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Making a Trac install work on Apache 2.2/Python 2.6/win32, 2010 edition

Lars Erik Jordet — Mon, 25 Jan 2010 11:14:25 +0000

About 10 months ago I wrote a short article on getting Trac to work on Python 2.6 and Windows. Recently I updated the install, and took a look at how the situation is now.

This guide assumes you have a working install of Trac on Python 2.5/mod_python/Apache2.2 already, as described in the Trac install guide, and that Python 2.6 is installed.

What needs to be done:

Install Python 2.6 and Trac for 2.6
Build a new version of mod_python
Optionally Replace Apache DLLs (mostly if you followed my previous guide)

Required software

You’ll need Visual C++ 2008 Express Edition or any retail version of VS 2008 if you want to build your own mod_python for 2.6 (I’ll provide a precompiled one in this post).

Preparing

Install Python 2.6 and Trac on 2.6 (using “ easy_install trac” is recommended)

You’ll probably also want to easy_install Pygments for source highlighting.

Building mod_python for 2.6

This guide to mod_python covers the creation and installation of a compatible version of the module.

At this point, you should be able to restart Apache and load up your “old” Trac on Python 2.6, but with the error message that “svn” support is not installed.

A pre-built version of this can be found here: mod_python-3.3.2-dev-20080819.win32-py2.6.exe

Python SVN bindings

My old guide had instructions on how to build these yourself, but after that article was made, “official” Python 2.6 bindings have been released.

Most recent version as of this writing is the SVN 1.6.6 version of the bindings.

Replacing Apache DLLs to make libsvn work

Note: Only use these instructions if you experience problems, and/or you’re running a self-built version of the Python SVN bindings already.

There’s a slight difference between libapr-1.dll as supplied with Apache 2.2 and the one we built together with libsvn, so the fix is to replace the one in your Apache2.2\bin folder with the one from your Python2.6\Lib\site-packages\libsvn folder (copy the libsvn_*.dlls from the same folder into the Apache2.2\bin folder if you still get problems).

Restarting Apache now should make Trac work fully, with Subversion support.

Printing to PDF from VBA in Excel

Lars Erik Jordet — Mon, 27 Jul 2009 12:50:35 +0000

Creating a PDF from Excel typically requires printing to the “Adobe PDF” printer, selecting the location and file name to save the .pdf as, and finally getting the newly created PDF opened in Acrobat. Automating this is not very straight-forward, and took quite a while to get “right”.

Background

There is no direct COM API that can be used to tell Acrobat to “convert this sheet to PDF please”, and all the solutions I’ve found on the net have been missing pieces of the puzzle (i.e. lots of hardcoded values, only works on the computer they were made on, or requires you to do manual steps before you can start.)

The most common manual step is that you have to uncheck “Don’t send fonts to Adobe PDF”, or as it’s called in recent versions of Acrobat:

Adobe PDF setting: Use system fonts

The problem here is that this setting is in no way persistent, often resetting to its checked state – and there is no registry setting or .ini file setting to force it unchecked.

What you’ll need

As usual, these are the specific versions I use – other versions should work just as well.

Excel 2003
Adobe Acrobat 8
A printer with a PostScript driver (you can also install a dummy printer if you don’t have a “real” printer)

The code

Some of this code is based on this PCreview.co.uk forums post (I can’t remember if this was my original source, but it’s the closest I can find)

You’ll need the file cAcroDist.cls, a class that handles the Distiller events – either import the linked file, or create a new class in VBA and paste the following:

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Option Explicit

Public WithEvents odist As PdfDistiller
Attribute odist.VB_VarHelpID = -1
Dim StartTime As Date

Private Sub Class_Initialize()
Set odist = New PdfDistiller
End Sub

Private Sub odist_OnJobDone(ByVal strInputPostScript As String, ByVal strOutputPDF As String)
Kill strInputPostScript ' deletes the input postscript, since it's not needed after PDF is made
End Sub

Private Sub odist_OnJobFail(ByVal strInputPostScript As String, ByVal strOutputPDF As String)
End Sub

Private Sub odist_OnJobStart(ByVal strInputPostScript As String, ByVal strOutputPDF As String)
End Sub

On to the PDF producing code – either use the code below, or import this handy pre-made module: PrintToPDF.bas (note that this needs some manual changes).

In a new module, create the following Sub:

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Sub PrintToPDF(sPDFFileName, SheetName)

Dim sPSFileName As String 'Name of PS to be created
Dim sJobOptions As String
Dim sCurrentPrinter As String 'Same current printer choice to resume at end
Dim sPDFVersionAndPort As String 'Version of Adobe
Dim sDummyPrinter As String ' Need a dummy printer to produce the PS
Dim appDist As cAcroDist

Set appDist = New cAcroDist
sCurrentPrinter = Application.ActivePrinter 'Save the currently active printer
sDummyPrinter = NetworkPrinter("Dummy Printer Name") ' Change this to match an installed PS-capable printer driver
Application.ActivePrinter = sDummyPrinter
sPSFileName = ThisWorkbook.Path & ThisWorkbook.Name & ".ps" 'Name of PS file
ThisWorkbook.Sheets(SheetName).PrintOut ActivePrinter:=sDummyPrinter, _
PrintToFile:=True, PrToFileName:=sPSFileName 'Prints to PS

Call appDist.odist.FileToPDF(sPSFileName, sPDFFileName, sJobOptions) 'Creates PDF

On Error Resume Next
Kill sPSFileName 'Removes PS
On Error GoTo 0

Application.ActivePrinter = sCurrentPrinter 'Change back to the original printer
End Sub

This procedure finds a specifically named printer, uses its driver to produce a PostScript file, then uses Acrobat Distiller to convert the .ps to .pdf. You will need to add a reference to Acrobat Distiller manually in the VBA editor.

