Internet
packages
Internet packages are
.cab-based setup programs that are designed to be downloaded from a Web
site. Internet Explorer uses a process known as Internet Component
Download to install your Internet application. The Package and Deployment
Wizard automatically includes information needed for this process in the
packages it creates. www.tartoos.com
There are several types
of Visual Basic applications or components that can be packaged for
Internet deployment, including:
-
ActiveX controls (.ocx
files) that are displayed on a Web page.
-
ActiveX .exe or .dll
files, designed to run on the client or the Web server.
-
ActiveX documents, that
are displayed in place of a Web page.
-
DHTML applications,
client-based applications that link HTML pages to Visual Basic code
through the use of Dynamic HTML.
-
IIS applications,
server-based applications that link HTML pages to an object called a
webclass. The webclass intercepts server requests from the browser and
responds to them with Visual Basic code.
For More Information Extensive
information about the Internet Component Download process can be found in
"Downloading ActiveX Components" in Building Internet Applications in the
Component Tools Guide. www.tartoos.com
Parts
of an Internet Package
There are several files
that are always part of your Internet packages. These include:
-
The primary .cab file for your application.
The primary .cab file for Internet packages is used as the setup program
for your application. The primary .cab file includes project components,
such as the executable or DLL for your application or your .ocx file for
controls, an .inf file referencing secondary cabs and containing safety
and registry information, and all required dependency files that are not
in secondary .cabs. wwww.tartoos.com
-
All required support files.
Support files for an Internet application may include HTML files, Active
Server Pages (.asp) files, graphics files in a variety of formats, or
other files your application must access to run.www.tartoos.com
-
Any secondary .cab files for your
application. In addition to
project files, applications often reference several run-time components,
such as the Visual Basic run-time DLL, individual ActiveX controls, and
data access objects. If these components are available online in
prepackaged .cab files, you can reference those .cab files in your
primary .cab, rather than shipping the files yourself.
Note When
you create a package for an ActiveX control that requires a license key,
the license file (.vbl) is not automatically included in your package. You
must add the file manually on the wizard's Included Files screen.
Secondary .cab files
provide an efficient way to ensure that the user has the most current
version of components. If a newer version of a component in a secondary
.cab file becomes available on the external Web site, users who download
your application will receive the updated version automatically.
Note If
you cannot or do not want your application setup to require a connection
to the Internet, you may place the secondary .cab files on a server within
your intranet. An intranet server often provides for faster downloading
and allows users to download from a secure network.
www.tartoos.com
How
Internet Component Download Works
After you package your
Internet application or component for download, you deploy it to a
specific location on a Web server, from which users can access it.
Usually, your package is referenced as part of an existing Web page — that
is, your control or other component is hosted by a Web page.
When a user accesses the
Web page that hosts your package, the system downloads your package to the
user's computer. The package is verified for safety, unpacked, registered,
installed, and then activated. All of this occurs in the background and is
controlled by the browser.
The Package and
Deployment Wizard plays two parts in the process described above:
-
It packages your
component and its associated files into a compressed (.cab) file that
the browser uses to download your component. The Package and Deployment
Wizard determines which files your project needs to run, gathers those
files, compresses them into a .cab file, and generates the HTML that
points to your component. www.tartoos.com
-
It deploys your
packaged files to the Web server location of your choice. For more
information on deploying your Internet component download package, see
"Application Deployment with the Wizard" later in this chapter.
www.tartoos.com
Safety
Issues
When you prepare Internet
applications and components for download, you must package them into a
file that can be delivered to the user through a browser. In addition, you
must perform a few precautionary steps to ensure users that your
application will not harm their computers. These steps can include:
-
Digitally signing your
components so that users can verify the contents of the component and
identify you as the software's source.
-
Setting safety levels
to vouch that your components will not damage users' computers or
corrupt their data. www.tartoos.com
-
Arranging for licensing
of any components that require it. When you add an ActiveX control to a
Web page, you are distributing it to any users who download the control
from the page. Unless you license the control, there is little to
prevent an end user from taking your control and using it in their own
applications. The license acts as a kind of copyright for your control,
preventing unauthorized use.
Safety settings can be
made within the Package and Deployment Wizard. When you work with an
Internet package, a screen in the wizard asks you to verify safety
settings. This screen appears lists only the objects in your project that
do not implement a safety interface called IObjectSafety.
Note Signing
and licensing must be done outside of the packaging process. You should
arrange licensing for any components before you package the component.
Digital signing can be done after you package the application — the
Package and Deployment Wizard reserves space within the .cab file for
information about the digital signature. www.tartoos.com
Data
Access Components in Internet Packages
If the application for
which you are creating an Internet package contains any of the files
listed in the table below, you must accept the default setting for these
files on the File Source screen. The default setting for each file is to
download it from an alternate location instead of including it in your
package. This ensures that special handling needed for each of these files
will occur.
The files and their
default settings are as follows:
|
File
|
Default Download Location
|
|
Msdaosp.dll
|
http://activex.microsoft.com/controls/vb6/mdac_typ.cab
|
|
Msado15.dll
|
http://activex.microsoft.com/controls/vb6/mdac_typ.cab
|
|
Msadcf.dll
|
http://activex.microsoft.com/controls/vb6/mdac_typ.cab
|
|
Odbc32.dll
|
http://activex.microsoft.com/controls/vb6/mdac_typ.cab
|
|
Msador15.dll
|
http://activex.microsoft.com/controls/vb6/mdac20.cab
|
|
Msadco.dll
|
http://activex.microsoft.com/controls/vb6/mdac20.cab
|
|
مدرسة
الكمبيوتر
