Typeahead Bloodhound POST request

Question

I cannot seem to get a remote query to use POST properly.

var creditors = new Bloodhound({
    datumTokenizer: function (d) {
        return Bloodhound.tokenizers.whitespace(d.value)
    },
    queryTokenizer: Bloodhound.tokenizers.whitespace,
    remote: {
        url: "../getCreditors",
        replace: function(url, query) {
            return url + "#" + query;
        },
        ajax : {
            type: "POST",
            data: $.param({q: queryInput.val()})
        }
    }
});

the queryInput.val() does not get the current value of the object only the value at the time bloodhound object is instantiated. How can I get the query string into the ajax data options?

Federicofedirko

https://mcmap.net/q/744620/-twitter-39-s-typeahead-bloodhound-what-is-the-equivalent-of-quot-query-quot-when-using-ajax-data-and-post without ajax – Grille

Answer 1

You can use beforeSend of $.ajax

var creditors = new Bloodhound({
    datumTokenizer: function (d) {
        return Bloodhound.tokenizers.whitespace(d.value)
    },
    queryTokenizer: Bloodhound.tokenizers.whitespace,
    remote: {
        url: "../getCreditors",

        replace: function(url, query) {
            return url + "#" + query;
        },
        ajax : {
            beforeSend: function(jqXhr, settings){
               settings.data = $.param({q: queryInput.val()})
            },
            type: "POST"

        }
    }
});

Groundsill

Although this code does call the Ajax method when it should, it doesn't set Content-Type correctly, so ASP.NET MVC, at least, doesn't parse the posted data. – Salicaceous

This will send with a content-type of "text/plain; charset=UTF-8", if you want it to send as json (like me :D) you'll need to set the content type on the jqXhr object like so: jqXhr.setRequestHeader('Content-Type', 'application/json; charset=UTF-8'); – Aceae

Since you're already calling replace, you can use that to store the query to a local variable that you use in beforeSend. It removes the coupling to queryInput. – Neutralize

@Neutralize Can you explain your comment a bit more? I tried adding a line in replace this.q = query and replacing queryInput.val() with this.q but this.q shows as undefined in debugger beforeSend function. – Huebner

This doesn't work anymore. The code in @Atropo's answer does work. – Worth

Answer 2

You can use the prepare property with remote or prefetch, mind that the function signature changes. An example with prefetch:

var Bloodhound = new Bloodhound({
                datumTokenizer: Bloodhound.tokenizers.whitespace,
                queryTokenizer: Bloodhound.tokenizers.whitespace,
                prefetch: {
                    url: remote,
                    prepare: function (settings) {
                        settings.type = "POST";
                        settings.contentType = "application/json; charset=UTF-8";
                        return settings;
                    },
                    remote: function (query, settings) {
                        settings.type = "POST";
                        settings.data = {q: query, foo: 'bar'}; // you can pass some data if you need to
                        return settings;
                    }
                }
            });

Remember that with remote the function signature changes with function(query, settings).

For reference: github.com/twitter/typeahead.js/issues/1236

Michelle

You can pass your custom data if you need to (e.g. the current value of another field etc.). The current typed-in value will be in the query variable – Worth

Answer 3

I found the ajax 'beforeSend' method holylaw mentioned worked the best.

It was important to alter the url as well though. Otherwise Typeahead didn't bother making another request. So I just added a bogus parameter at the end of the url. Like this

http://mylittleservice.com?blah=%QUERY

That way when the ajax data packaged changed I was assured a fresh request to the server.

Ilene