Using Scripts

This feature has been deprecated and by default is not available in the workbench interface. To enable proxy scripting please add AllowProxyScripting=true to your resource/conf/screen-scraper.properties file and restart screen-scraper.

Overview

screen-scraper has the ability to run custom-made scripts while the proxy server is running (more information on starting and stopping the server is available). This allows you to setup blacklists, filter web pages, or otherwise manipulate browser requests and server responses. It is recommended that you read about managing and using scripts before continuing.

Using the scripts

The scripts tab is used to associate scripts with a proxy. Depending on when you decide to run your script, certain built in objects will be in scope that are unique to the proxy environment.

Built-in objects

screen-scraper offers a few objects that you can work with in a script in the proxy environment. See the variable scope section and/or API documentation for more details.

• proxySession: This object allows for interaction with the currently running proxy session.
• request: This object allows for interaction with the currently received HTTP request.
• response: This object allows for interaction with the currently received HTTP response.

Variable scope

Depending on when a script gets run different variables may be in scope (available). The table that follows specifies what variables will be in scope depending on when a given script is run.

Debugging scripts

One of the best ways to fix errors is to simply watch the proxy session log (under the log tab in the proxy session) and the error.log file (located in the log directory of screen-scraper's install directory) for script errors. When a problem arises in executing a script screen-scraper will output a series of error-related statements to the logs. Often a good approach in debugging is to build your script bit by bit, running it frequently to ensure that it runs without errors as you add each piece.