INFO: WebCapture Service Technical Overview

This article will cover a technical overview of the WingScan WebCapture Service used in 10.5.2 and newer. For information on migrating your application in general, please see:
Migrating a WingScanbased app to 10.5.2

As of 10.5.2, our WingScan WebCapture browser plugins have been replaced by a new local service that will handle interaction with the scanner and uploading the  scanned files to the web server.

Installation

Instead of a plugin, your users will need to run the installer msi:
Kofax.WebCapture.Installer.msi

This is shipped with DotImage and can be found in this location:

C:\Program Files (x86)\Atalasoft\DotImage 10.7\bin\2.0\x86\WebResources\WebCapture\

Many users will find that it works for them to just provide the MSI to users when the application detects that scanning is present, but the service is not installed. If a user with administrative privleges runs the .msi, then service will be isntalled and become immediately available for scanning.

However, for environments where users do not have administrative privledges, or enterprise environments where installation needs to be scripted and/or pushed from Group Policy, The install can be pushed silently:

Enterprise deployment – silent install

msiexec /i Kofax.WebCapture.Installer.msi /quiet

Install location

%PROGRAMDATA%\WebCapture

Permissions Required

MutiUser Environments

If you are installing WebCaptureService on a machine that multiple users log into (Remote Desktop) then you will need to install the WebCaptureService as a system service instead of per user.

If it's already installed, you will first need to uninstall the WebCaptureService from the machine.

To install as a system service, install using the command line (as administrator)

msiexec /I Kofax.WebCapture.Installer.msi INSTALLASSERVICE=1

This will cause the WebCaptureService to install as a system service instead of as a local service under the current user... this should allow WingScan to work for multiple users

Supported Operating Systems

Windows 8.1 and up
Windows Server 2012 and up

NOTE: windows 7 (and earlier), and Windows Server 2008 R2 (and earlier) are NOT supported.

Supported Browsers

Chrome (current version)
Firefox (current Version)
Internet Explorer 11 and Edge
Safari (on MacOS .. supported in 11.1 and newer only)
 

Architecture

WEB PAGE <--> JAVASCRIPT API <-https/http-> WEB CAPTURE SERVICE HOST <--> One or more WebCapture worker

The architecture of the new WingScan is as follows: the hosting web page will include certain Web capture related JavaScript that will initialize the WingScan components and can detect if the web capture service is installed or not.

If it's not installed, the "onScanError" event will fire, giving the web developer an opportunity to direct the user to the .msi (or for enterprise customers, to inform the user to request installation of the service from the IT department, etc...)

see Migrating aWingScan based app to 10.5.2

The JavaScript API communicates with the Web Capture local service host via http/https. Normally, there is no direct interaction required, but for more advanced scripting/control please note the following:

Web Capture Service entry URLs:

http://127.0.0.1:23023/sessions
https://127.0.0.1:23024/sessions

Troubleshooting

There are multiple points at which you can apply logging for troubleshooting purposes:

* JavaScript Logs - Web JavaScript Console
* Web Browser Network Logs - Web Developer Console Network logging
* EZtwain logs - Logging utility: http://www.eztwain.com/eztwain4-diagnosis.htm
* Web Capture Service Logs - WebCapture service

JavaScript Logs
Direct logging in the Web Browser JavaScript console can be enabled by entering the following in the console
 Atalasoft.TraceEnabled = true

Web Capture JavaScript API logs will log the following things:
* Public API calls
* AJAX requests parameters
* Timings

Console logging is supported in IE version 9+ as well as in Chrome and FireFox.

On IE, Chrome, and Firefox hitting F12 while the web browser has focus should bring up the developer tools - select the Console option and you should find the browser-specific JavaScript console.

Network Logging
This is actually not part of WingScan directly, but is a feature of the Web Developer tools of current major browsers. On IE, Chrome, and Firefox hitting F12 while the web browser has focus should bring up the developer tools - select the Network options and you should find the browser-specific network logging tools.

Network logs provide insight into
* Request headers
* Response headers
* Timings

If you prefer to use a dedicated logging tool, Netshark and Fiddler are excellent browser-based network logging tools.

Web Capture Service logs
Installer logs (issues with certificate deployment, etc.)
You can obtain detailed logging of the install process from the .msi by setting logging (verbose) tag and specifying a log file like this:

msiexec /i Kofax.WebCapture.Installer.msi /l*v log.txt

The WebCapture service provides logging utilities, but these are Disabled by default. The low level logging is configured via the following:

Configured through configuration files:

Kofax.WebCapture.Host.exe.log.config
Kofax.WebCapture.ScanWorker.exe.log.config

EXAMPLE:
To log all statements, set the following parameters

DisableLogging=false
Filter="%Severity% >= trace"
Available log levels
trace, debug, info, warning, error, fatal

EZTwain Logs
WingScan is based upon similar TWAIN technology to that in our EZTwain product. It is possible to use the same logging tool designed for EZTwain for WingScan.

The tool is available free from here:
http://www.eztwain.com/eztwain4-diagnosis.htm

You run the logging tool, then perform a request to the page and select scanners/peform a scan... the logging utility will capture the communiation between WingScan and the system TWAIN controller.

This log is good for:
* Providing Excellent low-level TWAIN logs for scanning issues
* Scanning performance problems
* Image processing issues

Original Article:
Q10409 - INFO: WebCapture Service Technical Overview