How to Invoke WebView Extension from File Type - visual-studio-code

Question

I am creating a VS Code WebView extension that I wish to invoke/trigger when I open a file of a specific file extension name. e.g. MyFile.abc.
Within myExt I added the onFileSystem to the activationEvents within package.json:
{
"name": "myext",
"description": "A Webview API Sample",
"version": "0.0.2",
"publisher": "vscode-myext",
"engines": {
"vscode": "^1.25.0"
},
"categories": [
"Other"
],
"activationEvents": [
"onWebviewPanel:myExt",
"onFileSystem:abc",
"*"
],
"main": "./out/extension.js",
"contributes": {
"commands": [
{
"command": "myExt.start",
"title": "Start myExt ",
"category": "My Ext"
}
]
},
"scripts": {
"vscode:prepublish": "tsc -p ./",
"compile": "tsc -p ./",
"watch": "tsc -w -p ./",
"postinstall": "node ./node_modules/vscode/bin/install"
},
"dependencies": {
"supports-color": "^6.0.0",
"vscode": "^1.1.18"
},
"devDependencies": {
"#types/node": "^10.5.2",
"tslint": "^5.11.0",
"typescript": "^2.9.2"
}
}
When I add "onFileSystem:abc" to activationEvents in myExt I was expecting my webview extension to open anytime I opened a file with the extension .abc however nothing happened.
I then tried the activationEvents setting "*", expecting that my webview extension would open at the start of VSCode but that too did not open my extension.
I am able to open and run my extension through Ctrl+Shift+P as per normal.

Answer 1

I don't think there's any activation event that fires when a file with a specific name or extension is opened. The onFileSystem event you were trying has a different purpose and checks for the scheme of a file.
Normally you would use onLanguage for this, and use the language identifier that your .abc extension is associated with. If it's not a popular file extension, you might need to register it in the contributes.languages section.
I then tried the activationEvents setting "*", expecting that my webview extension would open at the start of VSCode but that too did not open my extension.
The activate() method of your extension should always be called if the activation event is *. I assume by "running it with the command palette" you mean debugging the extension through the extension development host? Unless your extension is in your <User>/.vscode/extensions directory, it wouldn't be included in regular VSCode executions. It should then also be listed in the Extensions panel.

Answer 2

I think that you need to use
"workspaceContains:*.abc" as activationEvents

Answer 3

I think you have to do something for below in package.json
{
"activationEvents": [
"onCommand:"**HERE WILL BE YOUR EXTENSION NAME WHICH YOU REGISTERED**"
],
"contributes": {
"menus": {
"explorer/context": [
{
"when": "resourceLangId == **abc**", // this is the extension of the file where you want to execute your command
"command": "**YOUR COMMAND NAME**",
"title": "Anything relevent title",
"group": "navigation"
}
]
}
}
}

Answer 4

According to custom-editor-sample example by Microsoft, you need to do the following configuration in package.json:
"contributes": {
"customEditors": [
{
"viewType": "catCustoms.catScratch",
"displayName": "Cat Scratch",
"selector": [
{
"filenamePattern": "*.cscratch"
}
]
},