Determine MIME type from base64

In writing my new Outlook Add-in (Send to Trello), I got stuck on attachments. The first version did not include an attachments option because of two unique problems that compounded each other:

  1. The Office Add-in API no longer provides a Media Type/MIME Type with an attachment request. I am able to get the “blob()” from Office, but other than the file extension there is not a way to determine the type. But sometimes a file does not have an extension, or the extension is wrong, etc.
  2. The Trello API will not let you upload without supplying a MIME type, you cannot just give it a Base64 string as an attachment and let them figure it out.

So, I found out something interesting while researching a workaround. Most every base64 string of a specific file type starts with the same “prolog” of text. Using this, combined with the fallback of the file extensions, I was able to get attachments to work (for the attachment types supported by Trello). So, v1.02 will now include attachments.

Anway, as for the workaround I found, this might be ugly, but wanted to share it anyway:

/**
* Returns the data type based on the base64 string
* @param {String} base64String
* @param {String} fileName
* @returns {String}
*/
detectMimeType(base64String, fileName) {
var ext = fileName.substring(fileName.lastIndexOf(".") + 1);
if (ext === undefined || ext === null || ext === "") ext = "bin";
ext = ext.toLowerCase();
const signatures = {
JVBERi0: "application/pdf",
R0lGODdh: "image/gif",
R0lGODlh: "image/gif",
iVBORw0KGgo: "image/png",
TU0AK: "image/tiff",
"/9j/": "image/jpg",
UEs: "application/vnd.openxmlformats-officedocument.",
PK: "application/zip",
};
for (var s in signatures) {
if (base64String.indexOf(s) === 0) {
var x = signatures[s];
// if an office file format
if (ext.length > 3 && ext.substring(0, 3) === "ppt") {
x += "presentationml.presentation";
} else if (ext.length > 3 && ext.substring(0, 3) === "xls") {
x += "spreadsheetml.sheet";
} else if (ext.length > 3 && ext.substring(0, 3) === "doc") {
x += "wordprocessingml.document";
}
// return
return x;
}
}
// if we are here we can only go off the extensions
const extensions = {
xls: "application/vnd.ms-excel",
ppt: "application/vnd.ms-powerpoint",
doc: "application/msword",
xml: "text/xml",
mpeg: "audio/mpeg",
mpg: "audio/mpeg",
txt: "text/plain",
};
for (var e in extensions) {
if (ext.indexOf(e) === 0) {
var xx = extensions[e];
return xx;
}
}
// if we are here – not sure what type this is
return "unknown";
}

New Outlook Add-in: Send to Trello

I have been using Trello for a while now and one of the features I have found most useful is to take an email I received and turn it into a Kanban item on my backlog to address later. This allows me to archive the email but keeps it on my “Trello radar” as I work at my own pace through my personal backlog.

Recently, Trello removed their add-in from the Microsoft Office store. If you have the add-in installed, you will see this error:

Well, since they say necessity is the mother of all invention and I really had to fill the gap as it is part of my routine, I rolled my own. ūü§ď To add a degree of difficulty, I wrote this in VS Code in Linux running in Windows Subsystem for Linux (WSL). See my previous post. It was a fun exercise as I am on vacation and using the time tom learn new things, engage in self-improvement and relax (coding is relaxing to me ūü§ďūü§ďūü§ď). In the end, I learned something and created something for everyone to enjoy.

Say hello to the recently published: Send to Trello Outlook Add-in.

Give it a try and let me know what you think.

Automating Excel and Add-ins Don’t load

There is a common problem I see when automating Excel from an external .NET application:

You will launch Excel, open a workbook, perform work, and then try to close Excel and find that it remains in memory. You might even have code in your solution¬†to try to re-use existing instance of Excel and find that it uses one of these “zombie” instances that do not have any of the add-ins loaded… and maybe an add-in your code relies on.

