Groovy_concatenate FIX value with Custom field post function

[Mateusz Janus]

Brothers and Sisters,

i am absolute NOOB regarding groovy. I need i guess simple help.

In post function i want to SET A VALUE for custom field.

I need groovy script which will concatenate BASE URL address with value from customfield.

Both together will create a URL so i can put it into my custom field. 

I found the solution in terms of FIELDS here
https://community.atlassian.com/forums/Jira-questions/Concatenation-of-multiple-custom-fields-with-separator/qaq-p/1067787

but i have no clue what to do with FIXED value.

[Mateusz Janus]

ok its simple as it is... "text based"+issue.get... My mistake to raise this query too early