 2015";
"Revised to replace Frame set layout with CSS/iframe";
"KRJ June 9, 2017";
"===========================================================";
if (caller != $httpd)
  return E_PERM;
endif
{user, ?message = ""} = args;
html = {};
base_url = tostr($encore_web_utils:baseurl(), "/Xpress_Login/");
login = tostr(base_url, "login");
"Revised Welcome Screen to use locally hosted webpage";
"Set page name in this.welcome_page";
welcome = tostr($xpress_client.external_baseurl, this.welcome_page);
if (message)
  message = tostr("onload=\"", message, "\"");
endif
html = $list_utils:append(html, this.login_css);
html = {@html, "<body>"};
html = {@html, "    <div id=\"wrap\">"};
html = {@html, "        <div id=\"login-frame\">"};
html = {@html, tostr("               <iframe src=\"", login, "\" name=\"login\" width=\"100%\" height=\"100%\" noresize=\"noresize\" marginwidth=\"", this.frame_marginwidth, "\" marginheight=\"", this.frame_marginheight, "\" frameborder=\"", this.frameborder, "\" title=\"Login frame\"></iframe>")};
html = {@html, "        </div>"};
html = {@html, "        <div id=\"welcome-frame\">"};
html = {@html, tostr("               <iframe src=\"", welcome, "\" name=\"welcome\" width=\"100%\" height=\"100%\" marginwidth=\"", this.frame_marginwidth, "\" marginheight=\"", this.frame_marginheight, "\" frameborder=\"", this.frameborder, "\" title=\"Welcome screen\"></iframe>")};
html = {@html, "        </div>"};
html = {@html, "    </div>"};
html = {@html, "</body>"};
html = this:build(user, html, "Login", message, "", "", "", this.doctype_frameset);
return html;
"Last modified Fri Jun  9 21:17:55 2017 MDT by Wizard (#2).";
"===========================================================";

And here is the CSS data:

<style>
        body,
 html {
     margin:0;
     padding:0;
     color:#000;
     background:grey;
 }
 #wrap {
     display: flex;
     height:100%;
 }
 #welcome-frame {
     flex: 1;  /* grow */
     background:white;
 }
 #login-frame {
     height:450px;/* fall back for old browsers */
     height:100vh;
            flex: 0 0 200px; /* do not grow, do not shrink, start at 200px */
 }
</style>

Note that this must be stored in .login_css as a list of strings. I used the object editor to store the CSS as a description and then copied that over using the program editor.

The magic here is the way the CSS "display:flex" allows the columns to dynamically resize as the browser window does. Because the CSS is held in a separate property it can be edited and adjusted without messing with the verb so lots of customization is possible.

To test this safely I did an "@dump with create $Xpress_Login", created a new enCore_CGI_Application object called Xpress_Login_Noframes, pasted the @dump into it making an exact copy of the original, then replaced the object number in #0 for the Xpress_Login with the new object. That way, as I messed things up (which happend A LOT) I could change the object number back to the default value when logged in through the text only client, and still be able to use Xpress. 

Next time I'll discuss the more complicated layout for the Xpress_Client.

Thanks for reading
KJ