Auto-Complete Suggestions

RediSearch includes the ability to maintain a special index or dictionary for the purposes of creating suggestions based on input.

The sample data project included in this repository will populate an auto-complete suggestion dictionary with city names as the string to index and the coordinates in longitude,latitude format as the payload.

Populating an Auto-Complete Suggestion Dictionary

In order to populate an auto-complete suggestion dictionary you'll use the AddSuggestion or AddSuggestionAsync extension methods.

The following is an example of adding an entries to the cities auto-complete suggestion dictionary:

await db.AddSuggestionAsync("cities", "Pensacola", 1, payload: "-87.275772,30.61428");

In the above example notice that I'm providing the optional payload parameter. The auto-complete suggestion dictionary gives us the opportunity to store a little bit of additional data, so in this case I'm storing the coordinates of the city.

Querying an Auto-Complete Suggestion Dictionary

Querying an auto-complete suggestion dictionary is pretty straight forward as it only requires calling the GetSuggestions or GetSuggestionsAsync method with the name of the dictionary and the partial term that we're searching for...

var suggestions = await _db.GetSuggestionsAsync("cities", "pensac");

By default, we will get a maximum of five results back. In order to expand that, we can provide the optional max parameter with the number of results that we want...

var suggestions = await _db.GetSuggestionsAsync("cities", "pensac", max: 15);

We can further augment our query by providing the following optional parameters:

• fuzzy: Will perform a "fuzzy" search for terms within a Levenshtein distance of 1.
• withScores: Will populate the score of a match in the result of the query.
• withPayload: Will populate the payload of a match in the result of the query.

Removing Entries from an Auto-Complete Suggestion Dictionary

Should it become necessary, we also have the ability to remove terms from an auto-complete suggestion dictionary.

The following is an example of removing an entry...

await _db.DeleteSuggestionAsync("cities", "Destin");