Forum OpenACS Q&A: "Logged In?"-Datasource and Template

I'm not familiar with the old ACS's, but in OpenACS you can find a good sample from the installation default home page:

index.adp:

      <p>
      <if @user_id@ gt 0>
        You are currently logged in as @name@ (<a href="/register/">change
        login</a>).
      </if>
      <else>
        Start by <b>logging in</b> in the box on the right, using the email
        address and password that you have just specified for the
        administrator.
      </else>
      </p>

In the <else> part you could have a link to yoursite.com/register or a form for the registration.

There might be a simple include that would render the login form, but I'm not sure of that. Maybe someone could confirm if this is true?

then, in index.tcl, you have to prepare the data source:

set user_id [ad_get_user_id]
if { $user_id == 0 } {
    set user_id ""
}

If you're not familiar with the adp/tcl file pairs, you might want to read the docs for ACS Templating (https://openacs.org/doc/acs-templating/).

Developer note: should user_id be also in acs_page_contract -properties of index.tcl? In the current implementation it doesn't seem to be.

Yes, everything inside [] brackets is a procedure call with the first word being the name of the proc and subsequent ones being the attributes.

I don't know what you mean by user name (the screen name or the real name), but ad_get_user_info gets the basic info (first names, last name, email) for the current user and might thus do the job (see https://openacs.org/api-doc/proc-view?proc=ad_get_user_info&source_p=1).

It sets the $email variable automatically, so if you call it in your site-wide master template's tcl file, you can refer to @email@, @first_names@ and @last_name@ in any adp page which is using that template. I don't know if that's the best practice, though, maybe some wiser people could answer that.

You need to write

set some_variable_name [ad_get_user_info]

AFAIK you don't have to use set here. ad_get_user_info sets automatically $first_names, $last_name and $email.

I think the problem is that when you are just calling a proc (without doing anything with the return value), you're not supposed to use [ ] brackets around it. So this should be sufficient:

ad_get_user_info

Just use the search box in https://openacs.org/api-doc/ and you'll find the explanation for every proc in the system 😊 (in this case, https://openacs.org/api-doc/proc-view?proc=ad%5freturn%5ferror)

In fact that proc doesn't seem to fit too good in this situation, since it returns a http error if the user_id is not defined. You could get around this by doing something like this:

set user_id [ad_get_user_id]
if { $user_id != 0 } {
    ad_get_user_info
}

This blows away part of the handiness of this function, though. In general I don't understand why ad_get_user_info returns an http error in the first place. At least it narrows the use of it a lot. Maybe that's why e.g. the default index page of an oacs installation uses an ad hoc sql query to get the user info. I think there should definitely be an allround proc for this.