Support to capture terminal contents

[kavitha-subr]

Feature Description:

As a developer, I would like the ability to capture the contents of the terminal so that I can identify errors and warnings for further action.
Currently, the only possible way to get terminal contents is to spawn a new terminal and have an event listener listen to the output data. I would like to have this feature without having to create a new terminal.

[tsmaeder]

Would something like this work?

    export interface TerminalObserver {

        /**
         * A regex to match against the latest terminal output.
         */
        readonly outputMatcherRegex: string;
        /**
         * The maximum number of lines to match the regex against. Maximum is 40 lines.
         */
        readonly nrOfLinesToMatch: number;
        /**
         * Invoked when the regex matched against the terminal contents.
         * @param groups The matched groups
         */
        matchOccurred(groups: RegExpMatchArray): void;
    }

    export namespace window {
        export function registerTerminalObserver(observer: TerminalObserver): void;
    }

[kavitha-subr]

Yup, this looks great!

[tsmaeder]

I've made a branch at https://github.com/tsmaeder/theia/tree/13085_terminal_observer with the necessary changes. Here's the source for a plugin using the API:

terminalobserver.zip

[tsmaeder]

To test, you'll have to build & run theia from the branch. To build the plugin, you will have to yarn link the @theia/plugin package. In order to do so, you have to

1. go into the <theia>/packages/plugin folder and type yarn link
2. go in the root folder of the example plugin source and type 'yarn link @theia/plugin`

Then you can just build the plugin and copy the resulting *.theia file into the theia plugins folder.

[kavitha-subr]

Thank you so much! I'll verify if everything works as expected.