The issue is that Excel is not able to close because  the primary thread of your application is holding on to a COM reference. Even adding Marshal.ComReleaseObject() and GC.Collect() like this probably will not improve the situation either:


Marshal.ReleaseComObject(excelWorkbook);
Marshal.ReleaseComObject(excelApp);
excelApp = null;
excelWorkbook = null;
GC.Collect();
GC.Collect();
GC.WaitForPendingFinalizers();
GC.WaitForFullGCComplete();

view raw

COMRelease.cs

hosted with ❤ by GitHub

From my experience, and from what I have gathered is that until the thread is stopped, the COM reference will be locked. Not sure where the issue lies (EXCEL, COM, or .NET), but I have found a workaround to this. What you have to do is terminate your thread. But because you do not want to terminate your application, you need to create a NEW thread. So the following pattern is what I have found works:


OpenFileDialog openFileDialog1 = new OpenFileDialog();
openFileDialog1.Filter = "Excel Files|*.xls*";
DialogResult result = openFileDialog1.ShowDialog();
if (result == DialogResult.OK)
{
new Thread(() =>
{
Excel.Application excelApp = null;
Excel.Workbook excelWorkbook = null;
this.Invoke(new Action(() =>
{
try
{
excelApp = (Microsoft.Office.Interop.Excel.Application)System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application");
}
catch
{
excelApp = new Excel.Application();
}
string workbookPath = openFileDialog1.FileName;
excelWorkbook = excelApp.Workbooks.Open(workbookPath);
excelApp.Visible = true;
}));
Marshal.ReleaseComObject(excelWorkbook);
Marshal.ReleaseComObject(excelApp);
excelApp = null;
excelWorkbook = null;
openFileDialog1 = null;
GC.Collect();
GC.Collect();
GC.WaitForPendingFinalizers();
GC.WaitForFullGCComplete();
}).Start();
}

 

 

JSDoc – Wow, I just learned something cool

As I start to delve deeper into the world of Office.JS and JavaScript, I am having some fits with how things are done and how things are implemented. Besides getting used to a whole new load of terms, finding out that there are more frameworks than there are developers (ok, maybe that is a small exaggeration), or that JavaScript is not “really” object-oriented (and that’s “ok”) is just nearly too much to handle.

Then there is one of my biggest complains with JavaScript is it use of types. You can get in a lot of trouble here and you can even break JavaScript from its root if you really prototype something wrong (see monkey patching).¬†Additionally, scope can be an issue. And then there is Visual Studio 2015 doing it’s best to try to help you with types, but then it fails you. For example, you¬†type “something(dot)” and you expect IntelliSense to come to the rescue – and low and behold, you get what I like to call: “The yellow¬†bangs of hell.“(tm)¬†wlEmoticon-hotsmile.png

yellow-bangs-of-hell.png

I have been coding with this problem thinking I am all alone in this world screaming every time an object, string, or number fails at IntelliSense. Then on an internal Microsoft email thread where the virtues of TypeScript and JavaScript were being contemplated, a whole world was opened before my eyes. Enter JSDoc. Turns out there is an entire specification around this. And even better РVisual Studio 2015 support it. And it is pretty easy to use. Plus type definition is just the tip of the iceberg, there is a LOT more for me to lesrn. But for now, here is an example of how to define a few common types I frequently use:

[code language=”javascript”]
/** @type {XMLDocument} */
var xmlDoc = $.parseXML(ewsResult.value);
/** @type {string} */
var theString;
/** @type {number} */
var myNumber;
[/code]

I have started to use this very recently in my proof of concepts I work on with my customers and I think I just increased my productivity by 50% (or more). Holy cow. wlEmoticon-winkingsmile.png

Great Office.js resource

As you might know (or I hope you do by now), Office Web Add-ins are the new thing. And if you have recently started a project in this new paradigm, you know that it is quite different from Office COM/VSTO/VBA based coding. There is a little bit of a learning curve and some of the new code patterns (namely async)¬†make doing things “the old way” not quite possible. As such¬†this can make getting your head around this programming model a tad tough. And then there is JavaScript too. wlEmoticon-disappointedsmile.png

One of my colleagues, Michael Zlatkovsky (a member of the Office.JS development team at Microsoft) is writing a book: Building Office Add-ins using Office.JS.

book-cover

 

I have had an opportunity to read this book and believe it to be a great resource to understanding the new model. Some of the best parts of the book are where he covers the concepts behind the model, its use of async (and why), how to get around some of the challenges of async with Promises (great chapter), the way to use the Office context objects with some great code patterns, and much, much more.

