Almost no services implements params overrides

[atighineanu]

So, I tried to test the sender creation feature.
The code looks like this:

url := "slack://A/B/C"
	sender, err := shoutrrr.CreateSender(url)
	if err != nil {
		fmt.Printf("%v", err)
	}
	var hej_da types.Params
	hej_da = make(map[string]string)
	hej_da["channel"] = "random"
	sender.Send("tralala", &hej_da)

NOTE: I have created the "random" channel and added the bot to it. Still, when adding the params to the sender, it still didn't send the message to the desired "random" channel. Instead, it sent it to the one corresponding to one of the tokens (I guess it must be C, not sure).

[piksel]

Yeah, the Params overrides need to implemented in every service, and I think SMTP might be the only service that fully implements it.
Slack, like you used in your code above, does not handle them at all:

shoutrrr/pkg/services/slack/slack.go

Lines 27 to 38 in 7857385

	func (service *Service) Send(message string, params *types.Params) error {
	config := service.config
	if err := validateToken(config.Token); err != nil {
	return err
	}
	if len(message) > maxlength {
	return errors.New("message exceeds max length")
	}
	return service.doSend(config, message)
	}

There should be a generic solution for all services to use by just adding a tag to their config.

Also, what parts can be overridden by params (and that it's that that they are used for) needs to be documented.