flag redefined - panic searching by key in YouTube data API 3 - go

Question

I am trying to search YouTube video by key like in the golang example. I modified that code a little to let it search by different keys several times.
When I search once it is ok.
func main() {
result1, err1 := SearchYoutubeByKey("hello")
if err1 != nil {
panic(err1)
}
fmt.Println(result1)
// result2, err2 := SearchYoutubeByKey("world")
// if err2 != nil {
// panic(err2)
// }
// fmt.Println(result2)
}
But if I search twice ...
func main() {
result1, err1 := SearchYoutubeByKey("hello")
if err1 != nil {
panic(err1)
}
fmt.Println(result1)
result2, err2 := SearchYoutubeByKey("world")
if err2 != nil {
panic(err2)
}
fmt.Println(result2)
}
... then it panics with error message ...
flag redefined: query
... on line ...
query := flag.String("query", str, "Search term")
Full code:
package main
import (
"code.google.com/p/google-api-go-client/googleapi/transport"
"code.google.com/p/google-api-go-client/youtube/v3"
"flag"
"fmt"
"net/http"
)
var (
maxResults = flag.Int64("max-results", 25, "Max YouTube results")
service *youtube.Service
response *youtube.SearchListResponse
)
const developerKey = "youtube developer key"
type YoutubeSearchResult struct {
Title, YoutubeId string
}
func SearchYoutubeByKey(str string) (result []*YoutubeSearchResult, err error) {
query := flag.String("query", str, "Search term")
flag.Parse()
client := &http.Client{
Transport: &transport.APIKey{Key: developerKey},
}
service, err = youtube.New(client)
if err != nil {
return
}
// Make the API call to YouTube.
call := service.Search.List("id,snippet").
Q(*query).
MaxResults(*maxResults)
response, err = call.Do()
if err != nil {
return
}
// Iterate through each item and add it to the correct list.
for _, item := range response.Items {
switch item.Id.Kind {
case "youtube#video":
result = append(result, &YoutubeSearchResult{Title: item.Snippet.Title, YoutubeId: item.Id.VideoId})
}
}
return
}
func main() {
result1, err1 := SearchYoutubeByKey("hello")
if err1 != nil {
panic(err1)
}
fmt.Println(result1)
result2, err2 := SearchYoutubeByKey("world")
if err2 != nil {
panic(err2)
}
fmt.Println(result2)
}
So it is impossible to use this code on a website. Only the first user will be able to search first time, the others will fail.
I cannot change flag during runtime but how to search by 2 different keys in one program?
Update
working solution:
package main
import (
"code.google.com/p/google-api-go-client/googleapi/transport"
"code.google.com/p/google-api-go-client/youtube/v3"
"flag"
"fmt"
"net/http"
)
var (
maxResults = flag.Int64("max-results", 25, "Max YouTube results")
service *youtube.Service
response *youtube.SearchListResponse
query = flag.String("query", "str", "Search term")
)
const developerKey = "youtube api key"
type YoutubeSearchResult struct {
Title, YoutubeId string
}
func SearchYoutubeByKey(str string) (result []*YoutubeSearchResult, err error) {
flag.Parse()
client := &http.Client{
Transport: &transport.APIKey{Key: developerKey},
}
service, err = youtube.New(client)
if err != nil {
return
}
// Make the API call to YouTube.
call := service.Search.List("id,snippet").
Q(str).
MaxResults(*maxResults)
response, err = call.Do()
if err != nil {
return
}
// Iterate through each item and add it to the correct list.
for _, item := range response.Items {
switch item.Id.Kind {
case "youtube#video":
result = append(result, &YoutubeSearchResult{Title: item.Snippet.Title, YoutubeId: item.Id.VideoId})
}
}
return
}
func main() {
result1, err1 := SearchYoutubeByKey("hello")
if err1 != nil {
panic(err1)
}
fmt.Println(result1)
result2, err2 := SearchYoutubeByKey("world")
if err2 != nil {
panic(err2)
}
fmt.Println(result2)
}

Answer 1

The panic message tells you exactly what's wrong. Your command line flags should be defined only once. If you try to redefine them during runtime, it panics.