Michael’s companion website is a must to bookmark as well. Check it out:¬†http://buildingofficeaddins.com.

 

Outlook Export Calendar to Word Add-in

I have been working with a number of customers over the years that come from the world of Lotus Notes. And one of the areas they often complain about with regards to Outlook is the calendar printing options. There are certain things you just cannot do in Outlook from the printing perspective that leaves them wont for more.

So, I have been working over the years on this add-in. This has actually gone through a few iterations Рthe current version 1.2.0.9 is the most recent and most fully-featured version.

The full source code is on GitHub, here. It is totally open source and free to use, modify, etc. Here is what it can do:

addin

  • Printing calendars not available in Outlook by default.
  • The ability to create your own custom calendar
  • The ability to combine calendars for multiple people at once:
    • Displaying only overlapping schedules on the same calendar
    • Displaying all meetings including overlapping meeting
  • The ability to export in daily, weekly, by-weekly, tri-weekly or monthly formats.

The exact details on customization, installation and usage are all covered in the user guide, here.

Developing an On-premises Web Add-in

A customer I was working with wanted help developing a fully on-premises Outlook web add-in. By this, they wanted no part of it to reach out to the Internet (Azure or Office 365). They wanted:

  • To connect to their internal Exchange server
  • An internal IIS website
  • And no references to the Internet (including the Office.js).

This is the topology we are trying to achieve:

topology

If you have developed an Office Web Add-in lately, you find it is inherently biased to the Internet. Even the samples and solutions provided assume Office 365/Exchange and Azure websites. In a default, new Visual Studio solution, the links to the Office.js libraries and stylesheets are all pointing to the web. And, so as you might expect, there are some challenges to getting it to work on-premises only.

This posting covers what you must do to get such a solution to work, including getting past some pitfalls.

  1. First, you have to download the Office.js files locally. And especially for Outlook because the Office.js files that are provided by default in your solution folder (“for offline debugging” as part of VS2015U3 or earlier) are missing some features to work with specific builds of Outlook 2013 and Outlook 2016. You will run into some strange “type” missing and “Office not defined” errors if you forget this step.
  2. Once you have downloaded the Office.JS files, you will delete all the files under the Scripts\Office\1 folder and copy in the contents you downloaded in step 1.
  3. Next, find¬†all your HTML pages where you have the following reference:[code language=”html”]
    <script src="https://appsforoffice.microsoft.com/lib/1/hosted/office.js&quot; type="text/javascript"></script>;
    [/code]
  4. Comment out that line and add the following two lines:
    [code language=”html”]
    <!– <script src="https://appsforoffice.microsoft.com/lib/1/hosted/office.js&quot; type="text/javascript></script> –>
    <script src="../../Scripts/Office/MicrosoftAjax.js" type="text/javascript"></script>;
    <script src="../../Scripts/Office/1.1/office.js" type="text/javascript"></script>;
    [/code]
  5. Once you have developed your solution, you must setup your IIS server. In general here is what you must do:
    • The IIS Server must have ASP.NET installed, it must have .NET4 installed and you must have the Web Application role enabled.
    • Open IIS Manager
    • Create a site, and figure the folder path
    • Convert the site to an Application
    • Apply an SSL certificate that is already trusted on all your client computers or that has a root certificate authority that is trusted on all your client computers. If you browse to your site using HTTPS and you get a RED warning about an untrusted site, then the certificate is not trusted or properly setup.
  6. Next, and this was a major issue to troubleshoot, your Exchange Web Services certificate cannot be expired. If it is, any EWS call you make will return “succeeded” but will be blank – missing data.¬†Digging into the logs you might find an error:¬†“ErrorInvalidClientAccessTokenRequest”¬†The Microsoft Exchange Server Auth Certificate that is used for OAuth needs to be updated. To do this you have to be logged into the Exchange server as administrator:
    • Run this cmdlet to identify the thumbprint of the certificate being used for OAUTH:Get-AuthConfig | FT currentcertificate*
    • Run this cmdlet to identify the thumbprint of certificates used for other Exchange servers (IIS, SMTP, etc.):Get-ExchangeCertificate | Fl *thumb*
    • Run these cmdlets to configure Exchange to use the valid certificate (copy/paste the thumbprint from the Get-ExchangeCertificate output):$today = Get-Date
      Set-AuthConfig -NewCertificateThumbprint newthumbprint -NewCertificateEffectiveDate $today -Force
    • Run this cmdlet to make sure the changes are published to the environmentSet-AuthConfig -PublishCertificate
    • Run this cmdlet to verify the certificate thumbprintGet-AuthConfig | FT currentcertificate*,previouscert*
  7. Now you can deploy your solution to IIS, update your manifest to point to the IIS server (do not forget the HTTPS) and then install it on the Exchange Server Control Panel (ECP) under the Organization / Add-ins option as a mandatory add-in.
  8. Finally, and this last bit is important: IF USING OUTLOOK 2013 or OUTLOOK 2016, YOU MUST BE LOGGED INTO WINDOWS ON THE SAME DOMAIN AS YOUR EMAIL. I know, I know… for some folks this sucks. I have reported this to our product team and they are looking into it. If you are not logged into the same domain controller as your email address is registered, you will not see the advertised add-in. It will load in Outlook Web Access (OWA), but will not appear in Outlook 2013/2016. The exact cause of this problem is unknown, but hopefully it will be addressed in a future version of the product (Exchange or Outlook or both).

