How to Inject a Global with Web Extensions in Manifest V3

Date:


For those of you not familiar with the world of web extension development, a storm is brewing with Chrome. Google will stop support for manifest version 2, which is what the vast majority of web extensions use. Manifest version 3 sees many changes but the largest change is moving from persistent background scripts to service workers. This…is…a…massive…change.

Changes from manifest version 2 to version 3 include:

  • Going from persistent background script to a service worker that can die after 5 minutes
  • No use of <iframe> elements or other DOM APIs from the service worker
  • All APIs have become Promise-based
  • Restrictions on content from a CSP perspective

One function that web extensions often employ is executing scripts upon each new page load. For a web extension like MetaMask, we need to provide a global window.ethereum for dApps to use. So how do we do that with manifest version 3?

As of Chrome v102, developers can define a world property with a value of isolated or main (in the page) for content scripts. While developers should define content_scripts in the extension’s manifest.json file, the main value really only works (due to a Chrome bug) when you programmatically define it from the service worker:

await chrome.scripting.registerContentScripts([
  {
    id: 'inpage',
    matches: ['http://*/*', 'https://*/*'],
    js: ['in-page.js'],
    runAt: 'document_start',
    world: 'MAIN',
  },
]);

In the example above, in-page.js is injected and executed within the main content tab every time a new page is loaded. This in-page.js file sets window.ethereum for all dApps to use. If the world is undefined or isolated, the script would still execute but would do so in an isolated environment.

Manifest version 3 work is quite the slog so please hug your closest extension developer. There are many huge structural changes and navigating those changes is a brutal push!



Source link

Share post:

[tds_leads title_text="Subscribe" input_placeholder="Email address" btn_horiz_align="content-horiz-center" pp_checkbox="yes" pp_msg="SSd2ZSUyMHJlYWQlMjBhbmQlMjBhY2NlcHQlMjB0aGUlMjAlM0NhJTIwaHJlZiUzRCUyMiUyMyUyMiUzRVByaXZhY3klMjBQb2xpY3klM0MlMkZhJTNFLg==" f_title_font_family="653" f_title_font_size="eyJhbGwiOiIyNCIsInBvcnRyYWl0IjoiMjAiLCJsYW5kc2NhcGUiOiIyMiJ9" f_title_font_line_height="1" f_title_font_weight="700" f_title_font_spacing="-1" msg_composer="success" display="column" gap="10" input_padd="eyJhbGwiOiIxNXB4IDEwcHgiLCJsYW5kc2NhcGUiOiIxMnB4IDhweCIsInBvcnRyYWl0IjoiMTBweCA2cHgifQ==" input_border="1" btn_text="I want in" btn_tdicon="tdc-font-tdmp tdc-font-tdmp-arrow-right" btn_icon_size="eyJhbGwiOiIxOSIsImxhbmRzY2FwZSI6IjE3IiwicG9ydHJhaXQiOiIxNSJ9" btn_icon_space="eyJhbGwiOiI1IiwicG9ydHJhaXQiOiIzIn0=" btn_radius="3" input_radius="3" f_msg_font_family="653" f_msg_font_size="eyJhbGwiOiIxMyIsInBvcnRyYWl0IjoiMTIifQ==" f_msg_font_weight="600" f_msg_font_line_height="1.4" f_input_font_family="653" f_input_font_size="eyJhbGwiOiIxNCIsImxhbmRzY2FwZSI6IjEzIiwicG9ydHJhaXQiOiIxMiJ9" f_input_font_line_height="1.2" f_btn_font_family="653" f_input_font_weight="500" f_btn_font_size="eyJhbGwiOiIxMyIsImxhbmRzY2FwZSI6IjEyIiwicG9ydHJhaXQiOiIxMSJ9" f_btn_font_line_height="1.2" f_btn_font_weight="700" f_pp_font_family="653" f_pp_font_size="eyJhbGwiOiIxMyIsImxhbmRzY2FwZSI6IjEyIiwicG9ydHJhaXQiOiIxMSJ9" f_pp_font_line_height="1.2" pp_check_color="#000000" pp_check_color_a="#ec3535" pp_check_color_a_h="#c11f1f" f_btn_font_transform="uppercase" tdc_css="eyJhbGwiOnsibWFyZ2luLWJvdHRvbSI6IjQwIiwiZGlzcGxheSI6IiJ9LCJsYW5kc2NhcGUiOnsibWFyZ2luLWJvdHRvbSI6IjM1IiwiZGlzcGxheSI6IiJ9LCJsYW5kc2NhcGVfbWF4X3dpZHRoIjoxMTQwLCJsYW5kc2NhcGVfbWluX3dpZHRoIjoxMDE5LCJwb3J0cmFpdCI6eyJtYXJnaW4tYm90dG9tIjoiMzAiLCJkaXNwbGF5IjoiIn0sInBvcnRyYWl0X21heF93aWR0aCI6MTAxOCwicG9ydHJhaXRfbWluX3dpZHRoIjo3Njh9" msg_succ_radius="2" btn_bg="#ec3535" btn_bg_h="#c11f1f" title_space="eyJwb3J0cmFpdCI6IjEyIiwibGFuZHNjYXBlIjoiMTQiLCJhbGwiOiIxOCJ9" msg_space="eyJsYW5kc2NhcGUiOiIwIDAgMTJweCJ9" btn_padd="eyJsYW5kc2NhcGUiOiIxMiIsInBvcnRyYWl0IjoiMTBweCJ9" msg_padd="eyJwb3J0cmFpdCI6IjZweCAxMHB4In0="]
spot_imgspot_img

Popular

More like this
Related