How to build a URL / Query in Golang - go

Question

Background -
I need to build a URL / query based on user input from a form that will be used to make an API call.
Problem -
When building the URL, the params are not properly escaped. For example, the query "bad santa" ends up with a space between it instead of "+".
Current Output -
e.g. https://api.example.org/3/search/movie?query=bad
santa&api_key=#######
Expected Output -
e.g. https://api.example.org/3/search/movie?query=bad+santa&api_key=#######
Code Example -
Root URL -
var SearchUrl = "https://www.example.org/3/search/movie?query="
Get params taken from user input -
var MovieSearch []string = r.Form["GetSearchKey"]
API Key -
var apiKey = "&api_key=######"
I am using the ArrayToString() to parse the form input data
func ArrayToString(array []string) string{
str := strings.Join(array, "+")
return str
}
Then building the URL -
var SearchUrl = "https://api.example.org/3/search/movie?query="
var MovieSearch []string = r.Form["GetSearchKey"]
var apiKey = "&api_key=########"
UrlBuild := []string {SearchUrl, ArrayToString(MovieSearch), apiKey}
OUTPUT_STRING := ArrayToString(UrlBuild)
Question -
How to build a URL with user input GET params that are escaped properly?

Answer 1

Normally, one should use url package's Values.
Here's an example, that does what I think you want, on play
Both a simple main, and in http.HandlerFunc form:
package main
import "fmt"
import "net/url"
import "net/http"
func main() {
baseURL := "https://www.example.org/3/search/movie"
v := url.Values{}
v.Set("query", "this is a value")
perform := baseURL + "?" + v.Encode()
fmt.Println("Perform:", perform)
}
func formHandler(w http.ResponseWriter, r *http.Request) {
baseURL := "https://www.example.org/3/search/movie"
v := url.Values{}
v.Set("query", r.Form.Get("GetSearchKey")) // take GetSearchKey from submitted form
v.Set("api_ley", "YOURKEY") // whatever your api key is
perform := baseURL + "?" + v.Encode() // put it all together
fmt.Println("Perform:", perform) // do something with it
}
Output:
Perform: https://www.example.org/3/search/movie?query=this+is+a+value
Notice how the values are put in to query string, properly escaped, for you.

Answer 2

You can escape parameters using https://golang.org/pkg/net/url/#QueryEscape, instead of doing it yourself.
Besides you should be using https://golang.org/pkg/net/url/#URL to build up your url:
params := fmt.Sprintf("?query=%s&api_key=######", url.QueryEscape("name"))
perform := url.URL{
Scheme: "https",
Host: "api.example.com",
Path: "3/search/movie",
RawQuery: params,
}
fmt.Println(perform) // <- Calls .String()
I recommend to check https://golang.org/doc/effective_go.html.
If your data comes in []string:
func ArrayToQuery(values []string) string {
return url.QueryEscape(strings.Join(values, " "))
}

Answer 3

If MovieSearch contains one element with the value "bad santa", what you're seeing looks correct. It's joining those three strings and putting "+" between them.

Answer 4

If there is a space in the word you will need to replace it.
Example
package main
import (
"fmt"
"strings"
)
func main() {
fmt.Println(strings.Replace("bad santa", " ", "+", -1))
}
So you should probably do it like this
func main() {
a := []string{"bad", "santa"}
fmt.Printf("%q\n", a)
j := ArrayToString(a)
strings.Replace(j, " ", "+",-1)
fmt.Printf("%q\n", j)
}
Here is a link to the Go Documentation - https://golang.org/pkg/strings/#Replace