My attempt on making an eggdrop script to parse music info

bowie.tcl

package require http
package require base64
package require xml

# Change these to point to your admin section
set host "localhost"
set port "8080"
set username "admin"
set password "hackme"

proc extract_music_info { xml } {
    set source_opening "<source mount=\"/audio.ogg\">"
    set source_closing "</source>"
    
    set title_opening "<title>"
    set title_closing "</title>"
    
    set artist_opening "<artist>"
    set artist_closing "</artist>"

    set source_opening_len [string length $source_opening]
    set title_opening_len [string length $title_opening]
    set artist_opening_len [string length $artist_opening]
   
    # Find the <source tag 
    set source_tag_start_idx [string first $source_opening $xml]
    if { $source_tag_start_idx eq -1 } {
        error "No music source was found"
    }
    set source_tag_idx [expr $source_tag_start_idx + $source_opening_len]

    set data_len [string length $xml]
    set sub_xml [string range $xml $source_tag_idx [expr $data_len - 1]]

    set source_end_idx [string first $source_closing $sub_xml]
    set source_xml [string range $sub_xml 0 [expr $source_end_idx - 1]]

    # Get artist
    set source_xml $sub_xml
    set artist_tag_idx [string first $artist_opening $source_xml]
    if { $artist_tag_idx eq -1 } {
        error "Artist could not be found"
    }
    set artist_start_idx [expr $artist_tag_idx + $artist_opening_len]
    set artist_end_idx [string first $artist_closing $source_xml]
    set song("artist") [string range $source_xml $artist_start_idx [expr $artist_end_idx - 1]]

    # Get title
    set title_tag_idx [string first $title_opening $sub_xml]
    if { $title_tag_idx eq -1 } {
        error "Title could not be found"
    }
    set title_start_idx [expr $title_tag_idx + $title_opening_len]
    set title_end_idx [string first $title_closing $source_xml]
    set song("title") [string range $source_xml $title_start_idx [expr $title_end_idx - 1]]

    return [array get song]
}

proc message_song_info { nick uhost handle channel txt } {
    global username
    global password

    global host
    global port

    set login "$username:$password"
    set auth "Basic [base64::encode $login]"
    set headers [list Authorization $auth]
    # set url "http://localhost:8000/admin/stats.xml"
    set url "http://$host:$port/admin/stats.xml"
    set token [http::geturl $url -headers $headers]
    # upvar 1 $res state
    set status [http::status $token]
    if {$status ne "ok"} {
        error $status
    }

    set data [http::data $token]
    array set song [extract_music_info $data]
#    puts $song("artist")
#    puts $song("title")

    set artist $song("artist")
    set title $song("title")

    putserv "privmsg $channel :$artist - $title"
}

# set val [message_song_info "test" "test" "Test" "#test" "teeeest"]
bind pubm * "% !np" message_song_info