Ubuntu (Windows Subsystem for Linux) Apache2 Configuration Overview

So Apache2 running on Ubuntu running on Windows Subsystem for Linux (WSL) on Windows 10 has a different configuration from other Apache2 installs. So there is a mismatch between documentation, if for example one is following Dedoimedo's Apache Web server Complete Guide. The config details are hiding in plain sight on the default index page that appears after a fresh install. Because we are meant to replace that page I am keeping a copy here.

Configuration Overview

Ubuntu's Apache2 default configuration is different from the upstream default configuration, and split into several files optimized for interaction with Ubuntu tools. The configuration system is fully documented in /usr/share/doc/apache2/README.Debian.gz. Refer to this for the full documentation. Documentation for the web server itself can be found by accessing the manual if the apache2-doc package was installed on this server.

The configuration layout for an Apache2 web server installation on Ubuntu systems is as follows:

/etc/apache2/
|-- apache2.conf
|       `--  ports.conf
|-- mods-enabled
|       |-- *.load
|       `-- *.conf
|-- conf-enabled
|       `-- *.conf
|-- sites-enabled
|       `-- *.conf
          

• apache2.conf is the main configuration file. It puts the pieces together by including all remaining configuration files when starting up the web server.
• ports.conf is always included from the main configuration file. It is used to determine the listening ports for incoming connections, and this file can be customized anytime.
• Configuration files in the mods-enabled/, conf-enabled/ and sites-enabled/ directories contain particular configuration snippets which manage modules, global configuration fragments, or virtual host configurations, respectively.
• They are activated by symlinking available configuration files from their respective *-available/ counterparts. These should be managed by using our helpers a2enmod, a2dismod, a2ensite, a2dissite, and a2enconf, a2disconf . See their respective man pages for detailed information.
• The binary is called apache2. Due to the use of environment variables, in the default configuration, apache2 needs to be started/stopped with /etc/init.d/apache2 or apache2ctl. Calling /usr/bin/apache2 directly will not work with the default configuration.

Document Roots

By default, Ubuntu does not allow access through the web browser to any file apart of those located in /var/www, public_html directories (when enabled) and /usr/share (for web applications). If your site is using a web document root located elsewhere (such as in /srv) you may need to whitelist your document root directory in /etc/apache2/apache2.conf.

The default Ubuntu document root is /var/www/html. You can make your own virtual hosts under /var/www. This is different to previous releases which provides better security out of the box.

Installing Apache into Ubuntu running on Windows Subsystem for Linux on Windows 10

Part A - Installing WSL

So in the previous post I discussed the merits of Apache and whilst installable directly onto Windows 10 there is a good case for running it on Linux. But fortunately we don't have to thanks to a new component of Windows 10 called Windows Subsystem for Linux (Wikipedia article) (hereafter WSL) which is more lightweight than a fully virtualised machine (though a VM remains an option).

Microsoft's own documentation is here. To install one can follow instruction on this web page Microsoft - Install the Linux Subsystem on Windows 10 - Microsoft Docs. However, I can supplement with some extra info and a few screenshots because not everything is spelt out and indeed some of it I didn't follow at all :) .

To install 'Windows Subsystem for Linux' one needs to go to the Control Panel->Programs and Features->Turn Windows features on or off

Taking the above update requires a reboot.

Then I opened the Windows Store. Then I searched for Ubuntu and made sure to match the one shown on the Microsoft installation web page, the correct app is published by Canonical Group Limited. Then I clicked Install and it began downloading. Ubuntu is the leading leading distribution or "Distro". Once installed I pinned to Start menu and then clicked the Launch button. A command windows opens and the installation continues

After a while I get a prompt to create a new UNIX username which I did, on the first machine I tried this there was such a long dealy I though the process had hung, but please be patient it will get there. Then it asks for a password which I entered and then confirmed. then I am dropped into a console session. Yea! Try 'cd /' and then 'ls' to see the contents of your root folder.

Part B - Installing Apache

So next we install Apache, and I followed (roughly) the instructions from Digital Ocean and at the prompt I did the following

sudo apt-get update

sudo apt-get install apache2

this completes the install. Now we start the server with

sudo /etc/init.d/apache2 start

Then in a browser naviaget to

http://127.0.0.1

and one should see the Apache2 Ubuntu Default page

By the way, to fans of Virtual Machines (VMs) who are not convinced all I can say in parting is that I had to tidy a user profile of late because it grew massive and I discovered huge VM disk images. WSL allows the native disk filing system to be mounted so there is no need for a separate disk image with WSL.

Installing Apache directly onto Windows 10

So, this blog gets many hits regarding how to use HTTP(S) and also how to parse JSON. It seems that using Excel as a web service client is quite trendy. The REST Api is an increasingly popular web service paradigm. Excel developers should seriously consider structuring their applications and solutions around a smart client GUI interacting with a middle and data tier sitting behind a web server.

In such an architecture, should we use Microsoft IIS for the web server? Well for developers running a desktop edition of Windows, e.g. Windows 10, the version of IIS is not representative of the version of IIS on a Windows Server edition but then Windows Server costs at least a thousand dollars/pounds/euros. The desktop edition will ALWAYS ship with fewer features which can be very frustrating. And there will ALWAYS be a look and feel difference between developer edition and server edition. In this blog post, we'll explore the open source alternative, Apache.

