Is this a big deal? Certainly not. We used to server trial downloads in a public accessible directory and web server automatically has this feature. However, we want to our user to get *versioned* filenames, as it will be easy for our users to tell which version they downloaded. Implementing resumable downloads in a scripting language is not a trivial task.

Resumable download in Firefox

Resumable Download in Internet Explorer

OK, the Jan rain library is not PHP 5.3 friendly. There are several warnings if you try included consumer test. The library also requires several extensions. To start you’d better read the README first and run the detect.php under its example directory. Fortunately, those warnings are easy to deal with and I won’t repeat them here.

$path = ini_get(’include_path’);
$path = APPLICATION_PATH . ‘/../library/openid-php’ . PATH_SEPARATOR . $path;
ini_set(’include_path’, $path);

The code starts with /openid/try action. It communicates with OpenID provider to obtain a URL that user will be redirected to. It also set the callback to /openid/finish. Note that I created class Application_Model_Account_OpenIDAdapter so that it fits Zend_Auth architecture. In reality, all it does is to write information to user account database and persist it to a storage in choice (such as session or cookie).

Morovia is an Invalid Extension.

difficult to understand uuuh? Obviously you have to put your full domain name - in this case, morovia.com. Otherwise it thinks morovia is the top domain name. But even so, why it is called “extension”? File names have extensions; while domain names have suffixes.

QR Code Image

A QR Code is a 2D barcode that can be scanned by smart phone’s camera. It is capable of encoding large amount of text; however most QR codes encode a few dozen characters. QR Code becomes increasingly popular because smart phones now have decoder programs that read the barcode and act on the content it reads.

So what is the big deal for that? It turns out that QR Code offers a convenient way to encode key information - such as your web site address, email and so on. A smart phone owner can capture the info to his phone by just scanning the QR Code.

You certainly want your web site gets more visits - but how? If you run a restaurant, you can print a QR Code at the bottom of receipt, or in news paper… people who are interest just scan the QR code and visit your web site.

Some more ideas:

1. QR Code on Business Card. There is a popular format called MECARD, which allows contact info to be encoded into a QR Code. A smart phone user scans the barcode and put your contact into his address book. Hey if you are in real estate agent, insurance broker or industry that you’d like everyone to remember you, QR Code is a must.

2. Product Label. If you are a manufacturer it is time to add a QR Code with your web site encoded on the product label. Customers who bought your stuff may scan the barcode and visit your web site. Even more, you can print something like - scan this QR code to get a 10% off coupon.

3. Promotions, Discounts and Coupons. The idea here is to get the user to visit your web site and receive the discount. If you just print a coupon barcode on the newspaper your web site won’t get visited. It is also easier to track users through your web site.

4. E-commerce. QR Code encodes a URL with extra parameters - and users can only see them when they scan the barcode. So you can easily offer different discounts to different audience.

QR code can encode many information: such as web site URL, E-mail address and contact info. This Morovia page lists the common usage in mobile industry. Even better, there is an online QR code generator that create QR codes for free.

If you are looking a solution to add QR Code to Word documents, we’d like to recommend Morovia’s excellent product QR Code Fonts & Encoder 5. With this word addin, creating a QRcode just takes two steps - highlight and convert; all can be done in 1 minute.

In this article, barcode is generated first in a front end script and the image is saved to a disk file. In the backend script the image is loaded and sent to the browser. Sometimes an in-memory solution is preferred, as programers will not have to deal with file permission, clean up and possible privacy issues.

The classic ASP example, which is included in the installer package, is an in-memory solution. It utilizes ADODB.Stream object. It exports barcode images to ADODB.Stream object, then calls Response.BinaryWrite to write all the bytes out. While it looks simple, the ADODB.Stream object’s Read method does not give back a sequence of bytes as defined in PHP. It is actually a COM SafeArray packaged in VARIANT type.

try {
$objBarcode = new COM("Morovia.BarcodeActiveX");
$objBarcode->RasterImageResolution = 96; //Set the resolution to 96 dpi (screen)
$objBarcode->NarrowBarWidth = 15; //Default NarrowBarWidth 15 mils
$objBarcode->BorderStyle = 0; //No border
$objBarcode->ShowComment = false; //No comment
$objBarcode->ShowHRText = false; //No human readable text
// By default the Barcode ActiveX creates margins around the symbol. The margins are around 100 mils
// You can increase or decrease the margins by setting 4 SymbolMargin properties like
$objBarcode->SymbolMarginTop = 100;

