I'm new to Go. I'm trying to build a simple app that lets users get photos from flickr by keying in a tag in a form. I'm stuck at my current code (pasted below) as nothing appears on the page /showimage when I click on the submit button. What am I doing wrong in the code?
package main
import (
"encoding/json"
"fmt"
"html/template"
"io/ioutil"
"log"
"net/http"
"net/url"
"os"
)
func main() {
http.HandleFunc("/", handler)
http.HandleFunc("/showimage", showimage)
fmt.Println("listening...")
err := http.ListenAndServe(GetPort(), nil)
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
func GetPort() string {
var port = os.Getenv("PORT")
if port == "" {
port = "4747"
fmt.Println("INFO: No PORT environment variable detected, defaulting to " + port)
}
return ":" + port
}
func handler (w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, rootForm)
}
const rootForm =
`<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Flickr photos</title>
</head>
<body>
<h1>Flickr photos</h1>
<p>Find photos by tags!</p>
<form action="/showimage" method="post" accept-charset="utf-8">
<input type="text" name="str" value="Type Tags..." id="str">
<input type="submit" value=".. and see the images!">
</form>
</body>
</html>`
var upperTemplate = template.Must(template.New("showimage").Parse(upperTemplateHTML))
func showimage(w http.ResponseWriter, r *http.Request) {
tag := r.FormValue("str")
safeTag := url.QueryEscape(tag)
apiKey := "MYAPIKEY"
fullUrl := fmt.Sprintf("https://api.flickr.com/services/rest/?method=flickr.people.getPhotos&api_key=%s&tags=%s", apiKey, safeTag)
client := &http.Client{}
req, err := http.NewRequest("GET", fullUrl, nil)
if err != nil {
log.Fatal("NewRequest: ", err)
return
}
resp, requestErr := client.Do(req)
if requestErr != nil {
log.Fatal("Do: ", requestErr)
return
}
defer resp.Body.Close()
body, dataReadErr := ioutil.ReadAll(resp.Body)
if dataReadErr != nil {
log.Fatal("ReadAll: ", dataReadErr)
return
}
res := make(map[string]map[string]map[string]interface{}, 0)
json.Unmarshal(body, &res)
owner, _ := res["photos"]["photo"]["owner"]
id, _ := res["photos"]["photo"]["id"]
queryUrl := fmt.Sprintf("http://flickr.com/photos/%s/%s", owner, id)
tempErr := upperTemplate.Execute(w, queryUrl)
if tempErr != nil {
http.Error(w, tempErr.Error(), http.StatusInternalServerError)
}
}
const upperTemplateHTML =
`<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Display images</title>
</head>
<body>
<h3>Images</h3>
<img src="{{html .}}" alt="Image" />
</body>
</html>`