Finally, we need the NetworkPrinter function, which locates which port a printer is on – you CAN hardcode sDummyPrinter to something like “HP Deskjet on Ne03:”, but that will only work on computers that have the printer on that exact port. The NetworkPrinter function – slightly modified solves this:

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Dim Prt_On As String

Function NetworkPrinter(ByVal myprinter As String)
On Error Resume Next

Dim NetWork As Variant
Dim X As Integer
Prt_On = " On "
'/// Define NetWork Array \\\
NetWork = Array("Ne00:", "Ne01:", "Ne02:", "Ne03:", "Ne04:", _
"Ne05:", "Ne06:", "Ne07:", "Ne08:", _
"Ne09:", "Ne10:", "Ne11:", "Ne12:", _
"Ne13:", "Ne14:", "Ne15:", "Ne16:", _
"LPT1:", "LPT2:", "File:", "SMC100:", _
"XPSPort:")
'Setup printer to Print
X = 0
TryAgain:
On Error Resume Next
'Printer
Application.ActivePrinter = myprinter & Prt_On & NetWork(X)
If Err.Number <> 0 And X < UBound(NetWork) Then
X = X + 1
GoTo TryAgain
ElseIf Err.Number <> 0 And X > UBound(NetWork) - 1 Then
GoTo PrtError
End If
On Error GoTo 0
NetworkPrinter = myprinter & Prt_On & NetWork(X)
errorExit:
Exit Function
PrtError:
'no printer found
NetworkPrinter = ""
Resume errorExit
End Function

This is also defined in PrintToPDF.bas linked above.

Example use

To convert the “Report” sheet in the currently active workbook to a PDF, use this code:

1	PrintToPDF "C:\MyReport.pdf", "Report"

Troubleshooting

No PDF produced

If the printer you use for conversion doesn’t support PostScript, you’ll only end up with a text file called MyReport.txt (following the example above) containing an error message. Change to a different printer to avoid this – alternatively install a fake printer (see next section) to get a compatible driver.

PDF produced has paper size “letter”, regardless of settings

I’m still working on fixing that one…

Installing a fake printer

From Start -> Printers and Faxes -> Add a printer

Installing a fake printer, step 1/6

Installing a fake printer, step 2/6

Installing a fake printer, step 3/6

Installing a fake printer, step 4/6

Installing a fake printer, step 5/6

Installing a fake printer, step 6/6

In short, add a new local printer on LPT1: – don’t search for PnP printers – using a random printer driver with PS in the name (I used the HP Color LaserJet PS – I’m not sure if a non-color printer would work, too), and don’t print a test page. It would probably be possible to share this printer with a network and have everyone install it to have a unified way of printing on a set of computers, but I haven’t tested this.

Fixing a RAID1 that suddenly becomes write protected (64 bit Windows)

Lars Erik Jordet — Thu, 14 May 2009 17:34:34 +0000

Today, after rebooting from some Windows updates, my RAID1 disk suddenly was write protected – but a way to change it was nowhere to be found. After some digging, I found that others have reported the same problem.

Background

As far as I can tell, it seems to be a weakness in the 64-bit drivers for the on-board RAID on some motherboards that causes it. For the record, mine is a Gigabyte GA-EP45-UD3P, and I’m running Windows 7 RC (7100) 64bit, but it seems to be reported for all 64 bit versions of Windows. Anyhow, the fix itself is simple, and seems to stick over reboots, and hopefully it’s permanently fixed.

Fixing the problem

To solve the problem, we need to open an elevated command prompt; in both Windows 7 and Vista, you do this easily by hitting the Windows button, typing “cmd”, right-clicking the “C:\ cmd” search result, and selecting “Run as administrator”. In Windows 7 you can also find Command Prompt in the Start menu and Ctrl-Shift-click it, to open it elevated.

(Disclaimer: The DISKPART tool can potentially remove/create partitions on your hard drive, so be 100% certain what you’re doing before you hit Enter)

In the elevated Command Prompt, type “diskpart” and press enter:

1	C:\> diskpart

On the diskpart prompt, list your volumes:

1	DISKPART> list volume

In my case, the volume on my RAID was volume 4, so I selected it:

1	DISKPART> select volume 4

…and then I marked it writeable like this:

1	DISKPART> attributes volume clear readonly

Here’s the entire segment in a screenshot (note that I did a couple of extra steps selecting the disk, this is apparently not necessary):

DISKPART commands for removing read-only