Installing Apache directly onto Windows is a cinch, the XAMPP technology stack which includes not only Apache but also MariaDB (formerly MySql), PHP and Perl. With XAMPP you even get a nice control panel applet to start and stop your server

However, there are two drawbacks with this configuration. Firstly, if you move from your computer to a web hosting company then you will still need Windows; your hosting company might be puzzled as to why after having accepted Apache you chose Windows and not Linux as the OS. Secondly, one will find that a huge amount of Apache documentation is written for a Unix implementation. At this point I will end this post because the next post shows how to install Linux-like Apache.

Excel on the Server? No thanks, Xml ADO recordsets please

I have encountered a variety of what I would call "Excel on the server" technologies and these include Microsoft SharePoint Server but also there is an Apache (and thus open source) Java Apache-POI, I chanced upon the latter whilst looking at StackOverflow bounties. Mulling the use case of generating excel workbooks on a server I think that the majority use case is the creation of reports, and the best way to do this is pivot tables and charts based on those pivot table. But is the creation of pivot tables in an Excel workbook on a server a smart thing to do? If you look at some sample Apachi-POI code it would appear a bit clunky.

In this older post I show worksheet cell contents converted to Xml and then to an ActiveX Data Objects (hereafter ADO) recordset. Use of ADO recordsets as a means to marshalling data between a client desktop and a computer room server should not be underestimated. Indeed, in the era of Visual Basic 6 the N-tier architecture was Windows DNA and all these distributed architectures require some state container/vessel to marshal data from one tier to another. For Windows DNA an ADO recordset that the state marshalling container/vessel.

So I would recommend web services emitting a Xml version of an ADO recordset to an Excel workbook. The magic line of code that eliminates a ton of scripting is the CopyFromRecordset method, it is the penultimate line in the following VBA example. You'll need the Xml to be saved into a file (I have chosen c:\temp\xl_persists_2.xml)

<xml xmlns:x="urn:schemas-microsoft-com:office:excel" 
    xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" 
    xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" 
    xmlns:rs="urn:schemas-microsoft-com:rowset" 
    xmlns:z="#RowsetSchema">
<x:PivotCache>
<x:CacheIndex>1</x:CacheIndex>
<s:Schema id="RowsetSchema">
<s:ElementType name="row" content="eltOnly">
<s:attribute type="Col1"/>
<s:attribute type="Col2"/>
<s:attribute type="Col3"/>
<s:extends type="rs:rowbase"/>
</s:ElementType>
<s:AttributeType name="Col1" rs:name="FirstName">
<s:datatype dt:maxLength="255"/>
</s:AttributeType>
<s:AttributeType name="Col2" rs:name="FamilyName">
<s:datatype dt:maxLength="255"/>
</s:AttributeType>
<s:AttributeType name="Col3" rs:name="Role">
<s:datatype dt:maxLength="255"/>
</s:AttributeType>
</s:Schema>
<rs:data>
<z:row Col1="John" Col2="Snow" Col3="President"/>
<z:row Col1="Ygritte" Col2="Wild" Col3="Vice-President"/>
</rs:data>
</x:PivotCache>
</xml>

For the VBA you'll need Tools->References to Microsoft ActiveX Data Object 6.1 Library (or similar) and Microsoft Xml, v6.0 (or similar)

Function RecordsetAsXml() As String
    '* in this example I'm loading from a file but it can be a webservice.
    
    RecordsetAsXml = VBA.CreateObject("Scripting.FileSystemObject").OpenTextFile("c:\temp\xl_persist_2.xml").ReadAll
End Function

Sub LoadXmlRecordset()

    'Tools->References:Microsoft ActiveX Data Object 6.1 Library
    Dim rs As ADODB.Recordset
    
    'Tools->References:Microsoft Xml, v6.0
    Dim domRecordsetAsXml As MSXML2.DOMDocument60
    Set domRecordsetAsXml = New MSXML2.DOMDocument60
    domRecordsetAsXml.LoadXML RecordsetAsXml
    Debug.Assert domRecordsetAsXml.parseError.ErrorCode = 0

    Dim rs As ADODB.Recordset
    Set rs = New ADODB.Recordset
    rs.Open domRecordsetAsXml
    
    '* placed a little under the original data for comparison
    Dim rngOrigin As Excel.Range
    Set rngOrigin = ThisWorkbook.Worksheets.Item(1).Cells(6, 1)
    
    Dim lFieldLoop As Long
    For lFieldLoop = 0 To rs.Fields.Count - 1
        rngOrigin.Offset(0, lFieldLoop).Value = rs.Fields(lFieldLoop).Name
    Next lFieldLoop
    
    rngOrigin.Offset(1).CopyFromRecordset rs

End Sub

From this point it is very easy to generate a pivot table and charts from the table of data zapped into the worksheet by CopyFromRecordSet. So, I prefer Xml ADO recordsets to Sharepoint or Apache POI generated workbooks.