Setting up for 100% on-premises is difficult, but it CAN be done. There are a lot of steps, but if you follow the above prescription, you should get it to work. In time, I hope to see this process get easier. But in an online world where Microsoft Office 365 and Azure are main focus, “old fashioned” on-premises solutions are going to¬†require a little more elbow grease.

NOTE: This entry was contributed to by Arthel Bibbens (MSFT) / Exchange PFE. You can follow his posts on this topic here:

 1-GetOrgConfig Administering Office Add-ins within Exchange 2013 and Exchange 2016

blogs.technet.microsoft.com

I recently worked with a developer to deploy an Office add-in within an Exchange 2013 on-premises environment. This project highlighted a capability of Exchange and Outlook that is a huge shift in the way mail add-ins are developed, deployed, and maintained. Let‚Äôs take a look at the key components of Exchange 2013 that support this…

 

Debugging an Office Web Add-in in Production

It is sometimes tough to determine what is happening in a production environment and you need to get logging information from the add-in to see what is happening. How can you do that?

One way is to build a console.log() option into your add-in that looks for a Debug flag in the manifest. So, you will create two manifest, one that enabled Debugging and another than disables it. More on that in a bit. To start, here is the basic class I created in order to handle this:

[code lang=”javascript” collapse=”true” title=”click to expand if the github.com embedding below is not visible.”]
/*!
* logger JavaScript Library v1.0.1
* http://davecra.com
*
* Copyright David E. Craig and other contributors
* Released under the MIT license
* https://tldrlegal.com/license/mit-license
*
* Date: 2016-08-09T12:00EST
*/
var console = (function () {
"use strict";

var console = {};

console.initialize = function () {
///
<summary>
/// Add a textarea/console to the bottom of the page and then setup the logger
/// </summary>

/// <param name="DebugMode" type="Boolean">If debug mode enabled – we show the console for logging</param>
var debugMode = getParameterByName("Debug") == "true";
if (debugMode) {
// add the console to the screen
$("body").append("<textarea id=’log’ style=’width:100%’ cols=’2000′ rows=’7′ wrap=’off’></textarea>");
$("body").append("<button id=’saveLog’>Copy Log to Clipboard</button>");
$("#saveLog").click(function () {
var field = $("#log");
field.select();
document.execCommand("copy");
});
}

console.log = function (msg) {
///
<summary>
/// GLOBAL: Logs to the textarea on the page
/// </summary>