// Retrieve input parameters through the URL query string
$objBarcode->Rotation = $_GET["rotation"];
$objBarcode->ShowHRText = (strlen($_GET["showhrtext"])==0 || $_GET['showhrtext']==0) ? 0 : 1;
$objBarcode->Symbology = $_GET["symbology"];
$objBarcode->NarrowBarWidth = $_GET['narrowbarwidth'];

$objBarcode->BarHeight = $_GET['barheight'];
$objBarcode->Message = $_GET['message'];

$objStream = null;
$objBarcode = null;
} catch(Exception $ex) {
header('Content-Type: text/plain');
echo($ex->getMessage());
}

It turns out that the solution is pretty simple - although PHP does not provide direct way to convert a COM safe array to string, it provides a way to iterate the content. Thus, we can write:


foreach ($buffer as $byte) echo chr($byte);


In the place of echo($buffer) statement. It worked.

[id(6)] HRESULT DataMatrixEncodeSet(
        [in] BSTR strDateToEncode,
        [in] LONG sizeID,
        [out,retval] LONG* chunks);

I was quite surprise that I got an “type mistach” error from Invoke function. My code is as below:

args[0].vt = VT_BSTR;
args[0].bstrVal = SysAllocString(L"this is data to encodeencodeencodeencodeencode");
args[1].vt = VT_I4;
args[1].lVal = 0;

dp.cArgs  = 2;   
dp.rgvarg = args;   
dp.cNamedArgs = 0;   
dp.rgdispidNamedArgs = NULL;

VARIANT vaRet;
VariantClear(&vaRet);
EXCEPINFO  exInfo;
unsigned int uErr;
hr = disp->Invoke(dispID[0], IID_NULL, LCID_NEUTRAL,
        DISPATCH_METHOD, &dp, &vaRet, &exInfo, &uErr);
BOOST_CHECK(SUCCEEDED(hr));

After some search, I finally found the cause: the arguments packed in DISPPARAMS must be in reverse order. In other words, the args[] array must be reversed. After I changed that, the error disappeared.

use Win32::OLE;
my $object = Win32::OLE->new(’Morovia.BarcodeActivex’, ”);
$object->{”Symbology”} = 8; #UPC-A symbology
$object->{”ShowComment”} = 0;
$object->{”BarHeight”}=1000;

for(my $number=0; $number<=999; $number++)
{
my $text_number = sprintf(”%03d”, $number);
$object->{”message”} = “81058201″ . $text_number;

print(”exporting image $text_number.\n”);

$object->ExportImage($object->{”message”} . “.jpg”, 1);
}

my $result = `zip all-images.zip *.jpg`;

The code above generates UPC-A barcode images for numbers 81058201xxx where xxx is from 000 to 999. At the end, the code calls zip command to zip all the images files into zip.

Follow the steps below to enable the Developer tab:

1. Click the Microsoft Office button.
2. Choose Word options.
3. Select Popular (at the top left).
4. Check Show Developer tab in the Ribbon.

Our project utilizes a different process, which can’t be managed entirely with GUI. To begin with, we manage our unit tests with boost.test, with each test file built into an executable file. In large projects we have hundreds of test files, and managing them through GUI interface is quite formidable.

Another issue is the frustration with displaying metrics. The interface provided is quite clunky, and you have to navigate thousands of functions and class methods in order to find coverage for the method you are focusing. The color display in the editor has a lot for improvement.

I recently investigated possibilities to collect and analyze code coverage data programmatically. It was a success. I noticed that the documentation on this aspect is quite weak, so I’d like to share some points with readers.

Collecting Data

In order for the code coverage to be collected, the executable must be instrumented. Some web pages I found like this state that link flag –PROFILE is required, while others not mentioning this requirement. In our build system, this link flag triggers the instrumentation. The build system we are using is boost.build, we changed the file msvc.jam slightly to launch instrumentation process once <linkflags>-PROFILE is passed.

Visual Studio documentation calls those related tools “Performance Tools” and they are located at C:\Program Files\Microsoft Visual Studio [Version]\Team Tools\Performance Tools directory. It is recommended to add this path into PATH variable in vcvars.bat so that you gain the access to the command after entering command prompt.

