How to generate query string in golang?

Question

In my use-case, I need to post data to url, however the data itself is a query string. Example:

curl -POST -d "username=abc&rememberme=on&authtype=intenal" "https..somemdpoint"

What I have is a method which takes in 3 values

function makePostRequest(username string, rememberme string, authtype string, endpoint string) {
  // post a curl request.
}

I am struggling to find any library that would return me a query string if I provided it with parameters.

I tried doing this:

q := req.URL.Query()
q.Add("api_key", "key_from_environment_or_flag")
q.Add("another_thing", "foobar")
fmt.Print(q)

But realized it actually returns Values which is a map so its no good.

Is there any method in golang that creates a queryString ?

Your curl example would send the data as a application/x-www-form-urlencoded payload, are you sure you want it in the query string (as part of the URL)? — Benjamin W.
– Benjamin W., Commented Jul 19, 2020 at 4:09

General Grievance · Accepted Answer · 2020-07-19 10:23:06Z

17

You almost got it. Call Values.Encode() to encode the map in URL-encoded form.

fmt.Print(q.Encode()) // another_thing=foobar&api_key=key_from_environment_or_flag

Create the map directly instead of using req.URL.Query() to return an empty map:

values := url.Values{}
values.Add("api_key", "key_from_environment_or_flag")
values.Add("another_thing", "foobar")
query := values.Encode()

Use strings.NewReader(query) to get an io.Reader for the POST request body.

General Grievance

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answered Jul 19, 2020 at 4:16

volker

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