/// <param name="msg" type="string">The message to log</param>
if (debugMode) {
var d = new Date(Date.now());
var current = d.getHours() + ":" + d.getMinutes() + ":" + d.getSeconds();
var data = $("#log").val();
$("#log").val(current + " – " + msg + "\r\n" + data);
}
};
}

function getParameterByName(name) {
///
<summary>
/// Get a parameter form the URL
/// </summary>

/// <param name="name" type="String">Name of the parameter to get from the query string</param>
/// <returns type="String">Value of the paramater</returns>
var url = window.location.href;
name = name.replace(/[\[\]]/g, "\\$&");
var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
results = regex.exec(url);
if (!results) return null;
if (!results[2]) return ”;
return decodeURIComponent(results[2].replace(/\+/g, " "));
}

return console;
})();
[/code]


/*!
* logger JavaScript Library v1.0.1
* http://davecra.com
*
* Copyright David E. Craig and other contributors
* Released under the MIT license
* https://tldrlegal.com/license/mit-license
*
* Date: 2016-08-09T12:00EST
*/
var console = (function () {
"use strict";
var console = {};
console.initialize = function () {
/// <summary>
/// Add a textarea/console to the bottom of the page and then setup the logger
/// </summary>
/// <param name="DebugMode" type="Boolean">If debug mode enabled – we show the console for logging</param>
var debugMode = getParameterByName("Debug") == "true";
if (debugMode) {
// add the console to the screen
$("body").append("<textarea id='log' style='width:100%' cols='2000' rows='7' wrap='off'></textarea>");
$("body").append("<button id='saveLog'>Copy Log to Clipboard</button>");
$("#saveLog").click(function () {
var field = $("#log");
field.select();
document.execCommand("copy");
});
}
console.log = function (msg) {
/// <summary>
/// GLOBAL: Logs to the textarea on the page
/// </summary>
/// <param name="msg" type="string">The message to log</param>
if (debugMode) {
var d = new Date(Date.now());
var current = d.getHours() + ":" + d.getMinutes() + ":" + d.getSeconds();
var data = $("#log").val();
$("#log").val(current + " – " + msg + "\r\n" + data);
}
};
}
function getParameterByName(name) {
/// <summary>
/// Get a parameter form the URL
/// </summary>
/// <param name="name" type="String">Name of the parameter to get from the query string</param>
/// <returns type="String">Value of the paramater</returns>
var url = window.location.href;
name = name.replace(/[\[\]]/g, "\\$&");
var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
results = regex.exec(url);
if (!results) return null;
if (!results[2]) return '';
return decodeURIComponent(results[2].replace(/\+/g, " "));
}
return console;
})();

view raw

console.js

hosted with ❤ by GitHub

To enable logging you will add the following code to your initialize:

[code language=”javascript”]

console.initialize();
console.log("Started…");

[/code]

Once initialized this will add a TEXTAREA to the¬†bottom on the page where the log entries will be loaded. Additionally, it will place a “Copy To Clipboard”¬†button at the bottom that when clicked will copy the contents of the TEXTAREA to the clipboard so that they can be forwarded to you as needed.

Once implemented and initialized, you can add a console.log() anywhere you want in your code to add an entry to the log. Now, how do you turn this on. What this is doing in initialize is to see if the debug flag is set in the Query String of the SourceLocation setting in the Manifest. To turn on debugging, you change the following line as such:

[code language=”xml”]

<DesktopSettings>
<SourceLocation DefaultValue="~remoteAppUrl/MessageRead.html?Debug=true"/>
<RequestedHeight>250</RequestedHeight>
</DesktopSettings>

[/code]

That is it. From this you will be able to share two manifests with your users/administrators. The first one will be your default production manifest and the second one can be loaded if you need debugging information from the add-in.

Office JavaScript API Code Explorers

Recently while preparing an internal Chalk Talk on Office Web Add-in Development, a co-worker presented me with two links I had not seen before and I wanted to share them with everyone:

These Code Explorers are pretty cool in that they contain some common use code patterns that you might find useful in your projects.

excelCodeExplorerCapture

Unfortunately, there does not appear to be one for PowerPoint and or Outlook yet. But the fact they are there for Excel and Word is pretty cool.