To instrument the executable, run the command:

vsinstr.exe <YOUR_EXE> /COVERAGE

As I stated, this process is added into our build system automatically – if <linkflags>-PROFILE is found, the executable will be instrumented.

Now the second step is to collect data. To collect data you first start vsperfmon process. Because you can run multiple executables in one session, this step is now carried out manually:

start VSPerfMon /COVERAGE /OUTPUT:<REPORT_FILE_NAME>

Here we use start  command to open a separate console, because execution will block the current console.

Now run the tests. Code coverage data will be collected.

After we have done testing, shut down the vsperfmon process:

vsperfcmd –shutdown

After this command is carried out, the coverage data is stored in the file we specified. The coverage file is in a proprietary format with no documentation about its structure. Fortunately, MS allows us to export using Visual Studio or calling code analysis API.

Converting to XML

You can drop the coverage file newly created into Visual Studio. You can not do much with its interface, as you have to navigate many functions to locate the ones you wanted to view. Furthermore, it does not code coverage ratio on source file basis, but rather on method basis.

You can export the XML file from Visual Studio, or use the code I provided below to export programmatically.  Oddly the two give different results – the one exported from Visual Studio is encoded in UTF-16 and with no line endings – I spent a quite a bit time to convert it into a UTF-8 with line endings so that my favorite editor can open it. It looks to me that Visual Studio uses a different method to export, and it might be written in native C++.

The programmatic way that Microsoft wants us to use is through assembly. There are several MSDN blogs on this topic; unfortunately the one I found contain two errors: it failed to point out that symbol path must be set, and the WriteXML call was wrong. I posted my code below:

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.VisualStudio.CodeCoverage;

namespace coverdump
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length != 3)
            {
                Console.WriteLine("Usage: coverdump coverage xml symbolpath");
                return;
            }

            String coveragepath = args[2];
            CoverageInfoManager.SymPath = coveragepath;
            CoverageInfoManager.ExePath = coveragepath;

            // Create a coverage info object from the file
            CoverageInfo ci = CoverageInfoManager.CreateInfoFromFile(args[0]);

            // Ask for the DataSet.  The parameter must be null
            CoverageDS data = ci.BuildDataSet(null);

            // Write to XML
            data.WriteXml(args[1]);
        }
    }
}

I had to overcome some issues not mentioned elsewhere. The first issue is references. You must add reference to two files: Microsoft.VisualStudio.Coverage.Analysis.dll and Microsoft.DbgHelp.manifest. Both are located under C:\Program Files\Microsoft Visual Studio [Version]\Common7\IDE\PrivateAssemblies. When I first ran the code, it complained that the assembly does not match the one requested, and I found that the file Microsoft.DbgHelp.manifest does not match dbghelp.dll. I do not know if the initially not match, or just because a subsequent update. Anyway I have to update the version number as well as remove publicKey attribute in order for the program to run properly.

The third argument is the symbol path and executable path. You can specify multiple paths separated by semicolon. If you work with Visual Studio 2010, the interface changed a little bit as the property SymPath and ExePath are now string arrays.

It is a little bit odd to ask for symbol path, considering that the fact that Visual Studio does not ask for it when loading a coverage file. In other words, the coverage file must contain the path to EXE (and PDB file name can be found in EXE for debug build).

Analyzing Data

PHP is my favorite script language, and I use it to analyze the data. As the first step, my goal is display the code coverage ratio for each source file specified at command line, also produce a code diff that our programmers can view subsequently. This is much better than what we did previously – programmers have to navigate thousands of methods before they can locate useful information. From project management perspective, now we are able to view code coverage ratio on source file basis.

The resulted XML file can be very big – or even huge. The first one I got was 200MBytes out of a mere 15M coverage file. If you load all the file into memory the process can take quite a while. In light of this issue, I choose XMLReader class to read the file – XMLReader reads XML file as a stream. I read all <Method> elements as well as all <SourceFiles> elements.

In order for programmers to view the difference, my script creates another file based on line coverage data. If the code is not covered, it writes a blank line into the file. After all lines are written, the script calls diff –u 100 to produce a diff file between the original and the new source file. The option –u 100 tells the diff to display 100 lines context, which basically produces a diff file containing all original source lines.

In the future we might expand the script to do more reporting. XSLT is an interesting option here.