4.3.2 URL retrieve

Add functions to ‘wwe-url-retrieve-functions’ to do something based on the requested URL such as call ‘wwe-url-retrieve’ with an altered URL or use a different browser with the requested URL.

Some examples of what to run on ‘wwe-url-retrieve-functions’:

• Change the protocol to use https some or all the time
• Download a video with youtube-dl and add that to an EMMS playlist

You can use a combination of retrieve and callback hooks to make powerful plugins.

Each function should take the following arguments:

• URL - The URL to visit. A string which might not yet be a valid or complete URL. Use ‘wwe-valid-url’ on URL if the function expects a protocol.
• SAVE - Whether or not to save the contents of URL. If t or a file name/path, the page is to be saved without displaying; if 'wait, the page isn’t to be saved (no file prompt comes) until a hook in ‘wwe-url-callback-functions’ changes the value of SAVE.
• BUFFER - If non-nil, a buffer to use, a Lisp buffer object.

Functions are called with ‘run-hook-with-args-until-success’, so if no other function is supposed to run after a certain function did its job, that function should return t. Otherwise return nil. Note also the order in which functions are called.