Home/ Questions/Q 174669
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-11T13:33:49+00:00

I used to be able to launch a locally installed helper application by registering

  • 0

I used to be able to launch a locally installed helper application by registering a given mime-type in the Windows registry. This enabled me to allow users to be able to click once on a link to the current install of our internal browser application. This worked fine in Internet Explorer 5 (most of the time) and Firefox but now does not work in Internet Explorer 7.

The filename passed to my shell/open/command is not the full physical path to the downloaded install package. The path parameter I am handed by IE is

'C:\Document and Settings\chq-tomc\Local Settings\Temporary Internet Files\   EIPortal_DEV_2_0_5_4[1].expd'

This unfortunately does not resolve to the physical file when calling FileExists() or when attempting to create a TFileStream object.

The physical path is missing the Internet Explorer hidden caching sub-directory for Temporary Internet Files of 'Content.IE5\ALBKHO3Q' whose absolute path would be expressed as

'C:\Document and Settings\chq-tomc\Local Settings\Temporary Internet Files\    Content.IE5\ALBKHO3Q\EIPortal_DEV_2_0_5_4[1].expd'

Yes, the sub-directories are randomly generated by IE and that should not be a concern so long as IE passes the full path to my helper application, which it unfortunately is not doing.

Installation of the mime helper application is not a concern. It is installed/updated by a global login script for all 10,000+ users worldwide. The mime helper is only invoked when the user clicks on an internal web page with a link to an installation of our Desktop browser application. That install is served back with a mime-type of 'application/x-expeditors'. The registration of the '.expd' / 'application/x-expeditors' mime-type looks like this.

[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.expd]  @='ExpeditorsInstaller' 'Content Type'='application/x-expeditors'  [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ExpeditorsInstaller] 'EditFlags'=hex:00,00,01,00  [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ExpeditorsInstaller\shell]  [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ExpeditorsInstaller\shell\open] @=''  [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ExpeditorsInstaller\shell\open\command] @='\'C:\\projects\\desktop2\\WebInstaller\\WebInstaller.exe\' \'%1\''  [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\MIME\Database\Content Type\application/x-expeditors] 'Extension'='.expd'

I had considered enumerating all of a user’s IE cache entries but I would be concerned with how long it may take to examine them all or that I may end up finding an older cache entry before the current entry I am looking for. However, the bracketed filename suffix '[n]' may be the unique key.

I have tried wininet method GetUrlCacheEntryInfo but that requires the URL, not the virtual path handed over by IE.

My hope is that there is a Shell function that given a virtual path will hand back the physical path.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Some follow-up to close out this question.

    Turned out the real issue was how I was creating the file handle using TFileStream. I changed to open with fmOpenRead or fmShareDenyWrite which solved what turned out to be a file locking issue.

    srcFile := TFileStream.Create(physicalFilename, fmOpenRead or fmShareDenyWrite);
    • 0