Hi quimby -
I'd recommend using the /s/suggest.json endpoint for auto-suggestions, rather than accessing padre-qs.cgi.
Calls to suggest.json can't be directly scoped to a metadata field, but they can be scoped to a profile within a collection, allowing you to create a separate source from all metadata values in a given field.
To use suggest.json in this way, some workflow will be required:
1. In the base collection, create a metadata facet for the field of interest
2. In your query processor options, set the results_in_facet_categories to a large value (>1000)
3. Create a stripped-back template (e.g. auto-completion.ftl) to ONLY show the outputs of the facet categories, outputting in format that conforms to the auto-completion.csv syntax, setting the form type to respond as a CSV mimetype.
4. In the base collection, create a new post-index workflow step to save the outputs of this form as CSV in a dedicated profile (e.g. $SEARCH_HOME/conf/COLLECTION/METACLASS/auto-suggestion.csv)
During the next collection index, you'll now have the following additional auto-suggestion endpoints to draw from:
1. /s/suggest.json?collection=COLLECTION&fmt=json++&profile=default&partialquery=PARTIAL
2. /s/suggest.json?collection=COLLECTION&fmt=json++&profile=METACLASS&partial_query=PARTIAL
Alternatively, if you're happy to blend organic suggestions and structured suggestions into the base collection's suggest.json responses, set a 'Category' value in the CSV output for each field you're wanting to source. You could then re-use the workflow to output multiple lists in the base collection config folder ($SEARCH_HOME/conf/COLLECTION/auto-suggestion-METACLASS.csv). Update your collection.cfg file to specify these additional CSV sources, and a reindex will give you a blended suggest.json endpoint.
That said, suggest.json defaults to sourcing it's suggestions from:
https://docs.funnelback.com/15.6/auto_completion_collection_cfg.html#autocompletiondetails
https://docs.funnelback.com/15.6/spelling_suggestion_sources_collection_cfg.html